Secondary battery charging system, campervan, secondary battery charging method

Abstract

To provide a secondary battery charging system with a simple structure that can efficiently charge secondary batteries while suppressing overcharging, a camper van equipped with this secondary battery charging system, and a secondary battery charging method. [Solution] The system includes a plurality of power supply units 10 connected in parallel to the battery C, each power supply unit 10 comprising a power supply unit 20, a power control unit 40, a voltage detection unit 70 for detecting the battery voltage, and a current detection unit 80 for detecting the current to be applied, the power control unit 10 is configured to charge the battery C by applying a set current, and to stop applying the current when the battery voltage reaches the set voltage, the plurality of power supply units 10 are set to different set voltages, and the power control unit 10 stops applying the current when the battery voltage reaches the set voltage due to charging, and reduces the current applied to the battery C as the battery voltage rises.

Description

Technical Field

[0005]

[0001] The present invention relates to a secondary battery charging system for efficiently and safely charging a secondary battery, a camping car equipped with this secondary battery charging system, and a secondary battery charging method.

Background Art

[0002] As is well known, secondary batteries such as lithium-ion batteries have become indispensable in modern society, and the need for increasing the capacity and rapid charging of secondary batteries is growing. For such an increase in the capacity and efficient charging of secondary batteries, safety measures against overcharging are essential, and it is necessary to control a large current, so the charging device becomes large, complex, and expensive.

[0003] Therefore, in order to control a large current with a simple structure, a technique of connecting a plurality of fixed small power sources in parallel and controlling the number of their outputs has been disclosed (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] However, the power supply device described in Patent Document 1 requires a complex applied current command to control the number of fixed small power sources. In addition, when applying the above power supply device to the charging of secondary batteries, for example, when charging a plurality of secondary batteries connected in parallel, if some secondary batteries are fully charged and their BMS (Battery Management System) operates, excess current is applied to other secondary batteries, causing deterioration of the secondary batteries. Therefore, it is necessary to detect the number of fully charged batteries, etc., and the configuration of the applied current command becomes even more complex. Therefore, there is a strong demand for secondary battery charging technology that is simple in structure, efficient, and safe by suppressing overcharging. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The present invention was devised to address the above-mentioned conventional problems, and aims to provide a secondary battery charging system that can efficiently charge secondary batteries while suppressing overcharging with a simple structure, a camper van equipped with this secondary battery charging system, and a secondary battery charging method. [Means for solving the problem]

[0007] The present invention A secondary battery charging system, It comprises multiple power supply units, each with a set current to be applied to the secondary battery and a set voltage to stop the application of current to the secondary battery. The aforementioned multiple power supply units are connected in parallel to the secondary battery, and at least some of the power supply units have their set voltages set to different values. The power supply unit is configured to stop applying current when the battery voltage of the secondary battery reaches a set voltage. When charging a secondary battery, the power supply unit applies current once the battery voltage reaches the set voltage. Stop This configuration reduces the charging power as the battery voltage of the secondary battery increases. It is characterized by the following: or A secondary battery charging system, in parallel Equipped with multiple connected power supply units, The aforementioned power supply unit is A power supply unit that converts AC power to DC power, A power control unit sets a set current to be applied to the secondary battery and a set voltage to stop the application of current to the secondary battery, and converts the power supplied from the power supply unit into charging power, A voltage detection unit for detecting the battery voltage of a secondary battery, A current detection unit for detecting the current applied to the secondary battery, Equipped with, At least a portion of the aforementioned power supply unit has its set voltage set to a different value. When charging a secondary battery, the power supply unit applies current once the battery voltage reaches the set voltage. Stop This configuration reduces the charging power as the battery voltage of the secondary battery increases. It is characterized by the following: or The power supply unit includes a voltage setting unit for setting the set voltage. It is characterized by the following: or The power supply unit includes a current setting unit for setting the set current. It is characterized by the following: or The power supply unit is composed of a CC-CV power supply device. It is characterized by the following: or The system includes a current interruption unit that interrupts the conduction between the plurality of power control units and the secondary battery, When setting the voltage of any of the power supply units, The power supply unit in question and its corresponding power interruption unit are set to a conductive state, while the power interruption units corresponding to other power supply units are set to a non-conductive state, thereby electrically isolating the power supply unit in question from other power supply units, and allowing the set voltage to be set independently. It is characterized by the following: or The system includes a current interruption unit that interrupts the conduction between the plurality of power control units and the secondary battery, When setting the current of any of the power supply units, By making the power interruption unit corresponding to the target power supply unit conductive, and the power interruption units corresponding to other power supply units non-conductive, the target power supply unit is electrically isolated from the other power supply units, and the target power supply unit is connected to the secondary battery or setting load, thereby enabling the setting current to be set independently. It is characterized by the following: Or, a camper van comprising the secondary battery charging system according to any one of the above items, characterized in that Or, a secondary battery charging method, wherein a plurality of power supply units having at least partially different set voltages are connected in parallel to a secondary battery, a set current is applied to the secondary battery by the plurality of power supply units to charge the secondary battery, as the battery voltage of the secondary battery rises and reaches the set voltage of any one of the power supply units, the application of current by that power supply unit is stopped, thereby reducing the current applied as the battery voltage rises, characterized in that.

Advantages of the Invention

[0008] According to the secondary battery charging system, the camper van equipped with this secondary battery charging system, and the secondary battery charging method according to the present invention, a secondary battery can be charged safely and efficiently with a simple structure.

Brief Description of the Drawings

[0009] [Figure 1] It is a schematic configuration diagram for explaining an example of a camper van equipped with a battery charging system (secondary battery charging system) according to an embodiment of the present invention. [Figure 2] It is a circuit diagram for explaining an example of the power system of a battery charging system (secondary battery charging system) according to an embodiment. [Figure 3] It is a block diagram for explaining an example of the schematic configuration of a battery charging system (secondary battery charging system) according to an embodiment. [Figure 4] It is a block diagram for explaining an example of the schematic of a power supply unit according to an embodiment. [Figure 5] It is a flowchart for explaining an example of the schematic operation of a power supply unit according to an embodiment. [Figure 6] This is a flowchart illustrating an example of CC-CV control according to one embodiment. [Figure 7] This is a conceptual diagram illustrating the operation of a power supply unit according to one embodiment. [Figure 8] This is a conceptual diagram illustrating the operation of a battery charging system (secondary battery charging system) according to one embodiment. [Modes for carrying out the invention]

[0010] A camper van according to one embodiment of the present invention will be described below with reference to Figure 1. Figure 1 is a schematic diagram illustrating an example of a camper van equipped with a battery charging system (secondary battery charging system) according to one embodiment. In Figure 1, reference numeral 1 denotes the camper van, reference numeral 4 denotes a charging connector for the camper van, reference numeral 5 denotes a household outlet, reference numeral 6 denotes a charging power supply for an electric vehicle, reference numeral 100 denotes the battery charging system (secondary battery charging system), and reference numeral C denotes a battery (secondary battery).

[0011] As shown in Figure 1, one embodiment of the campervan 1 includes, for example, a campervan body 2, a battery charging system (secondary battery charging system) 100 mounted on the campervan body 2, a charger activation circuit 3, a campervan charging connector 4, and a battery (secondary battery) C.

[0012] The system is configured such that a household power supply (e.g., 100V / 200V) 5 or an EV charging power supply 6 installed at a service area or roadside station is connected to the campervan charging connector 4 by a power supply means (e.g., a cable (dashed line)), and the charger start circuit 3 is activated. This converts the charging power supplied from the household power supply 5 or EV charging power supply 6 into charging power by the battery charging system (secondary battery charging system) 100, thereby charging the battery C. Here, the battery C is, for example, a lithium-ion battery (e.g., a lithium iron phosphate battery). However, the type of battery C is not limited to a lithium-ion battery and may be set arbitrarily.

[0013] Next, with reference to Figures 2 to 8, a battery charging system (secondary battery charging system) 100 according to one embodiment of the present invention will be described. Figure 2 is a circuit diagram illustrating an example of a power system of a battery charging system (secondary battery charging system) according to one embodiment; Figure 3 is a block diagram illustrating an example of a schematic configuration of the battery charging system; and Figure 4 is a block diagram illustrating an schematic of the power supply unit. In the diagram, reference numerals 10, 11, 12, and 13 indicate the power supply unit, reference numerals 20, 21, 22, and 23 indicate the power supply unit, and reference numerals 40, 41, 42, and 43 indicate the power control unit. Additionally, reference numeral A indicates the AC power supply, reference numerals B, B1, and B2 indicate the busbars, and reference numerals C, C1, C2, and C3 indicate the battery (rechargeable battery).

[0014] The battery charging system (secondary battery charging system) 100 includes, for example, three (or more) power supply units 11, 12, 13 (10) connected in parallel, as shown in Figures 2 and 3. Furthermore, as shown in Figure 2, the power supply units 11, 12, and 13(10) have their input side connected to AC power supply A, and their output side connected to three (or more) batteries C1, C2, and C3(C) connected in parallel via busbars B1 and B2(B). Here, batteries C1, C2, and C3(C) are, for example, lithium-ion batteries, and each of batteries C1, C2, and C3(C) is configured by connecting four single cells (individual lithium-ion batteries) in series. The number of single cells connected in series can be set arbitrarily. Furthermore, in this embodiment, the power supply units 11, 12, and 13 are equipped with current interruption units 91, 92, and 93 (90), as shown in Figure 2.

[0015] In this embodiment, the current interruption units 91, 92, 93(90) include, for example, jumper pins 91J, 92J, 93J(90J) and switching means (e.g., semiconductor switches) 91S, 92S, 93S(90S). Jumper pins 91J, 92J, and 93J (90J) are installed in power control units 41, 42, and 43, and are wired to be connectable (inserted) to terminals that control the ON / OFF state of the switching means 91S, 92S, and 93S (90S).

[0016] The switching means 91S, 92S, 93S (90S) are, for example, located between the power control units 41, 42, 43 and at least one of the busbars B1, B2 (B) for connecting batteries C1, C2, C3 (C) in parallel. They are configured to operate in conjunction with the insertion (connection) and disconnection of jumper pins 91J, 92J, 93J (90J).

[0017] Specifically, when jumper pins 91J, 92J, and 93J (90J) are inserted (connected) to the terminals of the power control units 41, 42, and 43 (40), the switching means 91S, 92S, and 93S (90S) are "closed (ON) (conductive state)", and when jumper pins 91J, 92J, and 93J (90J) are removed (detached), the switching means 91S, 92S, and 93S (90S) are "open (OFF) (non-conductive state)".

[0018] As a result, when jumper pins 91J, 92J, and 93J (90J) are inserted into the terminals of power control units 41, 42, and 43 (40), the power control units 41, 42, and 43 (40) are electrically connected to busbars B1 and B2 (B), and when jumper pins 91J, 92J, and 93J (90J) are removed from the terminals, the power control units 41, 42, and 43 (40) are electrically disconnected from busbars B1 and B2 (B). The configuration of the current interruption units 91, 92, and 93 (90) may be set arbitrarily.

[0019] The power supply units 11, 12, and 13(10) then convert the AC power supplied (e.g., 60Hz, 100V) input (supplied) from, for example, AC power source A, into DC power with a voltage of 12V to output charging power, which is then supplied (output) to batteries C1, C2, and C3(C) as charging power via busbars B1 and B2(B). The number of power supply units 10 and the number of batteries (secondary batteries) C connected in parallel may be set arbitrarily. In addition, the frequency and voltage of the power supplied from the applicable AC power supply A, and the voltage and current of the output charging power may be set arbitrarily. Note that the battery C shown in Figures 3 and 4 is an abbreviated representation of three batteries C1, C2, and C3 connected in parallel.

[0020] As shown in Figures 3 and 4, the power supply unit 10 (11, 12, 13) comprises, for example, a power supply unit 20 (21, 22, 23), a power control unit 40 (41, 42, 43), a voltage setting unit 50 (51, 52, 53), a current setting unit 60 (61, 62, 63), a voltage detection unit 70 (71, 72, 73), and a current detection unit 80 (81, 82, 83), thus constituting a CC-CV power supply device. Note that the current interruption units 91, 92, 93 (90) are omitted here.

[0021] As shown in Figures 3 and 4, the power supply unit 20 (21, 22, 23) transforms the voltage of the power supplied from the AC power supply A, for example from 100V to 12V, and also converts it from AC to DC before outputting it to the power control unit 40 (41, 42, 43).

[0022] The power control units 40 (41, 42, 43) convert the DC power supplied from the power supply units 20 (21, 22, 23) into charging power using CC-CV control, and supply the charging power to the batteries (secondary batteries) C (C1, C2, C3). Here, CC-CV control is a control method that, after charging begins, initially charges the secondary battery at a set constant current (Constant Current) to gradually increase the battery voltage, and then, once the battery voltage reaches the set voltage, switches to charging at a constant voltage (Constant Voltage) and reduces the charging current.

[0023] Furthermore, the power control units 41, 42, and 43(40) are set to different voltages, for example, and when the battery voltage of the battery (secondary battery) C being charged reaches the set voltage, the power control units 41, 42, and 43(40) each reduce the applied current to zero and stop supplying power for charging. In this embodiment, the set voltages of 41, 42, and 43 are set to, for example, 13.8V, 14.2V, and 14.6V. However, the set voltages may be set arbitrarily, as long as at least one of them is set to a different value.

[0024] As shown in Figures 3 and 4, the power control unit 40 (41, 42, 43) is connected to the voltage setting unit 50 (51, 52, 53), the current setting unit 60 (61, 62, 63), the voltage detection unit 70 (71, 72, 73), and the current detection unit 80 (81, 82, 83), and is configured to acquire signals from these units. The power control unit 40 (41, 42, 43) then applies PWM control (pulse width modulation control), for example, by repeatedly switching ON and OFF at a constant period, changing the ratio (duty cycle) of the ON time (pulse width). Initially, it outputs a constant current, and once the output side reaches a constant voltage, the application of the constant current stops, and the rise in battery voltage stops.

[0025] The voltage setting units 50 (51, 52, 53) set the upper limit voltage of the charging power supplied from the power control units 40 (41, 42, 43) to the batteries (secondary batteries) C (C1, C2, C3) as the set voltage for the power control units 40 (41, 42, 43). The voltage setting section 50 (51, 52, 53) is configured, for example, with a semi-fixed resistor. Note that the current setting sections 61, 62, 63 are not limited to semi-fixed resistors, and variable resistors or the like may be used as desired.

[0026] The current setting units 61, 62, and 63 set the constant current that the power control unit 40 (41, 42, 43) applies to the battery (secondary battery) C (C1, C2, C3) as the set current. The current setting sections 61, 62, and 63 are configured, for example, with semi-fixed resistors. However, the current setting sections 61, 62, and 63 are not limited to semi-fixed resistors and may be replaced with variable resistors or other components as desired.

[0027] The voltage detection unit 70 (71, 72, 73) is connected, for example, to the output terminal of the power control unit 40, detects (measures) the output voltage of the power control unit 40, and outputs it to the power control unit 40 (41, 42, 43). The voltage detected by the voltage detection unit 70 (71, 72, 73) can be the battery voltage of the battery (secondary battery) C (C1, C2, C3) while it is being charged.

[0028] The current detection units 80 (81, 82, 83) are connected, for example, between the output terminal of the power control unit 40 and the battery (secondary battery) C (C1, C2, C3), and detect the charging current of the battery (secondary battery) C (C1, C2, C3) and output it to the power control unit 40 (41, 42, 43). The voltage detection unit 70 and the current detection unit 80 may be, for example, built into the power control unit 40.

[0029] Next, referring to Figures 2 to 4, the method for setting the set voltage and the set current in the battery charging system (secondary battery charging system) 100 will be explained.

[0030] [Setting the voltage] First, we will explain how to set the voltage in the battery charging system 100. (1) For example, when setting the set voltage of the power supply unit 11, the electrical connection between the power supply unit 11 and the power supply units 12 and 13 is interrupted. Specifically, the jumper pin 91J of the power supply unit 11 is left inserted to connect the current interruption unit 91, while the jumper pins 92J and 93J of the power supply units 12 and 13 are removed to disable conductivity. (2) Next, the battery (secondary battery) C (C1, C2, C3) is disconnected from busbar B so that the output terminal of the power supply unit 11 is no longer affected by the battery (secondary battery) C (C1, C2, C3). Note that the disconnection from busbar B may be performed on only one of busbars B1 (positive terminal V+) or B2 (negative terminal V-). (3) Next, while referring to the voltage detection unit 71(70), the semi-fixed wires constituting the voltage setting unit 51(50) are adjusted to set the voltage of the power supply unit 11(10). When the voltage detected by the voltage detection unit 17 reaches the set voltage, the voltage setting of the power supply unit 11 is terminated. (4) Similarly, the same procedure as (1) to (3) above is repeated for all power supply units 12 and 30 other than power supply unit 11 to set the set voltage.

[0031] [Setting the current] Next, we will explain how to set the current in the battery charging system 100. (1) For example, when setting the set current of the power supply unit 11, the electrical connection between the power supply unit 11 and the power supply units 12 and 13 is interrupted. Specifically, the jumper pin 91J of the power supply unit 11 is left inserted to connect the current interruption unit 91, while the jumper pins 92J and 93J of the power supply units 12 and 13 are removed to disable conductivity. The battery (secondary battery) C (C1, C2, C3) is connected to busbar B, and the power supply unit 11 is connected to battery C. Alternatively, the battery (secondary battery) C (C1, C2, C3) may be disconnected and a setting load (resistor) may be connected instead. (2) Next, while referring to the current detection unit 81, the current applied to the power supply unit 11 is set by adjusting the semi-fixed wires that make up the current setting unit 61(60). When the current detected by the current detection unit 81 reaches the set current, the current setting of the power supply unit 11 is terminated. (3) Similarly, the same procedure as in (1) and (2) above is repeated for all power supply units 12 and 13 other than power supply unit 11 to set the current.

[0032] Note that you may choose to set the voltage or current first, or you may set them consecutively.

[0033] Next, the operation of the power supply unit 10 (11, 12, 13) and the power control unit 40 (41, 42, 43) will be described with reference to Figures 5 to 7. Figure 5 is a flowchart illustrating an example of the operation of a power supply unit according to one embodiment, and Figure 6 is a flowchart illustrating an example of CC-CV control according to one embodiment. Figure 7 is a conceptual diagram illustrating the operation of a power supply unit according to one embodiment. In Figure 7, the horizontal axis represents the elapsed time t after startup, and the vertical axis represents the applied current to the power supply unit 10 (11, 12, 13) and the battery voltage (=output voltage) of battery C. The symbol Ic represents the set current, the symbol V0 represents the voltage at the start of charging, and the symbol Vs represents the set voltage. Furthermore, T0 in the elapsed time t represents the start of charging, and Ts represents the timing when the battery voltage Vt reaches the set voltage Vs.

[0034] First, with reference to Figure 5, the operation of the power supply unit 10 (11, 12, 13) will be explained. (1) First, read the set voltage Vs (S01). For example, when the power supply unit 10 (11, 12, 13) is activated, the power control unit 40 (41, 42, 43) reads the set voltage Vs by referring to the voltage setting unit 50 (51, 52, 53). (2) Next, read the set current Ic (S02). For example, the power control unit 40 (41, 42, 43) reads the set current Ic by referring to the current setting unit 60 (61, 62, 63). (3) Next, CC-CV control is performed based on the set voltage Vs and set current Ic (S10). (4) When the CC-CV control by the power control unit 40 stops, the operation of the power supply unit 10 (11, 12, 13) is terminated. Note that the order in which the set voltage Vs is read (S01) and the set current Ic is read (S02) can be set arbitrarily.

[0035] Next, an example of CC-CV control in the power control unit 40 (41, 42, 43) will be described with reference to Figures 6 and 7. (1) First, as shown in Figure 6, when CC-CV control is started, the current detection unit 80 (81, 82, 83) detects the applied current It of the power control unit 40 (41, 42, 43) (S11). (2) Next, the power control units 40 (41, 42, 43) calculate the duty cycle (S12). The duty cycle is calculated, for example, by determining the current difference ("set current Ic" - "detected current It") and then determining the applied current (=detected current) at which the current difference becomes zero. In other words, the duty cycle is calculated such that "detected current" = "set current Ic". Note that the method for calculating the duty cycle can be set arbitrarily. (3) Next, the applied current is controlled (S13). Specifically, the applied current is controlled by adjusting the duty cycle in PWM control. As a result, when the power control unit 40 (41, 42, 43) starts CC-CV control at T0 as shown in Figure 7, it applies a set constant current (set current) Ic to charge the battery C. As a result, the battery voltage (=output voltage) Vt of the battery C gradually increases. (4) Next, the battery voltage (output voltage) Vt is detected (S14). (5) Check if the battery voltage Vt ≥ the set voltage Vs (S15). If the battery voltage Vt is greater than or equal to the set voltage Vs (Yes), proceed to S16; otherwise, proceed to S11. (6) Set the duty cycle in PWM control to zero (S16). By setting the duty cycle to zero, the applied current becomes zero, and as shown in the elapsed time Ts in Figure 7, the applied current becomes zero. Also, the output voltage (=battery voltage) Vt of the power control unit 40 (41, 42, 43) is maintained at the set voltage Vs. (7) Check for the presence or absence of a charging stop signal. (S17) If a charging stop signal is present (Yes), CC-CV control is terminated; if there is no charging stop signal (No), the process proceeds to S11.

[0036] Next, with reference to Figure 8, the operation of the battery charging system (secondary battery charging system) 100 will be explained. Figure 8 is a conceptual diagram illustrating the operation of a battery charging system (secondary battery charging system). In this embodiment, for example, power supply unit 11 is set to a voltage of 13.8V, power supply unit 12 to a voltage of 14.2V, and power supply unit 13 to a voltage of 14.6V. In addition, the set current Ic of power supply units 11, 12, and 13 is set to 120A.

[0037] (1) When the battery charging system 100 is started, the power supply units 11, 12, and 13 (10) are activated. As shown in Figure 8, the power supply units 11, 12, and 13 each output charging power with a set current Ic of, for example, 120A. As a result, the battery charging system 100 charges battery C by applying a current of 360A as charging power to the three power supply units 11, 12, and 13 between T0 and T1 in Figure 8, and the battery voltage of battery C gradually increases. Furthermore, the output voltages of the power supply units 11, 12, and 13(10) are equal to the battery voltage of battery C. (2) Next, at T1, when the battery voltage of battery C rises to 13.8V, the current applied to the power supply unit 11 becomes zero. As a result, the battery charging system 100 applies a total charging current of 240V through its two power supply units 12 and 13, causing the battery voltage of battery C to gradually increase. (3) Next, at T2, when the battery voltage of battery C rises to 14.2V, the current applied to the power supply unit 12 becomes zero. As a result, only the power supply unit 11 of the battery charging system 100 operates, applying a current of 120A to the battery C as charging power, and the battery voltage of the battery C gradually increases. (4) Next, at T3, when the battery voltage of battery C rises to 14.6V, the current applied to the power supply unit 11 becomes zero. As a result, the charging power output from the battery charging system 100 to battery C becomes zero, the battery voltage of battery C stops rising, and the battery voltage of the power supply unit 11 and battery C is maintained at 14.6V.

[0038] According to a battery charging system (secondary battery charging system) 100 and battery charging method (secondary battery charging method) according to one embodiment, the power supply units 11, 12, 13 (10) are sequentially stopped and the applied current decreases each time the battery voltage of battery C reaches a set voltage Vs, thereby suppressing overcharging and deterioration of battery C.

[0039] Furthermore, according to the battery charging system (secondary battery charging system) 100 and the battery charging method (secondary battery charging method), when charging multiple batteries (secondary batteries) C, even if some of the batteries C become fully charged, it is possible to suppress the application of excessive current to the other batteries C, which would otherwise cause the batteries C to deteriorate.

[0040] Furthermore, the battery charging system (secondary battery charging system) 100 allows for stable and safe rapid charging of battery C.

[0041] According to a battery charging system (secondary battery charging system) 100 according to one embodiment, the power supply units 11, 12, 13(10) are equipped with current interruption units 91, 92, 93(90), and the conductivity with other power supply units 11, 12, 13(10) can be controlled by attaching and detaching jumper pins 91J, 92J, 93J(90J), so that the set current and set voltage of each power supply unit 11, 12, 13(10) can be set efficiently. As a result, it is possible to provide an efficient method for setting the set current and set voltage in the battery charging system (secondary battery charging system) 100.

[0042] Furthermore, the battery charging system (secondary battery charging system) 100 ensures that when charging multiple batteries (secondary batteries) C, even if some of the batteries (secondary batteries) C become fully charged, excess current is not applied, thus enabling stable and safe charging.

[0043] It should be noted that the present invention is not limited to the embodiments described above and can be modified in various ways. For example, in the above embodiment, we described a case where the battery charging system 100 has three power supply units 10 (11, 12, 13) and charges three batteries (secondary batteries) C1, C2, and C3 (C). However, the number of power supply units 10 and the number of batteries C can be set arbitrarily.

[0044] Furthermore, in the above embodiment, the case in which the power supply units 11, 12, and 13 (10) are set to voltages of 14.6V, 14.2V, and 13.8V (voltage interval of 0.4V) was described. However, the set voltage of each power supply unit 10 (11, 12, 13) and the voltage difference between the power supply units 10 (11, 12, 13) can be set arbitrarily. The set voltages can be set to values ​​other than 14.6V, 14.2V, and 13.8V, and the voltage difference (interval) of the set voltages can be set to a value other than 0.4V. For example, the voltage difference between power supply unit 11 and power supply unit 12 can be set to 0.6V, and the voltage difference between power supply unit 12 and power supply unit 13 can be set to 0.2V, and various other voltage differences can be set.

[0045] Furthermore, although the above embodiment described a case in which the power supply units 11, 12, and 13(10) are set to different set voltages, some of the multiple power supply units 10 constituting the battery charging system (secondary battery charging system) 100 may be set to the same set voltage.

[0046] Furthermore, although the above embodiment described the case where the set current Ic of the power supply units 11, 12, and 13(10) is all set to the same current value (120A), the set current Ic of the power supply units 11, 12, and 13(10) may be set arbitrarily. Also, the set current Ic of any one of the power supply units 11, 12, and 13(10) may be set to different current values. For example, power supply unit 11 may be set to 180A, power supply unit 12 to 120A, and power supply unit 13 to 60A, etc.

[0047] Furthermore, although the above embodiment described a case in which the system includes current setting units 61, 62, 63(60) for setting the set current and voltage setting units 71, 72, 73(70) for setting the set voltage, the inclusion of the current setting units 61, 62, 63(60) and voltage setting units 71, 72, 73(70) can be arbitrarily determined. For example, the system may be configured without these units by setting the set current and set voltage to pre-set fixed values. Alternatively, the system may be configured to be configured using an externally installed PC or the like.

[0048] Furthermore, although the above embodiment described a case in which the power supply units 11, 12, and 13(10) each have voltage detection units 71, 72, and 73(70), the battery voltage may be detected using fewer voltage detection units 70 (for example, one) than the number of power supply units 11, 12, and 13(10) by having the power supply units 11, 12, and 13(10) share the voltage detection unit 70.

[0049] Furthermore, although the above embodiment described the case where the battery (secondary battery) C is a lithium-ion battery, it is not limited to lithium-ion batteries. For example, it may also be applied to secondary batteries such as lead-acid batteries, nickel-metal hydride batteries, various all-solid-state batteries, and semi-solid-state batteries. Furthermore, regarding lithium-ion batteries, this method is not limited to lithium iron phosphate batteries, but may be applied to various types of lithium-ion batteries such as cobalt-based, manganese-based, nickel-based, NCA-based, and ternary (NMC) batteries.

[0050] Furthermore, although the above embodiment described a case in which the current interruption unit 90 comprises a jumper pin 90J and a switching means 90S, the configuration of the current interruption unit 90 may be set arbitrarily. Also, whether or not to include a current interruption unit 90 may be set arbitrarily.

[0051] For example, a switch may be used instead of the jumper pin 90J, or a relay or power conversion switch may be used instead of a semiconductor switch as the switching means 90S.

[0052] Furthermore, although the above embodiment describes the case in which the battery charging system (secondary battery charging system) 100 is installed in a campervan, it may also be applied to charging batteries (secondary batteries) C in places other than campervans. For example, it may be applied to charging using AC power in factories or homes, or to charging systems that use a DC power source such as a solar system or fuel cell instead of AC power as the power source. [Explanation of Symbols]

[0053] 1 camper van 10, 11, 12, 13 Power supply section 20, 21, 22, 23 Power supply section 40, 41, 42, 43 Power control unit 50, 51, 52, 53 Voltage setting section 60, 61, 62, 63 Current setting section 70, 71, 72, 73 Voltage detection unit 80, 81, 82, 83 Current detection unit 90, 91, 92, 93 Current interruption section 90J, 91J, 92J, 93J Jumper Pins 100 Battery Charging System (Rechargeable Battery Charging System) A AC power supply B, B1, B2 bus bars C, C1, C2, C3 Batteries (rechargeable batteries)

Claims

1. A secondary battery charging system, It comprises multiple power supply units, each with a set current to be applied to the secondary battery and a set voltage to stop the application of current to the secondary battery. The aforementioned multiple power supply units are connected in parallel to the secondary battery, and at least some of the power supply units have their set voltages set to different values. The power supply unit is configured to stop applying current when the battery voltage of the secondary battery reaches a set voltage. When charging a secondary battery, the power supply unit stops applying current when the battery voltage reaches a set voltage, thereby reducing the charging power as the battery voltage of the secondary battery increases. A secondary battery charging system characterized by the following features.

2. A secondary battery charging system, It is equipped with multiple power supply units connected in parallel, The aforementioned power supply unit is A power supply unit that converts AC power to DC power, A power control unit sets a set current to be applied to the secondary battery and a set voltage to stop the application of current to the secondary battery, and converts the power supplied from the power supply unit into charging power, A voltage detection unit for detecting the battery voltage of a secondary battery, A current detection unit for detecting the current applied to the secondary battery, Equipped with, At least a portion of the aforementioned power supply unit has its set voltage set to a different value. When charging a secondary battery, the power supply unit stops applying current when the battery voltage reaches a set voltage, thereby reducing the charging power as the battery voltage of the secondary battery increases. A secondary battery charging system characterized by the following features.

3. The power supply unit includes a voltage setting unit for setting the set voltage. The secondary battery charging system according to feature 2.

4. The power supply unit includes a current setting unit for setting the set current. The secondary battery charging system according to feature 2.

5. The power supply unit is composed of a CC-CV power supply device. A secondary battery charging system according to claim 1 or 2.

6. The system includes a current interruption unit that interrupts the conduction between the plurality of power control units and the secondary battery, When setting the voltage of any of the power supply units, The power supply unit in question and its corresponding power interruption unit are set to a conductive state, while the power interruption units corresponding to other power supply units are set to a non-conductive state, thereby electrically isolating the power supply unit in question from other power supply units, and enabling the setting voltage to be set independently. The secondary battery charging system according to feature 2.

7. The system includes a current interruption unit that interrupts the conduction between the plurality of power control units and the secondary battery, When setting the current of any of the power supply units, By making the power interruption unit corresponding to the target power supply unit conductive, and the power interruption units corresponding to other power supply units non-conductive, the target power supply unit is electrically isolated from the other power supply units, and the target power supply unit is connected to the secondary battery or setting load, thereby enabling the setting current to be set independently. The secondary battery charging system according to feature 2.

8. A secondary battery charging system according to any one of claims 1 to 4, A campervan is characterized by this feature.

9. A method for charging secondary batteries, Multiple power supply units with at least some different set voltages are connected in parallel to the secondary battery. The aforementioned multiple power supply units apply a set current to the secondary battery to charge it. As the battery voltage of the secondary battery rises and reaches the set voltage of any power supply unit, the application of current by the power supply unit is stopped, thereby reducing the current applied in accordance with the rise in battery voltage. A secondary battery method characterized by the following:

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