Battery packs for field electrical equipment, and methods for diagnosing battery packs for field electrical equipment.

Abstract

This technology provides a method for detecting with greater accuracy when a malfunction occurs in at least one of several battery modules connected in series. [Solution] One aspect of the present disclosure provides a battery pack comprising a first positive terminal, a first negative terminal, first to nth battery modules (where n is any natural number greater than or equal to 2), and a control circuit. The control circuit is configured to detect a malfunction in at least one of the first to nth battery modules based on the fully charged capacity of each of the first to nth battery modules.

Description

Technical Field

[0001] The present disclosure relates to a battery pack for field electrical equipment.

Background Art

[0002] Patent Document 1 listed below discloses a battery pack that includes a plurality of battery cells connected in series, and is configured to output a charge prohibition signal to a charger in response to detecting a state where the difference between their voltage values is greater than or equal to a predetermined condition.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Recent battery packs used in power tools generally include a plurality of battery modules connected in series, and each battery module includes a plurality of battery cells connected in parallel. As the number of cells connected in parallel in the battery pack increases, the difference in voltage value behavior between the corresponding battery module and a normal battery module when a failure occurs in any of the battery cells decreases. Therefore, it may be difficult to detect with high accuracy that a failure has occurred in any of the battery modules based on the voltage value of each battery module.

[0005] Accordingly, one aspect of the present disclosure aims to provide a technique capable of detecting with higher accuracy that a failure has occurred in at least one of a plurality of battery modules connected in series.

Means for Solving the Problems

[0006] In this disclosure, terms such as “first,” “second,” etc., are intended merely to distinguish elements from one another and not to limit the order or number of elements. Therefore, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element. In addition, the first element may be present without the second element, and similarly, the second element may be present without the first element.

[0007] One aspect of the present disclosure is a battery pack for field electrical equipment, comprising a first positive terminal and a first negative terminal, first to n battery modules (where n is any natural number greater than or equal to 2), and a control circuit.

[0008] The first positive terminal and the first negative terminal are configured to receive charging power from the charger. The first through nth battery modules are connected in series in sequence. The first through nth battery modules are configured to be charged by the charging power.

[0009] Each of the first through n battery modules comprises multiple rechargeable battery cells. These multiple rechargeable battery cells are connected in parallel. The first battery module includes a second positive terminal, which is connected to the first positive terminal. The nth battery module includes a second negative terminal, which is connected to the first negative terminal.

[0010] The control circuit is configured to derive the full charge capacity of each of the first to n battery modules based on the respective measurements related to the charge state of each of the first to n battery modules.

[0011] The control circuit is configured to detect a malfunction in at least one of the first to nth battery modules based on the derived full charge capacity of each of the above.

[0012] The full charge capacity of each battery module decreases in proportion to the failure of at least one of the multiple rechargeable battery cells. Therefore, a battery pack configured as described above can detect with greater accuracy that a malfunction has occurred in at least one of the first to nth battery modules, based on the respective full charge capacities.

[0013] Another aspect of this disclosure is a method for diagnosing a battery pack for field electrical equipment, The method for deriving the full charge capacity of each of the multiple battery modules of a battery pack based on the charge status of each of the multiple battery modules, wherein the multiple battery modules are connected in series, and each of the multiple battery modules comprises multiple rechargeable battery cells connected in parallel. Based on the derived full charge capacity of each battery module, a malfunction is detected in at least one of the multiple battery modules. It provides a method that includes [the necessary features].

[0014] This method allows for more accurate detection of a malfunction in at least one of the first to nth battery modules. [Brief explanation of the drawing]

[0015] [Figure 1A-1B] Figure 1A is a schematic block diagram showing the circuit configuration of the battery pack in the first embodiment, and Figure 1B is a schematic circuit diagram of the battery module in the first embodiment. [Figure 2] This is a block diagram schematically showing the circuit configuration of the charger in the first embodiment. [Figure 3] This is a flowchart of the charging state detection process in the first embodiment. [Figure 4] This is a flowchart of the diagnostic process in the first embodiment. [Figure 5]This is an explanatory diagram showing the relationship between the state of charge of a battery module and the open circuit voltage. [Figure 6] This is an explanatory diagram schematically showing the effect of the first embodiment. [Figure 7] This is a flowchart of a diagnostic process in the third embodiment. [Mode for Carrying Out the Invention]

[0016] 1. Overview of Embodiments An embodiment may include at least any one of the following: - Feature 1: A battery pack for field electrical equipment; - Feature 2: The battery pack includes a first positive terminal and a first negative terminal configured to receive charging power from a charger; - Feature 3: The battery pack includes first to n-th battery modules connected in series in sequence (n is any natural number equal to or greater than 2); - Feature 4: The first to n-th battery modules are configured to be charged with the charging power; - Feature 5: Each of the first to n-th battery modules includes a plurality of rechargeable battery cells connected in parallel; - Feature 6: The first battery module includes a second positive terminal connected to the first positive terminal; - Feature 7: The n-th battery module includes a second negative terminal connected to the first negative terminal; - Feature 8: The battery pack includes a control circuit; - Feature 9: The control circuit is configured (or programmed) to derive the respective full charge capacities of the first to n-th battery modules based on respective measurement values related to the respective state of charge of the first to n-th battery modules; and Feature 10: The control circuit described above is configured (or programmed) to detect a malfunction in at least one of the first to nth battery modules based on their respective full charge capacities.

[0017] Embodiments having at least features 1 to 10 can detect with greater accuracy that a malfunction has occurred in at least one of the first to nth battery modules, based on the respective full charge capacities.

[0018] One embodiment may include, in addition to or instead of, at least one of features 1 to 10, at least one of the following: Feature 11: The battery pack includes a measuring circuit configured (or programmed) to measure the voltage value of each of the first to nth battery modules; Feature 12: The above measurement circuit is configured (or programmed) to transmit each of the above voltage values; and Feature 13: The control circuit described above is configured (or programmed) to receive each voltage value from the measurement circuit described above as part of each of the measured values ​​described above.

[0019] Embodiments having at least features 1 to 13 can derive the full charge capacity of each of the first to n battery modules based on the voltage values ​​of each of the first to n battery modules measured inside the battery pack.

[0020] One embodiment may include, in addition to or instead of, at least one of features 1 to 13, at least one of the following: Feature 14: The above measurement circuit is configured (or programmed) to measure a current value corresponding to the magnitude of the charging current supplied from the above charger to the above battery pack; Feature 15: The above measurement circuit is configured (or programmed) to transmit the above current value; and Feature 16: The control circuit described above is configured (or programmed) to receive the current values ​​described above from the measurement circuit described above as part of the respective measured values.

[0021] Embodiments having at least features 1 to 16 can derive the full charge capacity of each of the first to n battery modules based on the voltage values ​​of each of the first to n battery modules and the current values ​​measured within the battery pack.

[0022] One embodiment may include, in addition to or instead of, at least one of features 1 to 16, at least one of the following: Feature 17: The above charger is configured to transmit a current value corresponding to the magnitude of the charging current; Feature 18: The magnitude of the above charging current is the magnitude of the charging current supplied from the above charger to the above battery pack; and Feature 19: The control circuit described above is configured (or programmed) to receive the current values ​​described above from the charger described above as part of the respective measured values ​​described above.

[0023] In embodiments comprising at least features 1 to 13 and 17 to 19, the battery pack can derive the full charge capacity of each of the first to n battery modules based on the respective voltage values ​​of the first to n battery modules and the current values ​​received from the charger.

[0024] One embodiment may include, in addition to or instead of, at least one of features 1 to 19, at least one of the following: Feature 20: The control circuit described above is configured (or programmed) to derive the integrated value of the current value from the start to the end of charging of the battery pack; Feature 21: The control circuit is configured (or programmed) to derive the pre-charge rate and post-charge rate of each of the first to n battery modules based on the pre-charge voltage value and post-charge voltage value of each of the first to n battery modules; Feature 22: The control circuit is configured (or programmed) to derive the respective full charge capacity based on the cumulative value, the respective pre-charge rate, and the respective post-charge rate; Feature 23: Each of the above pre-charging voltage values ​​corresponds to the respective voltage values ​​of the first to nth battery modules before charging begins; Feature 24: The above post-charge voltage values ​​correspond to the above voltage values ​​of the first to nth battery modules after charging is complete; Feature 25: Each of the above pre-charge rates corresponds to each of the above pre-charge rates of the 1st to nth battery modules before charging begins; and Feature 26: The above post-charge rate corresponds to the respective charge rate of the first to nth battery modules after charging is complete.

[0025] Embodiments having at least features 1-16, 20-26 can derive the respective full charge capacity based on the cumulative value, the respective pre-charge rate, and the respective post-charge rate.

[0026] One embodiment may include, in addition to or instead of, at least one of features 1 to 26, at least one of the following: Feature 27: Each of the pre-charging voltage values ​​corresponds to the open-circuit voltage of each of the first to n battery modules before charging begins; Feature 28: The respective post-charge voltage values ​​correspond to the open-circuit voltages of the first to nth battery modules after charging is complete.

[0027] Embodiments having at least features 1-16 and 20-28 can derive the respective pre-charge rate and the respective post-charge rate based on the respective open-circuit voltages before and after charging, respectively. As a result, the respective full charge capacity can be derived with high accuracy.

[0028] One embodiment may include, in addition to or instead of, at least one of features 1 to 28, at least one of the following: Feature 29: Each of the pre-charge voltage values ​​corresponds to the stable open-circuit voltage of each of the first to n battery modules before charging of the first to n battery modules begins; and Feature 30: The respective post-charge voltage values ​​correspond to the stable open-circuit voltages of the first to nth battery modules after charging is complete.

[0029] Embodiments comprising at least features 1-16, 20-26, 29, and 30 can derive the respective pre-charge rate and the respective post-charge rate with greater accuracy based on the respective stable open-circuit voltages before and after charging. As a result, the respective full charge capacity can be derived with greater accuracy.

[0030] One embodiment may include, in addition to or instead of, at least one of features 1 to 30: Feature 31: The control circuit described above is configured (or programmed) to detect the malfunction based on the difference between the largest and smallest full charge capacities among the respective full charge capacities described above, and a preset first threshold.

[0031] Embodiments having at least features 1 to 10, 31 can detect the malfunction based on the difference between the largest full charge capacity and the smallest full charge capacity.

[0032] One embodiment may include, in addition to or instead of, at least one of features 1 to 31: Feature 32: The control circuit described above is configured (or programmed) to detect the malfunction based on the ratio of the smallest full charge capacity to the largest full charge capacity among the respective full charge capacities described above, and a preset second threshold.

[0033] Embodiments having at least features 1 to 10, 32 can detect the malfunction based on the ratio of the smallest full charge capacity to the largest full charge capacity.

[0034] One embodiment may include, in addition to or instead of, at least one of features 1 to 32: Feature 33: The above defect includes, in at least one of the first to nth battery modules, that at least one of the plurality of rechargeable battery cells is electrically disconnected from the remaining rechargeable battery cells.

[0035] Embodiments having at least features 1 to 10, 33 can detect a malfunction in which at least one of the rechargeable battery cells is electrically disconnected from the remaining rechargeable battery cells.

[0036] One embodiment may include, in addition to or instead of, at least one of features 1 to 33: Feature 34: Each of the first to n battery modules described above has the same rated capacity or the same nominal capacity.

[0037] In one embodiment, the control circuit may be integrated into a single electronic unit, a single electronic device, or a single circuit board. In one embodiment, the control circuit may be a combination of two or more electronic circuits, two or more electronic units, or two or more electronic devices individually provided in the battery pack.

[0038] In one embodiment, the control circuit may include a microcomputer (or microcontroller or microprocessor), wired logic, an image processing unit (GPU), an application-specific integrated circuit (ASIC), an application-specific general-purpose product (ASSP), a programmable logic device (PLD) (such as a field-programmable gate array (FPGA)), discrete electronic components, and / or a combination thereof.

[0039] In one embodiment, the measurement circuit may consist of an analog front-end (AFE), a battery management module (BMU), a battery management system (BMS), a battery protection circuit, a PLD, a microcomputer, or any combination thereof.

[0040] One embodiment may include at least one of the following: Feature 35: A method for diagnosing battery packs for field electrical equipment; Feature 36: The above method comprises deriving the full charge capacity of each of the multiple battery modules of the battery pack based on the charge status of each of the multiple battery modules; Feature 37: The above multiple battery modules are connected in series; Feature 38: Each of the above battery modules comprises multiple rechargeable battery cells connected in parallel; and Feature 39: The above method comprises detecting a malfunction in at least one of the multiple battery modules based on the derived full charge capacity of each of the above.

[0041] Embodiments having at least features 35 to 39 can detect that a malfunction has occurred in at least one of the first to nth battery modules. The above examples of on-site electrical equipment include various types of on-site electrical equipment used in work sites such as DIY, manufacturing, gardening, and construction, and configured to be battery-powered. Specifically, these include power tools for stonework, metalworking, and woodworking, gardening equipment, and equipment for improving the work environment. More specifically, these include electric blowers, electric hammers, electric hammer drills, electric drills, electric screwdrivers, electric wrenches, electric grinders, electric circular saws, electric reciprocating saws, electric jigsaws, electric cutters, electric chainsaws, electric planers, and electric nail guns (including nail guns). ), including electric hedge trimmers, electric lawnmowers, electric grass trimmers, electric brush cutters, electric cleaners, electric sprayers, electric sprayers, electric dust collectors, laser rangefinders (or laser distance measuring devices), laser levels, laser level receivers, wall scanners, radios, televisions, speakers, electric coolers / warmers, electric kettles, coffee machines (or coffee makers, or coffee stills), microwave ovens, robotic vacuum cleaners, battery-powered handcarts, battery-powered bicycles, fan vests, and heated jackets.

[0042] In one embodiment, features 1 to 39 may be combined in any combination. In one embodiment, any of features 1 to 39 may be excluded. 2. Specific exemplary embodiments Several specific exemplary embodiments are described below. These specific exemplary embodiments illustrate the battery pack 1 described below.

[0043] 2-1. First Embodiment 2-1-1. Battery Pack Circuit Configuration Battery pack 1 is configured to be detachably attached to any corresponding field electrical equipment (not shown) and to supply DC power to said field electrical equipment.

[0044] Specifically, as shown in Figure 1A, the battery pack 1 includes a first positive terminal 11, a first negative terminal 12, a first data communication terminal 13, a Vcc input terminal 14, a notification signal output terminal 15, a first positive-side current path Lp1, a first negative-side current path Ln1, a first diode D1, a second diode D2, a shunt resistor R1, a battery pack 16, a first power supply circuit 17, a first control circuit 18, a measurement circuit 19, a charge level display circuit 20, a first temperature measurement circuit 21, a connection detection circuit 22, and a notification signal generation circuit 23.

[0045] The first positive terminal 11 and the first negative terminal 12 are configured to receive charging power from the charger 5 shown in Figure 2, which will be described later. The first positive terminal 11 is connected to the first positive-side current path Lp1, which extends from the first positive terminal 11 to the positive electrode 16a of the battery pack 16, and is therefore electrically connected to the positive electrode 16a of the battery pack 16. The first positive terminal 11 is also connected to the anode of the first diode D1 via the first positive-side current path Lp1.

[0046] The first negative terminal 12 is connected to a first negative-side current path Ln1 that extends from the first negative terminal 12 to the negative terminal 16b of the battery pack 16, and is therefore electrically connected to the negative terminal 16b of the battery pack 16.

[0047] The first positive-side current path Lp1 and the first negative-side current path Ln1 are configured to transmit (i) a charging current Ichg supplied from the charger 5 connected to the battery pack 1 to the battery pack 16, and (ii) a discharge current Idis supplied from the battery pack 16 to the field electrical equipment connected to the battery pack 1. The first negative-side current path Ln1 is connected to the ground of the battery pack 1. This ground is also connected to the first power supply circuit 17, the first control circuit 18, the measurement circuit 19, the charge level display circuit 20, the first temperature measurement circuit 21, the connection detection circuit 22, and the notification signal generation circuit 23, and serves as the reference potential for these circuits.

[0048] The shunt resistor R1 is provided on the first negative electrode current path Ln1 so that the charging current Ichg and the discharge current Idis pass through the shunt resistor R1. The first data communication terminal 13 is connected to the first control circuit 18. The first data communication terminal 13 is a terminal for serial communication between the first control circuit 18 and the charger 5 or field electrical equipment connected to the battery pack 1.

[0049] The Vcc input terminal 14 is connected to (i) the anode of the second diode D2 and (ii) the connection detection circuit 22. The notification signal output terminal 15 is connected to the notification signal generation circuit 23.

[0050] The battery pack 16 has first to nth battery modules 25a1 to 25an connected in series between its positive electrode 16a and negative electrode 16b (where n is a natural number greater than or equal to 2).

[0051] The first to nth battery modules 25a1 to 25an are configured to be charged by charging power supplied from the charger 5. The first battery module 25a1 has a second positive terminal 25a1a which is electrically connected to the first positive terminal 11 via the positive terminal 16a. The nth battery module 25an has a second negative terminal 25anb which is electrically connected to the first negative terminal 12 via the negative terminal 16b. Each of the first to nth battery modules 25a1 to 25an has the same rated capacity or the same nominal capacity.

[0052] As shown in Figure 1B, each of the first to nth battery modules 25a1 to 25an comprises first to fourth rechargeable battery cells (hereinafter simply referred to as cells) 26a to 26d connected in parallel via spot welding. Each of the first to fourth cells 26a to 26d has the same rated capacity or the same nominal capacity. Each of the first to fourth cells 26d is a lithium-ion battery, but is not limited to a lithium-ion battery. In another embodiment, in each of the first to nth battery modules 25a1 to 25an, one or two of the first to fourth cells 26a to 26d may be excluded, or at least one additional cell may be connected in parallel.

[0053] The first power supply circuit 17 is a DC-DC converter connected to the cathode of the first diode D1 and the cathode of the second diode D2, and configured to generate a first power supply voltage Vdd. The cathode of the first diode D1 is connected to the cathode of the second diode D2. Therefore, the first power supply circuit 17 is configured to generate a first power supply voltage Vdd based on the higher of (i) the voltage between the positive electrode 16a and the negative electrode 16b of the battery pack 16 (hereinafter referred to as the battery voltage Vbat) and (ii) the second power supply voltage Vcc supplied to the Vcc input terminal 14. The first power supply voltage Vdd is supplied to the first control circuit 18, the measurement circuit 19, the charge level display circuit 20, the first temperature measurement circuit 21, and the connection detection circuit 22 to operate these circuits. The battery voltage Vbat is 18 volts DC, but is not limited to 18 volts DC. In another embodiment, the battery voltage Vbat may be 40 volts DC, 14.4 volts DC, or 10.8 volts DC. The first power supply voltage Vdd and the second power supply voltage Vcc are each 5 volts DC, but are not limited to 5 volts DC.

[0054] The first control circuit 18 is configured to control the charging and discharging of the battery pack 16 by transmitting and receiving various signals between the first control circuit 18 and various other circuits. More specifically, the first control circuit 18 is a microcomputer comprising a central processing unit (CPU), memory, input / output (I / O) ports, a serial communication interface (SCI), a digital-to-analog converter (DAC), and an analog-to-digital converter (ADC), but is not limited to such a microcomputer. In another embodiment, the first control circuit 18 may comprise an additional microcomputer. In yet another embodiment, the first control circuit 18 may comprise a logic circuit (or wired logic connection) comprising a plurality of electronic components in addition to, or instead of, a microcomputer. In yet another embodiment, the first control circuit 18 may comprise a GPU, ASIC, ASSP, and / or PLD in addition to, or instead of, a microcomputer.

[0055] The measurement circuit 19 is configured to measure (i) the battery voltage Vbat, (ii) all the individual voltages of the first to nth battery modules 25a1 to 25an (hereinafter referred to as the first to nth module voltages Vmj1 to Vmjn, respectively), and (iii) the voltage across the shunt resistor R1 (i.e., the magnitude of the charging current Ichg or the discharging current Idis). The measurement circuit 19 is also configured to transmit a series of measurements indicating (i) the battery voltage Vbat, (ii) the first to nth module voltages Vmj1 to Vmjn, and (iii) the voltage across the shunt resistor R1, respectively, to the first control circuit 18 via serial communication with the first control circuit 18. In addition, the measurement circuit 19 is configured to balance the first to nth module voltages Vmj1 to Vmjn.

[0056] Specifically, the measurement circuit 19 is an AFE, but is not limited to an AFE. In another embodiment, the measurement circuit 19 may be a BMU, BMS, battery protection circuit, PLD, microcomputer, or any combination thereof.

[0057] The first control circuit 18 is configured (or programmed) to recognize, based on a series of received measurements, (i) the battery voltage Vbat, (ii) the first to nth module voltages Vmj1 to Vmjn, and (iii) the voltage across the shunt resistor R1. In another embodiment, the first control circuit 18 may be integrated with a measurement circuit 19.

[0058] The charge level display circuit 20 is configured to receive a display control signal from the first control circuit 18 and to display the charge level of the battery pack 1 (more specifically, the battery pack 16) via a light source (e.g., a light-emitting diode (LED)), a 7-segment display, and / or a liquid crystal display (LCD) according to the received display control signal. The display control signal identifies a display pattern corresponding to the battery voltage Vbat recognized by the first control circuit 18. In another embodiment, the charge level display circuit 20 may be omitted from the battery pack 1.

[0059] The first temperature measurement circuit 21 is configured to measure the temperature of the battery pack 16 (or at least one of the first to nth battery modules 25a1 to 25an) (hereinafter referred to as battery temperature Tbat) using a temperature sensing element (e.g., a thermistor) not shown, and to transmit a first temperature measurement signal to the first control circuit 18. The first temperature measurement signal is an analog signal having a variable voltage corresponding to the battery temperature Tbat. The first control circuit 18 is configured (or programmed) to recognize the battery temperature Tbat based on the voltage of the first temperature measurement signal. In another embodiment, the first temperature measurement circuit 21 may be omitted from the battery pack 1. Such a circuit configuration is not recommended but is included in the present disclosure.

[0060] The connection detection circuit 22 is configured to detect whether or not the second power supply voltage Vcc is supplied to the Vcc input terminal 14 and to transmit a connection detection signal to the first control circuit 18. The connection detection signal is a digital signal, more specifically, a negative logic signal (or active-low signal). The connection detection circuit 22 is configured to (i) assert the connection detection signal in response to whether the second power supply voltage Vcc is supplied to the Vcc input terminal 14, and (ii) negate the connection detection signal in response to whether the second power supply voltage Vcc is not supplied to the Vcc input terminal 14. The first control circuit 18 is configured (or programmed) to (i) recognize that the battery pack 1 is connected to the charger 5 in response to receiving an asserted connection detection signal, and (ii) recognize that the battery pack 1 is not connected to the charger 5 in response to receiving a negated connection detection signal. In another embodiment, the connection detection signal may be a positive logic signal (or active-high signal).

[0061] The notification signal generation circuit 23 is configured to receive a current control signal from the first control circuit 18 and generate a notification signal corresponding to the received current control signal. The first control circuit 18 is configured (or programmed) to change the current control signal according to the required value of the charging current Ichg or the discharging current Idis. Specifically, the current control signal is a pulse width modulation (PWM) signal, but is not limited to a PWM signal. The notification signal may be an analog signal, a digital signal with positive or negative logic, or a pulse train signal.

[0062] 2-1-2. Charger Circuit Configuration As shown in Figure 2, the charger 5 includes a second positive terminal 31, a second negative terminal 32, a second data communication terminal 33, a Vcc output terminal 34, a signal input terminal 35, a second positive-side current path Lp2, a second negative-side current path Ln2, a pull-up resistor R2, a second control circuit 36, a second power supply circuit 37, an AC voltage measurement circuit 38, a second temperature measurement circuit 39, and a current measurement circuit 40.

[0063] The second positive terminal 31 is connected to a second positive-side current path Lp2 that extends from the second positive terminal 31 to the positive terminal 37a of the second power supply circuit 37, and is therefore electrically connected to the positive terminal 37a of the second power supply circuit 37. The second positive terminal 31 is configured to be detachably connected to the first positive terminal 11 of the battery pack 1 connected to the charger 5.

[0064] The second negative terminal 32 is connected to a second negative-side current path Ln2 that extends from the second negative terminal 32 to the negative terminal 37b of the second power supply circuit 37, and is therefore electrically connected to the negative terminal 37b of the second power supply circuit 37. The second negative terminal 32 is configured to be detachably connected to the first negative terminal 12 of the battery pack 1 connected to the charger 5. Therefore, when the battery pack 1 is connected to the charger 5, the second negative-side current path Ln2 is connected to the ground of the battery pack, and the charger 5 shares the same reference potential as the battery pack.

[0065] The second positive-side current path Lp2 and the second negative-side current path Ln2 are each configured to transmit the charging current Ichg. The second negative-side current path Ln2 is also connected to the second control circuit 36, the AC voltage measurement circuit 38, and the second temperature measurement circuit 39, and serves as the reference potential for these circuits.

[0066] The second data communication terminal 33 is connected to the second control circuit 36. The second data communication terminal 33 is also configured to be detachably connected to the first data communication terminal 13 of the battery pack 1, which is connected to the charger 5. The second data communication terminal 33 is a terminal for serial communication between the second control circuit 36 ​​and the first control circuit 18 in the battery pack 1 connected to the charger 5.

[0067] The Vcc output terminal 34 is configured to receive a second power supply voltage Vcc from the second power supply circuit 37. Furthermore, the Vcc output terminal 34 is configured to be detachably connected to the Vcc input terminal 14 of the battery pack 1, which is connected to the charger 5.

[0068] The signal input terminal 35 is configured to receive a second power supply voltage Vcc via a pull-up resistor R2. The signal input terminal 35 is also configured to be detachably connected to the notification signal output terminal 15 of the battery pack 1, which is connected to the charger 5. In this configuration, the signal input terminal 35 has a voltage equal to the second power supply voltage Vcc when (i) the charger 5 is not connected to the battery pack 1, and (ii) the signal input terminal 35 is open. When the charger 5 is connected to the battery pack 1, the voltage at the signal input terminal 35 falls below the second power supply voltage Vcc because the signal input terminal 35 is electrically connected to the notification signal generation circuit 23 of the battery pack 1 (in other words, the signal input terminal 35 is not open).

[0069] The second control circuit 36 ​​is configured to transmit and receive various signals between the second control circuit 36 ​​and other circuits to perform various controls related to charging the battery pack 1. Specifically, the second control circuit 36 ​​is a microcomputer comprising a CPU, memory, I / O ports, SCI, DAC, and ADC, but is not limited to such a microcomputer. In another embodiment, the second control circuit 36 ​​may comprise an additional microcomputer. In yet another embodiment, the second control circuit 36 ​​may comprise, in addition to or instead of a microcomputer, a logic circuit (or wired logic connection) comprising a plurality of electronic components. In yet another embodiment, the second control circuit 36 ​​may comprise, in addition to or instead of a microcomputer, a GPU, ASIC, ASSP, and / or PLD.

[0070] The aforementioned signal input terminal 35 is also connected to a second control circuit 36. The second control circuit 36 ​​is configured (or programmed) to (i) recognize that the charger 5 is not connected to the battery pack 1 when the signal input terminal 35 has a voltage equal to the second power supply voltage Vcc, and (ii) recognize that the charger 5 is connected to the battery pack 1 when the signal input terminal 35 has a voltage lower than the second power supply voltage Vcc.

[0071] The second power supply circuit 37 is a switching power supply circuit (or switching AC-DC converter) configured to receive AC power having 100-130 volts AC or 220-240 volts AC from an external power supply (not shown), and to generate (i) a second power supply voltage Vcc, (ii) a charging voltage Vchg, and (iii) a charging current Ichg based on the received AC power. The second power supply voltage Vcc is supplied to (i) the Vcc output terminal 34 and (ii) the pull-up resistor R2, as described above. The charging voltage Vchg is applied between the second positive-side current path Lp2 and the second negative-side current path Ln2 via the positive and negative terminals of the second power supply circuit 37. The charging voltage Vchg is 18 volts DC, but is not limited to 18 volts. In another embodiment, the charging voltage Vchg may be 40 volts DC, 14.4 volts DC, or 10.8 volts DC.

[0072] In addition, the second power supply circuit 37 is configured to receive a PWM signal from the second control circuit 36 ​​and to change the magnitude of the charging current Ichg according to the received PWM signal. The second control circuit 36 ​​is configured (or programmed) to change the duty cycle of the PWM signal in relation to the received notification signal.

[0073] The AC voltage measurement circuit 38 is configured to measure the AC voltage Vac supplied to the second power supply circuit 37 and transmit the AC voltage measurement signal to the second control circuit 36. The AC voltage measurement signal is an analog signal having a variable voltage corresponding to the magnitude of the measured AC voltage Vac. The second control circuit 36 ​​is configured (or programmed) to transmit a PWM signal to the second power supply circuit 37 that reduces or stops the charging current Ichg depending on whether the AC voltage measurement signal has a voltage that deviates from its appropriate range. In another embodiment, the AC voltage measurement circuit 38 may be omitted from the charger 5. Such a circuit configuration is not recommended but is included in the present disclosure.

[0074] The second temperature measurement circuit 39 is configured to measure the temperature of the second power supply circuit 37 using a temperature sensing element (e.g., a thermistor) not shown, and to transmit a second temperature measurement signal to the second control circuit 36. The second temperature measurement signal is an analog signal having a variable voltage corresponding to the temperature of the second power supply circuit 37. The second control circuit 36 ​​is configured (or programmed) to transmit a PWM signal to the second power supply circuit 37 that reduces or stops the charging current Ichg in response to (i) the second temperature measurement signal having a voltage that deviates from its appropriate level, or (ii) the second temperature measurement signal having a rapidly changing voltage. In another embodiment, the second temperature measurement circuit 39 may be omitted from the charger 5. Such a circuit configuration is not recommended but is included in the present disclosure.

[0075] The current measurement circuit 40 is provided on the second negative electrode side current path Ln2 so that the charging current Ichg passes through the current measurement circuit 40. The current measurement circuit 40 is configured to (i) measure the magnitude of the charging current Ichg and (ii) transmit a charging current measurement signal Sch to the second control circuit 36. The charging current measurement signal Sch is an analog signal having a variable voltage corresponding to the magnitude of the charging current Ichg. The current measurement circuit 40 may include a shunt resistor (not shown) on the second negative electrode side current path Ln2.

[0076] The following describes in detail the various processes performed by the first control circuit 18 of the battery pack 1. 2-1-3. Charging status detection process The first control circuit 18 repeatedly performs the charge state detection process shown in Figure 3 during its operation. The operation of the first control circuit 18 may be started, for example, when the first power supply voltage Vdd generated by the first power supply circuit 17 is supplied to the first control circuit 18. In other words, the battery pack 1 may be configured to start the charge information detection process in response to the supply of the first power supply voltage Vdd and the activation of the first control circuit 18.

[0077] In the charge state detection process, the first control circuit 18 first determines whether the battery pack 16 is discharging at S110 (where S represents a step). Specifically, the first control circuit 18 determines whether the battery pack 16 is discharging based on the measured value of the discharge current Idis received from the measurement circuit 19. Specifically, the first control circuit 18 determines that (i) the battery pack 16 is discharging if the measured value of the discharge current Idis exceeds a predetermined minimum value, and (ii) the battery pack 16 is not discharging if this measured value is less than or equal to the minimum value. In another embodiment, the first control circuit 18 may determine that the battery pack 16 is discharging in response to the first control circuit 18 receiving an arbitrary signal from the field electrical equipment indicating that the field electrical equipment is operating (for example, a signal indicating that a trigger switch is being operated).

[0078] If the battery pack 16 is not discharged (S110: NO), the first control circuit 18 proceeds to S130. If the battery pack 16 is discharged (S110: YES), the first control circuit 18 proceeds to S120.

[0079] In S120, the first control circuit 18 initializes the first to nth pre-charge OCVa1 to OCVan (collectively referred to as pre-charge OCVa in Figure 3) and the first to nth post-charge OCVb1 to OCVbn (collectively referred to as post-charge OCVb in Figure 3) to null values ​​(or zero). The first to nth pre-charge OCVa1 to OCVan are variables for storing the measured values ​​of the first to nth module voltages Vmj1 to Vmjn when the first to nth battery modules 25a1 to 25an are open before charging starts (i.e., when nothing is connected to the battery pack 1, or when something is connected but no charge / discharge current is flowing). The first to nth post-charge OCVb1 to OCVbn are variables for storing the measured values ​​of the first to nth module voltages Vmj1 to Vmin when the first to nth battery modules 25a1 to 25an are open after charging is complete (i.e., nothing is connected to battery pack 1, or something is connected but no charge / discharge current is flowing).

[0080] In the subsequent S130, the first control circuit 18 determines whether the first memory condition is met. The first memory condition is met if (i) the battery pack 16 is not discharged, and (ii) the first to nth module voltages Vmj1 to Vmjn are stable (i.e., the first to nth module voltages Vmj1 to Vmjn are not fluctuating).

[0081] If the first storage condition is not met (S130: NO), the first control circuit 18 proceeds to S150. If the first storage condition is met (S130: YES), the first control circuit 18 proceeds to S140 and stores the measured values ​​of the first to nth module voltages Vmj1 to Vmjn in the first to nth pre-charge OCVa1 to OCVan, respectively. In other words, in S140, the first control circuit 18 stores the first to nth pre-charge OCVa1 to OCVan based on the measured values ​​of the first to nth module voltages Vmj1 to Vmjn.

[0082] In the subsequent S150, the first control circuit 18 determines whether the charger 5 is connected to the battery pack 1. If the charger 5 is not connected to the battery pack 1 (S150: NO), the first control circuit 18 returns to S110.

[0083] If the charger 5 is connected to the battery pack 1 (S150: YES), the first control circuit 18 proceeds to S160 and starts charging the battery pack 1 (specifically, the battery pack 16) with the charger 5. Specifically, the first control circuit 18 outputs a current control signal to the notification signal generation circuit 23 that corresponds to the requested value of a charging current Ichg greater than 0 amperes. In response to such a current control signal, a notification signal corresponding to the current control signal is output from the notification signal generation circuit 23 to the second control circuit 36 ​​of the charger 5, and charging of the battery pack 1 begins. In addition, the first control circuit 18 initializes the integrated charging current value Si to zero. The integrated charging current value Si is a variable that represents the sum of the charging currents Ichg that have flowed into the battery pack 16.

[0084] In the subsequent S170, the first control circuit 18 determines whether or not the battery pack 16 is being charged. Specifically, the first control circuit 18 determines whether or not the battery pack 16 is being charged based on the current control signal (more specifically, its duty cycle) transmitted to the notification signal generation circuit 23. In another embodiment, the first control circuit 18 may determine whether or not the battery pack 16 is being charged based on the measured value of the charging current Ichg received from the measurement circuit 19.

[0085] If the battery pack 16 is being charged (S170: YES), the first control circuit 18 proceeds to S180, adds the measured value of the charging current Ich received from the measurement circuit 19 to the integrated charging current Si, and returns to S170.

[0086] If the battery pack 16 is not being charged (S170: NO), the first control circuit 18 proceeds to S190 to determine whether the second memory condition is met. The second memory condition is met if (i) the battery pack 16 is not discharging, and (ii) the measured values ​​of the first to nth module voltages Vmj11 to Vmjn are not fluctuating.

[0087] If the second memory condition is not met (S190: NO), the first control circuit 18 returns to S110. If the second storage condition is met (S190: YES), the first control circuit 18 proceeds to S200 and stores the measured values ​​of the first to nth module voltages Vmj1 to Vmjn in the first to nth post-charged OCVb1 to OCVbn, respectively. In other words, in S200, the first control circuit 18 stores the first to nth post-charged OCVb1 to OCVbn based on the measured values ​​of the first to nth module voltages Vmj1 to Vmjn.

[0088] In the subsequent S210, the first control circuit 18 determines whether the first to nth pre-charge OCVa1 to OCVan are stored. Specifically, it determines whether the first to nth pre-charge OCVa1 to OCVan are null values ​​(or zero). If the first to nth pre-charge OCVa1 to OCVan are null values ​​(or zero), the first control circuit 18 determines that they are not stored, and if the first to nth pre-charge OCVa1 to OCVan are not null values ​​(or zero), it determines that they are stored.

[0089] If the first to nth pre-charge OCVa1 to OCVan values ​​are not stored (S210: NO), the first control circuit 18 returns to S110. If the first to nth pre-charge OCVa1 to OCVan values ​​are stored (S210: YES), the first control circuit 18 proceeds to S220 and executes the diagnostic process.

[0090] 2-1-4. Diagnostic Processing In the diagnostic process, the first control circuit 18 derives the first to nth pre-charge SOCa1 to SOCan (collectively referred to as pre-charge SOCa in Figure 4) in S310. The first to nth pre-charge SOCa1 to SOCan are variables for storing the pre-charge rate of the first to nth battery modules 25a1 to 25an.

[0091] Specifically, the first control circuit 18 (i) derives the first to nth pre-charge SOCa1 to SOCan based on a lookup table pre-set in the first control circuit 18. This lookup table associates the open-circuit voltages of the first to nth battery modules 25a1 to 25an with the charge levels of the first to nth battery modules 25a1 to 25an, based on the open-circuit voltage (OCV) characteristics with respect to the state of charge (SOC) as shown in Figure 5. Therefore, the first control circuit 18 (i) obtains the charge levels corresponding to the first to nth pre-charge OCVa1 to OCVan from the lookup table, and (ii) stores the obtained charge levels in the first to nth pre-charge SOCa1 to SOCan, respectively. In another embodiment, the first control circuit 18 may (i) calculate the charge rate corresponding to the first to nth pre-charge OCVa1 to OCVan based on a function representing the characteristics shown in Figure 5, and (ii) store the calculated charge rates in the first to nth pre-charge SOCa1 to SOCan, respectively.

[0092] In the subsequent S320, the first control circuit 18 derives the first to nth post-charge SOCb1 to SOCbn (collectively referred to as post-charge SOCb in Figure 4). The first to nth post-charge SOCb1 to SOCbn are variables for storing the post-charge rate of the first to nth battery modules 25a1 to 25an.

[0093] Specifically, the first control circuit 18, similar to S310, (i) obtains the charge rates corresponding to the first to nth post-charged OCVb1 to OCVbn from a lookup table, and (ii) stores the obtained charge rates in the first to nth post-charged SOCb1 to SOCbn, respectively. In another embodiment, the first control circuit 18 may (i) calculate the charge rates corresponding to the first to nth post-charged OCVb1 to OCVbn based on the function representing the characteristics shown in Figure 5, and (ii) store the calculated charge rates in the first to nth post-charged SOCb1 to SOCbn, respectively.

[0094] In the subsequent S330, the first control circuit 18 calculates the first to nth charge difference values ​​Dfa1 to Dfan (collectively referred to as the charge difference value Dfa in Figure 4). Each of the first to nth charge difference values ​​Dfa1 to Dfan corresponds to the difference between one of the first to nth pre-charge SOCa1 to SOCan and the corresponding one of the first to nth post-charge SOCb1 to SOCbn. In another embodiment, the first control circuit 18 may calculate any one of the first to nth charge difference values ​​Dfa1 to Dfan.

[0095] In the subsequent S340, the first control circuit 18 determines whether all of the charge rate difference values ​​Dfa1 to Dfan for the first to nth battery modules are greater than a preset first threshold Th1. The first threshold Th1 is an arbitrary threshold for determining whether the charge rate of each of the first to nth battery modules 25a1 to 25an has increased sufficiently to detect a malfunction in the first to nth battery modules 25a1 to 25an. The first threshold Th1 may be set to a predetermined percentage. Specifically, the first threshold Th1 may be 25%, 50%, or 75%.

[0096] If any of the first to nth charge rate difference values ​​Dfa1 to Dfan is less than or equal to the first threshold Th1 (S340: NO), the first control circuit 18 immediately terminates the diagnostic process. If all of the charge rate difference values ​​Dfa1 to Dfan from the first to the nth are greater than the first threshold Th1 (S340: YES), the first control circuit 18 proceeds to S350.

[0097] In S350, the first control circuit 18 calculates the first to nth full charge capacities FCC1 to FCCn (collectively referred to as full charge capacity FCC in Figure 4) for each of the first to nth battery modules 25a1 to 25an. Specifically, the first control circuit 18 calculates the first to nth full charge capacities FCC1 to FCCn based on the integrated charging current Si, the first to nth pre-charging SOCa1 to SOCan, the first to nth post-charging SOCb1 to SOCbn, and the following equation 1.

[0098]

number

[0099] In the subsequent S360, the first control circuit 18 calculates the capacity difference value Dfb. The capacity difference value corresponds to the difference between the maximum and minimum values ​​of the first to nth full charge capacities FCC1 to FCCn.

[0100] In the subsequent S370, the first control circuit 18 determines whether the capacity difference value Dfb is greater than a pre-set second threshold Th2. The second threshold Th2 is set based on the difference between the full charge capacity of a normal battery module and the full charge capacity of a faulty battery module.

[0101] If the capacity difference value Dfb is less than the second threshold Th2 (S370: NO), the first control circuit 18 terminates the diagnostic process. If the capacity difference value Dfb is greater than or equal to the second threshold Th2 (S370: YES), the first control circuit 18 proceeds to S380 and executes the fault correction process (S380).

[0102] In the fault response process, the first control circuit 18 may count up the number of times it has detected a fault in any of the first to nth battery modules 25a1 to 25an. When this count reaches a predetermined number, the first control circuit 18 may execute a process to disable the battery pack 1. More specifically, the first control circuit 18 may transmit a prohibition signal to prohibit charging and discharging of the battery pack 1. This prohibition signal can prevent charging by the charger 5 connected to the battery pack 1, or discharging to field electrical equipment connected to the battery pack 1.

[0103] Alternatively, the first control circuit 18 may store data that identifies the battery module having the minimum full charge capacity. In this case, the faulty battery module can be identified retrospectively.

[0104] 2-1-5. Effects in the First Embodiment The effects of this first embodiment will be explained with reference to Figure 6. In Figure 6, the full charge capacity of a normal battery module 25 is the sum of the full charge capacities of the first to fourth cells 26a to 26d. In contrast, in a faulty battery module 25, one of the first to fourth cells 26a to 26d (the fourth cell 26d) is electrically disconnected from the remaining cells (the first to third cells 26a to 26c). In this case, the full charge capacity of the faulty battery module 25 is the sum of the individual charge capacities of the first to third cells 26a to 26c.

[0105] Therefore, a difference equivalent to the full charge capacity of the fourth cell 26d will occur between the full charge capacity of a normal battery module 25 and the full charge capacity of a faulty battery module 25.

[0106] In other words, the full charge capacity of the battery module 25 is proportional to the number of normal cells 26. Therefore, if at least one of the first to fourth cells 26a to 26d malfunctions, the capacity will decrease in proportion to the number of malfunctioning cells 26 compared to when all of the first to fourth cells 26a to 26d are normal.

[0107] Therefore, for example, by setting the second threshold Th2 to 90% of the full charge capacity of cell 26, it is possible to detect that a malfunction has occurred in at least one of the first to nth battery modules 25a to 25n.

[0108] Therefore, the measurement circuit 19 balances the first to nth battery modules 25a1 to 25an, which prevents the faulty battery module from being overcharged, and consequently prevents the battery pack 1 from malfunctioning.

[0109] Examples of the malfunctions described above include the electrical disconnection of any of the first to fourth cells 26a to 26d from the remaining cells, more specifically, the detachment of a spot weld, and the disconnection of the current collector inside any of the first to fourth cells 26a to 26d from its positive or negative terminal.

[0110] 2-1-6. Correspondence between terms In this first embodiment, the capacity difference value Dfb corresponds to an example of a difference value in the summary of the embodiment, and the second threshold Th2 corresponds to an example of a first threshold in the summary of the embodiment.

[0111] 2-2. Second Embodiment This second embodiment corresponds to a partially modified first embodiment. More specifically, this second embodiment differs from the first embodiment in that the first control circuit 18 receives the measured value of the charging current Ichg from the charger 5, rather than from the measurement circuit 19. Therefore, the following description will focus only on the differences from the first embodiment.

[0112] In the second embodiment, the charger 5 is configured such that the second control circuit 36 ​​transmits the magnitude of the charging current Ichg detected by the current measurement circuit 40 to the battery pack 1 (specifically, the first control circuit 18) via serial communication. At this time, the second control circuit 36 ​​transmits the magnitude of the charging current Ichg to the first control circuit 18 via the first data communication terminal 13 and the second data communication terminal 33.

[0113] Furthermore, the "magnitude of the charging current Ichg" that the charger 5 transmits to the battery pack 1 (specifically, the first control circuit 18) may be the "magnitude of the charging current Ichg" that the second control circuit 36 ​​notifies the second power supply circuit 37 of using a PWM signal. As described in the first embodiment, the second power supply circuit 37 is configured to change the magnitude of the charging current Ichg according to the PWM signal received from the second control circuit 36. In other words, the second control circuit 36 ​​has information on the "magnitude of the charging current Ichg" as a command value for the second power supply circuit 37. Therefore, without detecting the magnitude of the charging current Ichg in the current measurement circuit 40, the second control circuit 36 ​​may transmit the "magnitude of the charging current Ichg" that it notifies the second power supply circuit 37 of via serial communication to the battery pack 1 (specifically, the first control circuit 18).

[0114] Battery pack 1 is configured such that the "magnitude of charging current Ichg" used in S170 and S180 is the magnitude of charging current Ichg received from charger 5, not the magnitude of charging current Ichg received from measurement circuit 19.

[0115] With the battery pack 1 configured in this way, the first control circuit 18 can detect a malfunction in the battery module 25 using the "magnitude of the charging current Ichg" received from the charger 5.

[0116] In another embodiment, the shunt resistor R1 may be omitted from the battery pack 1. Such a circuit configuration is not recommended but is included in this disclosure. 2-3. Third Embodiment This third embodiment corresponds to a partially modified first embodiment. More specifically, this third embodiment differs from the first embodiment in some aspects of the diagnostic process. Therefore, the following description will focus only on the parts that differ from the first embodiment.

[0117] The diagnostic process of the third embodiment differs from the diagnostic process of the first embodiment in that it detects a malfunction in the battery module based on the "ratio" (capacity ratio Rfa = FCC maximum value / FCC minimum value) between the maximum and minimum values ​​of the first to nth fully charged capacities FCC1 to FCCn.

[0118] As shown in Figure 7, the processes S410-S450 and S480 in the diagnostic process of the third embodiment are the same as the processes S310-S350 and S380 in the first embodiment. In the third embodiment, at S460, the first control circuit 18 calculates the capacity ratio Rfa. The capacity ratio Rfa corresponds to the ratio between the maximum and minimum values ​​of the first to nth fully charged capacities FCC1 to FCCn (capacity ratio Rfa = FCC maximum value / FCC minimum value).

[0119] In the subsequent S470, the first control circuit 18 determines whether the capacity ratio Rfa is greater than a preset third threshold Th3. The third threshold Th3 is set based on the ratio of the full charge capacity of a normal battery module to the full charge capacity of a faulty battery module.

[0120] If the capacity ratio Rfa is less than or equal to the third threshold Th3 (S470: NO), the first control circuit 18 terminates the diagnostic process. If the capacity ratio Rfa is greater than the third threshold Th3 (S470: YES), the first control circuit 18 proceeds to S480 and executes the fault correction process (S480).

[0121] The third threshold Th3 may be set based on the ratio (=normal capacity FCCa / faulty capacity FCCb) of the full charge capacity FCC of a normal battery module (normal capacity FCCa) to the full charge capacity FCC of a faulty battery module. For example, the third threshold Th3 may be set to a value determined to identify a faulty battery module based on the ratio (=normal capacity FCCa / faulty capacity FCCb).

[0122] For example, if one of the first to fourth cells 26a to 26d is electrically disconnected from the remaining cells, the ratio (= normal capacity FCCa / faulty capacity FCCb) becomes "ratio = 4 / 3 ≈ 1.33". If two cells are electrically disconnected from the remaining cells, the ratio becomes "ratio = 4 / 2 = 2.0". For this reason, the third threshold Th3 may be set to "1.30", and the capacity ratio Rfa may be compared with the third threshold Th3 to determine whether or not there is a faulty battery module among the first to nth modules 25a1 to 25an. In other words, the first control circuit 18 may determine that a fault has occurred in the battery module with the smallest fully charged capacity among the first to nth modules 25a1 to 25an when the capacity ratio Rfa exceeds the third threshold Th3.

[0123] As a result, the battery pack of the third embodiment can detect that a malfunction has occurred in at least one of the first to nth battery modules 25a1 to 25an. In the third embodiment, as in the first embodiment, the measurement circuit 19 balances the first to nth battery modules 25a1 to 25an, thereby suppressing overcharging of faulty battery modules and ultimately preventing damage to the battery pack 1.

[0124] To explain the correspondence between terms, the volume ratio Rfa corresponds to an example of a ratio in the summary of the embodiment, and the third threshold Th3 corresponds to an example of a second threshold in the summary of the embodiment. 2-4. Further Embodiments Although embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above and can be implemented in various modified forms.

[0125] (1) In one of the further embodiments, the first control circuit 18 may calculate the deviations of the first to nth full charge capacities FCC1 to FCCn (hereinafter referred to as the first to nth capacity deviations Dvc1 to Dvcn), and based on the first to nth capacity deviations Dvc1 to Dvcn, it may detect that a malfunction has occurred in at least one of the first to nth battery modules 25a1 to 25an.

[0126] Specifically, the first control circuit 18 may calculate the first to nth capacity deviations Dvc1 to Dvcn in S360 of the first embodiment. More specifically, the first control circuit 18 may calculate the average value of the first to nth full charge capacities FCC1 to FCCn (hereinafter referred to as the average capacity Avc). In addition, the first control circuit 18 may calculate the first to nth capacity deviations Dvc1 to Dvcn by subtracting the average capacity Avc from the first to nth full charge capacities FCC1 to FCCn (full charge capacity FCC - average capacity Avc).

[0127] In the following S370, the first control circuit 18 may determine whether there is a faulty battery module among the first to nth battery modules 25a1 to 25an based on the first to nth capacity deviations Dvc1 to Dvcn. More specifically, the first control circuit 18 may determine whether each of the first to nth capacity deviations Dvc1 to Dvcn is smaller than a preset fourth threshold Th4.

[0128] The fourth threshold Th4 may be set to a value between the capacity deviation Dvc of a normal battery module (hereinafter also referred to as the normal capacity deviation FCCc) and the capacity deviation Dvc of a defective battery module (hereinafter also referred to as the defective capacity deviation FCCd). For example, the fourth threshold Th4 may be set to the midpoint between the normal capacity deviation FCCc and the defective capacity deviation FCCd (= (normal capacity deviation FCCc - defective capacity deviation FCCd) / 2 + defective capacity deviation FCCd). In other words, the fourth threshold Th4 may be set to a value determined to identify a defective battery module based on the normal capacity deviation FCCc and the defective capacity deviation FCCd.

[0129] (2) In one of the further embodiments, the first control circuit 18 may determine, using a predetermined reference value LV, whether or not there is a defective battery module among the first to nth battery modules 25a1 to 25an when the battery pack 16 has been fully charged to its full capacity without being stopped during charging.

[0130] For example, the first control circuit 18 may perform a diagnostic process in which, in the diagnostic process of the first embodiment, S330 is omitted and S340 is modified to determine whether the post-charge SOCb is greater than or equal to the fifth threshold Th5. In this case, the fifth threshold Th5 may be set to a value equivalent to 100% of the rated capacity of each of the first to nth battery modules 25a1 to 25an. As a result, if the battery pack 16 is fully charged and the post-charge SOCb is greater than or equal to the fifth threshold Th5 (S340: YES), the first control circuit 18 proceeds to S350. If the battery pack 16 is not fully charged and the post-charge SOCb is less than the fifth threshold Th5 (S340: NO), the first control circuit 18 immediately terminates the diagnostic process.

[0131] Furthermore, the first control circuit 18 may identify the battery module corresponding to the minimum value (FCC minimum value) among the first to nth full charge capacities FCC1 to FCCn in S360 of the diagnostic process of the first embodiment.

[0132] Furthermore, in step S370 of the diagnostic process in the first embodiment, the first control circuit 18 may compare the minimum FCC value with the reference value LV to determine whether or not there is a faulty battery module among the first to nth battery modules 25a1 to 25an. Specifically, in step S370, the first control circuit 18 may compare the minimum FCC value with the reference value LV to determine whether or not the minimum FCC value is smaller than the reference value LV (minimum FCC value < reference value LV). In other words, the first control circuit 18 executing step S370 may determine whether or not there is a faulty battery module among the first to nth battery modules 25a1 to 25an based on the comparison result between the minimum FCC value and the reference value LV. If in step S370 the minimum FCC value is less than the reference value LV (S370: YES), the first control circuit 18 may proceed to step S380. In S370, if the minimum FCC value is equal to or greater than the reference value LV (S370: NO), the first control circuit 18 may immediately terminate the diagnostic process. If the minimum FCC value is less than the reference value LV (S370: YES), it means that a faulty battery module exists. If the minimum FCC value is equal to or greater than the reference value LV (S370: NO), it means that no faulty battery modules exist.

[0133] The reference value LV may be set to a value determined based on the rated capacity of each of the first to nth battery modules 25a1 to 25an. For example, the reference value LV may be set to a value equivalent to 80% of the rated capacity of each of the first to nth battery modules 25a1 to 25an.

[0134] 2-5. Supplementary Information Multiple functions achieved by one component in the above embodiment may be achieved by multiple components, and one function achieved by one component may be achieved by multiple components. Also, multiple functions achieved by multiple components may be achieved by one component, and one function achieved by multiple components may be achieved by one component. Furthermore, some of the configurations of the above embodiment may be omitted. Also, at least some of the configurations of one embodiment may be added to or replaced by other configurations of one embodiment. [Explanation of Symbols]

[0135] 2...Battery pack, 5...Charger, 11...First positive terminal, 12...First negative terminal, 13...First data communication terminal, 14...Vcc input terminal, 15...Notification signal output terminal, 16...Battery pack, 18...First control circuit, 19...Measurement circuit, 20...Charge level display circuit, 23...Notification signal generation circuit, 25...Battery module, 26...Battery cell, 31...Second positive terminal, 32...Second negative terminal, 33...Second data communication terminal, 34...Vcc output terminal, 35...Signal input terminal, 36...Second control circuit, 40...Current measurement circuit, Ln1...First negative side current path, Ln2...Second negative side current path, Lp1...First positive side current path, Lp2...Second positive side current path.

Claims

1. A battery pack for on-site electrical equipment, A first positive terminal and a first negative terminal configured to receive charging power from a charger, (i) First to nth battery modules (n is any natural number of 2 or more) that are connected in series in order and (ii) are configured to be charged by the charging power, each of the first to nth battery modules comprises a plurality of rechargeable battery cells connected in parallel, the first battery module comprises a second positive terminal connected to the first positive terminal, and the nth battery module comprises a second negative terminal connected to the first negative terminal, (i) A control circuit configured to derive the full charge capacity of each of the first to n battery modules based on the respective measured values ​​relating to the charge state of each of the first to n battery modules, and (ii) to detect a malfunction in at least one of the first to n battery modules based on the derived full charge capacity, A battery pack equipped with this feature.

2. The battery pack according to claim 1, further, (i) A measuring circuit configured to measure the voltage value of each of the first to nth battery modules, and (ii) transmit each of the voltage values, The control circuit is configured to receive the respective voltage values ​​from the measurement circuit as part of the respective measured values. Battery pack.

3. A battery pack according to claim 2, The measurement circuit is configured to (i) measure a current value corresponding to the magnitude of the charging current supplied from the charger to the battery pack, and (ii) transmit the current value. The control circuit is configured to receive the current value from the measurement circuit as part of each of the measured values. Battery pack.

4. A battery pack according to claim 2, The charger is configured to transmit a current value corresponding to the magnitude of the charging current supplied from the charger to the battery pack. The control circuit is configured to receive the current value from the charger as part of each of the measured values. Battery pack.

5. A battery pack according to claim 3 or claim 4, The aforementioned control circuit is The cumulative value of the current value from the start to the end of charging of the battery pack is derived, Based on the pre-charge voltage values ​​of each of the first to n battery modules and the post-charge voltage values ​​of each of the first to n battery modules, the pre-charge rate and the post-charge rate of each of the first to n battery modules are derived. Based on the cumulative value, the respective pre-charge rate, and the respective post-charge rate, the respective full charge capacity is derived. It is configured in such a way, Each of the aforementioned pre-charging voltage values ​​corresponds to each of the aforementioned voltage values ​​of the first to nth battery modules before charging begins. Each of the above-mentioned post-charge voltage values ​​corresponds to each of the above-mentioned voltage values ​​after the completion of charging of the first to nth battery modules. Each of the aforementioned pre-charge rates corresponds to each of the aforementioned charge rates of the first to nth battery modules before charging begins. The respective post-charge rates mentioned above correspond to the respective charge rates of the first to nth battery modules after charging is complete. Battery pack.

6. A battery pack according to claim 5, Each of the aforementioned pre-charging voltage values ​​corresponds to the open-circuit voltage of each of the first to n battery modules before charging of the first to n battery modules begins. Each of the above post-charge voltage values ​​corresponds to the open-circuit voltage of each of the first to n battery modules after charging is complete. Battery pack.

7. A battery pack according to claim 5, Each of the aforementioned pre-charging voltage values ​​corresponds to the stable open-circuit voltage of each of the first to n battery modules before charging of the first to n battery modules begins. Each of the above post-charge voltage values ​​corresponds to the stable open-circuit voltage of each of the first to n battery modules after charging is complete. Battery pack.

8. A battery pack according to any one of claims 1 to 7, The control circuit is configured to detect the malfunction based on the difference between the largest and smallest full charge capacities among the respective full charge capacities, and a preset first threshold value. Battery pack.

9. A battery pack according to any one of claims 1 to 8, The control circuit is configured to detect the malfunction based on the ratio of the smallest full charge capacity to the largest full charge capacity among the respective full charge capacities, and a preset second threshold. Battery pack.

10. A battery pack according to any one of claims 1 to 9, The aforementioned malfunction includes, in at least one of the first to nth battery modules, that at least one of the plurality of rechargeable battery cells is electrically disconnected from the remaining rechargeable battery cells among the plurality of rechargeable battery cells. Battery pack.

11. A battery pack according to any one of claims 1 to 10, Each of the first to nth battery modules has the same rated capacity or the same nominal capacity. Battery pack.

12. A method for diagnosing battery packs for field electrical equipment, The method for deriving the full charge capacity of each of the multiple battery modules of the battery pack based on the charge state of each of the multiple battery modules, wherein the multiple battery modules are connected in series, and each of the multiple battery modules comprises multiple rechargeable battery cells connected in parallel. Based on the derived full charge capacity of each of the above, a malfunction in at least one of the plurality of battery modules is detected. A method that includes [the following features].

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