Battery pack, charger, charging system, and method of charging a battery pack with a charger

Abstract

One aspect of the present disclosure provides a battery pack including a battery module, an analog output generation circuit, and a control circuit. The control circuit is configured to (i) control the analog output generation circuit to generate an analog output voltage in accordance with a state of charge of the battery module, and (ii) transmit communication data to a charger. The communication data includes a plurality of parameters for the charger to create a relevant characteristic. The relevant characteristic associates a maximum required value of a charging current with the analog output voltage such that the maximum required value changes at a plurality of rates as the analog output voltage changes between a plurality of different voltage levels, wherein the plurality of different voltage levels are between a first voltage level and a second voltage level.

Description

Technical Field

[0001] This disclosure relates to the charging of battery packs. Background Technology

[0002] Japanese Patent No. 6767198 discloses an example of a battery pack for power tools, which includes a notification signal output circuit. This notification signal output circuit is configured to output an analog signal to a charger, the analog signal indicating the maximum charging current value that can be supplied to the battery pack. In both the battery pack and the charger, the voltage of the analog signal is correlated with the maximum charging current value, such that the maximum charging current value increases at a fixed rate as the voltage of the analog signal increases. Summary of the Invention

[0003] In recent years, the capacity (i.e., ampere-hours) of battery packs in the power tool market has been increasing, while power tool users want to shorten the charging time of battery packs. To meet this demand, it is necessary to increase the charging current.

[0004] However, in one example of the battery pack described above, if the maximum charging current is increased to shorten charging time, the rate of change of the maximum charging current relative to the analog signal voltage must also increase. In this case, the maximum charging current may change significantly with small changes in the analog signal voltage, causing the charger to be unable to accurately control the charging current.

[0005] One aspect of this disclosure aims to provide a technique that enables more precise control of a large charging current output by a charger via an analog output voltage from a battery pack.

[0006] Problem Solving Methods

[0007] In this disclosure, terms such as "first" and "second" are used only to distinguish between elements and not to limit the order or number of elements. Therefore, the first element can be called the second element, and similarly, the second element can be called the first element. Furthermore, an element can be present without the second element, and similarly, an element can be present without the first element.

[0008] One aspect of this disclosure provides a battery pack comprising a battery module, an analog output generation circuit, and a control circuit.

[0009] The battery module is configured to (i) receive charging current from a charger and (ii) be charged by the charging current.

[0010] The analog output generation circuit is configured to (i) generate an analog output voltage and (ii) output the analog output voltage to the charger. The analog output voltage varies into multiple different voltage levels, which are between a first voltage level and a second voltage level higher than the first voltage level.

[0011] The control circuit is configured to (i) control the analog output generation circuit to generate the analog output voltage according to the charging level of the battery module, and (ii) send communication data to the charger. The communication data includes multiple parameters for the charger to create relevant characteristics that correlate the maximum required value of the charging current with the analog output voltage, such that the maximum required value changes at multiple rates of change when the analog output voltage varies between multiple different voltage levels. The charger is configured to control the magnitude of the charging current by changing the maximum required value based on the analog output voltage and the relevant characteristics.

[0012] Based on the battery pack configured as described above, when the analog output voltage varies between the multiple different voltage levels, the maximum requirement in the charger can vary at the multiple rates of change, and consequently, the magnitude of the charging current can also vary at the multiple rates of change.

[0013] Therefore, if the relevant characteristics are defined in a way that causes the maximum required value to change at appropriate multiple rates of change, the battery pack can more accurately control the large charging current through the analog output voltage.

[0014] Another aspect of this disclosure provides a charger that includes a power supply circuit and a control circuit.

[0015] The power supply circuit is configured to (i) generate a charging current and (ii) output the charging current to the battery pack.

[0016] The control circuit is configured to: (i) receive an analog output voltage and communication data from the battery pack; (ii) change the maximum required value of the charging current according to the analog output voltage and multiple parameters included in the communication data; and (iii) control the power supply circuit to change the magnitude of the charging current according to the change in the maximum required value. The analog output voltage varies into multiple different voltage levels, which are between a first voltage level and a second voltage level higher than the first voltage level. The multiple parameters associate the maximum required value with the analog output voltage so that when the analog output voltage varies between the multiple different voltage levels, the maximum required value changes at multiple rates of change.

[0017] According to the charger configured as described above, when the analog output voltage varies between the multiple different voltage levels, the maximum required value can change at multiple rates of change, and consequently, the magnitude of the charging current can also change at multiple rates of change.

[0018] Therefore, if the relevant characteristics are defined in a way that causes the maximum required value to change at appropriate multiple rates of change, the charger can more accurately control the large charging current through the analog output voltage.

[0019] Another aspect of this disclosure provides a charging system comprising a battery pack and a charger.

[0020] The battery pack includes a battery module, an analog output generation circuit, and a first control circuit.

[0021] The battery module is configured to (i) receive charging current from the charger and (ii) be charged by the charging current.

[0022] The analog output generation circuit is configured to (i) generate an analog output voltage and (ii) output the analog output voltage to the charger. The analog output voltage varies into multiple different voltage levels, which are between a first voltage level and a second voltage level higher than the first voltage level.

[0023] The first control circuit is configured to (i) control the analog output generation circuit to generate the analog output voltage according to the charging level of the battery module, and (ii) send communication data to the charger. The communication data includes multiple parameters for the charger to create a correlation profile (correlation profile including a piecewise linear curve). The correlation profile correlates the maximum required value of the charging current with the analog output voltage such that the maximum required value changes at multiple rates of change when the analog output voltage varies between multiple different voltage levels.

[0024] The charger includes a power supply circuit and a second control circuit.

[0025] The power supply circuit is configured to (i) generate the charging current and (ii) output the charging current to the battery pack.

[0026] The second control circuit is configured to: (i) receive the analog output voltage and the communication data; (ii) create the relevant characteristics based on the plurality of parameters included in the communication data; (iii) change the maximum required value based on the analog output voltage and the relevant characteristics; and (iv) control the power supply circuit to change the magnitude of the charging current based on the maximum required value.

[0027] According to the charging system configured above, when the analog output voltage varies between the multiple different voltage levels, the maximum requirement in the charger can vary at the multiple rates of change, and consequently, the magnitude of the charging current can also vary at the multiple rates of change.

[0028] Therefore, if the relevant characteristics are defined in a way that causes the maximum required value to change at appropriate multiple rates of change, the charging system can more accurately control the large charging current through the analog output voltage.

[0029] Another aspect of this disclosure provides a method for charging a battery pack using a charger, the method comprising the following steps:

[0030] The battery pack outputs an analog output voltage to the charger, wherein the analog output voltage varies in multiple different voltage levels, which are between a first voltage level and a second voltage level higher than the first voltage level;

[0031] The charger receives the analog output voltage; and

[0032] In the charger, the maximum required value of the charging current for charging the battery pack is changed based on the analog output voltage and related characteristics, thereby controlling the magnitude of the charging current. The related characteristics associate the maximum required value with the analog output voltage so that the maximum required value changes at multiple rates of change when the analog output voltage varies between multiple different voltage levels.

[0033] According to the above method, if the relevant characteristic is defined in a way that causes the maximum required value to change at appropriate multiple rates of change, then the large charging current can be controlled more precisely by the analog output voltage. Attached Figure Description

[0034] Figure 1 A block diagram showing the overall structure of the charging system is provided.

[0035] Figure 2A This is a block diagram schematically showing the circuit configuration of the first battery pack; Figure 2B This is a circuit diagram showing the specific configuration of the analog output generation circuit.

[0036] Figure 3 This is a block diagram schematically showing the circuit configuration of the first charger.

[0037] Figure 4 The first relevant feature (Profile) is shown.

[0038] Figure 5 The second relevant characteristic (Profile) is shown.

[0039] Figure 6A It is part of a flowchart that shows the operation of the charging system when any one of the first to third battery packs is connected to the first charger.

[0040] Figure 6B This is another part of the flowchart, which shows the operation of the charging system when any one of the first to third battery packs is connected to the first charger.

[0041] Figure 7A It is part of a flowchart that shows the operation of the charging system when the first battery pack is connected to the second or third charger.

[0042] Figure 7B This is another part of the flowchart, which shows the operation of the charging system when the first battery pack is connected to the second or third charger.

[0043] Figure 8 This is a flowchart of the first control process executed by the first control circuit of the first battery pack.

[0044] Figure 9 This is a flowchart of the second control process executed by the second control circuit of the first charger.

[0045] Figure 10 This shows a variation of the first relevant characteristic (Profile). Detailed Implementation

[0046] 1. Overview of Implementation Methods

[0047] Some implementations may have at least one of the following features.

[0048] Feature 1: A battery pack having a battery module configured to (i) receive a charging current from a charger and (ii) be charged by the charging current;

[0049] Feature 2: The battery pack includes an analog output generation circuit, which is configured to (i) generate an analog output voltage and (ii) output the analog output voltage to the charger.

[0050] Feature 3: The analog output voltage changes into multiple different voltage levels, which are between a first voltage level and a second voltage level higher than the first voltage level;

[0051] Feature 4: The battery pack has a control circuit;

[0052] Feature 5: The control circuit is configured (or programmed) to control the analog output generation circuit to generate the analog output voltage according to the charging level of the battery module;

[0053] Feature 6: The control circuit is configured (or programmed) to send communication data to the charger;

[0054] Feature 7: The communication data includes multiple parameters for the charger to create relevant characteristics;

[0055] Feature 8: The associated characteristic correlates the maximum required value of the charging current with the analog output voltage such that the maximum required value changes at multiple rates of change when the analog output voltage varies between the multiple different voltage levels; and

[0056] Feature 9: The charger is configured to control the magnitude of the charging current by changing the maximum required value based on the analog output voltage and the related characteristics.

[0057] According to an embodiment having at least features 1 to 9, when the analog output voltage varies between the plurality of different voltage levels, the maximum required value in the charger changes with the plurality of rates of change, and consequently the magnitude of the charging current can also change with the plurality of rates of change.

[0058] Therefore, if the relevant characteristics are defined in a way that causes the maximum required value to change at appropriate multiple rates of change, the battery pack can more accurately control the large charging current through the analog output voltage.

[0059] Some implementations may include at least one of the following features in addition to at least one of features 1 to 9, or may replace at least one of features 1 to 9 with at least one of the following features.

[0060] Feature 10: The analog output voltage has an unsaturated voltage range between the first voltage level and the second voltage level, the unsaturated voltage range including the plurality of different voltage levels;

[0061] Feature 11: The unsaturated voltage range is divided into at least two voltage ranges in the relevant characteristics; and

[0062] Feature 12: In the relevant characteristics, the maximum required value varies at different rates in adjacent voltage ranges within at least two voltage ranges.

[0063] Some implementations may include at least one of the following features in addition to at least one of features 1 to 12, or may replace at least one of features 1 to 12 with at least one of the following features.

[0064] Feature 13: The control circuit is configured (or programmed) to control the analog output generation circuit so that the analog output voltage decreases as the charging level increases;

[0065] Feature 14: The at least two voltage ranges include, (i) a first voltage range, and (ii) a second voltage range adjacent to and higher than the first voltage range; and

[0066] Feature 15: In the relevant characteristics, the maximum required value has a first rate of change in the first voltage range and a second rate of change higher than the first rate of change in the second voltage range.

[0067] According to embodiments possessing at least features 1 to 15, the magnitude of the charging current can be controlled to increase the charging current when the charging level is low and decrease the charging current when the charging level is high. This control can both shorten the charging time and suppress overcharging of the battery module.

[0068] Some implementations may include at least one of the following features in addition to at least one of features 1 to 15, or may replace at least one of features 1 to 15 with at least one of the following features.

[0069] Feature 16: The second rate of change is three times the first rate of change.

[0070] Some implementations may include at least one of the following features in addition to at least one of features 1 to 16, or may replace at least one of features 1 to 16 with at least one of the following features.

[0071] Feature 17: The unsaturated voltage range is divided into twenty-four unit intervals; and

[0072] Feature 18: The total number of cell intervals included in the first voltage range is equal to the total number of cell intervals included in the second voltage range.

[0073] Some implementations may include at least one of the following features in addition to at least one of features 1 to 18, or may replace at least one of features 1 to 18 with at least one of the following features.

[0074] Feature 19: The plurality of parameters includes at least two pairs (or more) of parameters; and

[0075] Feature 20: Each of the at least two pairs of parameters includes (i) a first parameter representing the rate of change of the maximum required value, and (ii) a second parameter representing the number of unit intervals to which the rate of change represented by the first parameter applies.

[0076] According to embodiments possessing at least features 1 to 12, 17, 19, and 20, the amount of communication required for the charger to create the relevant characteristics can be reduced. Therefore, the likelihood of the charger failing to receive the communication data can be reduced, thereby enabling stable charging control between the charger and the battery pack.

[0077] Some implementations may include at least one of the following features in addition to at least one of features 1 to 20, or may replace at least one of features 1 to 20 with at least one of the following features.

[0078] Feature 21: The at least two pairs of parameters are five pairs of parameters;

[0079] Feature 22: The relevant characteristic is defined by two or more but no more than four of the five pairs of parameters; and

[0080] Feature 23: The remaining pairs of the five pairs of parameters are all represented as zero values.

[0081] According to the implementation method having at least features 1 to 12, 17, and 19 to 21, not only can simple related characteristics be defined through the multiple parameters, but also complex related characteristics can be defined.

[0082] Some embodiments may include at least one of the following features in addition to at least one of features 1 to 23, or may replace at least one of features 1 to 23 with at least one of the following features.

[0083] Feature 24: The control circuit is configured (or programmed) to send the communication data to the charger via serial communication with the charger.

[0084] Some embodiments may include at least one of the following features in addition to at least one of features 1 to 24, or may include at least one of the following features instead of at least one of features 1 to 24.

[0085] Feature 25: The analog output generation circuit includes a capacitor and a semiconductor switch; and

[0086] Feature 26: The analog output generation circuit is configured such that the capacitor is charged or discharged through the semiconductor switch to generate the analog output voltage.

[0087] According to embodiments having at least features 1 to 9, 25, and 26, a stable analog output voltage can be achieved through the capacitor.

[0088] Some embodiments may include the following features in addition to at least one of features 1 to 26, or may include the following features instead of at least one of features 1 to 26.

[0089] Feature 27: The control circuit is configured (or programmed) to send a pulse width modulation signal having a duty cycle corresponding to the maximum required value to the semiconductor switch to control the switching operation of the semiconductor switch.

[0090] According to embodiments having at least features 1 to 9 and 25 to 27, the analog output voltage can be controlled by the pulse width modulation signal.

[0091] Examples of the semiconductor switches include, but are not limited to, metal-oxide-semiconductor field-effect transistors (MOS FETs), junction field-effect transistors (JFETs), metal-semiconductor field-effect transistors (MESFETs), bipolar transistors, insulated-gate bipolar transistors (IGBTs), solid-state relays (SSRs), and thyristors.

[0092] Some implementations may have at least one of the following features.

[0093] Feature 28: A charger having a power supply circuit configured to (i) generate a charging current and (ii) output the charging current to a battery pack;

[0094] Feature 29: The charger has a control circuit;

[0095] Feature 30: The control circuit is configured (or programmed) to receive analog output voltage and communication data from the battery pack;

[0096] Feature 31: The control circuit is configured (or programmed) to change the maximum required value of the charging current according to the analog output voltage and multiple parameters included in the communication data;

[0097] Feature 32: The control circuit is configured (or programmed) to control the power supply circuit to change the magnitude of the charging current according to the change of the maximum required value;

[0098] Feature 33: The analog output voltage varies into multiple different voltage levels, which are between a first voltage level and a second voltage level higher than the first voltage level; and

[0099] Feature 34: The plurality of parameters associate the maximum required value with the analog output voltage such that the maximum required value changes at a plurality of rates of change when the analog output voltage varies between the plurality of different voltage levels.

[0100] According to an embodiment having at least features 28 to 34, when the analog output voltage varies between the plurality of different voltage levels, the maximum required value changes with the plurality of rates of change, and consequently the magnitude of the charging current can also change with the plurality of rates of change.

[0101] Therefore, if the relevant characteristics are defined in a way that causes the maximum required value to change at appropriate multiple rates of change, the charger can more accurately control the large charging current through the analog output voltage.

[0102] Some implementations may have at least one of the following features.

[0103] Feature 35: A charging system having a battery pack;

[0104] Feature 36: The charging system includes a charger;

[0105] Feature 37: The battery pack includes a battery module, the battery module being configured to (i) receive charging current from the charger, and (ii) be charged by the charging current;

[0106] Feature 38: The battery pack has an analog output generation circuit, which is configured to (i) generate an analog output voltage and (ii) output the analog output voltage to the charger;

[0107] Feature 39: The analog output voltage varies into multiple different voltage levels, which are between a first voltage level and a second voltage level higher than the first voltage level;

[0108] Feature 40: The battery pack includes a first control circuit;

[0109] Feature 41: The first control circuit is configured (or programmed) to control the analog output generation circuit to generate the analog output voltage according to the charging level of the battery module;

[0110] Feature 42: The first control circuit is configured (or programmed) to send communication data to the charger;

[0111] Feature 43: The communication data includes multiple parameters for the charger to create relevant characteristics;

[0112] Feature 44: The associated characteristic correlates the maximum required value of the charging current with the analog output voltage such that the maximum required value changes at multiple rates of change when the analog output voltage varies between the multiple different voltage levels;

[0113] Feature 45: The charger has a power supply circuit configured to (i) generate the charging current and (ii) output the charging current to the battery pack;

[0114] Feature 46: The charger includes a second control circuit;

[0115] Feature 47: The second control circuit is configured (or programmed) to receive the analog output voltage and the communication data;

[0116] Feature 48: The second control circuit is configured (or programmed) to create the relevant characteristics based on the plurality of parameters included in the communication data;

[0117] Feature 49: The second control circuit is configured (or programmed) to change the maximum required value based on the analog output voltage and the related characteristics; and

[0118] Feature 50: The second control circuit is configured (or programmed) to control the power supply circuit to change the magnitude of the charging current according to the maximum required value.

[0119] According to an embodiment having at least features 35 to 50, when the analog output voltage varies between the plurality of different voltage levels, the maximum required value in the charger changes with the plurality of rates of change, and consequently the magnitude of the charging current can also change with the plurality of rates of change.

[0120] Therefore, if the relevant characteristics are defined in a way that causes the maximum required value to change at appropriate multiple rates of change, the charging system can more accurately control the large charging current through the analog output voltage.

[0121] In some implementations, the first control circuit or the second control circuit may be integrated into a single electronic unit or a single electronic device or a single circuit board.

[0122] In some embodiments, the first control circuit or the second control circuit may be a combination of two or more electronic circuits, two or more electronic units, or two or more electronic devices respectively disposed on the battery pack or the charger.

[0123] In some implementations, the first control circuit or the second control circuit may be a microcomputer (or microcontroller or microprocessor), wired logic, graphics processor (GPU), application-specific integrated circuit (ASIC), application-specific standard product (ASSP), programmable logic device (PLD) (e.g., field-programmable gate array (FPGA), etc.), discrete electronic components, and / or combinations thereof.

[0124] Some implementations may have at least one of the following features.

[0125] Feature 51: Outputting an analog output voltage from the battery pack to the charger;

[0126] Feature 52: The analog output voltage varies into multiple different voltage levels, which are between a first voltage level and a second voltage level higher than the first voltage level;

[0127] Feature 53: The charger receives the analog output voltage;

[0128] Feature 54: In the charger, the maximum required value of the charging current for charging the battery pack is changed based on the analog output voltage and related characteristics, thereby controlling the magnitude of the charging current; and

[0129] Feature 55: The associated characteristic correlates the maximum required value with the analog output voltage such that the maximum required value changes at multiple rates of change when the analog output voltage varies between the multiple different voltage levels.

[0130] According to an embodiment having at least features 51 to 55, if the relevant characteristics are defined such that the maximum required value changes at appropriate multiple rates of change, the large charging current can be controlled more precisely by the analog output voltage.

[0131] In some implementations, the battery pack can be detachably connected to the electric work machine and provide DC power to the electric work machine.

[0132] Examples of the electric work machines include: various battery-powered field electrical equipment used in woodworking, manufacturing, gardening, construction, and other work sites, specifically including power tools for stone processing, metalworking, and woodworking, gardening work machines, and devices for improving the work site environment; more specifically, electric blowers, electric hammers, electric hammer drills, electric drills, electric screwdrivers, electric wrenches, electric grinders, electric circular saws, electric reciprocating saws, electric jigsaws, electric cutting machines, electric chainsaws, electric planers, and electric nail guns (including...). Rivet guns, electric hedge trimmers, electric lawn mowers, electric brush cutters, electric vacuum cleaners, electric sprayers, electric spreaders, electric dust collectors, laser rangefinders (or laser distance measuring devices), laser markers, laser marker receivers, wall detectors, radios, televisions, speakers, electric insulated boxes, electric kettles, coffee makers (or coffee pots, or coffee extractors), microwave ovens, robotic vacuum cleaners, battery-powered trolleys, battery-powered bicycles, fan vests, and heated jackets, etc., but not limited to the examples mentioned above.

[0133] In some implementations, features 1 to 55 can be combined in any way.

[0134] In some implementations, any one of features 1 to 55 may be eliminated.

[0135] 2. Specific Exemplary Implementations

[0136] Specific exemplary embodiments of this disclosure will now be described with reference to the accompanying drawings. These specific exemplary embodiments illustrate a charging system 1, which will be described below.

[0137] 2-1. Overall Composition of the Charging System

[0138] like Figure 1 As shown, the charging system 1 includes a first battery pack 2 to a third battery pack 4, and a first charger 5 to a third charger 7.

[0139] Each of the first battery pack 2 to the third battery pack 4 is configured to be detachably mounted to any corresponding electric work machine (not shown) and to provide DC power to that electric work machine.

[0140] Each of the first charger 5 to the third charger 7 is configured to be compatible with the first battery pack 2 to the third battery pack 4, and to be detachably connected to any one of the first battery pack 2 to the third battery pack 4 for charging that battery pack.

[0141] In other embodiments, at least one of the second battery pack 3, the third battery pack 4, the second charger 6, and the third charger 7 may be excluded from the charging system 1.

[0142] 2-2. Circuit configuration of battery packs 1 to 3

[0143] like Figure 2A As shown, the first battery pack 2 includes a first positive terminal 11, a first negative terminal 12, a first data communication terminal 13, a Vcc input terminal 14, an analog 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 module 16, a first power supply circuit 17, a first control circuit 18, a monitoring circuit 19, a charging level display circuit 20, a first temperature measurement circuit 21, a connection detection circuit 22, and an analog output generation circuit 23.

[0144] The first positive terminal 11 is connected to the first positive side current path Lp1 extending from the first positive terminal 11 to the positive terminal of the battery module 16, thereby being electrically connected to the positive terminal of the battery module 16. In addition, the first positive terminal 11 is connected to the anode of the first diode D1 via the first positive side current path Lp1.

[0145] The first negative terminal 12 is connected to the first negative terminal side current path Ln1 extending from the first negative terminal 12 to the negative terminal of the battery module 16, and is thus electrically connected to the negative terminal of the battery module 16.

[0146] The first positive electrode side current path Lp1 and the first negative electrode side current path Ln1 are each configured to transmit (i) the charging current Ichg supplied from any one of the first chargers 5 to 7 connected to the first battery pack 2 to the battery module 16, and (ii) the discharging current Idis supplied from the battery module 16 to the electric motor connected to the first battery pack 2. The first negative electrode side current path Ln1 is connected to the ground terminal of the first battery pack 2. This ground terminal is also connected to the first power supply circuit 17, the first control circuit 18, the monitoring circuit 19, the charging level display circuit 20, the first temperature measurement circuit 21, the connection detection circuit 22, and the analog output generation circuit 23, and serves as a reference potential for the above circuits.

[0147] A shunt resistor R1 is provided on the current path Ln1 on the first negative electrode side so that the charging current Ichg and the discharging current Idis can pass through the shunt resistor R1.

[0148] The first data communication terminal 13 is connected to the first control circuit 18. The first data communication terminal 13 is a terminal used for serial communication between the first control circuit 18 and any one of the first charger 5 to the third charger 7 connected to the first battery pack 2.

[0149] The Vcc input terminal 14 is connected to (i) the anode of the second diode D2 and (ii) the detection circuit 22.

[0150] The analog output terminal 15 is connected to the analog output generation circuit 23.

[0151] The battery module 16 has multiple rechargeable battery cells connected in series and / or in parallel between its positive and negative terminals. Each of the multiple rechargeable battery cells is a lithium-ion battery, but is not limited to lithium-ion batteries.

[0152] The first power supply circuit 17 is a DC-DC converter connected to the cathodes of the first diode D1 and the second diode D2, and configured to generate a first power supply voltage Vdd. The cathodes of the first diode D1 and the second diode D2 are connected. Thus, the first power supply circuit 17 is configured to generate the first power supply voltage Vdd based on the higher of (i) the voltage between the positive and negative terminals of the battery module 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 monitoring circuit 19, the charging level display circuit 20, the first temperature measurement circuit 21, and the connection detection circuit 22, thereby enabling the aforementioned circuits to operate. The battery voltage Vbat is 18 volts DC, but is not limited to 18 volts DC. In other embodiments, the battery voltage Vbat can 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 both 5 volts DC, but are not limited to 5 volts DC.

[0153] The first control circuit 18 is configured to control the charging and discharging of the battery module 16 by sending and receiving various signals between itself and other various circuits. More specifically, the first control circuit 18 is a microcomputer including, but not limited to, 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). In other embodiments, the first control circuit 18 may include an additional microcomputer. In still other embodiments, in addition to or instead of a microcomputer, the first control circuit 18 may include logic circuits (or wired logic connections) including multiple electronic components. In still other embodiments, in addition to or instead of a microcomputer, the first control circuit 18 may include a GPU, ASIC, ASSP, and / or PLD.

[0154] The monitoring circuit 19 is configured to monitor (i) the battery voltage Vbat, (ii) the individual voltages of all rechargeable battery cells (hereinafter referred to as cell voltages Vcel), and (iii) the voltage across the shunt resistor R1 (i.e., the magnitude of the charging current Ichg or the discharging current Idis). Furthermore, the monitoring circuit 19 is configured to perform equalization processing on all cell voltages Vcel. Additionally, the monitoring circuit 19 is configured to send monitoring results representing (i) the battery voltage Vbat, (ii) all cell voltages Vcel, and (iii) the voltage across the shunt resistor R1 to the first control circuit 18 via serial communication. The first control circuit 18 is configured (or programmed) to identify (i) the battery voltage Vbat, (ii) all cell voltages Vcel, and (iii) the voltage across the shunt resistor R1 based on the received monitoring results. In other embodiments, the first control circuit 18 may be integrated with the monitoring circuit 19. In other embodiments, the monitoring circuit 19 may be configured to (i) not monitor at least one cell voltage Vcel, or (ii) not perform equalization processing on all cell voltages Vcel, or the monitoring circuit 19 may be removed from the first battery pack 2. Such circuit configurations are also included in this disclosure, but are not recommended for use.

[0155] The charging level display circuit 20 is configured to receive a display control signal from the first control circuit 18 and display the charging level of the first battery pack 2 (more specifically, battery module 16) via a light source (e.g., a light-emitting diode (LED)), a seven-segment display, and / or a liquid crystal display (LCD) according to the received display control signal. The display control signal specifies a display mode corresponding to the battery voltage Vbat identified by the first control circuit 18. In other embodiments, the charging level display circuit 20 may be omitted from the first battery pack 2.

[0156] The first temperature measurement circuit 21 is configured to measure the temperature of the battery module 16 (hereinafter referred to as battery temperature Tbat) using a temperature sensing element (e.g., a thermistor, not shown) and send the 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 identify the battery temperature Tbat based on the voltage of the first temperature measurement signal. In other embodiments, the first temperature measurement circuit 21 may be omitted from the first battery pack 2. Such a circuit configuration is also included in this disclosure but is not recommended.

[0157] The connection detection circuit 22 is configured to detect whether the second power supply voltage Vcc is supplied to the Vcc input terminal 14 and send 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 a low-level active signal). The connection detection circuit 22 is configured to (i) assert the connection detection signal in response to the second power supply voltage Vcc being supplied to the Vcc input terminal 14, and (ii) negate the connection detection signal in response to the second power supply voltage Vcc not being supplied to the Vcc input terminal 14. The first control circuit 18 is configured (programmed) to (i) identify that the first battery pack 2 is connected to any one of the first charger 5 to the third charger 7 in response to receiving an asserted connection detection signal, and (ii) identify that the battery pack 2 is not connected to any one of the first charger 5 to the third charger 7 in response to receiving a negated connection detection signal. In other embodiments, the connection detection signal may be a positive logic signal (or a high-level active signal).

[0158] The analog output generation circuit 23 is configured to receive a pulse width modulation (PWM) signal from the first control circuit 18 and generate an analog output voltage Vout according to the received PWM signal. The first control circuit 18 is configured (or programmed) to change the maximum required value Imax of the charging current Ichg based at least on the battery voltage Vbat identified by the first control circuit 18, and to change the duty cycle of the PWM signal according to the change in the maximum required value Imax. More specifically, the first control circuit 18 is configured (or programmed) to (i) increase the maximum required value Imax when the battery voltage Vbat (in other words, the charging level of the battery module 16) is low, and (ii) decrease the maximum required value Imax when the battery voltage Vbat is high. Thus, the generated analog output voltage Vout varies to multiple different voltage levels as the maximum required value Imax changes.

[0159] like Figure 2BAs shown in the specific configuration, the analog output generation circuit 23 includes a capacitor C1 and a semiconductor switch Q1 connected in parallel. The first terminal of capacitor C1 is connected to the analog output terminal 15. The second terminal of capacitor C1 is connected to the ground terminal of the first battery pack 2. The semiconductor switch Q1 is configured to receive a PWM signal from the first control circuit 18 and to turn on or off according to the received PWM signal. In other words, the analog output generation circuit 23 is configured such that (i) in response to the semiconductor switch Q1 being turned off, capacitor C1 is charged by current introduced into capacitor C1 from the analog output terminal 15, and (ii) in response to the semiconductor switch Q1 being turned on, capacitor C1 is discharged to ground through the semiconductor switch Q1. The semiconductor switch Q1 is an n-channel MOSFET, but is not limited to an n-channel MOSFET. In other embodiments, the semiconductor switch Q1 can be any of other types of semiconductor switches, including JFETs (Junction Field-Effect Transistors), MESFETs (Metal-Semiconductor Field-Effect Transistors), bipolar transistors, IGBTs (Insulated Gate Bipolar Transistors), SSRs (Solid State Relays), and thyristors.

[0160] The second battery pack 3 and the third battery pack 4 each have the same circuit configuration as the first battery pack 2. In other words, the second battery pack 3 and the third battery pack 4 each have all the aforementioned components of the first battery pack 2.

[0161] However, the first battery pack 2 to the third battery pack 4 differ from each other in the following aspects: (i) the specifications or characteristics of their components, (ii) the signals sent from their first control circuit 18, and (iii) the processes performed by their first control circuit 18.

[0162] As one of the differences mentioned above, the first battery pack 2 to the third battery pack 4 (specifically, their battery modules 16, and more specifically, their multiple rechargeable battery cells) have different charging rates.

[0163] Between battery pack 2 and battery pack 4, battery pack 2 has the highest charging rate, battery pack 3 has the second highest charging rate, and battery pack 4 has the lowest charging rate.

[0164] Due to the different charging rates, the upper limit (or maximum or allowable value) of the charging current Ichg for each of the first battery pack 2 to the third battery pack 4 is also different. The first battery pack 2 has a first upper limit. The second battery pack 3 has a second upper limit, which is lower than the first upper limit. The third battery pack 4 has a third upper limit, which is lower than the second upper limit.

[0165] The battery modules 16 of the first battery pack 2 to the third battery pack 4 can have the same capacity (i.e., ampere-hours) or different capacities.

[0166] In this embodiment, it is assumed that the battery modules 16 of the first battery pack 2 to the third battery pack 4 have the same capacity, specifically, 12 ampere-hours. Furthermore, it is assumed that the charging rate of the first battery pack 2 is 2C, the charging rate of the second battery pack 3 is 1C, and the charging rate of the third battery pack 4 is 0.75C. Under this assumption, the first upper limit, the second upper limit, and the third upper limit are set to 24 amperes, 12 amperes, and 9 amperes, respectively.

[0167] 2-3. Circuit configuration of chargers 1 through 3

[0168] like Figure 3 As shown, the first charger 5 has a second positive terminal 31, a second negative terminal 32, a second data communication terminal 33, a Vcc output terminal 34, an analog 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, and a second temperature measurement circuit 39.

[0169] The second positive terminal 31 is connected to the second positive side current path Lp2 extending from the second positive terminal 31 to the positive terminal of the second power supply circuit 37, and is thus electrically connected to the positive terminal 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 any one of the first battery packs 2 to 4 of the first battery pack 5 connected to the first charger 5.

[0170] The second negative terminal 32 is connected to the second negative side current path Ln2 extending from the second negative terminal 32 to the negative terminal of the second power supply circuit 37, and is thus electrically connected to the negative terminal 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 any one of the first battery packs 2 to 4 connected to the first charger 5. Thus, in response to any one of the first battery packs 2 to 4 being connected to the first charger 5, the second negative side current path Ln2 is connected to the ground terminal of that battery pack, and the first charger 5 shares the same reference potential with the battery pack.

[0171] 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 a reference potential for the above circuits.

[0172] The second data communication terminal 33 is connected to the second control circuit 36. Furthermore, the second data communication terminal 33 is configured to be detachably connected to the first data communication terminal 13 of any one of the first battery packs 2 to 4 of the first 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 connected to any one of the first battery packs 2 to 4 of the first charger 5.

[0173] 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 any one of the first battery pack 2 to the third battery pack 4 connected to the first charger 5.

[0174] The analog input terminal 35 is configured to supply the second power supply voltage Vcc via a pull-up resistor R2. Furthermore, the analog input terminal 35 is configured to be detachably connected to the analog output terminal 15 of any one of the first battery packs 2 to 4 of the first charger 5. (i) When the first charger 5 is not connected to any one of the first battery packs 2 to 4, and (ii) when the analog input terminal 35 is in an open-circuit state, the voltage of the analog input terminal 35 with the above configuration is equal to the second power supply voltage Vcc. When the first charger 5 is connected to any one of the first battery packs 2 to 4, since the analog input terminal 35 is electrically connected to the analog output generation circuit 23 of that battery pack, the voltage of the analog input terminal 35 is lower than the second power supply voltage Vcc. The capacitor C1 of the connected battery pack is charged by the current introduced from the analog input terminal 35 via the analog output terminal 15.

[0175] The second control circuit 36 ​​is configured to send and receive various signals between itself and other circuits to perform various controls related to the charging of the first battery pack 2 to the third battery pack 4. More specifically, the second control circuit 36 ​​is a microcomputer including, but not limited to, 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). In other embodiments, the second control circuit 36 ​​may include an additional microcomputer. In still other embodiments, in addition to or instead of a microcomputer, the second control circuit 36 ​​may include logic circuits (or wired logic connections) including multiple electronic components. In still other embodiments, in addition to or instead of a microcomputer, the second control circuit 36 ​​may include a GPU, ASIC, ASSP, and / or PLD.

[0176] The analog input terminal 35 is also connected to the second control circuit 36. The second control circuit 36 ​​is configured (or programmed) to: (i) identify that the first charger 5 is not connected to any one of the first battery pack 2 to the third battery pack 4 in response to the voltage of the analog input terminal 35 being equal to the second power supply voltage Vcc; and (ii) identify that the first charger 5 is connected to any one of the first battery pack 2 to the third battery pack 4 in response to the voltage of the analog input terminal 35 being lower than the second power supply voltage Vcc.

[0177] The second power supply circuit 37 employs a switching power supply circuit (or a switching AC-DC converter), configured to receive 100–130 volts or 220–240 volts of AC power from an external power source (not shown), and 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. As described above, the second power supply voltage Vcc is supplied to (i) the Vcc output terminal 34 and (ii) the pull-up resistor R2. The charging voltage Vchg is applied between the second positive side current path Lp2 and the second negative side current path Ln2 through 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 other embodiments, the charging voltage Vchg can be 40 volts DC, 14.4 volts DC, or 10.8 volts DC.

[0178] Furthermore, the second power supply circuit 37 is configured to receive the PWM signal from the second control circuit 36 ​​and 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 according to the change of the maximum required value Imax.

[0179] The AC voltage measurement circuit 38 is configured to measure the AC voltage Vac supplied to the second power supply circuit 37 and send the AC voltage measurement signal to the second control circuit 36. The AC voltage measurement signal is an analog signal with a variable voltage corresponding to the magnitude of the measured AC voltage Vac. The second control circuit 36 ​​is configured (or programmed) to send a PWM signal to the second power supply circuit 37 to reduce or stop the charging current Ichg in response to the AC voltage measurement signal having a voltage deviating from its appropriate range. In other embodiments, the AC voltage measurement circuit 38 can be omitted from the first charger 5. Such a circuit configuration is also included in this disclosure but is not recommended.

[0180] The second temperature measurement circuit 39 is configured to measure the temperature of the second power supply circuit 37 (hereinafter referred to as the power supply temperature Tsup) using a temperature sensing element (not shown) (e.g., a thermistor), and send the 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 power supply temperature Tsup. The second control circuit 36 ​​is configured (or programmed) to (i) send a PWM signal to the second power supply circuit 37 to reduce or stop the charging current Ichg in response to the second temperature measurement signal having a voltage deviating from its appropriate level, or (ii) in response to the second temperature measurement signal having a rapidly changing voltage. In other embodiments, the second temperature measurement circuit 39 may be removed from the first charger 5. Such a circuit configuration is also included in this disclosure but is not recommended.

[0181] The second charger 6 and the third charger 7 each have the same circuit configuration as the first charger 5. In other words, the second charger 6 and the third charger 7 both have all the aforementioned components of the first charger 5.

[0182] However, the first charger 5 to the third charger 7 differ from each other in the following aspects: (i) the specifications or characteristics of their components, (ii) the signals transmitted from their second control circuit 36, and (iii) the processing performed by their second control circuit 36.

[0183] As one of the aforementioned differences, the first charger 5 to the third charger 7 (more specifically, their second power supply circuit 37) have different upper limits for the charging current Ichg. Therefore, the first charger 5 to the third charger 7 (more specifically, their second control circuit 36 ​​and second power supply circuit 37) are compatible with different charging controls.

[0184] Specifically, the first charger 5 is compatible with the first to third charging controls. Therefore, the first charger 5 can execute the first to third charging controls. The first charging control sets the magnitude of the charging current Ichg according to a first relevant characteristic. The second charging control sets the magnitude of the charging current Ichg according to a second relevant characteristic. The third charging control fixes the magnitude of the charging current Ichg to be less than a third upper limit.

[0185] The second charger 6 is incompatible with the first charging control, but compatible with the second and third charging controls. Therefore, the second charger 6 is capable of performing the second and third charging controls.

[0186] The third charger 7 is incompatible with the first and second charging controls, but compatible with the third charging control. Therefore, the third charger 7 can only perform the third charging control.

[0187] 2-4. Specific details of the first and second relevant characteristics.

[0188] The specific details of the first and second relevant characteristics are as follows.

[0189] 2-4-1. First Relevant Feature

[0190] The first relevant characteristic (or relevant equation or relevant function) correlates the maximum required value Imax with the analog output voltage Vout, so that the maximum required value Imax is as follows: Figure 4 The figure shows how it varies with the analog output voltage Vout.

[0191] As described above, the second control circuit 36 ​​of the first charger 5 sends a PWM signal corresponding to the maximum required value Imax to the second power supply circuit 37. Therefore, the magnitude of the charging current Ichg also changes along the first related characteristic as the analog output voltage Vout changes.

[0192] Specifically, the analog output voltage Vout can vary from 0 volts to less than the second supply voltage Vcc (i.e., 5 volts). In the first relevant characteristic, the analog output voltage Vout is associated with the maximum required value Imax such that the maximum required value Imax varies from 0 amperes to the first upper limit value (i.e., 24 amperes) within the unsaturated voltage range of the analog output voltage Vout, which is above 0 volts and below 5 volts, more specifically from 1.6 volts to 4 volts.

[0193] More specifically, the analog output voltage Vout is divided into a first voltage range and a second voltage range within the unsaturated voltage range. Each of the first and second voltage ranges is further divided into twelve unit intervals. Each unit interval is set to 0.1 volts.

[0194] The first voltage range is from 1.6 volts to 2.8 volts. Within this first voltage range, the maximum required value Imax is associated with the analog output voltage Vout so that it varies from 0 amps to 6 amps at a first rate of change (or slope). The first rate of change is set to 0.5 amps per unit interval, i.e., 0.5 amps / 0.1 volts.

[0195] The second voltage range is from 2.8 volts to 4 volts. Within this second voltage range, the maximum required value Imax is associated with the analog output voltage Vout so that it varies from 6 amps to 24 amps at a second rate of change. The second rate of change is set to three times the first rate of change, specifically 1.5 amps per unit interval, more specifically 1.5 amps / 0.1 volts.

[0196] In other words, the first relevant characteristic is set such that (i) in the first voltage range where the battery module 16 is close to full charge, the maximum required value Imax (and thus the charging current Ichg) changes smoothly, and (ii) in the second voltage range where the battery module 16 is at a lower charging level, the maximum required value Imax changes sharply.

[0197] 2-4-2. Second Relevant Characteristic

[0198] like Figure 5 As shown, the second relevant characteristic correlates the maximum required value Imax with the analog output voltage Vout, such that the maximum required value Imax varies from 0 Amperes to the second upper limit (i.e., 12 Amperes) at a fixed rate within the aforementioned unsaturated voltage range. The fixed rate of change is set to 0.5 Amperes per unit interval, i.e., 0.5 Amperes / 0.1 Volts.

[0199] 2-5. Operation of the charging system

[0200] In the charging system 1 having the above configuration, the first battery pack 2 to the third battery pack 4 can be combined with the first charger 5 to the third charger 7 in the following manner:

[0201] Option 1: Battery pack 2 and charger 5;

[0202] The second combination: the first battery pack 2 and the second charger 6;

[0203] The third combination: the first battery pack 2 and the third charger 7;

[0204] The fourth combination: the second battery pack 3 and the first charger 5;

[0205] Fifth combination: Second battery pack 3 and second charger 6;

[0206] The sixth combination: the second battery pack 3 and the third charger 7;

[0207] The seventh combination: the third battery pack 4 and the first charger 5;

[0208] The eighth combination: the third battery pack 4 and the second charger 6; and

[0209] The 9th combination: the 3rd battery pack 4 and the 3rd charger 7.

[0210] 2-5-1. Operations in combinations 1, 4, or 7

[0211] When any one of the first battery packs 2 to the third battery pack 4 is charged by the first charger 5, the charging system 1 operates in the following manner through serial communication between the first control circuit 18 connected to the battery pack and the second control circuit 36 ​​connected to the first charger 5.

[0212] like Figure 6A and Figure 6B As shown, when any one of the first battery packs 2 to the third battery pack 4 is connected to the first charger 5 (S10), the first charger 5 (more specifically, the second control circuit 36) sends a transmission request command to the connected battery pack (more specifically, the first control circuit 18) (S20). This transmission request command is used to request information about the connected battery pack.

[0213] In response to the transmission request command, the connected battery pack sends the first communication data shown in Table 1 to the first charger 5 (S30).

[0214] Table 1

[0215]

[0216] As shown in Table 1, the first communication data includes the first to fourth parameters, each of which represents (i) the battery voltage Vbat, (ii) the capacity of the battery pack, (iii) the total number of charging operations performed so far, and (iv) the compatible charging control.

[0217] When the aforementioned first communication data is converted into a serial digital signal, it contains the bit sequence shown in Table 2.

[0218] Table 2

[0219]

[0220] As shown in Table 2, the first communication data sent from each of the first battery packs 2 to the third battery pack 4 contains a logic value indicating whether it is compatible with the first charging control in the (m-1)th byte (where m is any natural number greater than or equal to 2). Furthermore, the first communication data contains a logic value indicating whether it is compatible with the second charging control in the mth byte.

[0221] More specifically, the logical values ​​of the 0th bit in the (m-1)th byte and the 6th bit in the mth byte of the first communication data sent from the first battery pack 2 are both "true (1)". This combination of logical values ​​indicates that the first battery pack 2 is compatible with the first charging control to the third charging control.

[0222] The logical value of the 0th bit in the (m-1)th byte of the first communication data sent from the second battery pack 3 is "false (0)", and the logical value of the 6th bit in the mth byte is "true (1)". The above combination of logical values ​​indicates that the second battery pack 3 is incompatible with the first charging control, but compatible with both the second and third charging controls.

[0223] The logical values ​​of bit 0 in the (m-1)th byte and bit 6 in the mth byte of the first communication data sent from battery pack 4 are both "false (0)". This combination of logical values ​​indicates that battery pack 4 is only compatible with the third charging control.

[0224] The second control circuit 36 ​​of the first charger 5 is configured (or programmed) to identify the logical values ​​of the 0th bit in the (m-1)th byte and the 6th bit in the mth byte.

[0225] The second control circuit 36 ​​of the second charger 6 is not configured (or programmed) to recognize the logical value of the 0th bit in the (m-1)th byte, but is configured (or programmed) to recognize the logical value of the 6th bit in the mth byte.

[0226] The second control circuit 36 ​​of the third charger 7 is not configured (or not programmed) to recognize the logical values ​​of both the 0th bit in the (m-1)th byte and the 6th bit in the mth byte.

[0227] If the connected battery pack is not compatible with the second charging control (S40 and S50: No), the first charger 5 and the connected battery pack perform the third charging control (S60 and S70).

[0228] If the connected battery pack is compatible with the second charging control (S40 and S50: Yes), the first charger 5 sends the second communication data shown in Table 3 to the connected battery pack (S80).

[0229] Table 3

[0230]

[0231] As shown in Table 3, the second communication data includes at least the first parameter and the second parameter, which represent (i) the upper limit of the charging current Ichg of the charger and (ii) the compatible charging control, respectively.

[0232] When the second communication data is converted into a digital signal in serial format, it contains the bit sequence shown in Table 4.

[0233] Table 4

[0234]

[0235] As shown in Table 4, the logical value of the 6th bit in the nth byte (n is any natural number greater than or equal to 1) of the second communication data sent from the first charger 5 is "true (1)". This logical value indicates that the first charger 5 is compatible with the first charging control to the third charging control.

[0236] The first control circuit 18 of each of the first battery pack 2 and the second battery pack 3 is configured (or programmed) to identify the logic value of the 6th bit in the nth byte.

[0237] The first control circuit 18 of the third battery pack 4 is not configured (or not programmed) to recognize the logic value of the 6th bit in the nth byte.

[0238] If the connected battery pack fails to receive the second communication data within a predetermined time (S90: No), the connected battery pack performs the third charging control (S70).

[0239] If the connected battery pack successfully receives the second communication data within a predetermined time (S90: Yes), the connected battery pack sends the third communication data shown in Table 5 to the first charger 5 (S100).

[0240] Table 5

[0241]

[0242] As shown in Table 5, the third communication data includes the first and second parameters that define the second relevant characteristic. The first parameter represents the upper limit of the maximum required value Imax. The second parameter represents the change (i.e., the rate of change) of the maximum required value Imax per unit interval.

[0243] If the first charger 5 fails to receive the third communication data within a predetermined time (S110: No), the first charger 5 enters its error mode (S120). In error mode, the first charger 5 operates by not supplying charging current Ichg to the connected battery pack.

[0244] If (i) the first charger 5 successfully receives the third communication data within a predetermined time (S110: Yes), and (ii) the connected battery pack is not compatible with the first charging control (S130 and S140: No), then the first charger 5 and the connected battery pack (i.e., the second battery pack 3) perform the second charging control (S150 and S160).

[0245] If the connected battery pack is compatible with the first charging control (S130 and S140: Yes), the connected battery pack (i.e., the first battery pack 2) begins to prepare to receive the fourth communication data (S170).

[0246] Subsequently, the first charger 5 sends the fourth communication data shown in Table 6 (S180) to the first battery pack 2.

[0247] Table 6

[0248]

[0249] As shown in Table 6, the fourth communication data includes at least the first parameter and the second parameter, each parameter representing (i) the first set of charger information and (ii) the second set of charger information, respectively. The first set of charger information and the second set of charger information are two sets of information for the first charger 5 required to perform the first charging control.

[0250] If the first battery pack 2 fails to receive the fourth communication data within a predetermined time (S190: No), the first battery pack 2 enters its error mode (S200). In error mode, the first battery pack 2 operates without supplying charging current Ichg from the first charger 5 to the first battery pack 2.

[0251] If the first battery pack 2 successfully receives the fourth communication data within a predetermined time (S190: Yes), the first battery pack 2 sends the fifth communication data shown in Table 7 to the first charger 5 (S210).

[0252] Table 7

[0253]

[0254] As shown in Table 7, the fifth communication data includes five pairs of parameters (parameters 1 through 10) defining the first relevant characteristic. Specifically, each pair of parameters represents: (i) the change (i.e., the rate of change) of the maximum required value Imax per unit interval, and (ii) the number of unit intervals to which this rate of change applies. More specifically, parameter 1 represents the change of the maximum required value Imax per unit interval within the first voltage range. Parameter 2 represents the number of unit intervals within the first voltage range. Parameter 3 represents the change of the maximum required value Imax per unit interval within the second voltage range. Parameter 4 represents the number of unit intervals within the second voltage range. The first relevant characteristic has a total of twenty-four unit intervals within the unsaturated voltage range. Since the unsaturated voltage range cannot include additional unit intervals, parameters 5 through 10 are set to zero.

[0255] If the first charger 5 fails to receive the fifth communication data within a predetermined time (S220: No), the first charger 5 enters the above-mentioned error mode (S230).

[0256] If the first charger 5 successfully receives the fifth communication data within a predetermined time (S220: Yes), then the first charger 5 and the first battery pack 2 perform the first charging control (S240).

[0257] 2-5-2. Operations in the second or third combination

[0258] When the first battery pack 2 is charged by the second charger 6 or the third charger 7, the charging system 1 operates in the following manner through serial communication between the first control circuit 18 of the first battery pack 2 and the second control circuit 36 ​​of the connected charger.

[0259] like Figure 7A and 7B As shown, when the first battery pack 2 is connected to the second charger 6 or the third charger 7 (S300), the connected charger (more specifically, the second control circuit 36) sends the aforementioned transmission request instruction to the first battery pack 2 (more specifically, the first control circuit 18) (S310).

[0260] In response to the sending request command, the first battery pack 2 sends the first communication data (S320) to the connected charger.

[0261] If the connected charger cannot recognize the logical value of the 6th bit of the mth byte in the first communication data as "true (1)", that is, incompatible with the second charging control (S330 and S335: no), then the charger (i.e., the third charger 7) and the first battery pack 2 perform the third charging control (S340 and S370).

[0262] If the connected charger identifies the logic value of the 6th bit of the m-th byte in the first communication data as "true (1)", that is, compatible with the second charging control (S330: yes), then the charger (i.e., the second charger 6) sends the aforementioned second communication data to the first battery pack 2 (S350). The logic value of the 6th bit of the n-th byte in the second communication data sent from the second charger 6 is "false (0)". This logic value indicates that the second charger 6 is not compatible with the first charging control, but is compatible with both the second and third charging controls.

[0263] If the first battery pack 2 fails to receive the second communication data within a predetermined time (S360: No), the first battery pack 2 performs the third charging control (S370).

[0264] If the first battery pack 2 successfully receives the second communication data within a predetermined time (S360: Yes), then the first battery pack 2 sends the third communication data to the second charger 6 (S380).

[0265] If the second charger 6 fails to receive the third communication data within a predetermined time (S390: No), the second charger 6 enters its error mode (S400). In error mode, the second charger 6 operates without supplying charging current Ichg to the first battery pack 2.

[0266] If the first battery pack 2 incorrectly determines that the second charger 6 is compatible with the first charging control (S410: Yes), the first battery pack 2 enters its error mode (S420) because it has not received the fourth communication data mentioned above within a predetermined time. In the error mode, the first battery pack 2 operates in a manner that it does not supply charging current Ichg from the second charger 6 to the first battery pack 2.

[0267] If (i) the second charger 6 successfully receives the third communication data within a predetermined time (S390: Yes), and (ii) the first battery pack 2 determines that the second charger 6 is not compatible with the first charging control (S410: No), then the second charger 6 and the first battery pack 2 execute the second charging control (S430).

[0268] 2-5-3. Operations in combinations 5, 6, 8, or 9

[0269] When the second battery pack 3 or the third battery pack 4 is connected to the second charger 6 or the third charger 7, the operation of the charging system 1 is as described by those skilled in the art. Figure 6A , Figure 6B , Figure 7A ,as well as Figure 7B It is obvious.

[0270] Therefore, the operation instructions for charging system 1 in combinations 5, 6, 8, or 9 are omitted.

[0271] 2-6. Specific details of the operation of the first battery pack in the first combination.

[0272] The first control process performed by the first control circuit 18 of the first battery pack 2 in the first combination will be described in detail below.

[0273] like Figure 8 As shown, in the first control process, the first control circuit 18 first stops generating the analog output voltage Vout (S500). Specifically, the first control circuit 18 sets the duty cycle of the PWM signal to 0%. Therefore, the analog output voltage Vout is set to 0 volts.

[0274] In subsequent S510, the first control circuit 18 determines whether the first battery pack 2 is connected to the first charger 5. If the first battery pack 2 is not connected to the first charger 5 (S510: No), the first control circuit 18 returns to S500. If the first battery pack 2 is connected to the first charger 5 (S510: Yes), the first control circuit 18 performs data communication with the first charger 5 (more specifically, the second control circuit 36 ​​of the first charger 5) (S520). In this data communication, refer to... Figure 6A , 6B As mentioned above, the first control circuit 18 and the first charger 5 send and receive transmission request commands and first to fifth communication data.

[0275] After data communication is completed, the first control circuit 18 determines whether the first battery pack 2 is connected to the first charger 5 (S530). If the first battery pack 2 is not connected to the first charger 5 (S530: No), the first control circuit 18 returns to S500.

[0276] If the first battery pack 2 is connected to the first charger 5 (S530: Yes), the first control circuit 18 calculates the maximum required value Imax based on the identified battery voltage Vbat (S540). Then, the first control circuit 18 determines the analog output voltage Vout corresponding to the calculated maximum required value Imax based on the first relevant characteristic, and sets the duty cycle of the PWM signal so that the analog output generation circuit 23 generates the determined analog output voltage Vout (S550).

[0277] In the subsequent S560, the first control circuit 18 determines whether it has received a charging completion signal from the first charger 5 via serial communication. If the first control circuit 18 has not received a charging completion signal (S560: No), the first control circuit 18 returns to S530.

[0278] If the first control circuit 18 has received a charging completion signal (S560: Yes), the first control circuit 18 sets the duty cycle of the PWM signal to 0% so that the analog output generation circuit 23 stops generating the analog output voltage Vout (S570).

[0279] In the subsequent S580, the first control circuit 18 determines whether the first battery pack 2 is connected to the first charger 5. If the first battery pack 2 is connected to the first charger 5 (S580: Yes), the first control circuit 18 repeats S580. If the first battery pack 2 is not connected to the first charger 5 (S580: No), the first control circuit 18 returns to S500.

[0280] 2-7. Specific details of the operation of the first charger in the first combination.

[0281] The second control process performed by the second control circuit 36 ​​of the first charger 5 in the first combination will be described in detail below.

[0282] like Figure 9 As shown, in the second control process, the second control circuit 36 ​​first determines whether the first charger 5 is connected to the first battery pack 2 (S600). If the first charger 5 is not connected to the first battery pack 2 (S600: No), the second control circuit 36 ​​repeats S600. If the first charger 5 is connected to the first battery pack 2 (S600: Yes), the second control circuit 36 ​​performs data communication with the first battery pack 2 (more specifically, the first control circuit 18 of the first battery pack 2) (S610). In this data communication, refer to... Figure 6A , 6B As mentioned above, the second control circuit 36 ​​and the first battery pack 2 send and receive transmission request commands and the first to fifth communication data.

[0283] When data communication is completed, the second control circuit 36 ​​creates (or constructs or derives) the first relevant characteristic based on the fifth communication data received from the first battery pack 2 (S620).

[0284] In the subsequent S630, the second control circuit 36 ​​determines whether the first charger 5 is connected to the first battery pack 2. If the first charger 5 is not connected to the first battery pack 2 (S630: No), the second control circuit 36 ​​returns to S600.

[0285] If the first charger 5 is connected to the first battery pack 2 (S630: Yes), the second control circuit 36 ​​obtains the analog output voltage Vout from the first battery pack 2 (S640). Then, the second control circuit 36 ​​obtains the maximum required value Imax based on (i) the obtained analog output voltage Vout and (ii) the first related characteristic created (S650).

[0286] In the subsequent S660, the second control circuit 36 ​​sets the duty cycle of the PWM signal so that the second power supply circuit 37 outputs a charging current Ichg, which has a magnitude corresponding to the maximum required value Imax obtained (S660).

[0287] In the subsequent S670, the second control circuit 36 ​​determines whether the charging of the first battery pack 2 is complete based on the acquired analog output voltage Vout. If the charging of the first battery pack 2 is not complete (S670: No), the second control circuit 36 ​​returns to S630. If the charging of the first battery pack 2 is complete (S670: Yes), the second control circuit 36 ​​sets the duty cycle of the PWM signal to 0% so that the second power supply circuit 37 stops outputting the charging current Ichg (S680).

[0288] In the subsequent S690, the second control circuit 36 ​​sends a charging completion signal to the first battery pack 2 via serial communication and determines whether the first charger 5 is connected to the first battery pack 2 (S700).

[0289] If the first charger 5 is connected to the first battery pack 2 (S700: Yes), the second control circuit 36 ​​repeats S700. If the first charger 5 is not connected to the first battery pack 2 (S700: No), the second control circuit 36 ​​returns to S600.

[0290] 2-8. Effects of the Implementation Method

[0291] In the above embodiment, the following effects can be achieved in the first combination consisting of the first battery pack 2 and the first charger 5.

[0292] The maximum required value Imax can be: (i) a gradual change when the analog output voltage Vout changes within the first voltage range; or (ii) a sharp change when the analog output voltage Vout changes within the second voltage range. Thus, the charging current Ichg can be controlled more precisely by controlling the analog output voltage Vout, thereby both shortening the charging time of the first battery pack 2 and suppressing overcharging of the battery module 16.

[0293] The format of the fifth communication data reduces the amount of communication required for the first charger 5 to create the first relevant feature. Therefore, the possibility of the first charger 5 failing to receive the fifth communication data can be reduced, thereby enabling stable first charging control between the first charger 5 and the first battery pack 2.

[0294] Since the fifth communication data format includes parameters 1 through 10, it is possible to define not only simple correlation characteristics but also complex correlation characteristics.

[0295] The analog output generation circuit 23 can generate a stable analog output voltage Vout through capacitor C1.

[0296] 2-9. Correspondence of Terms

[0297] In this embodiment, "battery pack" in the embodiment summary is exemplified as "first battery pack 2". "Charger" in the embodiment summary is exemplified as "first charger 5". "First voltage level" in the embodiment summary is exemplified as "0 volts". "Second voltage level" in the embodiment summary is exemplified as "a voltage level below 5 volts". "Related characteristics" in the embodiment summary is exemplified as "first related characteristic". "Power supply circuit" in the embodiment summary is exemplified as "second power supply circuit 37".

[0298] 2-10. Variations

[0299] This disclosure is not limited to the above-described embodiments and can be implemented in various variations.

[0300] In some variations, the first relevant characteristic can be determined according to... Figure 10 Defined as shown.

[0301] exist Figure 10 In the first relevant characteristic shown, the analog output voltage Vout is divided into the first voltage range to the fifth voltage range within the unsaturated voltage range.

[0302] The first voltage range is from 1.6 volts to 2 volts, divided into four unit intervals (0.1 volts). The rate of change of the maximum required value Imax within the first voltage range is set to 0.5 amperes / 0.1 volts.

[0303] The second voltage range, from 2 volts to 2.6 volts, is divided into six unit intervals. The rate of change of the maximum required value Imax within the second voltage range is set to 1 ampere / 0.1 volt.

[0304] The third voltage range, from 2.6 volts to 3 volts, is divided into four unit intervals. The rate of change of the maximum required value Imax within the third voltage range is set to 2 amperes / 0.1 volts.

[0305] The fourth voltage range, from 3 volts to 3.6 volts, is divided into six unit intervals. The rate of change of the maximum required value Imax within the fourth voltage range is set to 1 ampere / 0.1 volt.

[0306] The fifth voltage range, from 3.6 volts to 4 volts, is divided into four unit intervals. The maximum required value Imax for the fifth voltage range is set at a rate of 0.5 amperes / 0.1 volts.

[0307] When the first relevant characteristic is set in the manner described above, the first control circuit 18 in the first battery pack 2 sends the fifth communication data shown in Table 8 to the first charger 5.

[0308] Table 8

[0309]

[0310] Based on the first relevant characteristic mentioned above, the maximum required value Imax can be controlled more precisely, and thus the magnitude of the charging current Ichg can be controlled more precisely.

[0311] In other variations, the first correlation characteristic can be defined as any function of the analog output voltage Vout (e.g., an exponential function) whose maximum required value Imax has more than two rates of change. In this case, the first control circuit 18 of the first battery pack 2 can send fifth communication data including parameters representing the function to the second control circuit 36 ​​of the first charger 5, and the second control circuit 36 ​​can create the first correlation characteristic in S620 based on the received function.

[0312] 2-11. Alternative Implementation Methods

[0313] In an alternative embodiment, the fifth communication data may include the first to tenth parameters as shown in Tables 9, 10, or 11 below. Such fifth communication data is also included in this disclosure, but its use is not recommended.

[0314] Table 9

[0315]

[0316] Table 10

[0317]

[0318] Table 11

[0319]

[0320] 2-12. Supplementary Explanation

[0321] Multiple functions of one constituent element in the above embodiments can be implemented by multiple constituent elements, or one function of one constituent element can be implemented by multiple constituent elements. Furthermore, multiple functions of multiple constituent elements can be implemented by one constituent element, or one function implemented by multiple constituent elements can be implemented by one constituent element. Additionally, a portion of the configuration of the above embodiments can be omitted. At least a portion of the configuration of the above embodiments can be added to the configurations of the other embodiments described above, or at least a portion of the configuration of the above embodiments can be replaced by the configurations of the other embodiments described above.

[0322] 2-13. Further Plans

[0323] Based on the above description, this disclosure provides the following further solutions 1 to 9.

[0324] 1. A battery pack, comprising:

[0325] A battery module configured to (i) receive charging current from a charger and (ii) be charged by said charging current;

[0326] An analog output generation circuit is configured to (i) generate an analog output voltage and (ii) output the analog output voltage to the charger, the analog output voltage varying through multiple different voltage levels, the multiple different voltage levels being between a first voltage level and a second voltage level higher than the first voltage level; and

[0327] A control circuit, configured (or programmed) to: (i) control the analog output generation circuit to generate the analog output voltage according to the charging level of the battery module; and (ii) send communication data to the charger, wherein the communication data includes five pairs of parameters used by the charger to create a related characteristic that associates the change in the maximum required value of the charging current with each of twenty-four unit intervals in an unsaturated voltage range between the first voltage level and the second voltage level, the unsaturated voltage range including the plurality of different voltage levels; each of the five pairs of parameters includes (i) a first parameter representing the rate of change of the maximum required value, and (ii) a second parameter representing the number of unit intervals to which the rate of change represented by the first parameter applies; the charger is configured to: (i) create the related characteristic based on the five pairs of parameters; (ii) change the maximum required value based on the analog output voltage and the related characteristic; and (iii) change the magnitude of the charging current according to the change in the maximum required value.

[0328] 2. The battery pack according to Scheme 1, wherein,

[0329] The control circuit is configured (or programmed) to control the analog output generation circuit so that the analog output voltage decreases as the charging level increases.

[0330] 3. The battery pack according to scheme 1 or 2, wherein,

[0331] The relevant characteristics are defined by one or more but no more than four of the five pairs of parameters.

[0332] The remaining pairs of the five pairs of parameters are all represented as zero.

[0333] 4. The battery pack according to any one of schemes 1 to 3, wherein,

[0334] The control circuit is configured (or programmed) to send the communication data to the charger via serial communication.

[0335] 5. The battery pack according to any one of schemes 1 to 4, wherein,

[0336] The analog output generation circuit includes a capacitor and a semiconductor switch, and the analog output generation circuit is configured such that the capacitor is charged or discharged through the semiconductor switch to generate the analog output voltage.

[0337] 6. The battery pack according to Scheme 5, wherein,

[0338] The control circuit is configured (or programmed) to control the switching operation of the semiconductor switch by sending a pulse width modulation signal having a duty cycle corresponding to the maximum required value to the semiconductor switch.

[0339] 7. A charger comprising:

[0340] The power supply circuit is configured to (i) generate a charging current and (ii) output the charging current to the battery pack; and

[0341] A control circuit configured (or programmed) to: (i) receive analog output voltage and communication data from the battery pack; (ii) create a correlation characteristic based on five pairs of parameters included in the communication data; (iii) change the maximum required value of the charging current based on the analog output voltage and the correlation characteristic; and (iv) control the power supply circuit to change the magnitude of the charging current according to the change in the maximum required value, wherein the analog output voltage changes to a plurality of different voltage levels, the plurality of different voltage levels being between a first voltage level and a second voltage level higher than the first voltage level; the correlation characteristic associating the change in the maximum required value with each of twenty-four unit intervals within an unsaturated voltage range between the first voltage level and the second voltage level, the unsaturated voltage range including the plurality of different voltage levels; and each of the five pairs of parameters including (i) a first parameter representing the rate of change of the maximum required value, and (ii) a second parameter representing the number of unit intervals to which the rate of change represented by the first parameter applies.

[0342] 8. A charging system comprising a battery pack and a charger,

[0343] The battery pack includes:

[0344] A battery module configured to (i) receive charging current from the charger and (ii) be charged by the charging current;

[0345] An analog output generation circuit is configured to (i) generate an analog output voltage and (ii) output the analog output voltage to the charger, wherein the analog output voltage varies through multiple different voltage levels, the multiple different voltage levels being between a first voltage level and a second voltage level higher than the first voltage level; and

[0346] A first control circuit, configured (or programmed) to: (i) control the analog output generation circuit to generate the analog output voltage according to the charging level of the battery module; and (ii) send communication data to the charger, wherein the communication data includes five pairs of parameters used by the charger to create a related characteristic that associates the change in the maximum required value of the charging current with each of twenty-four unit intervals within an unsaturated voltage range between the first voltage level and the second voltage level, the unsaturated voltage range including the plurality of different voltage levels; each of the five pairs of parameters includes (i) a first parameter representing the rate of change of the maximum required value, and (ii) a second parameter representing the number of unit intervals to which the rate of change represented by the first parameter applies.

[0347] The charger has the following features:

[0348] The power supply circuit is configured to (i) generate the charging current and (ii) output the charging current to the battery pack; and

[0349] The second control circuit is configured (or programmed) to: (i) receive the analog output voltage and the communication data from the battery pack; (ii) create the relevant characteristics based on the five pairs of parameters included in the communication data; (iii) change the maximum required value based on the analog output voltage and the relevant characteristics; and (iv) control the power supply circuit to change the magnitude of the charging current based on the change in the maximum required value.

[0350] 9. A method for charging a battery pack using a charger, comprising the following steps:

[0351] The battery pack outputs an analog output voltage to the charger, wherein the analog output voltage varies in multiple different voltage levels, which are between a first voltage level and a second voltage level higher than the first voltage level;

[0352] Communication data is sent from the battery pack to the charger, wherein the communication data includes five pairs of parameters used by the charger to create related characteristics that associate the change in the maximum required value of the charging current used to charge the battery pack with each of twenty-four unit intervals in an unsaturated voltage range between the first voltage level and the second voltage level, the unsaturated voltage range including the plurality of different voltage levels, and each of the five pairs of parameters includes (i) a first parameter representing the rate of change of the maximum required value, and (ii) a second parameter representing the number of unit intervals to which the rate of change represented by the first parameter applies;

[0353] Based on the five pairs of parameters included in the communication data, the relevant characteristics are created in the charger; and

[0354] The magnitude of the charging current is controlled by changing the maximum required value in the charger, based on the analog output voltage and the relevant characteristics.

[0355] In Schemes 1 and 7 through 9, by appropriately setting the first parameter (i.e., the rate of change) and the second parameter (i.e., the number of unit intervals), the charging current can be controlled more precisely by simulating the output voltage. Furthermore, since only five pairs of parameters are sent from the battery pack to the charger, the amount of communication required for the charger to create relevant characteristics can be reduced. Therefore, the possibility of the charger failing to receive communication data can be reduced, thereby enabling stable charging control between the charger and the battery pack.

Claims

1. A battery pack, characterized in that, have: A battery module configured to (i) receive charging current from a charger and (ii) be charged by the charging current; An analog output generation circuit is configured to (i) generate an analog output voltage and (ii) output the analog output voltage to the charger, wherein the analog output voltage varies through multiple different voltage levels, the multiple different voltage levels being between a first voltage level and a second voltage level higher than the first voltage level; and A control circuit is configured to (i) control the analog output generation circuit to generate the analog output voltage according to the charging level of the battery module, and (ii) send communication data to the charger, wherein the communication data includes multiple parameters for the charger to create related characteristics that associate a maximum required value of the charging current with the analog output voltage such that the maximum required value changes at multiple rates of change when the analog output voltage changes between multiple different voltage levels, and the charger is configured to change the maximum required value based on the analog output voltage and the related characteristics, thereby controlling the magnitude of the charging current.

2. The battery pack according to claim 1, characterized in that, The analog output voltage has an unsaturated voltage range between the first voltage level and the second voltage level, and the unsaturated voltage range includes the plurality of different voltage levels. The unsaturated voltage range is divided into at least two voltage ranges in the relevant characteristics. In the relevant characteristics, the maximum required value varies at different rates in adjacent voltage ranges within the at least two voltage ranges.

3. The battery pack according to claim 2, characterized in that, The control circuit is configured to control the analog output generation circuit so that the analog output voltage decreases as the charging level increases. The at least two voltage ranges include (i) a first voltage range and (ii) a second voltage range that is adjacent to and higher than the first voltage range. In the relevant characteristics, the maximum required value has a first rate of change in the first voltage range and a second rate of change higher than the first rate of change in the second voltage range.

4. The battery pack according to claim 3, characterized in that, The second rate of change is three times the first rate of change.

5. The battery pack according to claim 3 or 4, characterized in that, The unsaturated voltage range is divided into twenty-four unit intervals. The total number of cell intervals included in the first voltage range is equal to the total number of cell intervals included in the second voltage range.

6. The battery pack according to any one of claims 2 to 5, characterized in that, The unsaturated voltage range is divided into twenty-four unit intervals. The plurality of parameters includes at least two pairs of parameters, each of the at least two pairs of parameters including (i) a first parameter representing the rate of change of the maximum required value, and (ii) a second parameter representing the number of unit intervals to which the rate of change represented by the first parameter applies.

7. The battery pack according to claim 6, characterized in that, The at least two pairs of parameters are five pairs of parameters.

8. The battery pack according to claim 7, characterized in that, The relevant characteristics are defined by two or more but no more than four of the five pairs of parameters. The remaining pairs of the five pairs of parameters are all represented as zero.

9. The battery pack according to any one of claims 1 to 8, characterized in that, The control circuit is configured to send the communication data to the charger via serial communication.

10. The battery pack according to any one of claims 1 to 9, characterized in that, The analog output generation circuit includes a capacitor and a semiconductor switch, and the analog output generation circuit is configured such that the capacitor is charged or discharged through the semiconductor switch to generate the analog output voltage.

11. The battery pack according to claim 10, characterized in that, The control circuit is configured to send a pulse width modulation signal with a duty cycle corresponding to the maximum required value to the semiconductor switch to control the switching operation of the semiconductor switch.

12. A charger, characterized in that, have: A power supply circuit, wherein the power supply circuit is configured to (i) generate a charging current and (ii) output the charging current to the battery pack; as well as A control circuit configured to: (i) receive an analog output voltage and communication data from the battery pack; (ii) change a maximum required value of the charging current according to the analog output voltage and a plurality of parameters included in the communication data; and (iii) control the power supply circuit to change the magnitude of the charging current according to the change in the maximum required value, wherein the analog output voltage changes to a plurality of different voltage levels, the plurality of different voltage levels being between a first voltage level and a second voltage level higher than the first voltage level, and the plurality of parameters associating the maximum required value with the analog output voltage such that the maximum required value changes at a plurality of rates of change when the analog output voltage changes between the plurality of different voltage levels.

13. A charging system comprising a battery pack and a charger, characterized in that, The battery pack includes: A battery module configured to (i) receive charging current from the charger and (ii) be charged by the charging current; An analog output generation circuit is configured to (i) generate an analog output voltage and (ii) output the analog output voltage to the charger, wherein... The analog output voltage changes into multiple different voltage levels, which are between a first voltage level and a second voltage level higher than the first voltage level; as well as A first control circuit is configured to: (i) control the analog output generation circuit to generate the analog output voltage according to the charging level of the battery module; and (ii) send communication data to the charger, wherein the communication data includes multiple parameters for the charger to create relevant characteristics that correlate a maximum required value of the charging current with the analog output voltage, such that the maximum required value changes at multiple rates of change when the analog output voltage varies between multiple different voltage levels. The charger has the following features: A power supply circuit, configured to (i) generate the charging current and (ii) output the charging current to the battery pack; and The second control circuit is configured to: (i) receive the analog output voltage and the communication data; (ii) create the relevant characteristics based on the plurality of parameters included in the communication data; (iii) change the maximum required value based on the analog output voltage and the relevant characteristics; and (iv) control the power supply circuit to change the magnitude of the charging current based on the maximum required value.

14. A method for charging a battery pack using a charger, characterized in that, Includes the following steps: The battery pack outputs an analog output voltage to the charger, wherein the analog output voltage varies in multiple different voltage levels, which are between a first voltage level and a second voltage level higher than the first voltage level; The charger receives the analog output voltage; and In the charger, the maximum required value of the charging current for charging the battery pack is changed based on the analog output voltage and related characteristics, thereby controlling the magnitude of the charging current. The related characteristics associate the maximum required value with the analog output voltage so that the maximum required value changes at multiple rates of change when the analog output voltage varies between multiple different voltage levels.

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