battery pack

Abstract

A battery pack capable of coping with a plurality of chargers having different rates is provided. The battery pack includes a mounting portion, a battery, a voltage detection portion, a current acquisition portion, a next current calculation portion, a first charge stop portion, and a second charge stop portion. With respect to the first charge stop portion, in a case where a charge current value acquired by the current acquisition portion is equal to or higher than a completion current value, charging of the battery is stopped based on satisfaction of a first condition. The first condition is that a voltage value detected by the voltage detection portion is equal to or higher than a completion voltage value, and a next current value calculated by the next current calculation portion is lower than the completion current value. With respect to the second charge stop portion, in a case where the charge current value acquired by the current acquisition portion is lower than the completion current value, charging of the battery is stopped based on satisfaction of a second condition different from the first condition.

Description

Technical Field

[0001] This invention relates to a rechargeable battery pack. Background Technology

[0002] Patent document 1 describes a relatively large high-speed charger.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2019-80406 Summary of the Invention

[0004] Because charging times can be longer than those of high-speed chargers, users desire inexpensive chargers. To achieve inexpensive chargers with lower heat resistance, it's necessary to use inexpensive components and reduce the charging current. When charging a battery pack using a low-speed charger with a smaller charging current, the voltage drop caused by the battery pack's internal resistance is less compared to charging with a high-speed charger. Therefore, for battery packs, charging to the specified capacity using a low-speed charger requires different charging control than with a high-speed charger.

[0005] One aspect of the present invention provides a battery pack capable of handling various chargers with different charging speeds.

[0006] One aspect of the present invention provides a battery pack comprising a mounting section, a battery, a voltage detection section, a current acquisition section, a next current calculation section, a first charging stop section, and a second charging stop section. The mounting section is configured to be mounted on a charger. The battery is connected to the mounting section. The voltage detection section is configured to detect the voltage value of the battery. The current acquisition section is configured to acquire the charging current value flowing to the battery in the current processing cycle. The next current calculation section is configured to calculate an allowable value for the charging current value in the next processing cycle, i.e., the next current value, based on the charging current value acquired by the current acquisition section. The first charging stop section is configured to stop charging the battery based on the fulfillment of a first condition when the charging current value acquired by the current acquisition section reaches or exceeds the completion current value. The first condition is as follows: the voltage value detected by the voltage detection section reaches or exceeds the completion voltage value, and the next current value calculated by the next current calculation section is less than the completion current value. The second charging stop unit is configured to stop charging the battery when the charging current value obtained by the current acquisition unit is less than the completion current value, based on the fulfillment of a second condition that is different from the first condition.

[0007] In one aspect of the battery pack of the present invention, charging is stopped when the charging current reaches or exceeds the completion current value, based on the fulfillment of a first condition. Furthermore, when the charging current is less than the completion current value, charging is stopped based on the fulfillment of a second condition, different from the first condition. That is, charging control is performed differently when charging with a smaller charging current than when charging with a larger charging current. Therefore, a battery pack capable of handling various chargers with different charging rates can be realized.

[0008] It may also include: a target voltage calculation unit configured to calculate a target voltage value, which is equivalent to the open-circuit voltage value of the battery when charging is stopped by the first charging stop unit. The second condition is set such that the open-circuit voltage value of the battery when charging is stopped by the second charging stop unit is consistent with the target voltage value.

[0009] When charging the battery with a smaller charging current, the voltage drop caused by the battery's internal resistance is smaller compared to when charging with a larger charging current. Therefore, when charging with a smaller charging current, if charging is stopped at the same completion voltage as when charging with a larger charging current, the open-circuit voltage at the end of charging is greater than the target voltage. That is, the battery's charging capacity increases. Therefore, the target voltage can be calculated based on the battery's state. Furthermore, when charging with a smaller charging current, the second condition is set such that the open-circuit voltage at the end of charging matches the target voltage. Accordingly, the open-circuit voltage at the end of charging when charging with a smaller charging current can be made the same as the open-circuit voltage at the end of charging when charging with a larger charging current.

[0010] It may also include: a temperature detection unit configured to detect the temperature of the battery; and a target voltage calculation unit configured to calculate a target voltage value based on the temperature detected by the temperature detection unit and / or the degree of battery degradation.

[0011] The target voltage value is calculated based on temperature and / or the degree of battery degradation, thereby suppressing battery overcharging and thus providing appropriate protection for the battery.

[0012] The second condition can be as follows: the voltage value detected by the voltage detection unit reaches or exceeds the judgment value. The judgment value is equivalent to the value obtained by adding the correction value and the target voltage value. The correction value is equivalent to (Vset - Vtg) × Inow / Icut. Vset is equivalent to the completed voltage value. Vtg is equivalent to the target voltage value. Inow is equivalent to the charging current value obtained by the current acquisition unit. Icut is equivalent to the completed current value.

[0013] The voltage drop of the current charging current is calculated as a correction value, and the sum of the calculated correction value and the target voltage value is calculated as a decision value. Based on this, the open-circuit voltage value at the time of charging, based on the fulfillment of condition 2, can be made consistent with the target voltage value.

[0014] The charging system of another aspect of the present invention can be the following items A-1 and A-2.

[0015] [Project A-1]

[0016] A charging system is disclosed, comprising: a battery pack including lithium-ion batteries; a high-speed charger configured to be connected to the battery pack; and a low-speed charger configured to be connected to the battery pack, wherein the high-speed charger can output a maximum current value that is greater than or equal to a completion current value, and the low-speed charger can output a maximum current value that is less than the completion current value, wherein the completion current value is equivalent to the charging current value when the lithium-ion battery is fully charged under constant current and constant voltage conditions.

[0017] According to another aspect of the charging system of the present invention, both the high-speed charger and the low-speed charger can be connected to the battery pack, and either the high-speed charger or the low-speed charger can be used to charge the battery pack.

[0018] [A-2]

[0019] Based on the charging system described in A-1, the battery pack includes: a request current calculation unit configured to calculate a request current value based on the state of the battery; and a request output unit configured to output the request current value calculated by the request current calculation unit to the high-speed charger or the low-speed charger connected to the battery pack. The high-speed charger and the low-speed charger include: an upper limit current calculation unit configured to calculate an upper limit current value based on the state of the charger; and a current output unit that outputs a current having the smaller of the upper limit current value calculated by the upper limit current calculation unit and the request current value output from the battery pack.

[0020] High-speed and low-speed chargers can suppress overheating of the charger and overcharging of the battery pack by outputting a current with the smaller of the upper limit current value and the requested current value, thereby protecting both the charger and the battery pack. Attached Figure Description

[0021] Figure 1 This diagram illustrates the battery pack and high-speed charger of the charging system involved in this embodiment.

[0022] Figure 2 This diagram illustrates the battery pack and low-speed charger of the charging system involved in this embodiment.

[0023] Figure 3 This is a block diagram illustrating the electrical structure of the charging system according to this embodiment.

[0024] Figure 4 The diagram shows the time-varying values ​​of the battery voltage and charging current when the charger, having reached a value above the completion current using the maximum output current, terminates charging based on the fulfillment of condition 1.

[0025] Figure 5 The diagram illustrates the time-varying battery voltage and charging current values ​​when charging is terminated based on the fulfillment of condition 1 using a charger whose maximum output current is less than the completion current.

[0026] Figure 6 The diagram shows the time-varying battery voltage and charging current values ​​when charging ends based on the fulfillment of condition 2, using a charger whose maximum output current is less than the completion current.

[0027] Figure 7 This is a flowchart illustrating the charging control process performed by the battery pack and the high-speed charger or low-speed charger.

[0028] Figure 8 It is a table of target voltage values ​​corresponding to the degree of degradation and battery temperature.

[0029] Explanation of reference numerals in the attached figures

[0030] 1…Charging system; 10…Battery side terminal; 11…First positive terminal; 12…First negative terminal; 13…First charging terminal; 14…Discharging terminal; 15…First detection terminal; 16…First communication terminal; 18…First positive line; 19…First negative line; 20…Battery side mounting part; 35…First temperature detection circuit; 50…Battery MCU; 61…Regulator; 62…Current interruption element; 63…Battery shunt resistor; 71…Charging control circuit; 72…Discharging control circuit; 73…First detection circuit; 74…First communication circuit; 100…Battery pack; 200…High High-speed charger; 210, 310… Charger-side terminal section; 220, 320… Charger-side mounting section; 300… Low-speed charger; 410… Switching power supply circuit; 411… Second positive terminal; 412… Second negative terminal; 413… Second charging terminal; 415… Second detection terminal; 416… Second communication terminal; 420… FET; 430… Interlock circuit; 440… Second temperature detection circuit; 450… Charger shunt resistor; 460… Second detection circuit; 470… Second communication circuit; 480… Second positive line; 490… Second negative line; 400… Charger MCU. Detailed Implementation

[0031] Hereinafter, the methods for carrying out the present invention will be described with reference to the accompanying drawings.

[0032] <1. Structure>

[0033] <1-1. System Structure>

[0034] Reference Figure 1 and Figure 2 The charging system 1 according to this embodiment will be described.

[0035] The charging system 1 according to this embodiment includes a battery pack 100, a high-speed charger 200, and a low-speed charger 300.

[0036] The battery pack 100 includes a rechargeable battery 30, which will be described later. The battery 30 includes multiple battery cells connected in series, such as lithium-ion batteries. The battery pack 100 includes a battery-side mounting portion 20 and a battery-side terminal portion 10.

[0037] A battery-side mounting portion 20 is provided on the lower surface of the battery pack 100 and configured to be mounted on both the high-speed charger 200 and the low-speed charger 300. A battery-side terminal portion 10 is provided on the battery-side mounting portion 20 and has a plurality of terminals described later. Additionally, the battery-side mounting portion 20 is configured to be mounted on a power work machine (not shown). When the battery-side mounting portion 20 is mounted on the power work machine, the battery pack 100 supplies power to the power work machine, which is driven using the power received from the battery pack 100. Power work machines include: impact screwdrivers, circular saws, and other power tools; lawnmowers, trimmers, and other gardening tools; laser marking machines; lights, etc.

[0038] Both the high-speed charger 200 and the low-speed charger 300 have power cords that connect to an external power source, such as a commercial power supply. The high-speed charger 200 and the low-speed charger 300 generate power to supply to the battery 30 based on the power supplied from the external power source.

[0039] The high-speed charger 200 is a charger for high-speed charging of the battery 30. The maximum output current of the high-speed charger 200 is greater than or equal to the completion current value Icut, and the high-speed charger 200 can charge the battery pack 100 with a current greater than or equal to the completion current value Icut. The completion current value Icut is equivalent to the charging current value at the end of charging when the battery 30 is under constant current and constant voltage charging conditions.

[0040] The low-speed charger 300 is a charger for charging the battery 30 at a low speed. The maximum output current of the low-speed charger 300 is less than the completion current value Icut, and the low-speed charger 300 can only charge the battery pack 100 with a current less than the completion current value Icut.

[0041] The high-speed charger 200 includes a charger-side mounting portion 220 and a charger-side terminal portion 210. The charger-side mounting portion 220 is disposed on the upper surface of the high-speed charger 200, and the charger-side terminal portion 210 is disposed on the charger-side mounting portion 220. Similarly, the low-speed charger 300 includes a charger-side mounting portion 320 and a charger-side terminal portion 310. The charger-side mounting portion 320 is disposed on the upper surface of the low-speed charger 300, and the charger-side terminal portion 310 is disposed on the charger-side mounting portion 320.

[0042] The charger-side mounting portion 220 has the same shape as the charger-side mounting portion 320. Furthermore, the charger-side terminal portion 210 and the charger-side terminal portion 310 have a plurality of terminals, which will be described later. The plurality of terminals in the charger-side terminal portion 210 are each configured to have the same shape as each of the plurality of terminals in the charger-side terminal portion 310. The charger-side mounting portions 220 and 320 are configured to be able to accommodate the battery-side mounting portion 20. The charger-side terminal portions 210 and 310 are configured to connect to the battery-side terminal portion 10 when the battery-side mounting portion 20 is mounted on the charger-side mounting portions 220 and 320.

[0043] The high-speed charger 200 is larger than the low-speed charger 300. The high-speed charger 200 can output a larger maximum current than the low-speed charger 300. Therefore, the high-speed charger 200 uses larger, more expensive components with higher heat resistance than the low-speed charger 300. Hence, the high-speed charger 200 is larger than the low-speed charger 300.

[0044] <1-2. Electrical Structure>

[0045] Next, refer to Figure 3 The electrical structures of the battery pack 100, high-speed charger 200, and low-speed charger 300 are described below. The electrical structure of the high-speed charger 200 is the same as that of the low-speed charger 300.

[0046] <1-2-1. Electrical Structure of Battery Pack>

[0047] First, the electrical structure of the battery pack will be described. The battery pack 100 includes a battery 30, a battery microcontroller unit (MCU) 50, an analog front end (AFE) 40, a regulator 61, a current-cutting element 62, a battery shunt resistor 63, a first temperature detection circuit 35, a charging control circuit 71, a discharging control circuit 72, a first detection circuit 73, and a first communication circuit 74.

[0048] The battery-side terminal section 10 includes six terminals. Specifically, the battery-side terminal section 10 includes a first positive terminal 11, a first negative terminal 12, a first charging terminal 13, a discharging terminal 14, a first detection terminal 15, and a first communication terminal 16.

[0049] The first positive terminal 11 is connected to the positive terminal of the battery 30 via the first positive wire 18. The first negative terminal 12 is connected to the negative terminal of the battery 30 via the first negative wire 19. The first charging terminal 13 is connected to the charging control circuit 71. The discharging terminal 14 is connected to the discharging control circuit 72. The first detection terminal 15 is connected to the first detection circuit 73. The first communication terminal 16 is connected to the first communication circuit 74.

[0050] The regulator 61 is connected to the positive terminal of the battery 30, receives power from the battery 30, and generates power to supply various circuits in the battery pack 100, such as the battery MCU 50 and AFE 40.

[0051] The interrupting element 62 is disposed on the first positive line 18. The interrupting element 62 is a component that can cut off the conduction of the first positive line 18, such as a Field Effect Transistor (FET) or a Self Control Protector (SCP).

[0052] The battery shunt resistor 63 is located on the first negative line 19 to detect the charging current flowing into the battery 30 and the discharging current flowing out of the battery 30, and outputs the detected current value to AFE40. The first temperature detection circuit 35 detects the battery temperature of the battery 30 and outputs the detected battery temperature to the battery MCU50.

[0053] AFE40 is an analog circuit configured to communicate with the battery MCU50 via a Serial Peripheral Interface (SPI). AFE40 detects the cell voltage values ​​of each battery cell in the battery 30 and the battery voltage value of the battery 30 according to instructions from the battery MCU50. Furthermore, AFE40 performs cell balancing processing to even out the remaining capacity of the multiple battery cells. In addition, AFE40 converts the detected cell voltage values, battery voltage values, and input current values ​​into digital signals and sends these converted digital signals to the battery MCU50. Furthermore, AFE40 determines the state of the battery 30 based on various input values, and if charging of the battery 30 should be stopped (e.g., in an overcharged state), it sends a charging stop signal to the charging control circuit 71. When a charging stop signal is received from AFE40, the charging control circuit 71 outputs a discharging stop signal to the charger from the first charging terminal 13.

[0054] The battery MCU 50 includes a microcomputer with a CPU 50a, a memory 50b, and I / O. The battery MCU 50 is connected to the discharge control circuit 72, the first detection circuit 73, and the first communication circuit 74.

[0055] The first detection circuit 73 detects whether the charger or electric work machine is connected or disconnected relative to the battery pack 100 based on the potential of the first detection terminal 15, and outputs a connection signal or disconnection signal to the battery MCU 50. Even if the power supply to the charger connected to the battery pack 100 is disconnected, the first detection circuit 73 still detects the connection of the charger.

[0056] The first communication circuit 74 is a Universal Asynchronous Receiver / Transmitter (UART) for performing half-duplex serial communication. The first communication circuit 74 receives and transmits data via the first communication terminal 16.

[0057] If a connection signal is input from the first detection circuit 73, the battery MCU 50 switches from energy-saving mode to active mode. For the battery MCU 50, when the battery pack 100 is connected to the charger, it performs charging control of the battery 30; when the battery pack 100 is connected to the electric work machine, it performs discharging control of the battery 30.

[0058] Specifically, the battery MCU 50 performs charging and discharging control of the battery 30 based on the cell voltage, battery voltage, current value received from the AFE 40, and the temperature input from the first temperature detection circuit 35.

[0059] The battery MCU50 performs different charging controls based on the charger's charging rate. Specifically, such as... Figure 4 As shown, the battery MCU 50 performs constant current and constant voltage charging while charging the battery 30 using the high-speed charger 200, and stops charging based on the fulfillment of the first condition. The first condition is as follows: the battery voltage value Vnow reaches or exceeds the completion voltage value Vset, and the next current value Inext is less than the completion current value Icut.

[0060] In this case, the battery 30 is charged with a constant charging current value Inow, which is greater than the completion current value Icut, until the battery voltage reaches the completion voltage value Vset. If the battery voltage value Vnow reaches the completion voltage value Vset, the charging current value Inow decreases, causing the battery voltage value Vnow to remain constant at the completion voltage value Vset. Furthermore, if the next current value Inext is less than the completion current value Icut, charging stops. The next current value Inext is a value calculated based on the charging current value Inow in the current processing cycle and corresponds to the allowable value of the charging current value in the next processing cycle. In addition, the open-circuit voltage value at the end of charging corresponds to the target voltage value Vtg.

[0061] Here, as Figure 5 As shown, when the battery 30 is charged using the low-speed charger 300, if charging stops based on the fulfillment of the first condition, the charging current value Inow is initially less than the completion current value Icut. Therefore, charging stops when the battery voltage value Vnow reaches the completion voltage value Vset. The open-circuit voltage value at the end of charging is greater than the target voltage value Vtg. That is, when the battery 30 is charged using the low-speed charger 300, if charging stops based on the fulfillment of the first condition, the charging capacity of the battery 30 increases compared to the case where the battery 30 is charged using the high-speed charger 200.

[0062] The open-circuit voltage at the end of charging is equivalent to the battery voltage Vnow minus the voltage drop caused by the internal resistance of the battery 30. The charging current when charging the battery 30 using the low-speed charger 300 is less than the charging current when charging the battery 30 using the high-speed charger 200. Therefore, the voltage drop caused by the internal resistance of the battery 30 is smaller when charging the battery 30 using the low-speed charger 300 compared to when charging the battery 30 using the high-speed charger 200. Consequently, when charging the battery 30 using the low-speed charger 300, if charging is stopped when the battery voltage Vnow reaches or exceeds the completion voltage Vset, the open-circuit voltage at the end of charging becomes the target voltage Vtg + ΔVocv. ΔVocv is equivalent to the difference between the voltage drop when charging using the high-speed charger 200 and the voltage drop when charging using the low-speed charger 300.

[0063] Therefore, when the battery 30 is charged using the low-speed charger 300, the battery MCU 50 stops charging based on the fulfillment of a second condition, which differs from the first condition. Figure 6 As shown, the second condition is as follows: the open-circuit voltage value when the low-speed charger 300 is fully charged is set to be consistent with the target voltage value Vtg.

[0064] Specifically, the battery MCU 50 stops charging when the battery voltage Vnow reaches or exceeds the judgment value Vb. The judgment value Vb is the sum of the correction value Δva and the target voltage value Vtg. The correction value Δva is equivalent to the voltage drop when charging with the low-speed charger 300 at a charging current of Inow, and is represented by ΔVa = (Vset - Vtg) × Inow / Icut. Therefore, the open-circuit voltage and charging capacity of the battery 30 when charging with the low-speed charger 300 are completed are the same as those when charging with the high-speed charger 200 are completed.

[0065] Furthermore, when the electric work machine is connected to the battery pack 100 and the battery 30 is determined to be in a non-dischargeable state (e.g., over-discharged state, overheated state), the battery MCU 50 outputs a discharge prohibition signal to the discharge control circuit 72, prohibiting discharge from the battery 30. The discharge control circuit 72 outputs the discharge prohibition signal input from the battery MCU 50 to the electric work machine from the discharge terminal 14. Conversely, when the battery 30 is determined to be in a dischargeable state, the battery MCU 50 outputs a watchdog pulse signal (a pulse signal with a constant period) to the discharge control circuit 72. The discharge control circuit 72 outputs a discharge prohibition signal to the electric work machine from the discharge terminal 14 when no watchdog pulse signal is input.

[0066] Furthermore, for the battery MCU 50, if the discharge does not stop even when a discharge inhibit signal is output to the electric work machine, the current interruption element 62 is operated to cut off the conduction of the first positive line 18. For example, if the current interruption element 62 is a FET, the battery MCU 50 cuts off the FET. Alternatively, if the current interruption element 62 is an SCP, the battery MCU 50 blows the fuse of the SCP.

[0067] The battery MCU 50 is shut down when it is in an over-discharge state. When the battery MCU 50 is off, if the battery pack 100 is connected to the charger, auxiliary power is supplied from the charger via the discharge terminal 14. The regulator 61 receives the auxiliary power via the discharge terminal 14 and generates and supplies power to the battery MCU 50. If power is received from the regulator 61, the battery MCU 50 starts up from the off state.

[0068] <1-2-2. Electrical Structure of the Charger>

[0069] The high-speed charger 200 and the low-speed charger 300 include a charger MCU 400, a switching power supply circuit 410, a FET 420, an interlock circuit 430, a second temperature detection circuit 440, a charger shunt resistor 450, a second detection circuit 460, and a second communication circuit 470.

[0070] The charger-side terminal portions 210 and 310 include a second positive terminal 411, a second negative terminal 412, a second charging terminal 413, a power terminal 414, a second detection terminal 415, and a second communication terminal 416.

[0071] The second positive terminal 411 is configured to be connected to the first positive terminal 11. The second negative terminal 412 is configured to be connected to the first negative terminal 12. The second charging terminal 413 is configured to be connected to the first charging terminal 13. The power terminal 414 is configured to be connected to the discharge terminal 14. The second detection terminal 415 is configured to be connected to the first detection terminal 15. The second communication terminal 416 is configured to be connected to the first communication terminal 16.

[0072] The switching power supply circuit 410 is connected to the second positive terminal 411 via the second positive line 480, and to the second negative terminal 412 via the second negative line 490. The switching power supply circuit 410 performs operations and outputs charging current according to control commands from the charger MCU 400.

[0073] FET420 is located on the second positive line 480. Charger shunt resistor 450 is located on the second negative line 490. Charger shunt resistor 450 detects the charging current flowing from the switching power supply circuit 410 to the battery pack 100 and outputs the detected value to the charger MCU 400. Second temperature detection circuit 44 detects the temperature of the switching power supply circuit 410 and outputs the detected charger temperature to the charger MCU 400.

[0074] The interlock circuit 430 is connected to the second charging terminal 413. When a charging stop signal is input via the second charging terminal 413, the operation of the switching power supply circuit 410 is stopped.

[0075] The charger MCU 400 includes a microcomputer with a CPU 400a, a memory 400b, and I / O. The charger MCU 400 is connected to the second detection circuit 460 and the second communication circuit 470.

[0076] The second detection circuit 460 detects whether the battery pack 100 is connected or disconnected relative to the charger based on the potential of the second detection terminal 415, and outputs a connection signal or disconnection signal to the charger MCU 400.

[0077] The second communication circuit 470 is a Universal Asynchronous Receiver / Transmitter (UART) for performing half-duplex serial communication. The second communication circuit 470 receives and transmits data via the second communication terminal 416.

[0078] The charger MCU400 performs charging control of the battery 30. In addition, if the interlock circuit 430 fails to stop the operation of the switching power supply circuit 410, the charger MCU400 turns off the FET420, stopping the power supply from the switching power supply circuit 410 to the battery pack 100.

[0079] <2. Processing>

[0080] Next, refer to Figure 7 The flowchart illustrates the charging control performed by the battery MCU50 and the charger MCU400. This process begins when the battery-side mounting portion 20 is mounted on the charger-side mounting portion 220 or the charger-side mounting portion 320.

[0081] First, in S200, the charger MCU400 is set to 0A as the initial value of the charging current Inow.

[0082] Next, in S210, the charger MCU400 notifies the battery pack 100 of the charging current value Inow in the current processing cycle.

[0083] Next, in S220, the charger MCU400 obtains the charger temperature.

[0084] Next, in S230, the charger MCU400 determines the current upper limit current value Icg_limit based on the charger temperature obtained in S220. For example, if the charger temperature exceeds a threshold, the charger MCU400 reduces the upper limit current value Icg_limit to prevent the high-speed charger 200 or the low-speed charger 300 from overheating.

[0085] On the other hand, in S10, the battery MCU50 receives the charging current value Inow from the charger installed in the battery pack 100.

[0086] Next, in S20, the battery MCU50 obtains the battery voltage value Vnow and battery temperature in the current processing cycle.

[0087] Next, in S30, the battery MCU 50 calculates the final voltage value Vset based on the state of the battery 30. Specifically, the battery MCU 50 calculates the final voltage value Vset based on the degree of degradation and / or the battery temperature of the battery 30. A table of final voltage values ​​Vset corresponding to the degree of degradation and battery temperature can be pre-stored in the memory 50b, and the table can be used to calculate the final voltage value Vset.

[0088] Next, in S40, the battery MCU 50 calculates the completion current value Icut based on the state of the battery 30. Specifically, the battery MCU 50 calculates the completion current value Icut based on the degree of degradation of the battery 30 and / or the battery temperature. The battery MCU 50 can use a table pre-stored in the memory 50b to calculate the completion current value Icut. Furthermore, the degree of degradation of the battery 30 is updated and stored in the memory 50b each time the battery pack 100 is used.

[0089] Next, in S50, the battery MCU 50 calculates the next current value Inext based on the charging current value Inow. Specifically, the battery MCU 50 compares the battery voltage value Vnow and the final voltage value Vset, and determines whether to maintain the charging current value Inow, decrease it, or increase it as the next current value Inext. Furthermore, the battery MCU 50 calculates the charging current value Inow, or calculates the value obtained by decreasing or increasing the charging current value Inow, and uses this as the next current value Inext.

[0090] Next, in S60 and S70, the battery MCU50 determines whether the first condition is met. Specifically, in S60, it determines whether the battery voltage value Vnow has reached or exceeded the completion voltage value Vset. If it is determined that the battery voltage value Vnow has reached or exceeded the completion voltage value Vset, the process proceeds to S70; if it is determined that the battery voltage value Vnow is less than the completion voltage value Vset, the process proceeds to S80.

[0091] In S70, it is determined whether the next current value Inext is less than the final current value Icut. If it is determined that the next current value Inext is less than the final current value Icut, the first condition is met, so the process proceeds to S110 to complete charging. If it is determined that the next current value Inext reaches or exceeds the final current value Icut, the process proceeds to S80.

[0092] In steps S80 to S100, the battery MCU 50 determines whether the second condition is met. Specifically, in S80, it determines whether the charging current value Inow is less than the completion current value Icut. If it is determined that the charging current value Inow is less than the completion current value Icut, the process proceeds to step S90. On the other hand, if it is determined that the charging current value Inow reaches or exceeds the completion current value Icut, both the first and second conditions are not met, so the process proceeds to step S120 and charging control continues.

[0093] In S90, the battery MCU 50 calculates the target voltage value Vtg. Specifically, the target voltage value Vtg is calculated based on the degree of degradation of the battery 30 and / or the battery temperature. The battery MCU 50 decreases the target voltage value Vtg as the degree of degradation increases. Furthermore, compared to the case where the battery temperature is within an appropriate range, the battery MCU 50 decreases the target voltage value Vtg when the battery temperature is lower or higher than an appropriate range. For example, as... Figure 8 As shown, a table of target voltage values ​​Vtg corresponding to the degree of degradation and battery temperature is pre-stored in memory 50b, and the target voltage value Vtg is calculated using the table. The target voltage value Vtg calculated here is equivalent to the open-circuit voltage of battery 30 when charging of battery 30 is complete, based on the fulfillment of the first condition.

[0094] Next, in S100, the battery MCU 50 calculates the correction value Δva and adds it to the target voltage value Vtg calculated in S90 to calculate the judgment value Vb. Furthermore, the battery MCU 50 determines whether the battery voltage value Vnow reaches or exceeds the judgment value Vb.

[0095] If the battery voltage value Vnow is determined to be above the determination value Vb, the second condition is met, and the process proceeds to S110 to complete charging. If the battery voltage value Vnow is determined to be below the determination value Vb, neither the first nor the second condition is met, and the process proceeds to S120 to continue charging control.

[0096] Here, since the determination value Vb is less than the completion voltage value Vset, if the charging current value Inow is less than the completion current value Icut, the second condition is met before the first condition is met, and charging stops. On the other hand, if the charging current value Inow reaches or exceeds the completion current value Icut, the second condition is not determined, only the first condition is determined, and charging stops based on the fulfillment of the first condition.

[0097] Next, in S120, the next current value Inext calculated in S50 is sent to the charger connected to the battery pack 100. Then, the process returns to S10 to begin the next processing cycle. The battery MCU 50 repeatedly executes the processes of S10 to S120 until charging is complete.

[0098] On the other hand, in S240, the charger MCU400 receives the next current value Inext sent from the battery pack 100.

[0099] In S250, the charger MCU400 determines whether the received next current value Inext is greater than the upper limit current value Icg_limit determined in S230. If it is determined that the next current value Inext is below the upper limit current value Icg_limit, the process proceeds to S260; if it is determined that the next current value Inext is greater than the upper limit current value Icg_limit, the process proceeds to S270.

[0100] In S260, the charger MCU400 outputs a control command to the switching power supply circuit 410 so that the current of the next current value Inext is output to the battery pack 100 and enters the processing in S280.

[0101] In S270, the charger MCU400 outputs a control command to the switching power supply circuit 410 so that the current of the power supply upper limit value Icg_limit is output to the battery pack 100 and enters the processing in S280.

[0102] In S280, the charger MCU400 sets the current output current value to the charging current value Inow. Then, the charger MCU400 returns to the processing in S210 and begins the next processing cycle. The charger MCU400 repeatedly executes the processing in S210 to S280, and ends the charging process when the next current value Inext becomes 0.

[0103] <3. Effects>

[0104] According to the above-described embodiment, the following effects can be obtained.

[0105] (1) When the charging current value Inow reaches or exceeds the completion current value Icut, charging is stopped based on the fulfillment of the first condition. Furthermore, when the charging current value Inow is less than the completion current value Icut, charging is stopped based on the fulfillment of a second condition, different from the first condition. That is, when charging with a smaller charging current value Inow, charging control is performed differently than when charging with a larger charging current value Inow. Therefore, the battery pack 100 can handle both the high-speed charger 200 and the low-speed charger 300.

[0106] (2) When the battery 30 is charged with a smaller charging current value Inow, the second condition is set so that the open-circuit voltage value at the end of charging is consistent with the target voltage value Vtg. Accordingly, the open-circuit voltage value at the end of charging when the battery 30 is charged with a smaller charging current value Inow can be consistent with the open-circuit voltage value at the end of charging when the battery 30 is charged with a larger charging current value Inow.

[0107] (3) The target voltage value Vtg is calculated based on the state of the battery 30, which can suppress the overcharging of the battery 30 and thus protect the battery 30 appropriately.

[0108] (4) The voltage drop at the charging current value Inow is calculated using the correction value ΔVa, and the correction value Δva is calculated as the determination value Vb. The result is the sum of the correction value Δva and the target voltage value Vtg. Based on this, the open-circuit voltage value at the time of charging based on the fulfillment of condition 2 can be made consistent with the target voltage value Vtg.

[0109] (Other implementation methods)

[0110] The above describes the methods for implementing the present invention, but the present invention is not limited to the above embodiments and can be implemented in various modifications.

[0111] (a) It can be configured such that multiple structural elements realize the multiple functions of one structural element in the above embodiments, or that multiple structural elements realize the single function of one structural element. Alternatively, it can be configured such that one structural element realizes the multiple functions of multiple structural elements, or that one constituent element realizes the single function realized by multiple structural elements. Furthermore, a portion of the structure in the above embodiments can be omitted. Additionally, at least a portion of the structure in the above embodiments can be added to or replaced with structures from other above embodiments.

[0112] (b) In addition to the battery pack described above, the present invention can also be implemented in various forms, such as a charging system in which the battery pack is a structural element, a program executed by the MCU of the battery pack, a non-transitional physical storage medium such as a semiconductor memory containing the program, and a charging control method executed by the battery pack.

Claims

1. A battery pack, characterized in that, The battery pack includes: Mounting section, configured to be mounted on the charger; A storage battery connected to the mounting portion; A voltage detection unit configured to detect the voltage value of the battery; A current acquisition unit is configured to acquire the charging current value flowing to the battery in the current processing cycle. The next current calculation unit is configured to calculate the allowable value of the charging current value in the next processing cycle, i.e., the next current value, based on the charging current value obtained by the current acquisition unit. The first charging stop unit is configured to stop charging the battery when the charging current value obtained by the current acquisition unit reaches or exceeds the completion current value, based on the fulfillment of a first condition. The first condition is that the voltage value detected by the voltage detection unit reaches or exceeds the completion voltage value, and the next current value calculated by the next current calculation unit is less than the completion current value. as well as The second charging stop unit is configured to stop charging the battery when the charging current value obtained by the current acquisition unit is less than the completion current value, based on the fulfillment of a second condition different from the first condition.

2. The battery pack according to claim 1, characterized in that, The battery pack further includes a target voltage calculation unit configured to calculate a target voltage value, which is equivalent to the open-circuit voltage value of the battery when charging of the battery is stopped by the first charging stop unit. The second condition is set such that the open-circuit voltage of the battery when charging is stopped by the second charging stop unit is consistent with the target voltage.

3. The battery pack according to claim 2, characterized in that, The battery pack further includes a temperature detection unit configured to detect the temperature of the battery. The target voltage calculation unit is configured to calculate the target voltage value based on the temperature detected by the temperature detection unit and / or the degree of degradation of the battery.

4. The battery pack according to claim 2 or 3, characterized in that, The second condition is as follows: the voltage value detected by the voltage detection unit reaches or exceeds the judgment value. The judgment value is equivalent to the value obtained by adding the correction value to the target voltage value. The correction value is equivalent to (Vset-Vtg)×Inow / Icut, where Vset is equivalent to the completed voltage value, Vtg is equivalent to the target voltage value, Inow is equivalent to the charging current value obtained by the current acquisition unit, and Icut is equivalent to the completed current value.

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