Charging system, battery pack

Abstract

To provide a battery pack which is compatible with a plurality of chargers of which rates are different.SOLUTION: A battery pack comprises a mounting part, a battery, a voltage detection part, a current acquisition part, a next current calculation part, a first charging stop part, and a second charging stop part. The first charging stop part stops charging of the battery in response to establishment of a first condition in the case where a charging current value acquired by the current acquisition part is a completion current value or larger. The first condition is that a voltage value detected by the voltage detection part becomes the completion voltage value or larger, and a next current value calculated by the next current calculation part becomes less than the completion current value. The second charging stop part stops the charging of the battery in response to establishment of a second condition that is different from the first condition in the case where the charging current value acquired by the current acquisition part is less than the completion current value.SELECTED DRAWING: Figure 7

Description

Technical Field

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[0001] The present disclosure relates to a rechargeable battery pack.

Background Art

[0002] Patent Document 1 describes a relatively large high-rate charger.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There may be users who desire an inexpensive charger even if the charging time is longer than that of the high-rate charger as described above. In order to realize an inexpensive charger with low heat resistance or the like, it is necessary to use inexpensive components and reduce the charging current value. When charging a battery pack with a low-rate charger having a relatively small charging current value, the voltage drop amount due to the internal resistance of the battery pack is smaller than when charging the battery pack with a high-rate charger. Therefore, when charging the battery pack to a predetermined charging capacity with a low-rate charger, it is necessary to perform charging control different from that of a high-rate charger.

[0005] One aspect of the present disclosure provides a battery pack capable of corresponding to a plurality of chargers with different rates.

Means for Solving the Problems

[0006] A battery pack in one aspect of the present disclosure comprises a mounting unit, a battery, a voltage detection unit, a current acquisition unit, a next current calculation unit, a first charge stop unit, and a second charge stop unit. The mounting unit is configured to be mounted on a charger. The battery is connected to the mounting unit. The voltage detection unit is configured to detect the voltage value of the battery. The 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 next current value, which is an allowable value for the charging current value in the next processing cycle, based on the charging current value acquired by the current acquisition unit. The first charge stop unit is configured to stop charging the battery when the charging current value acquired by the current acquisition unit is equal to or greater than the completion current value, in accordance with the fulfillment of a first condition. The first condition is that the voltage value detected by the voltage detection unit is equal to or greater than the completion voltage value, and the next current value calculated by the next current calculation unit 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, in response to the fulfillment of a second condition different from the first condition.

[0007] In one aspect of this disclosure, the battery pack stops charging when the charging current is equal to or greater than the completion current, in accordance with the fulfillment of a first condition. Furthermore, when the charging current is less than the completion current, the battery pack stops charging when a second condition, different from the first condition, is fulfilled. In other words, different charging control is performed when charging with a relatively small charging current compared to when charging with a relatively large charging current. Therefore, a battery pack compatible with multiple chargers of different rates can be realized.

[0008] The system may further include a target voltage calculation unit configured to calculate a target voltage value corresponding to the open-circuit voltage of the battery when the battery charging is stopped by the first charging stop unit. The second condition is that the open-circuit voltage of the battery when charging is stopped by the second charging stop unit is set to match the target voltage.

[0009] When charging a battery with a relatively small charging current, the voltage drop due to the battery's internal resistance is smaller than when charging with a relatively large charging current. Therefore, when charging a battery with a relatively small charging current, if charging is stopped at the same completion voltage value as when charging with a relatively large charging current, the open-circuit voltage value at the time charging stops will be greater than the target voltage value. In other words, the battery's charging capacity will be greater. Therefore, a target voltage value is calculated based on the battery's state. Then, when charging a battery with a relatively small charging current, a second condition is set so that the open-circuit voltage value at the time charging stops matches the target voltage value. This makes it possible to match the open-circuit voltage value at the completion of charging when charging with a relatively small charging current to the open-circuit voltage value at the completion of charging when charging with a relatively large charging current.

[0010] The system may further include a temperature detection unit configured to detect the battery temperature. The target voltage calculation unit may calculate a target voltage value based on the temperature detected by the temperature detection unit and / or the degree of battery degradation. By calculating a target voltage value based on temperature and / or the degree of battery degradation, battery overcharging can be suppressed and the battery can be properly protected.

[0011] The second condition is that the voltage value detected by the voltage detection unit is equal to or greater than the judgment value. The judgment value corresponds to the target voltage value plus a correction value. The correction value corresponds to (Vset-Vtg)×Inow / Icut. Vset corresponds to the completion voltage value. Vtg corresponds to the target voltage value. Inow corresponds to the charging current value obtained by the current acquisition unit. Icut corresponds to the completion current value.

[0012] The voltage drop at the current charging current is calculated as a correction value, and the calculated correction value is added to the target voltage value to determine the result. This allows the open-circuit voltage value when charging is complete to match the target voltage value, depending on whether the second condition is met.

[0013] Another aspect of the charging system of this disclosure may be items A-1 and A-2 below. [Item A-1] A battery pack containing a lithium-ion battery, A high-rate charger configured to be connected to the aforementioned battery pack, A low-rate charger configured to be connected to the aforementioned battery pack, The maximum current value that the aforementioned high-rate charger can output is equal to or greater than the completion current value. The maximum current value that the low-rate charger can output is less than the completion current value. The completion current value corresponds to the charging current value at the completion of constant current constant voltage charging of the lithium-ion battery. Charging system.

[0014] According to another aspect of the charging system of this disclosure, both high-rate and low-rate chargers can be connected to the battery pack, and either high-rate or low-rate charger can be used to charge the battery pack.

[0015] [A-2] The aforementioned battery pack is A current request calculator configured to calculate the requested current value based on the state of the battery. Department and, The system includes a request output unit configured to output the request current value calculated by the request current calculation unit to the high-rate charger or the low-rate charger connected to the battery pack, The high-rate charger and the low-rate charger are, An upper limit current calculation unit configured to calculate an upper limit current value based on the charger status, A current output unit that outputs a current having a smaller current value between the upper limit current value calculated by the upper limit current calculation unit and the required current value output from the battery pack. The charging system according to A-1.

[0016] By outputting a current having a smaller current value between the upper limit current value and the required current value, the high-rate charger and the low-rate charger can suppress overheating of the charger and overcharging of the battery pack, and protect both the charger and the battery pack.

Brief Description of the Drawings

[0017] [Figure 1] It is a diagram showing the battery pack and the high-rate charger of the charging system according to the present embodiment. [Figure 2] It is a diagram showing the battery pack and the low-rate charger of the charging system according to the present embodiment. [Figure 3] It is a block diagram showing the electrical configuration of the charging system according to the present embodiment. [Figure 4] Shows the time change of the battery voltage value and the charging current value when charging is terminated in response to the establishment of the first condition in a charger whose maximum output current value is equal to or greater than the completion current value. [Figure 5] Shows the time change of the battery voltage value and the charging current value when charging is terminated in response to the establishment of the first condition in a charger whose maximum output current value is less than the completion current value. [Figure 6] [[ID=**29**]]Shows the time change of the battery voltage value and the charging current value when charging is terminated in response to the establishment of the second condition in a charger whose maximum output current value is less than the completion current value. [Figure 7] It is a flowchart showing the charging control process executed by the battery pack and the high-rate charger or the low-rate charger. [[ID=3**4**]] [Figure 8] It is a table of target voltage values according to the degree of deterioration and the battery temperature.

Embodiments for Carrying Out the Invention

[0018] The following describes the implementation of this disclosure with reference to the drawings. <1. Structure> <1-1. System Configuration> The charging system 1 according to this embodiment will be described with reference to Figures 1 and 2.

[0019] The charging system 1 according to this embodiment comprises a battery pack 100, a high-rate charger 200, and a low-rate charger 300. The battery pack 100 includes a rechargeable battery 30, which will be described later. The battery 30 is, for example, a lithium-ion battery, which includes a plurality of battery cells connected in series. The battery pack 100 includes a battery-side mounting portion 20 and a battery-side terminal portion 10.

[0020] The battery-side mounting section 20 is provided on the lower surface of the battery pack 100 and is configured to be mounted on the high-rate charger 200 and the low-rate charger 300. The battery-side terminal section 10 is provided on the battery-side mounting section 20 and has a plurality of terminals, which will be described later. Furthermore, the battery-side mounting section 20 is configured to be mounted on an electric work implement (not shown). When the battery-side mounting section 20 is mounted on an electric work implement, the battery pack 100 supplies power to the electric work implement, and the electric work implement is driven by the power received from the battery pack 100. Electric work implements include power tools such as impact drivers and circular saws, gardening tools such as brush cutters and trimmers, laser levels, lights, etc.

[0021] The high-rate charger 200 and the low-rate charger 300 are equipped with power cords, which are connected to an external power source such as a commercial power supply. The high-rate charger 200 and the low-rate charger 300 generate power to supply to the battery 30 from the power supplied from the external power source.

[0022] The high-rate charger 200 is a charger that charges the battery 30 at a high rate. The maximum output current value of the high-rate charger 200 is equal to or greater than the completion current value Icut, and the high-rate charger 200 can charge the battery pack 100 with a current equal to or greater than the completion current value Icut. The completion current value Icut corresponds to the charging current value at the completion of charging when the battery 30 is charged with constant current and constant voltage.

[0023] The low-rate charger 300 is a charger that charges the battery 30 at a low rate. The maximum current that the low-rate charger 300 can output is less than the completion current value Icut, and the low-rate charger 300 can only charge the battery pack 100 with a current less than the completion current value Icut.

[0024] The high-rate charger 200 comprises a charger-side mounting portion 220 and a charger-side terminal portion 210. The charger-side mounting portion 220 is provided on the upper surface of the high-rate charger 200, and the charger-side terminal portion 210 is provided on the charger-side mounting portion 220. The low-rate charger 300 comprises a charger-side mounting portion 320 and a charger-side terminal portion 310. The charger-side mounting portion 320 is provided on the upper surface of the low-rate charger 300, and the charger-side terminal portion 310 is provided on the charger-side mounting portion 320.

[0025] The charger-side mounting section 220 is configured to have the same shape as the charger-side mounting section 320. The charger-side terminal section 210 and the charger-side terminal section 310 are equipped with multiple terminals, which will be described later. Each of the multiple terminals on the charger-side terminal section 210 is configured to have the same shape as each of the multiple terminals on the charger-side terminal section 310. The charger-side mounting sections 220 and 320 are configured to accommodate the battery-side mounting section 20. The charger-side terminal sections 210 and 310 are configured to connect to the battery-side terminal section 10 when the battery-side mounting section 20 is attached to the charger-side mounting sections 220 and 320.

[0026] The high-rate charger 200 is larger than the low-rate charger 300. The high-rate charger 200 has a higher maximum output current than the low-rate charger 300. Therefore, the high-rate charger 200 uses larger, more expensive components with higher heat resistance and other properties than the low-rate charger 300. As a result, the high-rate charger 200 is larger than the low-rate charger 300. <1-2. Electrical Configuration> Next, the electrical configurations of the battery pack 100, the high-rate charger 200, and the low-rate charger 300 will be explained with reference to Figure 3. The electrical configuration of the high-rate charger 200 is the same as that of the low-rate charger 300.

[0027] <1-2-1. Electrical configuration of the battery pack> First, let's explain the electrical configuration of the battery pack. The battery pack 100 consists of a battery 30, a battery Micro Control Unit (hereinafter referred to as MCU) 50, an Analog Front End (hereinafter referred to as AFE) 40, a regulator 61, a blocking element 62, and a battery shunt resistor 6 It comprises 3, 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.

[0028] The battery-side terminal section 10 includes six terminals. Specifically, the battery-side terminal section 10 comprises a first positive terminal 11, a first negative terminal 12, a first charging terminal 13, a discharge terminal 14, a first detection terminal 15, and a first communication terminal 16.

[0029] The first positive terminal 11 is connected to the positive terminal of the battery 30 via the first positive line 18. The first negative terminal 12 is connected to the negative terminal of the battery 30 via the first negative line 19. The first charging terminal 13 is connected to the charging control circuit 71. The discharge terminal 14 is connected to the discharge 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.

[0030] The regulator 61 is connected to the positive terminal of the battery 30 and receives power from the battery 30 to generate power that supplies to various circuits within the battery pack 100, such as the battery MCU 50 and AFE 40.

[0031] The blocking element 62 is provided on the first positive electrode line 18. The blocking element 62 is an element that can block the conduction of the first positive electrode line 18, and is an example of a Field Effect Transistor (FET) or Self Control Protector (SCP).

[0032] The battery shunt resistor 63 is located on the first negative electrode line 19 and detects the value of the charging current flowing into the battery 30 and the value of the discharge current flowing out of the battery 30, and outputs the detected current value to the AFE 40. The first temperature detection circuit 35 detects the battery temperature of the battery 30 and outputs the detected battery temperature to the battery MCU 50.

[0033] The AFE40 is an analog circuit configured to perform Serial Peripheral Interface (SPI) communication with the battery MCU50. Following instructions from the 50, the AFE 40 detects the cell voltage value of each battery cell contained in the battery 30 and the battery voltage value of the battery 30. The AFE 40 also performs cell balancing to equalize the remaining capacity of multiple battery cells. Furthermore, the AFE 40 converts the detected cell voltage value, battery voltage value, and input current value into digital signals and transmits each converted digital signal to the battery MCU 50. The AFE 40 also determines the state of the battery 30 based on the various input values ​​and sends a charge stop signal to the charge control circuit 71 if it is necessary to stop charging the battery 30 (for example, if it is in an overcharged state). When the charge stop signal is input from the AFE 40, the charge control circuit 71 outputs a discharge stop signal to the charger from the first charging terminal 13.

[0034] The battery MCU 50 includes a microcomputer equipped with a CPU 50a, memory 50b, and I / O, etc. The battery MCU 50 is connected to a discharge control circuit 72, a first detection circuit 73, and a first communication circuit 74.

[0035] The first detection circuit 73 detects whether a charger or electric work machine is connected to or disconnected from 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. The first detection circuit 73 detects the connection of the charger even if the power to the charger connected to the battery pack 100 is turned off.

[0036] The first communication circuit 74 is a Universal Asynchronous Receiver / Transmitter (UART) that performs half-duplex serial communication. The first communication circuit 74 communicates via the first communication terminal 16. Then, data is sent and received.

[0037] When the battery MCU 50 receives a connection signal from the first detection circuit 73, it switches from energy-saving mode to active mode. The battery MCU 50 performs charging control of the battery 30 when the battery pack 100 is connected to a charger, and performs discharge control of the battery 30 when the battery pack 100 is connected to an electric work machine.

[0038] Specifically, the battery MCU 50 performs charging and discharging control of the battery 30 based on the cell voltage, battery voltage, and current value received from the AFE 40, and the temperature input from the first temperature detection circuit 35.

[0039] The battery MCU 50 performs different charging control depending on the charger rate. Specifically, as shown in Figure 4, when charging the battery 30 with the high-rate charger 200, the battery MCU 50 performs constant current constant voltage charging and stops charging when the first condition is met. The first condition is that the battery voltage value Vnow is equal to or greater than the completion voltage value Vset, and the next current value Inext is less than the completion current value Icut.

[0040] In this case, the battery 30 is charged with a constant charging current value Inow that is greater than the completion current value Icut, until the battery voltage reaches the completion voltage value Vset. When the battery voltage Vnow reaches the completion voltage value Vset, the charging current value Inow decreases so that the battery voltage Vnow remains constant at the completion voltage value Vset. Then, when the next current value Inext becomes 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 in the next processing cycle. The open-circuit voltage value at the completion of charging corresponds to the target voltage value Vtg.

[0041] Here, as shown in Figure 5, when charging the battery 30 with the low-rate charger 300, if charging is stopped when the first condition is met, the charging current value Inow is initially smaller than the completion current value Icut, so charging stops when the battery voltage value Vnow reaches the completion voltage value Vset. The open-circuit voltage value at the completion of charging becomes larger than the target voltage value Vtg. In other words, when charging the battery 30 with the low-rate charger 300, if charging is stopped when the first condition is met, the charging capacity of the battery 30 becomes larger than when charging the battery 30 with the high-rate charger 200.

[0042] The open-circuit voltage at the end of charging corresponds to the battery voltage Vnow at the end of charging minus the voltage drop due to the internal resistance of the battery 30. The charging current when charging the battery 30 with the low-rate charger 300 is smaller than the charging current when charging the battery 30 with the high-rate charger 200. Therefore, when charging the battery 30 with the low-rate charger 300, the voltage drop due to the internal resistance of the battery 30 is smaller than when charging the battery 30 with the high-rate charger 200. As a result, when charging the battery 30 with the low-rate charger 300, if charging is stopped when the battery voltage Vnow becomes equal to or greater than the completion voltage Vset, the open-circuit voltage at the end of charging will be the target voltage Vtg + ΔVocv. ΔVocv corresponds to the difference between the voltage drop when charging with the high-rate charger 200 and the voltage drop when charging with the low-rate charger 300.

[0043] Therefore, when charging the battery 30 with the low-rate charger 300, the battery MCU 50 stops charging in response to a second condition, which is different from the first condition, being met. As shown in Figure 6, the second condition is set so that the open-circuit voltage value at the completion of charging by the low-rate charger 300 matches the target voltage value Vtg.

[0044] Specifically, the battery MCU50 checks if the battery voltage value Vnow is equal to or greater than the judgment value Vb. Depending on the result, charging is stopped. The judgment value Vb is the target voltage value Vtg plus the correction value ΔVa. The correction value ΔVa corresponds to the voltage drop when charging with the low-rate charger 300 at a charging current value Inow, and is expressed as ΔVa = (Vset - Vtg) × Inow / Icut. As a result, the open-circuit voltage value and charging capacity when the battery 30 is fully charged by the low-rate charger 300 match the open-circuit voltage value and charging capacity when the battery 30 is charged by the high-rate charger 200.

[0045] Furthermore, if the battery MCU 50 determines that an electric work machine is connected to the battery pack 100 and that the battery 30 is in a state where it cannot be discharged (for example, over-discharged or overheated), it outputs a discharge prohibition signal to the discharge control circuit 72 to prohibit discharge from the battery 30. The discharge control circuit 72 outputs the discharge prohibition signal received from the battery MCU 50 to the electric work machine from the discharge terminal 14. Also, if the battery MCU 50 determines that the battery 30 is in a state where it can be discharged, it outputs a watchdog pulse signal (a pulse signal with a fixed period) to the discharge control circuit 72. If the watchdog pulse signal is not input to the discharge control circuit 72, it outputs a discharge prohibition signal to the electric work machine from the discharge terminal 14.

[0046] Furthermore, if the battery MCU 50 outputs a discharge prohibition signal to the electric work machine but the discharge is not stopped, it operates the interruption element 62 to interrupt the conduction of the first positive electrode line 18. For example, if the interruption element 62 is an FET, the battery MCU 50 turns off the FET. Also, if the interruption element 62 is an SCP, the battery MCU 50 blows the fuse of the SCP.

[0047] The battery MCU 50 shuts down when it is over-discharged. When the battery pack 100 is connected to the charger while the battery MCU 50 is shut down, 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. When the battery MCU 50 receives power from the regulator 61, it starts up from the shut-down state.

[0048] <1-2-2. Electrical configuration of the charger> The high-rate charger 200 and the low-rate charger 300 each include a charger MCU 400, a switching power supply circuit 410, an 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.

[0049] The charger-side terminal sections 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.

[0050] 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.

[0051] 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 operates in response to control commands from the charger MCU 400 and outputs a charging current.

[0052] The FET 420 is located on the second positive electrode line 480. The charger shunt resistor 450 is located on the second negative electrode line 490. The charger shunt resistor 450 detects the value of 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. The second temperature detection circuit 44 detects the temperature of the switching power supply circuit 410 as the charger temperature and outputs the detected charger temperature to the charger MCU 400.

[0053] The interlock circuit 430 is connected to the second charging terminal 413 and stops the operation of the switching power supply circuit 410 when a charging stop signal is input via the second charging terminal 413.

[0054] The charger MCU400 includes a microcomputer equipped with a CPU400a, memory400b, and I / O, etc. The charger MCU400 is connected to a second detection circuit460 and a second communication circuit470.

[0055] The second detection circuit 460 detects whether the battery pack 100 is connected to the charger or not based on the potential of the second detection terminal 415, and outputs a connected signal or a disconnected signal to the charger MCU 400.

[0056] The second communication circuit 470 is a Universal Asynchronous Receiver / Transmitter (UART) that performs half-duplex serial communication. The second communication circuit 470 is connected to the second communication terminal 416 Data is sent and received via this method.

[0057] The charger MCU 400 controls the charging of the battery 30. Furthermore, if the interlock circuit 430 fails to stop the operation of the switching power supply circuit 410, the charger MCU 400 turns off the FET 420, thereby stopping the power supply from the switching power supply circuit 410 to the battery pack 100.

[0058] <2. Processing> Next, the charging control performed by the battery MCU 50 and the charger MCU 400 will be explained with reference to the flowchart in Figure 7. The battery MCU 50 and the charger MCU 400 start this process when the battery-side mounting section 20 is mounted on the charger-side mounting section 220 or the charger-side mounting section 320.

[0059] First, in the S200, the charger MCU400 sets the initial value of the charging current value Inow to 0A. Next, in S210, the charger MCU400 notifies the battery pack 100 of the charging current value Inow for the current processing cycle.

[0060] Next, in the S220, the charger MCU400 acquires the charger temperature. Next, in S230, the charger MCU400 determines the current upper limit current value Icg_limit according to the charger temperature obtained in S220. For example, charger MCU40 A value of 0 means that if the charger temperature exceeds a threshold, the upper limit current value Icg_limit is reduced to prevent the high-rate charger 200 or low-rate charger 300 from overheating.

[0061] Meanwhile, in S10, the battery MCU50 receives the charging current value Inow from the charger attached to the battery pack 100. Next, in S20, the battery MCU50 acquires the battery voltage value Vnow and the battery temperature for the current processing cycle.

[0062] Next, in S30, the battery MCU 50 calculates the completion voltage value Vset according to the state of the battery 30. Specifically, the battery MCU 50 calculates the completion voltage value Vset according to the degree of degradation of the battery 30 and / or the battery temperature. A table of completion voltage values ​​Vset corresponding to the degree of degradation and battery temperature may be stored in memory 50b in advance, and the completion voltage value Vset may be calculated using the table.

[0063] Next, in S40, the battery MCU 50 calculates the completion current value Icut according to the state of the battery 30. Specifically, the battery MCU 50 calculates the completion current value Icut according to the degree of degradation of the battery 30 and / or the battery temperature. The battery MCU 50 may also calculate the completion current value Icut using a table previously stored in memory 50b. The degree of degradation of the battery 30 is updated each time the battery pack 100 is used and stored in memory 50b.

[0064] Next, in S50, the battery MCU50 calculates the next current value Inext based on the charging current value Inow. Specifically, the battery MCU50 compares the battery voltage value Vnow and the completion voltage value Vset to determine whether to continue with the charging current value Inow, decrease it, or increase it as the next current value Inext. Then, the battery MCU50 calculates the charging current value Inow as the next current value Inext, or calculates a value that is a decrease or increase to the charging current value Inow.

[0065] 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 is equal to or greater than the completion voltage value Vset. If it is determined that the battery voltage value Vnow is equal to or greater than 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.

[0066] In S70, it is determined whether the next current value Inext is less than the completion current value Icut. If it is determined that the next current value Inext is less than the completion current value Icut, the first condition is met, and the process proceeds to S110 to complete charging. If it is determined that the next current value Inext is greater than or equal to the completion current value Icut, the process proceeds to S80.

[0067] In steps S80 to S100, the battery MCU50 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 the charging current value Inow is less than the completion current value Icut, the process proceeds to S90. On the other hand, if the charging current value Inow is greater than or equal to the completion current value Icut, neither the first nor the second condition is met, so the process proceeds to S120 and charging control continues.

[0068] In the S90, the battery MCU 50 calculates a target voltage value Vtg. Specifically, it calculates the target voltage value Vtg according to 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. Also, if the battery temperature is lower or higher than the appropriate range, the battery MCU 50 decreases the target voltage value Vtg more than when the battery temperature is within the appropriate range. For example, as shown in Figure 8, a table of target voltage values ​​Vtg according to the degree of degradation and battery temperature is stored in memory 50b in advance, and the target voltage value Vtg is calculated using the table. The target voltage value Vtg calculated here corresponds to the open-circuit voltage value of the battery 30 when charging of the battery 30 is completed according to the fulfillment of the first condition.

[0069] Next, in S100, the battery MCU50 calculates a correction value ΔVa, and adds the correction value ΔVa to the target voltage value Vtg calculated in S90 to calculate the judgment value Vb. Then, the battery The MCU50 determines whether the battery voltage value Vnow is equal to or greater than the judgment value Vb.

[0070] If the battery voltage value Vnow is determined to be equal to or greater than the judgment 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 less than the judgment value Vb, neither the first nor the second condition is met, and the process proceeds to S120 to continue charging control.

[0071] Here, since the judgment value Vb is smaller than the completion voltage value Vset, if the charging current value Inow is smaller than the completion current value Icut, the second condition is met before the first condition is met, and charging is stopped. On the other hand, if the charging current value Inow is equal to or greater than the completion current value Icut, the determination of whether the second condition is met is not made, and only the determination of whether the first condition is met is made, and charging is stopped in accordance with the determination of the first condition.

[0072] Next, in S120, the next current value Inext, calculated in S50, is sent to the charger connected to the battery pack 100. After that, the process returns to S10 and the next processing cycle begins. The battery MCU 50 repeatedly executes processes S10 to S120 until charging is complete.

[0073] Meanwhile, in S240, the charger MCU400 receives the next current value Inext transmitted from the battery pack 100. 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 xt is less than or equal to the upper limit current value Icg_limit, proceed to processing S260. If the next current value Inext is determined to be greater than the upper limit current value Icg_limit, The process then proceeds to S270.

[0074] In S260, the charger MCU 400 outputs a control command to the switching power supply circuit 410 so that the next current value Inext is output to the battery pack 100, and then proceeds to the process in S280.

[0075] In the S270, the charger MCU400 has a current limit of Icg_limit. A control command is output to the switching power supply circuit 410 so that it is output to the repack 100, and the process proceeds to S280.

[0076] In S280, the charger MCU400 sets the current output current value as the charging current value Inow. Then, the charger MCU400 returns to the process in S210 and starts the next processing cycle. The charger MCU400 repeatedly executes the processes in S210 to S280, and terminates the charging process when the next current value Inext becomes 0.

[0077] <3. Effects> According to the embodiment described above, the following effects can be obtained. (1) If the charging current value Inow is equal to or greater than the completion current value Icut, charging is stopped in accordance with the fulfillment of the first condition. Also, if the charging current value Inow is less than the completion current value Icut, charging is stopped in accordance with the fulfillment of a second condition which is different from the first condition. In other words, when charging with a relatively small charging current value Inow, different charging control is performed compared to when charging with a relatively large charging current value Inow. Therefore, the battery pack 100 can be used with both the high-rate charger 200 and the low-rate charger 300.

[0078] (2) When charging battery 30 with a relatively small charging current value Inow, charging complete A second condition is set so that the open-circuit voltage value at the end of charging matches the target voltage value Vtg. This makes it possible to match the open-circuit voltage value at the end of charging when the battery 30 is charged with a relatively small charging current value Inow to the open-circuit voltage value at the end of charging when the battery 30 is charged with a relatively large charging current value Inow.

[0079] (3) By calculating a target voltage value Vtg based on the state of the battery 30, overcharging of the battery 30 can be suppressed and the battery 30 can be properly protected. (4) The voltage drop at the charging current value Inow is calculated as a correction value ΔVa, and the value obtained by adding the correction value ΔVa to the target voltage value Vtg is calculated as a determination value Vb. This makes it possible to match the open-circuit voltage value when charging is completed to the target voltage value Vtg, depending on whether the second condition is met.

[0080] (Other embodiments) The above describes the forms for implementing this disclosure, but this disclosure is not limited to the embodiments described above and can be implemented in various modified forms.

[0081] (a) Multiple functions of one component in the above embodiment may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Furthermore, some of the configuration of the above embodiment may be omitted. Furthermore, at least some of the configuration of the above embodiment may be added to or replaced with the configuration of other above embodiments.

[0082] (b) In addition to the battery pack described above, the disclosure can also be realized in various forms, such as a charging system that uses the battery pack as a component, a program executed by the MCU of the battery pack, a non-transitional physical recording medium such as a semiconductor memory that records this program, and a charging control method executed by the battery pack. [Explanation of symbols]

[0083] 1...Charging system, 10...Battery side terminal section, 11...First positive terminal, 12...First negative terminal, 13...First charging terminal, 14...Discharge terminal, 15...First detection terminal, 16...First communication terminal, 18...First positive line, 19...First negative line, 20...Battery side mounting section, 35...First temperature detection circuit, 50...Battery MCU, 61...Regulator, 62...Blocking element, 63...Battery shunt resistor, 71...Charging control circuit, 72...Discharge control circuit, 73...First detection circuit, 74...First communication circuit, 100...Battery pack, 200...High-voltage Charger, 210, 310... Charger side terminal section, 220, 320... Charger side mounting section, 300... Low rate 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.

Claims

1. A high-rate charger configured to connect to a battery pack containing a lithium-ion battery, A low-rate charger configured to be connected to the aforementioned battery pack, The maximum current that the aforementioned high-rate charger can output is equal to or greater than the completion current value. The maximum current that the low-rate charger can output is less than the completion current value. The aforementioned completion current value corresponds to the magnitude of the charging current at the completion of charging when the lithium-ion battery is charged at a constant current and constant voltage. The high-rate charger is configured to stop outputting the charging current when it is determined that the battery pack has met a first condition while charging the battery pack connected to the high-rate charger. The low-rate charger is configured to stop outputting the charging current when it is determined that a second condition, different from the first condition, has been met by the battery pack while the battery pack connected to the low-rate charger is being charged. Charging system.

2. The high-rate charger and the low-rate charger are charger control units, The maximum current value is calculated based on the charger's status. The charging current output to the battery pack has the smaller of the calculated upper limit current value and the requested current value corresponding to the magnitude of the charging current requested by the battery pack. A charger control unit is provided, configured as follows: The charging system according to claim 1.

3. The charger control unit, The charger is configured to acquire the temperature of the charger. The state of the charger is the temperature of the charger obtained by the charger control unit. The charging system according to claim 2.

4. A battery pack comprising a lithium-ion battery and a battery control unit, configured to be connected to a high-rate charger or low-rate charger of a charger system, The maximum current that the aforementioned high-rate charger can output is equal to or greater than the completion current value. The maximum current that the low-rate charger can output is less than the completion current value. The aforementioned completion current value corresponds to the magnitude of the charging current at the completion of charging when the lithium-ion battery is charged at a constant current and constant voltage. The battery control unit, The voltage value of the lithium-ion battery is obtained, Obtain a charging current value corresponding to the magnitude of the charging current in the current processing cycle. Based on the acquired charging current value, a required current value corresponding to the magnitude of the charging current allowed in the next processing cycle is calculated. If the acquired charging current value is equal to or greater than the completion current value, the charging of the lithium-ion battery is stopped in accordance with the first condition being met. The system is configured to stop charging the lithium-ion battery when the charging current value obtained by the battery control unit is less than the completion current value, and the second condition is met. The first condition is met based on the fact that the voltage value obtained by the battery control unit is equal to or greater than the completion voltage value, and the requested current value calculated by the battery control unit is less than the completion current value. The second condition is different from the first condition. Battery pack.

5. The battery control unit is configured to output the calculated required current value to the high-rate charger or the low-rate charger connected to the battery pack. The battery pack according to claim 4.

6. The battery control unit is configured to calculate a target voltage value. The target voltage value corresponds to the open-circuit voltage of the lithium-ion battery when charging of the lithium-ion battery is stopped in accordance with the fulfillment of the first condition. The second condition is set such that the open-circuit voltage value when charging of the lithium-ion battery is stopped in accordance with the fulfillment of the second condition matches the target voltage value. The battery pack according to claim 4 or 5.

7. The battery control unit, The temperature of the lithium-ion battery is obtained, The system is configured to calculate the target voltage value based on the acquired temperature and / or the degree of degradation of the lithium-ion battery. The battery pack according to claim 6.

8. The second condition is met based on the fact that the voltage value obtained by the battery control unit is equal to or greater than the determination value. The determination value corresponds to the value obtained by adding a correction value to the target voltage value. The correction value corresponds to (Vset - Vtg) × Inow / Icut, where Vset corresponds to the completion voltage value, Vtg corresponds to the target voltage value, Inow corresponds to the charging current value obtained by the battery control unit, and Icut corresponds to the completion current value. The battery pack according to claim 6 or 7.

9. The battery control unit, The temperature of the lithium-ion battery is obtained, The system is configured to calculate the completion current value based on the acquired temperature and / or the degree of degradation of the lithium-ion battery. The battery pack according to any one of claims 4 to 8.

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