JP2007280840A - Inspection circuit, battery pack, and battery pack unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection circuit capable of surely inspecting the operation of a protection circuit protecting overcharge of a secondary battery and to provide a battery pack and a battery pack unit. <P>SOLUTION: A D/A converter 22 is connected to secondary batteries Vb1-Vb4, convert the terminal voltage of the secondary batteries Vb1-Vb4 from digital values to analog values, an MPU 21 varies the output voltage of the D/A converter 22, artificially rises the terminal voltage of the secondary batteries Vb1-Vb4 to first overcharge protection voltage value V1, and when voltage values detected with the A/D converters 231-244 reach the first overcharge protection voltage value V1, the MPU 21 confirms the execution of the protection operation of a first control IC2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a test circuit that is provided in a battery pack that includes a secondary battery and a protection circuit that protects the secondary battery from overcharging, and that tests the operation of the protection circuit. The present invention also relates to a battery pack including a secondary battery, a protection circuit that protects the secondary battery from overcharge, and an inspection circuit that inspects the operation of the protection circuit. Furthermore, the present invention relates to a battery pack unit including a plurality of battery packs.

  Conventionally, lithium secondary batteries are required to have particularly high safety, and various protection measures against overcharge have been proposed. For example, in Patent Document 1, the first protection circuit that cuts off the supply of the charging current to the battery in a state where it can be recovered by detecting the overcharge of the battery and the first protection circuit did not operate normally. In such a case, a second protection circuit that cuts off the supply of charging current to the battery in a state in which the battery cannot be restored is provided, and the battery is reliably protected by these two protection circuits.

  FIG. 16 is a diagram showing a configuration of a conventional battery pack inspection system. When charging the secondary batteries Vb1 to Vb4 of the battery pack 100, the charging device 200 is connected to the connection terminals T1 and T2. When switch 201 of charging device 200 is turned on, secondary batteries Vb1 to Vb4 included in battery pack 100 are charged by power supply EE1.

  The battery pack 100 includes a first protection circuit 110 and a second protection circuit 120. The first protection circuit 110 turns off the FET (Field Effect Transistor) Q1 when the voltages of the secondary batteries Vb1 to Vb4 reach a preset overcharge protection voltage V1. Usually, the secondary battery is used at a voltage of 4.2 V or less per cell. Therefore, the overcharge protection voltage V1 in the first protection circuit 110 is set to 4.35V.

  The second protection circuit 120 is activated when the first protection circuit 110 is not operated due to failure or the like, and the overcharge protection voltage in which the voltages of the secondary batteries Vb1 to Vb4 are set in advance. When V2 is reached, the FET Q3 is turned on. The overcharge protection voltage V2 in the first protection circuit 110 is set to 4.45 V, which is larger than the overcharge protection voltage V1 of the first protection circuit 110. When the FET Q3 is turned on, the temperature fuse F1 disposed between the secondary batteries Vb1 to Vb4 and the connection terminal T1 is heated and melted, and charging of the secondary batteries Vb1 to Vb4 is stopped.

  In the manufacturing process of the battery pack 100, it is inspected whether the first protection circuit 110 and the second protection circuit 120 operate normally. In this case, the inspection device 300 is connected to the battery pack 100. The battery pack 100 includes a test pad TP1 connected to the positive electrode of the secondary battery Vb1, a test pad TP2 connected to the positive electrode of the secondary battery Vb2, a test pad TP3 connected to the positive electrode of the secondary battery Vb3, and a secondary battery. A test pad TP4 connected to the positive electrode of Vb4 and a test pad TPG connected to the negative electrode of the secondary battery Vb4 are provided.

  The inspection apparatus 300 includes power supplies Eb1 to Eb4 connected in series, the positive electrode of the power supply Eb1 is connected to the test pad TP1, the positive electrode of the power supply Eb2 is connected to the test pad TP2, and the positive electrode of the power supply Eb3 is connected to the test pad TP3. Connected, the positive electrode of the power supply Eb4 is connected to the test pad TP4, and the negative electrode of the power supply Eb4 is connected to the test pad TPG. A switch 301 is disposed between the positive electrode of the power supply Eb1 and the test pad TP1, and a switch 302 is disposed between the positive electrode of the power supply Eb2 and the test pad TP2, and the positive electrode of the power supply Eb3 and the test pad TP3 are connected. A switch 303 is disposed between them, a switch 304 is disposed between the positive electrode of the power supply Eb4 and the test pad TP4, and a switch 305 is disposed between the negative electrode of the power supply Eb4 and the test pad TPG. Yes.

  Here, the inspection of the first protection circuit 110 and the second protection circuit 120 when the secondary battery Vb1 is overcharged will be described. First, the inspection apparatus 300 turns on the switches 301 and 302 and turns off the switches 303 to 305. Next, the inspection apparatus 300 increases the voltage of the power supply Eb1. The inspection device 300 confirms whether a signal for turning on the FET Q1 is output from the first protection circuit 110 when the detected voltage reaches the overcharge protection voltage V1. In this way, it is possible to inspect whether the protection operation of the first protection circuit 110 has been performed normally.

Next, the inspection apparatus 300 further increases the voltage of the power supply Eb1. Then, the inspection apparatus 300 confirms whether a signal for turning on the FET Q3 is output from the second protection circuit 120 when the detected voltage reaches the overcharge protection voltage V2. In this way, it is possible to check whether the protection operation of the second protection circuit 120 has been performed normally. Similarly, the operation of the first protection circuit 110 and the second protection circuit 120 when the secondary batteries Vb2 to Vb4 are overcharged is also inspected.
JP 2000-166107 A

  However, in the case of the conventional inspection system, an inspection device for inspection is separately required, and highly accurate power supplies Eb1 to Eb4 are required. In addition, since a voltage is directly applied from the outside using the test pad, there is a possibility that an inspection failure due to a contact failure between the test pad and the inspection device may occur. Furthermore, at the time of inspection, a surge voltage may enter from the outside, and troubles such as destruction of the control circuit may occur.

  The present invention has been made to solve the above problems, and provides an inspection circuit, a battery pack, and a battery pack unit that can reliably inspect the operation of a protection circuit that protects overcharge of a secondary battery. It is for the purpose.

  An inspection circuit according to the present invention is provided in a battery pack including a secondary battery and a protection circuit that protects overcharge of the secondary battery, and is an inspection circuit that inspects the operation of the protection circuit, The protection circuit includes a first switching unit disposed on the power supply path of the secondary battery, a voltage value detection unit that detects a voltage value of the secondary battery, and a voltage detected by the voltage value detection unit. And a first protection means for turning off the first switching means when the value reaches a preset first overcharge protection voltage value, and is connected to the secondary battery, the secondary battery A digital-to-analog converter that converts the terminal voltage of the battery from a digital value to an analog value, and the output voltage of the digital-to-analog converter is changed, so that the terminal voltage of the secondary battery is simulated to the first overcharge protection voltage value In Voltage control means for increasing, and protection for confirming that the protection operation of the first protection circuit is executed when the voltage detected by the voltage value detection means reaches the first overcharge protection voltage value Operation confirmation means.

  According to this configuration, when the voltage value of the secondary battery detected by the voltage value detection means reaches the preset first overcharge protection voltage value, the first protection means The first switching means disposed on the power supply path is turned off. A digital / analog converter that converts the terminal voltage of the secondary battery from a digital value to an analog value when the voltage control means is connected to the secondary battery at the time of inspection to check whether the first protection means operates normally And the terminal voltage of the secondary battery is artificially increased to the first overcharge protection voltage value. Then, the protection operation confirmation unit confirms that the protection operation of the first protection unit is performed when the voltage detected by the voltage value detection unit reaches the first overcharge protection voltage value.

  Therefore, the output voltage of the digital / analog converter connected to the secondary battery is changed and the terminal voltage of the secondary battery is artificially raised to the first overcharge protection voltage value, so the voltage is applied to the secondary battery. The operation of the protection circuit that protects the secondary battery from overcharging can be reliably inspected without connecting an inspecting device that includes a power source for the purpose. Further, since no special inspection device is required, the protection circuit can be inspected in the battery pack in the actual market.

  In the inspection circuit, the protection circuit includes a second switching unit that blows a temperature fuse disposed on a power supply path of the secondary battery, a voltage value of the secondary battery, and the first circuit. A second overcharge protection voltage value greater than the second overcharge protection voltage value, and the second switching means when the voltage value of the secondary battery is greater than the second overcharge protection voltage value. And the voltage control means changes the output voltage of the digital / analog converter to simulate the terminal voltage of the secondary battery up to the second overcharge protection voltage value. The protection operation confirmation means performs the protection operation of the second protection circuit when the voltage detected by the voltage value detection means reaches the second overcharge protection voltage value. Make sure It is preferred.

  According to this configuration, the second protection means compares the voltage value of the secondary battery with the second overcharge protection voltage value that is larger than the first overcharge protection voltage value, and determines the voltage of the secondary battery. When the value is larger than the second overcharge protection voltage value, the second switching means that blows the thermal fuse disposed on the power supply path of the secondary battery is turned on. A digital-to-analog converter that converts the terminal voltage of the secondary battery from a digital value to an analog value when the voltage control means is connected to the secondary battery at the time of inspection for checking whether the second protection means operates normally And the terminal voltage of the secondary battery is artificially increased to the second overcharge protection voltage value. Then, the protection operation confirmation unit confirms that the protection operation of the second protection unit is executed when the voltage detected by the voltage value detection unit reaches the second overcharge protection voltage value. Therefore, the operation of the second protection means that reliably cuts off the charging current when the first protection means does not operate normally can be reliably inspected.

  In the above inspection circuit, the secondary battery includes a plurality of secondary batteries connected in series, and an output terminal of the digital / analog converter is connected to one of the secondary batteries. It is preferable to further include a third switching means for switching to the secondary battery.

  According to this configuration, the secondary battery includes a plurality of secondary batteries connected in series, and the third switching unit connects the output terminal of the digital / analog converter to the plurality of secondary batteries. Switch to one of the secondary batteries. Therefore, even when a plurality of secondary batteries are connected in series, the operation of the protection circuit when the individual secondary batteries are excessively charged can be inspected.

  Further, in the above inspection circuit, the voltage value detection means includes a plurality of voltage value detection means connected to a positive electrode of each secondary battery, and when the plurality of secondary batteries is an even number, the plurality of voltage value detection means Two of the secondary batteries are grouped together, and a terminal of the third switching means is provided between the negative electrode of one secondary battery and the positive electrode of another secondary battery in each group of secondary batteries. Is connected, and the number of the secondary batteries is an odd number, two of the plurality of secondary batteries are taken as one set, and the negative electrode of one of the secondary batteries of each set And a terminal of the third switching means is connected between the positive electrode of the other secondary battery and the terminal of the third switching means is connected to the positive electrode of the remaining one secondary battery. The switching means includes a plurality of connection destinations of the output terminals of the digital / analog converter. The voltage control means instructs the third switching means to switch to a set including the secondary battery to be inspected or a terminal connected to the secondary battery to be inspected. , By dropping the output voltage of the digital / analog converter, the terminal voltage of the secondary battery of the first is increased to the first overcharge protection voltage value in a pseudo manner, and the output voltage of the digital / analog converter is increased. By raising the terminal voltage of the other secondary battery or the remaining one secondary battery in a pseudo manner up to the first overcharge protection voltage value, the protection operation confirmation means It is preferable to confirm that the protection operation of the first protection means for each secondary battery is performed when the voltage detected by the detection means reaches the first overcharge protection voltage value. There.

  According to this configuration, the plurality of voltage value detection means are connected to the positive electrode of each secondary battery connected in series. When the number of secondary batteries is an even number, two of the plurality of secondary batteries are set as one set, and the negative electrode of one secondary battery and the other secondary battery in each set of secondary batteries. A terminal of the third switching means is connected between the positive electrode of the secondary battery. Further, when the plurality of secondary batteries is an odd number, two of the plurality of secondary batteries are set as one set, and the negative electrode of one of the secondary batteries of each set and the other secondary battery The terminal of the third switching means is connected to the positive electrode of the secondary battery, and the terminal of the third switching means is connected to the positive electrode of the remaining one secondary battery. The third switching means switches the connection destination of the output terminal of the digital / analog converter to one of a plurality of terminals. The voltage control means instructs the third switching means to switch to a set including the secondary battery to be inspected or a terminal connected to the secondary battery to be inspected, and outputs the output voltage of the digital / analog converter. By lowering, the terminal voltage of one secondary battery is artificially increased to the first overcharge protection voltage value. The voltage control means increases the output voltage of the digital / analog converter in a pseudo manner to increase the terminal voltage of another secondary battery or the remaining one secondary battery to the first overcharge protection voltage value. Let The protection operation confirmation means confirms that the protection operation of the first protection means for each secondary battery is executed when the voltage detected by each voltage value detection means reaches the first overcharge protection voltage value. To do.

  Therefore, by decreasing or increasing the output voltage of the digital / analog converter, the terminal voltage of each secondary battery can be artificially increased to the first overcharge protection voltage value, and a plurality of secondary batteries are connected in series. Even when connected to the battery, it is possible to easily check the operation of the first protection means when the individual secondary batteries are excessively charged.

  In the above inspection circuit, the voltage control unit instructs the third switching unit to switch to a set including the secondary battery to be inspected or a terminal connected to the secondary battery to be inspected. Then, by dropping the output voltage of the digital / analog converter, the terminal voltage of the first secondary battery is artificially increased to the second overcharge protection voltage value, and the output voltage of the digital / analog converter is increased. To increase the terminal voltage of the other secondary battery or the remaining one secondary battery to the second overcharge protection voltage value in a pseudo manner. Confirming that the protection operation of the second protection means for each secondary battery is executed when the voltage detected by the value detection means reaches the second overcharge protection voltage value. It is preferable that the butterflies.

  According to this configuration, the voltage control means instructs the third switching means to switch to a set including the secondary battery to be inspected or a terminal connected to the secondary battery to be inspected, and By dropping the output voltage of the analog converter, the terminal voltage of one secondary battery is artificially raised to the second overcharge protection voltage value. Further, the voltage control means increases the output voltage of the digital / analog converter in a pseudo manner to increase the terminal voltage of another secondary battery or the remaining one secondary battery to the second overcharge protection voltage value. Let The protection operation confirming means executes the protection operation of the second protection means for each secondary battery when the voltage detected by each voltage value detection means reaches the second overcharge protection voltage value. Confirm.

  Therefore, by decreasing or increasing the output voltage of the digital / analog converter, the terminal voltage of each secondary battery can be artificially increased to the second overcharge protection voltage value, and a plurality of secondary batteries are connected in series. Even when it is connected to the battery, it is possible to easily inspect the operation of the second protection means when the individual secondary batteries are excessively charged.

  The inspection circuit preferably further includes an inspection result storage unit that stores an inspection result by the protection operation confirmation unit. According to this configuration, since the inspection result is stored in the inspection result storage unit, the inspector or the user can read and check the inspection result after the inspection is completed. In addition, since inspection determination can be performed simply by reading the inspection result, the inspection time can be shortened.

  The inspection circuit preferably further includes transmission means for transmitting the inspection result stored in the inspection result storage means to an external device. According to this configuration, since the inspection result is transmitted to the external device by the transmission unit, the inspector or the user can check the inspection result using the external device.

  The inspection circuit further includes identification information storage means for storing identification information for specifying the battery pack, and the transmission means adds the identification information stored in the identification information storage means. It is preferable to transmit the inspection result to the external device.

  According to this configuration, the identification information storage means stores identification information for specifying the battery pack, and the transmission means sends the inspection result to which the identification information stored in the identification information storage means is added to the external device. Send to. Therefore, the inspector or the user can identify the battery pack that is confirmed not to operate normally by confirming the identification information added to the inspection result.

  In the inspection circuit, it is preferable that the identification information storage unit stores the encrypted identification information. According to this configuration, the identification information storage unit stores the encrypted identification information, and the transmission unit transmits the inspection result to which the encrypted identification information is added to the external device. Can increase the sex.

  In the inspection circuit described above, it is preferable that the transmission unit transmits the inspection result to an external device by wireless communication. According to this configuration, since the inspection result is transmitted to the external device by wireless communication, it is not necessary to directly connect the external device for acquiring the inspection result, and the inspection result can be acquired without contact.

  The inspection circuit preferably further includes: a light emitting unit; and a light emission control unit that causes the light emitting unit to emit light when the protection operation confirmation unit confirms that the protection operation of the protection circuit is not performed. .

  According to this configuration, the light emission control unit causes the light emission unit to emit light when it is confirmed by the protection operation confirmation unit that the protection operation of the protection circuit is not executed. Therefore, the inspector or the user can confirm that the protection operation of the protection circuit has not been executed by confirming that the light emitting means emits light.

  The inspection circuit preferably further includes a light emission unit and a light emission control unit that causes the light emission unit to blink according to the inspection result stored in the inspection result storage unit. According to this configuration, the light emission control means causes the light emission means to blink according to the inspection result stored in the inspection result storage means. Therefore, the external device can acquire the inspection result by detecting the blinking state of the light emitting means, and the inspection circuit can transmit the inspection result in a non-contact manner.

  The battery pack which concerns on this invention is equipped with a secondary battery, the protection circuit which protects the overcharge of the said secondary battery, and the test | inspection circuit in any one of Claims 1-10. According to this configuration, the battery pack has the function of the inspection circuit according to any one of claims 1 to 10.

  A battery pack unit according to the present invention includes a plurality of secondary batteries connected in series, a protection circuit for protecting overcharge of the secondary battery, and the inspection circuit according to any one of claims 1 to 12. Are connected in series. According to this configuration, a battery pack unit in which a plurality of battery packs are connected in series has the function of the inspection circuit according to any one of claims 1 to 10.

  In the above battery pack unit, the battery pack includes N (N is an integer of 2 or more) secondary batteries connected in series and (N-1) secondary batteries in series. Preferably, at least one battery pack connected thereto is included. According to this configuration, the battery pack unit includes at least a battery pack in which N (N is an integer of 2 or more) secondary batteries are connected in series and (N−1) secondary batteries are connected in series. It is comprised with one battery pack, and can respond to the various voltages which a load apparatus desires.

  According to the present invention, the output voltage of the digital / analog converter connected to the secondary battery is changed, and the terminal voltage of the secondary battery is artificially increased to the first overcharge protection voltage value. The operation of the protection circuit that protects the overcharge of the secondary battery can be reliably inspected without connecting an inspection device having a power source for applying a voltage to the secondary battery. Further, since no special inspection device is required, the protection circuit can be inspected in the battery pack in the actual market.

  Hereinafter, an inspection circuit, a battery pack, and a battery pack unit according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing the configuration of the battery pack according to the first embodiment of the present invention. 1 includes a first control IC (Integrated Circuit) 2, a second control IC 3, external connection terminals 11 to 14, a plurality of secondary batteries Vb1 to Vb4, FETs (Field Effect Transistors) Q1, Q2 and Q3 and a thermal fuse F1 are provided. The secondary batteries Vb1 to Vb4 are rechargeable secondary batteries such as a lithium ion secondary battery, a lithium polymer secondary battery, a nickel hydride secondary battery, or a nickel cadmium secondary battery.

  The external connection terminals 11 and 12 connect charging devices for charging the secondary batteries Vb1 to Vb4, or mobile devices such as mobile phones and digital cameras driven by discharge currents from the secondary batteries Vb1 to Vb4. This is a connection terminal for connecting a power source for driving a personal computer, an electric tool, a robot, an electric bicycle or the like. The external connection terminal 11 is connected to the positive electrodes of the secondary batteries Vb1 to Vb4 via the temperature fuse F1, the FET Q1, and the FET Q2, and the external connection terminal 12 is connected to the negative electrodes of the secondary batteries Vb1 to Vb4.

  The FET Q1 is set so that the anode of the parasitic diode is on the secondary battery Vb1 to Vb4 side, and the FET Q2 is set on the direction where the anode of the parasitic diode is on the external connection terminal 11 side. The FET Q1 is used as an overcharge protection switch that cuts off the charging current when the secondary batteries Vb1 to Vb4 are overcharged, and the FET Q2 has an excessive discharge current of the secondary batteries Vb1 to Vb4. It is used as an overdischarge protection switch that cuts off the discharge current in the case of

  Further, the FET Q3 is connected to the temperature fuse F1 in parallel with the secondary batteries Vb1 to Vb4. The FET Q3 is in a direction in which the anode of the parasitic diode becomes the external connection terminal 12 side. The FET Q3 is used as an overcharge protection switch that blows the thermal fuse F1 and cuts off the charging current when the secondary batteries Vb1 to Vb4 are overcharged.

  The external connection terminals 13 and 14 are terminals for connecting to an external device such as a personal computer. The external connection terminal 13 is connected to the data line, and the external connection terminal 14 is connected to the clock line.

  The first control IC 2 includes an MPU (Micro Processing Unit) 21, a D / A (digital / analog) converter 22, A / D (analog / digital) converters 231 to 234, a comparator 24, a memory 25, and a switch SW1.

  The input terminal of the A / D converter 231 is connected to the positive electrode of the secondary battery Vb1, and the output terminal is connected to the MPU 21. The input terminal of the A / D converter 232 is connected to the positive electrode of the secondary battery Vb2 via the resistor R1, and the output terminal is connected to the MPU 21. The input terminal of the A / D converter 233 is connected to the positive electrode of the secondary battery Vb3, and the output terminal is connected to the MPU 21. The input terminal of the A / D converter 234 is connected to the positive electrode of the secondary battery Vb4 via the resistor R2, and the output terminal is connected to the MPU 21.

  The A / D converter 231 detects the voltage value of the secondary battery Vb1, converts the detected voltage value from an analog value to a digital value, and outputs the converted value to the first control IC 2. The A / D converter 232 detects the voltage value of the secondary battery Vb2, converts the detected voltage value from an analog value to a digital value, and outputs the converted value to the first control IC2. The A / D converter 233 detects the voltage value of the secondary battery Vb3, converts the detected voltage value from an analog value to a digital value, and outputs the converted value to the first control IC 2. The A / D converter 234 detects the voltage value of the secondary battery Vb4, converts the detected voltage value from an analog value to a digital value, and outputs the converted value to the first control IC 2.

  The MPU 21 compares the voltage values of the secondary batteries Vb1 to Vb4 input from the A / D converters 231 to 234 with the first overcharge protection voltage value V1 set in advance. When the voltage values of the secondary batteries Vb1 to Vb4 reach the first overcharge protection voltage value V1, the MPU 21 turns off the FET Q1. As described above, when the voltage value of each of the secondary batteries Vb1 to Vb4 reaches the first overcharge protection voltage value V1, the connection between the external connection terminal 11 and the secondary batteries Vb1 to Vb4 is interrupted, and charging is stopped. And protected from overcharging. The first overcharge protection voltage value V1 in the present embodiment is set in advance to 4.35 V, for example, because the rated voltage of the secondary batteries Vb1 to Vb4 is 4.2V.

  The MPU 21 also compares the voltage values of the secondary batteries Vb1 to Vb4 input from the A / D converters 231 to 234 with preset overdischarge voltage values. When the voltage value of each of the secondary batteries Vb1 to Vb4 reaches the overdischarge voltage value, the MPU 21 turns off the FET Q2. Thus, when the voltage values of the secondary batteries Vb1 to Vb4 reach the overdischarge voltage value, the secondary batteries Vb1 to Vb4 are cut off from the circuit and protected. The overdischarge voltage value in the present embodiment is set in advance to the minimum voltage value in a range that does not deteriorate the characteristics of the secondary batteries Vb1 to Vb4.

  The input terminal of the D / A converter 22 is connected to the MPU 21, and the output terminal is connected to the switch SW1. The D / A converter 22 converts the terminal voltage of each of the secondary batteries Vb1 to Vb4 from a digital value to an analog value, and outputs a voltage corresponding to the input value.

  The switch SW1 switches the output destination of the D / A converter 22 to one of the terminal OFF, the terminal CN1, and the terminal CN2 based on the control from the MPU 21. Terminal CN1 is connected between the negative electrode of secondary battery Vb1 and the positive electrode of secondary battery Vb2, and terminal CN2 is connected between the negative electrode of secondary battery Vb3 and the positive electrode of secondary battery Vb4.

  When the protection operation of the first control IC 2 is inspected, the MPU 21 changes the output voltage of the D / A converter 22 to simulate each terminal voltage of the secondary batteries Vb1 to Vb4 up to the first overcharge protection voltage value V1. Increase. Further, the MPU 21 confirms that the protection operation of the first control IC 2 is executed when the output voltage of the D / A converter 22 reaches the first overcharge protection voltage value V1. The memory 25 is composed of, for example, a non-volatile memory, and stores the inspection result by the MPU 21.

  The second control IC 3 includes a logic circuit 31, comparators M1 to M4, and reference voltage sources E1 to E4. The positive electrode of the secondary battery Vb1 is connected to the plus terminal of the comparator M1, and the reference voltage Ref1 (second overcharge protection voltage value V2) output from the reference voltage source E1 is applied to the minus terminal of the comparator M1, The output terminal of the comparator M1 is connected to the logic circuit 31. When the secondary battery Vb1 is charged by a charging device (not shown) connected to the external connection terminals 11 and 12 and the voltage of the secondary battery Vb1 exceeds the reference voltage Ref1, the comparator M1 outputs a detection signal indicating overcharge. Output to the circuit 31.

  The positive electrode of the secondary battery Vb2 is connected to the plus terminal of the comparator M2, and the reference voltage Ref2 (second overcharge protection voltage value V2) output from the reference voltage source E2 is applied to the minus terminal of the comparator M2. The output terminal of the comparator M2 is connected to the logic circuit 31. When the secondary battery Vb2 is charged by a charging device (not shown) connected to the external connection terminals 11 and 12 and the voltage of the secondary battery Vb2 exceeds the reference voltage Ref2, the comparator M2 outputs a detection signal indicating overcharge. Output to the circuit 31.

  The positive electrode of the secondary battery Vb3 is connected to the plus terminal of the comparator M3, and the reference voltage Ref3 (second overcharge protection voltage value V2) output from the reference voltage source E3 is applied to the minus terminal of the comparator M3. The output terminal of the comparator M3 is connected to the logic circuit 31. When the secondary battery Vb3 is charged by a charging device (not shown) connected to the external connection terminals 11 and 12 and the voltage of the secondary battery Vb3 exceeds the reference voltage Ref3, the comparator M3 outputs a detection signal indicating overcharge. Output to the circuit 31.

  The positive electrode of the secondary battery Vb4 is connected to the plus terminal of the comparator M4, and the reference voltage Ref4 (second overcharge protection voltage value V2) output from the reference voltage source E4 is applied to the minus terminal of the comparator M4. The output terminal of the comparator M4 is connected to the logic circuit 31. When the secondary battery Vb4 is charged by a charging device (not shown) connected to the external connection terminals 11 and 12 and the voltage of the secondary battery Vb4 exceeds the reference voltage Ref4, the comparator M4 outputs a detection signal indicating overcharge. Output to the circuit 31.

  Note that the reference voltages Ref1 to Ref4 in the present embodiment are set in advance to 4.45 V, for example, which is larger than the first overcharge protection voltage value V1.

  When the detection signal indicating overcharge is output from the comparators M1 to M4, the logic circuit 31 turns on the FET Q3 by outputting a control signal to the base of the FET Q3 in order to stop the charging of the secondary batteries Vb1 to Vb4. In the thermal fuse F1, when the FET Q3 is turned on, a current flows through an internal resistor. As a result, the resistor generates heat, and when the fuse portion thermally connected to the resistor rises to a predetermined temperature, it melts and cuts off, and the charging current is cut off completely. The second control IC 3 protects the secondary batteries Vb1 to Vb4 from excessive charging when the first control IC 2 does not operate normally due to some abnormality.

  The minus terminal of the comparator 24 is connected between the gate of the FET Q3 and the logic circuit 31, and the plus terminal of the comparator 24 is connected to the positive electrode of the reference voltage source E5. Note that the negative electrode of the reference voltage source E5 is grounded. When the charging is normally performed, the FET Q3 is turned off, so the comparator 24 outputs a high level detection signal to the MPU 21. On the other hand, when the FET Q3 is turned on, the comparator 24 outputs a low level detection signal to the MPU 21.

  When the protection operation of the second control IC 3 is inspected, the MPU 21 changes the output voltage of the D / A converter 22 to simulate the terminal voltages of the secondary batteries Vb1 to Vb4 up to the second overcharge protection voltage value V2. Increase. Further, the MPU 21 confirms that the protection operation of the second control IC 3 is executed when the output voltage of the D / A converter 22 reaches the second overcharge protection voltage value V2.

  In the present embodiment, the first control IC 2 corresponds to an example of an inspection circuit, the FET Q1 corresponds to an example of a first switching unit, and the A / D converters 231 to 234 serve as an example of a voltage value detection unit. The MPU 21 corresponds to an example of a first protection unit, the D / A converter 22 corresponds to an example of a digital / analog converter, the MPU 21 corresponds to an example of a voltage control unit, and the MPU 21 serves as a protection operation confirmation unit. It corresponds to an example. The FET Q3 corresponds to an example of a second switching means, the second control IC 2 corresponds to an example of a second protection means, the switch SW1 corresponds to an example of a third switching means, and the secondary battery Vb1 To Vb4 correspond to an example of the first to fourth secondary batteries, the A / D converters 231 to 234 correspond to an example of the first to fourth voltage value detection means, and the terminal CN1 is the first terminal. This corresponds to an example, and the terminal CN2 corresponds to an example of the second terminal. Furthermore, the memory 25 corresponds to an example of a test result storage unit, and the MPU 21 corresponds to an example of a transmission unit.

  Here, a description will be given of whether or not the first control IC 2 and the second control IC 3 that protect excessive charging operate normally. The following description is an inspection process performed in the battery pack manufacturing factory. First, a personal computer is connected to the external connection terminals 13 and 14, and an inspection start signal is input to the MPU 21 from the personal computer. When the inspection start signal is input, the MPU 21 shifts to the inspection mode. In the inspection mode, the MPU 21 switches the switch SW1 from the terminal OFF to the terminal CN1.

  The MPU 21 decreases the output voltage of the D / A converter 22 and increases the terminal voltage of the secondary battery Vb1 in a pseudo manner. That is, by decreasing the output voltage of the D / A converter 22, the terminal voltage of the secondary battery Vb1 increases in a pseudo manner, and the voltage value detected by the A / D converter 231 increases. The A / D converter 231 detects the voltage value of the secondary battery Vb1 and outputs it to the MPU 21. The MPU 21 determines whether or not the voltage value of the secondary battery Vb1 detected by the A / D converter 231 has reached a preset first overcharge protection voltage value V1. Here, when it is determined that the voltage value of the secondary battery Vb1 has not reached the first overcharge protection voltage value V1, the MPU 21 further decreases the output voltage of the D / A converter 22, and the secondary battery Vb1. Further increase the terminal voltage.

  On the other hand, when it is determined that the voltage value of the secondary battery Vb1 has reached the first overcharge protection voltage value V1, the MPU 21 stops dropping the output voltage of the D / A converter 22 and turns off the FET Q1. Output a control signal. At this time, the MPU 21 checks whether or not the detected voltage value of the A / D converter 231 is within the normal range. The normal range is, for example, within the range of the first overcharge protection voltage value V1 ± 0.05V. For example, when the first overcharge protection voltage value V1 is 4.35V, if the detected voltage value of the A / D converter 231 is within the range of 4.345V to 4.355V, the MPU 21 performs the first control. It is determined that IC2 operates normally. Further, when the detected voltage value of the A / D converter 231 is smaller than 4.345V, or when the detected voltage value of the A / D converter 231 is larger than 4.355V, the MPU 21 operates the first control IC 2 normally. Judge that it did not.

  When the detected voltage value of the A / D converter 231 is within the normal range, the MPU 21 stores a test result indicating that the first control IC 2 has normally operated in the memory 25. On the other hand, when the detected voltage value of the A / D converter 231 is not within the normal range, the MPU 21 stores a test result indicating that the first control IC 2 does not operate normally in the memory 25.

  Thereafter, the MPU 21 again decreases the output voltage of the D / A converter 22 and increases the terminal voltage of the secondary battery Vb1 in a pseudo manner again in order to confirm the operation of the second control IC 3. The MPU 21 determines whether or not the voltage value of the secondary battery Vb1 has reached the preset second overcharge protection voltage value V2 and the FET Q3 is turned on. Specifically, the MPU 21 detects that the output signal from the comparator 24 has been switched from the high level to the low level, and determines that the FET Q3 is turned on. If it is determined that the FET Q3 is not turned on, the MPU 21 further decreases the output voltage of the D / A converter 22 and further increases the terminal voltage of the secondary battery Vb1.

  When it is determined that the FET Q3 is turned on, the MPU 21 stops dropping the output voltage of the D / A converter 22. And MPU21 confirms whether the voltage value of the secondary battery Vb1 when FETQ3 is turned on is in a normal range. That is, the MPU 21 confirms whether or not the detected voltage value of the A / D converter 231 when the FET Q3 is turned on is within a normal range. The normal range is, for example, in the range of the second overcharge protection voltage value V2 ± 0.05V. For example, when the second overcharge protection voltage value V2 is 4.45V, the MPU 21 performs the second control if the detection voltage value of the A / D converter 231 is within the range of 4.445V to 4.455V. It is determined that IC3 operates normally. Further, when the detected voltage value of the A / D converter 231 is smaller than 4.445V, or when the detected voltage value of the A / D converter 231 is larger than 4.455V, the MPU 21 operates the second control IC 3 normally. Judge that it did not.

  When the detected voltage value of the A / D converter 231 is within the normal range, the MPU 21 stores a test result indicating that the second control IC 3 has normally operated in the memory 25. On the other hand, when the detected voltage value of the A / D converter 231 is not within the normal range, the MPU 21 stores a test result indicating that the second control IC 3 did not operate normally in the memory 25.

  Next, the MPU 21 switches the switch SW1 from the terminal CN1 to the terminal OFF. As a result, the voltage value of the secondary battery Vb1 becomes 0, and the logic circuit 31 outputs a signal for turning off the FET Q3. When the FET Q3 is turned off, the current supply to the thermal fuse F1 is stopped. Next, the MPU 21 outputs a control signal for turning on the FET Q1.

  Even when the secondary batteries Vb2 to Vb4 are excessively charged, it is confirmed whether the first control IC 2 and the second control IC 3 operate normally in the same manner as the secondary battery Vb1. When inspecting the operation of the first control IC 2 and the second control IC 3 when the secondary battery Vb2 is excessively charged, the MPU 21 connects the switch SW1 to the terminal CN1 and the D / A converter 22 By raising the output voltage, the terminal voltage of the secondary battery Vb2 is artificially raised. Further, when inspecting the operation of the first control IC 2 and the second control IC 3 when the secondary battery Vb3 is excessively charged, the MPU 21 connects the switch SW1 to the terminal CN2, and the D / A converter 22 By decreasing the output voltage, the terminal voltage of the secondary battery Vb3 is increased in a pseudo manner. Furthermore, when inspecting the operation of the first control IC 2 and the second control IC 3 when the secondary battery Vb4 is excessively charged, the MPU 21 connects the switch SW1 to the terminal CN2, and the D / A converter 22 By raising the output voltage, the terminal voltage of the secondary battery Vb4 is artificially raised.

  Next, in order to confirm the inspection result, the personal computer transmits an inspection result acquisition request for requesting acquisition of the inspection result from the external connection terminal 13. When receiving the inspection result acquisition request, the MPU 21 determines whether or not the inspection for all the secondary batteries Vb1 to Vb4 has been completed. When it is determined that the inspection for all the secondary batteries Vb1 to Vb4 has not been completed, the MPU 21 sends a reply to that effect to the personal computer. Thereafter, after a predetermined time elapses, the personal computer transmits an inspection result acquisition request again.

  On the other hand, when it is determined that the inspection for all the secondary batteries Vb1 to Vb4 has been completed, the MPU 21 reads out the inspection result from the memory 25 and transmits it to the personal computer. The personal computer displays the received inspection result on the monitor. The inspector can inspect the operations of the first control IC 2 and the second control IC 3 when the secondary batteries Vb1 to Vb4 are excessively charged by confirming the displayed inspection results.

  As described above, the MPU 21 of the first control IC 2 reaches the first overcharge protection voltage value V1 in which the voltage values of the secondary batteries Vb1 to Vb4 detected by the A / D converters 231 to 234 have been set in advance. In this case, the FET Q1 disposed on the power supply path of the secondary batteries Vb1 to Vb4 is turned off. At the time of inspection for inspecting whether the first control IC 2 operates normally, the MPU 21 is connected to the secondary batteries Vb1 to Vb4 and converts the terminal voltages of the secondary batteries Vb1 to Vb4 from digital values to analog values. The output voltage of the D / A converter 22 is changed, and the terminal voltages of the secondary batteries Vb1 to Vb4 are artificially increased to the first overcharge protection voltage value V1. Then, the MPU 21 confirms that the protection operation of the MPU 21 is executed when the voltage detected by the A / D converters 231 to 234 reaches the first overcharge protection voltage value V1.

  Therefore, the output voltage of the D / A converter 22 connected to the secondary batteries Vb1 to Vb4 is changed, and the terminal voltage of the secondary batteries Vb1 to Vb4 is increased in a pseudo manner up to the first overcharge protection voltage value V1. The operation of the protection circuit that protects the overcharge of the secondary batteries Vb1 to Vb4 can be reliably tested without connecting an inspection device having a power source for applying a voltage to the secondary batteries Vb1 to Vb4. Further, since a special inspection device is not required, the protection circuit can be inspected in the actual market. Furthermore, an expensive and high-performance inspection apparatus that has been necessary in the past is unnecessary.

  In addition, the second control IC 3 compares the voltage values of the secondary batteries Vb1 to Vb4 with the second overcharge protection voltage value V2 that is larger than the first overcharge protection voltage value V1, and the secondary battery Vb1. When the voltage value of .about.Vb4 is larger than the second overcharge protection voltage value V2, the FET Q3 that blows the thermal fuse F1 disposed on the power supply path of the secondary batteries Vb1 to Vb4 is turned on. At the time of inspection for inspecting whether the second control IC 3 operates normally, the MPU 21 of the first control IC 2 changes the output voltage of the D / A converter 22 connected to the secondary batteries Vb1 to Vb4, The terminal voltages of the secondary batteries Vb1 to Vb4 are artificially raised to the second overcharge protection voltage value V2. Then, the MPU 21 confirms that the protection operation of the second control IC 3 is executed when the voltage detected by the A / D converters 231 to 234 reaches the second overcharge protection voltage value V2. Accordingly, the operation of the second control IC 3 that reliably cuts off the charging current when the first control IC 2 does not operate normally can be reliably inspected.

  Further, the switch SW1 switches the connection destination of the output terminal of the D / A converter 22 to one secondary battery among the plurality of secondary batteries Vb1 to Vb4. Therefore, even when a plurality of secondary batteries Vb1 to Vb4 are connected in series, the operation of the protection circuit when the individual secondary batteries are excessively charged can be inspected.

  Furthermore, A / D converters 231 to 234 are connected to the positive electrodes of the secondary batteries Vb1 to Vb4 connected in series. When there are an even number of the plurality of secondary batteries, two of the plurality of secondary batteries are set as one set, and the negative electrode of one of the secondary batteries of each set and the other secondary battery The terminal of the switch SW1 is connected to the positive electrode. The switch SW1 connects the output terminal of the D / A converter 22 to the terminal CN1 connected between the negative electrode of the secondary battery Vb1 and the positive electrode of the secondary battery Vb2, and the negative electrode of the secondary battery Vb3. Switching to the terminal CN2 connected between the positive electrode of the secondary battery Vb4. The MPU 21 switches the switch SW1 to the terminal CN1 and lowers the output voltage of the D / A converter 22 to increase the terminal voltage of the secondary battery Vb1 in a pseudo manner to the first overcharge protection voltage value V1. Further, the MPU 21 switches the switch SW1 to the terminal CN1 and raises the output voltage of the D / A converter 22 to increase the terminal voltage of the secondary battery Vb2 to the first overcharge protection voltage value V1 in a pseudo manner. . Further, the MPU 21 switches the switch SW1 to the terminal CN2 and decreases the output voltage of the D / A converter 22 to increase the terminal voltage of the secondary battery Vb3 to the first overcharge protection voltage value V1 in a pseudo manner. . Furthermore, the MPU 21 artificially increases the terminal voltage of the secondary battery Vb4 to the first overcharge protection voltage value V1 by switching the switch SW1 to the terminal CN2 and increasing the output voltage of the D / A converter 22. Let The MPU 21 confirms that the protection operation for the secondary batteries Vb1 to Vb4 is executed when the voltage detected by the A / D converters 231 to 234 reaches the first overcharge protection voltage value V1.

  Therefore, by decreasing or increasing the output voltage of the D / A converter 22, the terminal voltage of each secondary battery can be increased in a pseudo manner up to the first overcharge protection voltage value V1, and a plurality of secondary batteries can be increased. Even when Vb1 to Vb4 are connected in series, the protection operation of the first control IC 2 when the individual secondary batteries are excessively charged can be easily inspected.

  In addition, the MPU 21 switches the switch SW1 to the terminal CN1 and decreases the output voltage of the D / A converter 22 to increase the terminal voltage of the secondary battery Vb1 in a pseudo manner to the second overcharge protection voltage value V2. . Further, the MPU 21 switches the switch SW1 to the terminal CN1 and raises the output voltage of the D / A converter 22 to increase the terminal voltage of the secondary battery Vb2 to the second overcharge protection voltage value V2 in a pseudo manner. . Further, the MPU 21 switches the switch SW1 to the terminal CN2 and decreases the output voltage of the D / A converter 22 to increase the terminal voltage of the secondary battery Vb3 to the second overcharge protection voltage value V2 in a pseudo manner. . Furthermore, the MPU 21 artificially increases the terminal voltage of the secondary battery Vb4 to the second overcharge protection voltage value V2 by switching the switch SW1 to the terminal CN2 and increasing the output voltage of the D / A converter 22. Let Then, the MPU 21 confirms that the protection operation for the secondary batteries Vb1 to Vb4 is executed when the voltage detected by the A / D converters 231 to 234 reaches the second overcharge protection voltage value V2.

  Therefore, by decreasing or increasing the output voltage of the D / A converter 22, the terminal voltage of each secondary battery can be increased in a pseudo manner up to the second overcharge protection voltage value V2, and a plurality of secondary batteries can be increased. Even when Vb1 to Vb4 are connected in series, the protective operation of the second control IC 3 when the individual secondary batteries are excessively charged can be easily inspected.

  In addition, since the inspection result is stored in the memory 25, the inspector or the user can read and check the inspection result after the inspection is completed. In addition, since inspection determination can be performed simply by reading the inspection result, the inspection time can be shortened. In addition, since the inspection result is transmitted to the external device such as the personal computer by the MPU 21, the inspector or the user can confirm the inspection result by the external device.

  Note that the MPU 21 may turn off the FETs Q1 and Q2 when an inspection result is obtained that at least one of the first control IC 2 and the second control IC 3 does not operate normally. In this case, at least one of the first control IC 2 and the second control IC 3 did not operate normally by confirming that the output terminal voltage from the battery pack after the inspection was not performed. You can easily know that.

  Further, although the present embodiment describes the inspection in the battery pack manufacturing factory, the present invention is not particularly limited to this, and may be self-inspected in the actual market. For example, the inspection may be performed periodically using a timer. In this case, the MPU 21 periodically shifts to the inspection mode, inspects the overcharge protection operation of the first control IC 2 and the second control IC 3, and stores the inspection result in the memory 25. Moreover, you may test | inspect at the time of power-off of the apparatus to which the battery pack was connected. In this case, a signal indicating that the power is turned off is transmitted from the device to the MPU 21. When the MPU 21 receives the signal, the MPU 21 shifts to the inspection mode, and the overcharge protection operation of the first control IC 2 and the second control IC 3 is performed. An inspection is performed and the inspection result is stored in the memory 25.

  Further, the inspection may be performed when the battery pack is connected to the charging device. In this case, the MPU 21 detects that it is connected to the charging device, shifts to the inspection mode, inspects the overcharge protection operation of the first control IC 2 and the second control IC 3, and stores the inspection result in the memory 25. Remember. And when a battery pack is connected to the apparatus provided with a display part, or when the power supply of the apparatus to which the battery pack is connected is turned on, MPU21 reads a test result from the memory 25, and transmits to the apparatus side. The device displays the received inspection result on the display unit. The user can inspect the operations of the first control IC 2 and the second control IC 3 when the secondary batteries Vb1 to Vb4 are excessively charged by confirming the displayed inspection results.

  Furthermore, in the present embodiment, four secondary batteries are connected in series. However, the present invention is not particularly limited to this, and three secondary batteries may be connected in series. FIG. 2 is a diagram showing a configuration of another battery pack according to the first embodiment of the present invention. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

  The battery pack 1 shown in FIG. 2 includes a first control IC 2, a second control IC 3, external connection terminals 11 to 14, a plurality of secondary batteries Vb1 to Vb3, FETs Q1, Q2, Q3, and a thermal fuse F1. Is done. The external connection terminal 11 is connected to the positive electrodes of the secondary batteries Vb1 to Vb3 via the temperature fuse F1, the FET Q1, and the FET Q2, and the external connection terminal 12 is connected to the negative electrodes of the secondary batteries Vb1 to Vb3.

  The first control IC 2 includes an MPU 21, a D / A converter 22, A / D converters 231 to 233, a comparator 24, a memory 25, and a switch SW1. The switch SW1 switches the output destination of the D / A converter 22 to one of the terminal OFF, the terminal CN1, and the terminal CN2 based on the control from the MPU 21. Terminal CN1 is connected between the negative electrode of secondary battery Vb1 and the positive electrode of secondary battery Vb2, and terminal CN2 is connected to the positive electrode of secondary battery Vb3. The second control IC 3 includes a logic circuit 31, comparators M1 to M3, and reference voltage sources E1 to E3.

  Here, the operation of the battery pack 1 shown in FIG. 2 will be described. The inspection when the secondary batteries Vb1 and Vb2 are excessively charged is the same as the inspection of the battery pack 1 shown in FIG. When inspecting the operation of the first control IC 2 and the second control IC 3 when the secondary battery Vb3 is excessively charged, the MPU 21 connects the switch SW1 to the terminal CN2 and outputs the output voltage of the D / A converter 22 Is increased in a pseudo manner to increase the terminal voltage of the secondary battery Vb3.

  That is, when the plurality of secondary batteries Vb1, Vb2, and Vb3 are an odd number, two of the plurality of secondary batteries (secondary batteries Vb1 and Vb2) are set as one set, and the secondary battery of each set The terminal CN1 of the switch SW1 is connected between the negative electrode of one of the secondary batteries Vb1 and the positive electrode of the other secondary battery Vb2, and the terminal CN2 of the switch SW1 is connected to the positive electrode of the remaining one secondary battery Vb3. Connected. When the secondary battery Vb3 is the inspection target, the MPU 21 instructs the switch SW1 to switch to the terminal CN2 connected to the positive electrode of the secondary battery Vb3 to be inspected, and the switch SW1 is connected to the D / A converter 22. The connection destination of the output terminal is switched to the terminal CN2. Then, by raising the output voltage of the D / A converter 22, the terminal voltage of the remaining one secondary battery Vb3 is artificially raised to the first overcharge protection voltage value V1. The MPU 21 confirms that the protection operation of the first control IC 2 for the secondary battery Vb3 is executed when the voltage detected by the A / D converter 233 reaches the first overcharge protection voltage value V1.

  Further, the MPU 21 increases the output voltage of the D / A converter 22 to increase the terminal voltage of the remaining one secondary battery Vb3 in a pseudo manner to the second overcharge protection voltage value V2. Then, the MPU 21 confirms that the protection operation of the second control IC 3 for the secondary battery Vb3 is executed when the voltage detected by the A / D converter 233 reaches the second overcharge protection voltage value V2. To do.

  Therefore, the terminal voltage of each secondary battery is artificially increased to the first overcharge protection voltage value V1 and the second overcharge protection voltage value V2 by decreasing or increasing the output voltage of the D / A converter 22. Even when a plurality of secondary batteries Vb1 to Vb3 are connected in series, the first control IC 2 and the second control IC 2 when the individual secondary batteries are excessively charged The protection operation of the control IC 3 can be easily inspected.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the first embodiment, only the inspection result is transmitted to the external device. In the second embodiment, identification information for identifying the battery pack is added to the inspection result and transmitted to the external device. .

  FIG. 3 is a diagram showing the configuration of the inspection system according to the second embodiment of the present invention. The inspection system shown in FIG. 3 includes a battery pack 1, a personal computer 4, and a server 5. The battery pack 1 is connected to the personal computer 4 and functions as a power source for the personal computer 4. The personal computer 4 and the server 5 are connected via a network 6 so that they can communicate with each other. The network 6 is, for example, the Internet or a LAN (Local Area Network).

  FIG. 4 is a diagram showing the configuration of the battery pack according to the second embodiment of the present invention. In FIG. 4, the same components as those in FIG. In the battery pack 1 according to the second embodiment, in addition to the configuration of the battery pack 1 according to the first embodiment, the first control IC 2 further includes an encryption ID storage unit 26.

  The encryption ID storage unit 26 stores an encryption ID obtained by encrypting identification information (ID) for identifying the battery pack. The MPU 21 transmits the inspection result stored in the memory 25 and the encryption ID stored in the encryption ID storage unit 26 to the personal computer 4. The battery pack 1 and the personal computer 4 are connected to each other via external connection terminals 13 and 14 so as to communicate with each other. The personal computer 4 transmits the received inspection result and encryption ID to the server 5 via the network 6. In the present embodiment, the encryption ID storage unit 26 corresponds to an example of identification information storage means, and the server 5 corresponds to an example of an external device.

  FIG. 5 is a diagram illustrating a configuration of a server according to the second embodiment of the present invention. The server 5 includes a communication unit 51, a decryption unit 52, an authentication unit 53, an ID storage unit 54, and a data storage unit 55. The communication unit 51 receives the inspection result and the encryption ID transmitted by the personal computer 4. The decryption unit 52 decrypts the encryption ID received by the communication unit 51. Specifically, the decryption unit 52 decrypts the encryption ID with the encryption key used when encrypting the ID. The ID storage unit 54 stores IDs of a plurality of battery packs. The authentication unit 53 compares the ID decrypted by the decryption unit 52 with the ID stored in the ID storage unit 54. If they match, the authentication unit 53 determines that the authentication is successful, and if they do not match, determines that the authentication fails. . The authentication unit 53 stores the ID determined to be successful by the authentication unit 53 and the test result received by the communication unit 51 in the data storage unit 55 in association with each other. If the authentication unit 53 determines that the authentication has failed, the ID and the inspection result are discarded. Then, the server 5 maintains and manages the battery pack based on the ID and the inspection result stored in the data storage unit 55.

  Thus, the encryption ID storage unit 26 stores identification information for specifying the battery pack 1, and the MPU 21 displays the inspection result with the identification information stored in the encryption ID storage unit 26 added to a server or the like. To the external device. Therefore, the inspector or the user can identify the battery pack that is confirmed not to operate normally by confirming the identification information added to the inspection result.

  The encryption ID storage unit 26 stores encrypted identification information, and the MPU 21 transmits the inspection result with the encrypted identification information added to an external device such as a server. Can be increased.

  The server 5 may further include a display unit, and the ID and the inspection result stored in the data storage unit 55 may be displayed on the display unit. In this case, the inspector can identify the battery pack whose operation is not normal by confirming the displayed inspection result.

  Further, the ID storage unit 54 stores the ID and user information related to the user who owns the battery pack corresponding to the ID in association with each other, and the data storage unit 55 associates the ID with the inspection result and the user information. You may remember. The user information includes the user's name and email address. Then, the server 5 may transmit the inspection result stored in the data storage unit 55 to the mail address associated with the inspection result.

  Furthermore, in this embodiment, the encrypted ID is added to the inspection result and transmitted to the server 5. However, the present invention is not particularly limited to this, and an unencrypted ID is added to the inspection result. May be sent to the server. In this case, the confidentiality of the information is lowered, but the decrypting unit 52 of the server 5 is not necessary, and the data processing speed in the server 5 can be improved.

  In addition, the inspection process in the second embodiment may be performed periodically using a timer, or may be performed when the device to which the battery pack 1 is connected is turned off, and the battery pack 1 is connected to the charging device. You may go if you do.

  Furthermore, in the present embodiment, four secondary batteries are connected in series, but the present invention is not particularly limited to this, and three secondary batteries may be connected in series. FIG. 6 is a diagram showing a configuration of another battery pack according to the second embodiment of the present invention. In FIG. 6, the same components as those in FIGS. 2 and 4 are denoted by the same reference numerals, and description thereof is omitted. Also, the operation of the battery pack 1 in FIG. 6 is the same as the operation of the battery pack 1 in FIG.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In the second embodiment, the inspection result is transmitted to the server via the network. In the third embodiment, the inspection result is transmitted to the inspection apparatus by wireless communication.

  FIG. 7 is a diagram showing a configuration of an inspection system according to the third embodiment of the present invention. The inspection system shown in FIG. 7 includes a battery pack 1 and an inspection device 7. In FIG. 7, the same components as those in FIGS. 1 and 4 are denoted by the same reference numerals, and description thereof is omitted.

  In the battery pack 1 according to the third embodiment, in addition to the configuration of the battery pack 1 according to the second embodiment, the first control IC 2 further includes a wireless communication unit 28. The wireless communication unit 28 transmits the inspection result stored in the memory 25 and the encryption ID stored in the encryption ID storage unit 26 to the inspection device 7 via the antenna 281.

  In FIG. 7, a current detection resistor Rs is connected between the negative electrode of the secondary battery Vb4 and the external connection terminal 12, and an operational amplifier 27 is connected to both ends of the resistor Rs. The output terminal is connected to the MPU 21. The operational amplifier 27 detects a charging current or a discharging current passed through the secondary batteries Vb <b> 1 to Vb <b> 4 and outputs detection data to the MPU 21. The MPU 21 confirms whether charging or discharging is performed based on the detection data output from the operational amplifier 27. That is, the MPU 21 confirms whether charging or discharging is in progress when shifting to the inspection mode, and stops transitioning to inspection mode when charging or discharging. Thereby, it is possible to prevent the overcharge protection operation of the first control IC 2 and the second control IC 3 from being inspected during charging or discharging.

  FIG. 8 is a diagram showing a configuration of the inspection apparatus 7 according to the third embodiment of the present invention. 8 includes a wireless communication unit 71, a decryption unit 72, an authentication unit 73, an ID storage unit 74, a data storage unit 75, and a display unit 76.

  The wireless communication unit 71 receives the inspection result and the encryption ID transmitted by the wireless communication unit 28 of the first control IC 2 via the antenna 70. The decryption unit 72 decrypts the encryption ID received by the wireless communication unit 71. Specifically, the decryption unit 72 decrypts the encryption ID with the encryption key used when encrypting the ID. The ID storage unit 74 stores IDs of a plurality of battery packs. The authentication unit 73 compares the ID decrypted by the decryption unit 72 with the ID stored in the ID storage unit 74, and determines that the authentication is successful if they match, and determines that the authentication fails if they do not match. . The authentication unit 73 stores the ID determined to be successful by the authentication unit 73 in association with the inspection result received by the wireless communication unit 71 in the data storage unit 75. If the authentication unit 73 determines that the authentication has failed, the ID and the inspection result are discarded. The display unit 76 displays the ID and the inspection result stored in the data storage unit 75.

  Here, the inspection result acquisition process by the inspection device 7 will be described. First, the wireless communication unit 71 transmits a test result acquisition request to the battery pack 1. The wireless communication unit 28 of the battery pack 1 receives the inspection result acquisition request transmitted by the wireless communication unit 71 and outputs it to the MPU 21. When the inspection result acquisition request is input, the MPU 21 reads out the inspection result stored in the memory 25 and the encryption ID stored in the encryption ID storage unit 26 and outputs them to the wireless communication unit 28. Then, the wireless communication unit 28 transmits the inspection result and the encryption ID input from the MPU 21 to the inspection device 7.

  The wireless communication unit 71 of the inspection device 7 receives the inspection result and the encryption ID transmitted by the wireless communication unit 28 of the battery pack 1. Next, the decryption unit 72 decrypts the encryption ID received by the wireless communication unit 71. The authentication unit 73 compares the ID decrypted by the decryption unit 72 with the ID stored in the ID storage unit 74. Here, when an ID that matches the decrypted ID is stored in the ID storage unit 74, the authentication unit 73 determines that the authentication is successful, and the authenticated ID and the inspection result received by the wireless communication unit 71. Are stored in the data storage unit 75 in association with each other. On the other hand, when an ID that matches the decrypted ID is not stored in the ID storage unit 74, the authentication unit 73 determines that the authentication has failed and discards the ID and the inspection result. Next, the display unit 76 reads out and displays the ID and the inspection result stored in the data storage unit 75.

  In this way, the inspector checks the operation of the first control IC 2 and the second control IC 3 when the secondary batteries Vb1 to Vb4 are excessively charged by confirming the displayed inspection result. be able to. Further, since the inspection result is displayed together with the battery pack ID, it is possible to identify the battery pack from which the inspection result indicating that it did not operate normally was obtained.

  In addition, since the inspection result is transmitted to an external device such as the inspection device 7 by wireless communication, it is not necessary to directly connect an external device for acquiring the inspection result, and the inspection result can be acquired without contact. Further, since the inspection result is transmitted to the inspection device 7 by wireless communication, the inspection can be performed by performing the inspection in a state where the battery pack is packed in the box.

  In the present embodiment, the encrypted ID is added to the inspection result and transmitted to the inspection device 7. However, the present invention is not particularly limited to this, and an unencrypted ID is added to the inspection result. May be transmitted to the inspection device 7. In this case, the confidentiality of the information is lowered, but the decoding unit 72 of the inspection device 7 is not necessary, and the data processing speed in the inspection device 7 can be improved.

  Further, in the present embodiment, four secondary batteries are connected in series, but the present invention is not particularly limited to this, and three secondary batteries may be connected in series. FIG. 9 is a diagram showing the configuration of another inspection system according to the third embodiment of the present invention. In FIG. 9, the same components as those in FIGS. 2 and 4 are denoted by the same reference numerals, and description thereof is omitted. Further, the operation of the battery pack 1 in FIG. 9 is the same as the operation of the battery pack 1 in FIG.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, the inspection result is displayed by an LED (Light Emitting Diode) or the like. FIG. 10 is a diagram showing a configuration of a battery pack according to the fourth embodiment of the present invention. In FIG. 10, the same components as those in FIG.

  The battery pack 1 in the fourth embodiment further includes an LED 8 in addition to the configuration of the battery pack 1 in the first embodiment. The MPU 21 turns on the LED 8 when an inspection result is obtained that at least one of the first control IC 2 and the second control IC 3 does not operate normally. Since the inspection process in the fourth embodiment is the same as that in the first embodiment, the description thereof is omitted. Thus, the user can inspect the operation of the first control IC 2 and the second control IC 3 when the secondary batteries Vb1 to Vb4 are excessively charged by checking the lighting state of the LED 8. .

  The inspection process in the fourth embodiment may be performed periodically using a timer, or may be performed when the device to which the battery pack 1 is connected is turned off, and the battery pack 1 is connected to the charging device. You may go if you do.

  Further, the battery pack 1 may be provided with an LED for displaying only the inspection result, but when the battery pack 1 includes an LED for displaying the remaining capacity of the secondary battery, the inspection result is displayed on the LED. May be. In this case, the MPU 21 displays the display color when displaying the inspection result in a color different from the display color when displaying the remaining capacity. Further, in this case, the MPU 21 may display the display pattern when displaying the inspection result in a pattern different from the display pattern when displaying the remaining capacity.

  Further, the battery pack 1 has an LED to be turned on when an inspection result indicating that the first control IC 2 does not operate normally and an inspection result that the second control IC 3 does not operate normally. And an LED that is lit when it is illuminated.

  Thus, when it is confirmed that the protection operation of the first control IC 2 or the second control IC 3 is not executed, the MPU 21 causes the LED 8 to emit light. Therefore, the inspector or the user can confirm that the protection operation of the first control IC 2 or the second control IC 3 has not been executed by confirming that the LED 8 emits light.

  Furthermore, in the present embodiment, four secondary batteries are connected in series. However, the present invention is not particularly limited to this, and three secondary batteries may be connected in series. FIG. 10 is a diagram showing a configuration of another battery pack according to the fourth embodiment of the present invention. 10, the same components as those in FIGS. 2 and 4 are denoted by the same reference numerals, and the description thereof is omitted. Further, the operation of the battery pack 1 in FIG. 10 is the same as the operation of the battery pack 1 in FIG.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, the LED is blinked according to the inspection result, the blinking state of the LED is detected by the inspection device to detect the inspection result, and the detected inspection result is notified to the inspector or the user. FIG. 12 is a diagram showing a configuration of an inspection system according to the fifth embodiment of the present invention. In FIG. 12, the same components as those in FIG. Moreover, since the inspection process in the fifth embodiment is the same as that in the first embodiment, description thereof is omitted.

  The inspection system in the fifth embodiment includes a battery pack 1 and an inspection device 9. The battery pack 1 further includes an LED 8. The MPU 21 reads the inspection result from the memory 25 and controls the LED 8 to blink according to the read inspection result.

  FIG. 13 is a diagram showing a configuration of an inspection apparatus according to the fifth embodiment of the present invention. The inspection device 9 includes a light detection unit 91, a data processing unit 92, and a display unit 93. The light detection unit 91 receives the light output from the LED 8, converts it into an electrical signal, and outputs it to the data processing unit 92. The data processing unit 92 processes the data input from the light detection unit 91, detects the inspection result from the blinking state of the LED 8, and outputs it to the display unit 93. The display unit 93 displays the inspection result input from the data processing unit 92. The user can inspect the operations of the first control IC 2 and the second control IC 3 when the secondary batteries Vb1 to Vb4 are excessively charged by confirming the displayed inspection results.

  In this way, the MPU 21 blinks the LED 8 according to the inspection result stored in the memory 25. Therefore, an external device such as the inspection device 9 can acquire the inspection result by detecting the blinking state of the LED 8, and the MPU 21 can transmit the inspection result without contact.

  In this embodiment, the inspection result is transmitted to the inspection device 9 by blinking the LED 8 that outputs visible light. However, the present invention is not particularly limited to this, and inspection is performed using infrared light. The result may be transmitted to the inspection device 9.

  Further, in the present embodiment, four secondary batteries are connected in series, but the present invention is not particularly limited to this, and three secondary batteries may be connected in series. FIG. 14 is a diagram showing the configuration of another inspection system according to the fifth embodiment of the present invention. In FIG. 14, the same components as those in FIGS. 2 and 4 are denoted by the same reference numerals, and description thereof is omitted. Further, the operation of the battery pack 1 in FIG. 14 is the same as the operation of the battery pack 1 in FIG.

  In the first to fifth embodiments, the battery pack 1 includes three or four secondary batteries connected in series. However, the present invention is not particularly limited thereto, and one or Two secondary batteries may be provided, or five or more secondary batteries may be provided.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described. In the sixth embodiment, a battery pack unit is configured by connecting a plurality of battery packs in the first to fifth embodiments in series.

  FIG. 15 is a diagram showing a configuration of a battery pack unit according to the sixth embodiment of the present invention. The battery pack unit 10 shown in FIG. 15 has a plurality of battery packs 1a, 1b, 1c connected in series. The battery pack unit 10 is connected to an external device 4a such as a PC, an electric bicycle, and an electric motorcycle. The external device 4a and each of the battery packs 1a, 1b, and 1c are connected to each other via the control lines 101a, 101b, and 101c so as to communicate with each other. The control lines 101a, 101b, and 101c include a data line and a clock line, and are connected to the external terminals 13 and 14 of the battery packs 1a, 1b, and 1c, respectively.

  Further, the external terminal (plus terminal) 11 of the battery pack 1a is connected to the external device 4a, and the external terminal (minus terminal) 12 of the battery pack 1a is connected to the external terminal 11 of the battery pack 1b. The external terminal 12 of the battery pack 1b is connected to the external terminal 11 of the battery pack 1c, and the external terminal 12 of the battery pack 1c is connected to the external device 4a.

  The configurations of the battery packs 1a, 1b, and 1c are the same as the configurations of the battery pack 1 in the first to fifth embodiments. Each of the battery packs 1a, 1b, and 1c includes N (N = 1 to an integer of 1 to 8) secondary batteries.

  Although the battery pack unit 10 in FIG. 15 is configured with three battery packs, the present invention is not particularly limited thereto, and may be configured with two or four or more battery packs. Further, the number of secondary batteries in each battery pack is not limited to 1 to 8, and more secondary batteries may be connected.

  Furthermore, the battery pack unit 10 in the present embodiment is configured by battery packs 1a, 1b, and 1c including N (N = 1 to 8) secondary batteries, but the present invention is particularly limited to this. Battery pack 1a in which N (N = 2 to an integer of 2 to 8) secondary batteries are connected in series, and battery packs 1b and 1c in which (N-1) secondary batteries are connected in series. The battery pack unit 10 may be configured.

  In this case, the battery pack unit includes at least one battery pack in which N (N = 2 to 8) secondary batteries are connected in series and (N−1) secondary batteries are connected in series. The battery pack can be adapted to various voltages desired by the load device. The number N of secondary batteries is not limited to 2 to 8, and may be more than 8.

  Furthermore, in the present embodiment, the external device 4a and the battery packs 1a, 1b, and 1c are connected to each other via separate control lines 101a, 101b, and 101c, but the present invention is particularly effective. The present invention is not limited to this, and one control line may be connected to the external device 4a, and the control line may be divided according to the number of battery packs and connected to each battery pack 1a, 1b, 1c.

  Furthermore, the external device 4a and one of the plurality of battery packs are connected to each other via a control line so that they can communicate with each other, and one battery pack and another battery pack are connected via the control line. You may connect so that communication is mutually possible. When controlling another battery pack, the external device 4a outputs a control signal to one battery pack, and the one battery pack outputs the control signal to another battery pack.

  INDUSTRIAL APPLICABILITY The inspection circuit, battery pack and battery pack unit according to the present invention can reliably inspect the operation of the protection circuit that protects the overcharge of the secondary battery, and protects the secondary battery and the overcharge of the secondary battery. It is provided in a battery pack provided with a protection circuit to be used, and is useful as an inspection circuit, a battery pack, a battery pack unit, and the like for inspecting the operation of the protection circuit.

It is a figure which shows the structure of the battery pack which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of another battery pack which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the test | inspection system in the 2nd Embodiment of this invention. It is a figure which shows the structure of the battery pack in the 2nd Embodiment of this invention. It is a figure which shows the structure of the server in the 2nd Embodiment of this invention. It is a figure which shows the structure of another battery pack in the 2nd Embodiment of this invention. It is a figure which shows the structure of the test | inspection system in the 3rd Embodiment of this invention. It is a figure which shows the structure of the test | inspection apparatus in the 3rd Embodiment of this invention. It is a figure which shows the structure of another test | inspection system in the 3rd Embodiment of this invention. It is a figure which shows the structure of the battery pack in the 4th Embodiment of this invention. It is a figure which shows the structure of another battery pack in the 4th Embodiment of this invention. It is a figure which shows the structure of the test | inspection system in the 5th Embodiment of this invention. It is a figure which shows the structure of the test | inspection apparatus in the 5th Embodiment of this invention. It is a figure which shows the structure of another test | inspection system in the 5th Embodiment of this invention. It is a figure which shows the structure of the battery pack unit in the 6th Embodiment of this invention. It is a figure which shows the structure of the inspection system of the conventional battery pack.

Explanation of symbols

1 battery pack 2 first control IC
3 Second control IC
11, 12, 13, 14 External connection terminal 21 MPU
22 D / A converter 24 Comparator 25 Memory 31 Logic circuit 231 to 234 A / D converter E1 to E5 Reference voltage source F1 Thermal fuse M1 to M4 Comparator Q1, Q2, Q3 FET
R1, R2 resistance SW1 switch Vb1-Vb4 secondary battery

Claims (15)

A test circuit provided in a battery pack comprising a secondary battery and a protection circuit for protecting the secondary battery from overcharging, and testing the operation of the protection circuit,
The protection circuit is detected by first switching means disposed on a power supply path of the secondary battery, voltage value detection means for detecting a voltage value of the secondary battery, and the voltage value detection means. A first protection means for turning off the first switching means when the voltage value reaches a preset first overcharge protection voltage value;
A digital-to-analog converter connected to the secondary battery and converting a terminal voltage of the secondary battery from a digital value to an analog value;
Voltage control means for changing the output voltage of the digital-analog converter and increasing the terminal voltage of the secondary battery to the first overcharge protection voltage value in a pseudo manner;
And a protection operation confirmation unit that confirms that the protection operation of the first protection unit is performed when the voltage detected by the voltage value detection unit reaches the first overcharge protection voltage value. Inspection circuit characterized by The protection circuit includes: a second switching unit that blows a thermal fuse disposed on a power supply path of the secondary battery; a voltage value of the secondary battery; and a first overcharge protection voltage value. A second protection unit that compares the second overcharge protection voltage value and turns on the second switching unit when the voltage value of the secondary battery is greater than the second overcharge protection voltage value. And further including
The voltage control means changes the output voltage of the digital-analog converter to increase the terminal voltage of the secondary battery in a pseudo manner up to the second overcharge protection voltage value,
The protection operation confirmation unit confirms that the protection operation of the second protection unit is executed when the voltage detected by the voltage value detection unit reaches the second overcharge protection voltage value. The inspection circuit according to claim 1. The secondary battery includes a plurality of secondary batteries connected in series,
3. The inspection according to claim 1, further comprising third switching means for switching a connection destination of the output terminal of the digital / analog converter to one of the plurality of secondary batteries. circuit. The voltage value detection means includes a plurality of voltage value detection means connected to the positive electrode of each secondary battery,
When there are an even number of the plurality of secondary batteries, two of the plurality of secondary batteries are set as one set, and the negative electrode of one of the secondary batteries of each set and the other two The terminal of the third switching means is connected between the positive electrode of the secondary battery,
When the plurality of secondary batteries is an odd number, two of the plurality of secondary batteries are set as one set, and the negative electrode of one secondary battery and the other two of the secondary batteries of each set The terminal of the third switching means is connected between the positive electrode of the secondary battery, and the terminal of the third switching means is connected to the positive electrode of the remaining one secondary battery,
The third switching means switches the connection destination of the output terminal of the digital / analog converter to one of a plurality of terminals,
The voltage control means instructs the third switching means to switch to a set including a secondary battery to be inspected or a terminal connected to the secondary battery to be inspected, and the digital / analog converter By decreasing the output voltage, the terminal voltage of the secondary battery of 1 is increased in a pseudo manner up to the first overcharge protection voltage value, and by increasing the output voltage of the digital / analog converter, the other The terminal voltage of the secondary battery or the remaining one secondary battery is increased to the first overcharge protection voltage value in a pseudo manner,
The protection operation confirmation means performs the protection operation of the first protection means for each secondary battery when the voltage detected by each voltage value detection means reaches the first overcharge protection voltage value. The inspection circuit according to claim 3, wherein the inspection circuit is confirmed. The voltage control means instructs the third switching means to switch to a set including a secondary battery to be inspected or a terminal connected to the secondary battery to be inspected, and the digital / analog converter By decreasing the output voltage, the terminal voltage of the first secondary battery is increased to the second overcharge protection voltage value in a pseudo manner, and by increasing the output voltage of the digital / analog converter, the other The terminal voltage of the secondary battery or the remaining one secondary battery is artificially increased to the second overcharge protection voltage value,
The protection operation confirmation unit performs the protection operation of the second protection unit on each secondary battery when the voltage detected by each voltage value detection unit reaches the second overcharge protection voltage value. The inspection circuit according to claim 4, wherein the inspection circuit is confirmed.   6. The inspection circuit according to claim 1, further comprising inspection result storage means for storing an inspection result by the protection operation confirmation means.   The inspection circuit according to claim 6, further comprising a transmission unit that transmits the inspection result stored in the inspection result storage unit to an external device. An identification information storage means for storing identification information for specifying the battery pack;
The inspection circuit according to claim 7, wherein the transmission unit transmits the inspection result to which the identification information stored in the identification information storage unit is added to the external device.   9. The inspection circuit according to claim 8, wherein the identification information storage means stores the encrypted identification information.   The inspection circuit according to claim 7, wherein the transmission unit transmits the inspection result to an external device by wireless communication. Light emitting means;
The inspection circuit according to claim 1, further comprising: a light emission control unit that causes the light emitting unit to emit light when it is confirmed that the protection operation of the protection circuit is not executed by the protection operation confirming unit. Light emitting means;
The inspection circuit according to claim 1, further comprising: a light emission control unit that causes the light emitting unit to blink according to an inspection result stored in the inspection result storage unit. A secondary battery,
A protection circuit for protecting the secondary battery from overcharging;
A battery pack comprising the inspection circuit according to claim 1.   A plurality of battery packs comprising a plurality of secondary batteries connected in series, a protection circuit for protecting overcharge of the secondary battery, and a test circuit according to any one of claims 1 to 12, A battery pack unit characterized by being connected.   The battery pack includes a battery pack in which N (N is an integer of 2 or more) secondary batteries are connected in series, and at least one battery pack in which (N-1) secondary batteries are connected in series. The battery pack unit according to claim 14, comprising:

Images