Power Supply System

Abstract

To provide a power supply system including a detachable battery detachable from a drive system and having a small power loss.SOLUTION: A power supply system includes: a fixed battery that is fixed to a drive system driven by electric power; a detachable battery group that is detachable from the drive system, is connected in parallel with the fixed battery, and has a plurality of detachable batteries connected in series; and a first switch that drives the drive system by switching to the electric power from one or both of the fixed battery and the detachable battery group.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a power supply system. [Background technology]

[0002] Patent Document 1 discloses an energy storage system in which multiple battery packs are connected in parallel, each having a chargeable and dischargeable battery, a converter that changes the discharge current and charge current of the battery, and a pack control unit that detects the state of the battery and controls the converter, and at least some of the battery packs are detachable.

[0003] When a high-voltage battery and a low-voltage battery are connected in parallel, an excessive current flows as an equalization current. However, in the configuration of Patent Document 1, the battery pack has a converter, which adjusts the voltage difference between the batteries and prevents excessive current from flowing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-025791 Summary of the Invention [Problem to be solved by the invention]

[0005] In the configuration of Patent Document 1, the converter functions as a resistor against the equalization current from the high-voltage battery, preventing excessive current from flowing, resulting in a large power loss. Furthermore, since the battery pack has a converter, it increases in weight, reducing portability, and also complicates the configuration, leading to increased costs.

[0006] The present disclosure has been made in view of the above, and has an object to provide a power supply system that includes a detachable battery that can be attached to a drive system and that has low power loss. [Means for solving the problem]

[0007] The power supply system of the present disclosure comprises a fixed battery fixed to a drive system driven by electricity, a removable battery group that is detachable from the drive system and connected in parallel with the fixed battery, and has a plurality of removable batteries connected in series, and a first switch that switches to power from either or both of the fixed battery or the removable battery group to drive the drive system. [Effects of the Invention]

[0008] According to the present disclosure, a power supply system with small power loss can be realized, which includes a detachable battery that can be attached to a drive system. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic configuration diagram of a power supply system according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] A power supply system according to an embodiment of the present disclosure will be described with reference to the drawings. Note that components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially identical.

[0011] (Embodiment) [Configuration of the power supply system] Fig. 1 is a schematic configuration diagram of a power supply system according to an embodiment. As shown in Fig. 1, in a vehicle 100 as a drive system, a power supply system 1 that supplies power to a drive load 2 includes a fixed battery 3, a removable battery group 4, a DC-DC converter 5, voltage monitoring units 61 to 63 as detectors, an ECU (Electronic Control Unit) 7 as a controller, switches SW1 and SW2 as first switches, and switches SW3 to SW6 as second switches.

[0012] Vehicle 100 is, for example, an electric vehicle (BEV: Battery Electric Vehicle) or a plug-in hybrid electric vehicle (PHEV: Plug-in Hybrid Electric Vehicle), but is not limited to a vehicle as long as it has a drive system that can be driven by power supplied from power supply system 1.

[0013] The driving load 2 is a motor mounted on the vehicle 100.

[0014] The fixed battery 3 is fixed to the vehicle 100, but may be replaceable. The fixed battery 3 is, for example, a battery pack with 12 battery cells connected in series, but the number of battery cells is not particularly limited. In the following description, it is assumed that the voltages of the battery cells are the same, but battery cells with different voltages may also be used. When the voltages of the battery cells are the same, the voltage of the fixed battery 3 is proportional to the number of battery cells. Furthermore, the fixed battery 3 is capable of driving the drive load 2 using the power of the fixed battery 3 alone.

[0015] The removable battery group 4 is connected in parallel with the fixed battery 3 and includes removable batteries 41, 42 that can be attached to and detached from the two vehicles 100. The voltage of each removable battery in the removable battery group 4 may be any value obtained by dividing the voltage of the fixed battery 3 by an integer, and the voltage of the removable batteries 41, 42 is approximately half the voltage of the fixed battery 3. In this case, the removable batteries 41, 42 are, for example, a battery pack in which six battery cells are connected in series. Furthermore, the removable battery group 4 is capable of driving the drive load 2 using the power of the removable battery group 4 alone.

[0016] The DC-DC converter 5 converts the voltage from the fixed battery 3 and supplies power to the removable battery 41 or the removable battery 42 .

[0017] The voltage monitoring unit 61 detects the voltage state of the fixed battery 3. The voltage monitoring unit 62 detects the voltage state of the removable battery 41. The voltage monitoring unit 63 detects the voltage state of the removable battery 42. The voltage monitoring units 61-63 are, for example, voltmeters or ammeters, but may be configured to detect the voltage states of the fixed battery 3 and the removable battery group 4. The voltage monitoring units 61-63 are provided on the vehicle 100 side, but the voltage monitoring unit 62 may be provided on the removable battery 41 side, and the voltage monitoring unit 63 may be provided on the removable battery 42 side. By providing the voltage monitoring units 62 and 63 on the vehicle 100 side, the weight of the removable battery 41 and the removable battery 42 can be reduced, improving portability, and the configuration of the removable battery 41 and the removable battery 42 can be simplified, reducing costs. In this case, the charger that charges the detachable batteries 41 and 42 is provided with a configuration that detects the voltage state of the detachable batteries 41 and 42.

[0018] The ECU 7 is configured with an information processing device such as a microcomputer including a CPU (Central Processing Unit), FPGA (Field-Programmable Gate Array), ROM (Read Only Memory), and RAM (Random Access Memory). The ECU 7 comprehensively controls the electrical operation of each part of the vehicle 100. The ECU 7 is configured to perform calculations using input data and pre-stored data and programs, and output the calculation results as control command signals. The ECU 7 also selects a removable battery to supply power from the fixed battery 3 based on the detection results of the voltage monitoring units 61-63. The ECU 7 also supplies power from the fixed battery 3 to the removable battery 41 or the removable battery 42, sets the fixed battery 3 and the removable battery group 4 at the same voltage, and connects the fixed battery 3 and the removable battery group 4 in parallel to drive the vehicle 100.

[0019] Switches SW1 and SW2 switch the power source to either or both of the fixed battery 3 and the removable battery group 4 to drive the vehicle 100.

[0020] Switches SW3 to SW6 switch between the removable batteries that receive power from the DC-DC converter 5. Switches SW3 to SW6 are provided on the vehicle 100 side, but switches SW3 and SW4 may be provided on the removable battery 41 side, and switches SW5 and SW6 may be provided on the removable battery 42 side. By providing switches SW3 to SW6 on the vehicle 100 side, the weight of the removable battery 41 and the removable battery 42 can be reduced, improving portability, and the configuration of the removable battery 41 and the removable battery 42 can be simplified, reducing costs.

[0021] The power supply system 1 described above includes a removable battery 41 and a removable battery 42 that can be attached to and detached from the vehicle 100, and the circuit that supplies power from the removable battery group 4 to the drive load 2 does not include a converter, so power loss is small.

[0022] Furthermore, according to the power supply system 1, the removable battery 41 and the removable battery 42 do not include a converter, so the weight of each removable battery is reduced, making them highly portable, and the configuration is simplified, resulting in reduced costs.

[0023] Furthermore, according to the power supply system 1, the removable battery group 4 is divided into the removable battery 41 and the removable battery 42, which reduces the weight of each removable battery, making them highly portable and easy to remove and carry. Therefore, the removable batteries 41 and 42 can be used as auxiliary power sources during disasters or outdoor activities.

[0024] The voltage of each removable battery in the removable battery group 4 can be any value obtained by dividing the voltage of the fixed battery 3 by an integer. For example, if this integer is 3, the removable battery group 4 has three removable batteries. In this case, each removable battery is a battery pack with four battery cells connected in series. This configuration further increases the portability of the removable battery.

[0025] [Method for driving a vehicle using a power supply system] When the vehicle 100 is driven by the power supply system 1, the ECU 7 preferentially uses the power of the removable battery group 4 to drive the vehicle 100. Because each removable battery of the removable battery group 4 can be replaced with a charged removable battery, preferentially using the power of the removable battery group 4 allows the vehicle 100 to be used continuously for a long period of time. Furthermore, when the power of the removable battery group 4 is used up, the weight of the vehicle 100 can be reduced by removing the removable batteries 41 and 42, and the vehicle 100 can be driven using power from the fixed battery 3, thereby improving power consumption. Furthermore, by preferentially using the power of the removable battery group 4, the lifespan of the removable batteries 41 and 42 will shorten first, but because the removable batteries are replaceable, the battery life of the vehicle 100 can be extended.

[0026] Furthermore, if the voltages of removable battery 41 and removable battery 42 are different, the low-capacity removable battery will reach its discharge stop voltage, making the other removable batteries unusable. Therefore, ECU 7 selects the low-capacity removable battery as the removable battery to which power is supplied from fixed battery 3, based on the detection results of voltage monitoring units 61-63. Then, by charging the low-capacity removable battery with power from fixed battery 3 up to the same capacity as the high-capacity removable battery, removable battery group 4 can be used for a long time.

[0027] Furthermore, when the vehicle 100 is driven by the detachable battery group 4 in a state where the voltages of the detachable battery 41 and the detachable battery 42 are different, the fixed battery 3 supplements the output of the low-capacity detachable battery, allowing the vehicle 100 to be driven by the detachable battery group 4.

[0028] Furthermore, the ECU 7 supplies power from the fixed battery 3 to the removable battery 41 or the removable battery 42, equalizes the voltage of the fixed battery 3 and the removable battery group 4, and connects the fixed battery 3 and the removable battery group 4 in parallel to drive the vehicle 100. First, by equalizing the voltage of the fixed battery 3 and the removable battery group 4, it is possible to prevent excessive current from flowing as an equalization current. Then, by connecting the fixed battery 3 and the removable battery group 4 in parallel to drive the vehicle 100, heat generation is suppressed, and the vehicle 100 can be driven efficiently, enabling it to be used continuously for long periods of time.

[0029] [Charging method for power supply system] When charging the fixed battery 3 and the removable battery group 4 from the vehicle 100, the ECU 7 gives priority to charging the fixed battery 3. Because each removable battery in the removable battery group 4 can be replaced with a charged removable battery, giving priority to charging the fixed battery 3 allows the vehicle 100 to be used continuously for a long period of time. Furthermore, by giving priority to charging the fixed battery 3, even if the voltages of the removable battery 41 and the removable battery 42 are different, the vehicle 100 can be driven by the removable battery group 4 by supplying power from the fixed battery 3 to the lower-capacity removable battery, allowing the vehicle 100 to be used continuously for a long period of time.

[0030] When charging the removable battery group 4 from the vehicle 100, the ECU 7 preferentially charges the removable battery with a low total voltage or a small charge capacity. This reduces the voltage difference between the removable batteries, allowing the vehicle 100 to be driven for a long period of time by the removable battery group 4.

[0031] In the embodiment, an example has been described in which the ECU 7 selects the removable battery to which power is supplied from the fixed battery 3 in accordance with the detection results of the voltage monitoring units 61 to 63, but the DC-DC converter 5 may have the function of selecting the removable battery to which power is supplied from the fixed battery 3 in accordance with the detection results of the voltage monitoring units 61 to 63. Similarly, the DC-DC converter 5 may have some of the functions of the ECU 7.

[0032] Further advantages and modifications will readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0033] 1. Power supply system 2 Drive Load 3 Fixed battery 4. Removable battery group 5 DC-DC converter 7 ECU 41, 42 Detachable battery 61, 62, 63 Voltage monitoring unit SW1 to SW6 switches 100 vehicles

Claims

1. a fixed battery fixed to a drive system driven by electricity; a removable battery group that is detachable from the drive system and connected in parallel with the fixed battery, the removable battery group having a plurality of removable batteries connected in series; a first switch that switches to power from either or both of the fixed battery and the removable battery group to drive the drive system; A power supply system comprising:

2. a DC-DC converter that converts the voltage from the fixed battery and supplies power to any one of the removable batteries; a second switch for switching the removable battery that supplies power from the DC-DC converter; The power supply system according to claim 1 , comprising:

3. The power supply system according to claim 1 , further comprising a detection unit that detects the voltage states of the fixed battery and the removable battery.

4. The power supply system according to claim 3 , further comprising a control unit that selects the removable battery to supply power from the fixed battery in accordance with the detection result of the detection unit.

5. 5. The power supply system according to claim 4, wherein the control unit supplies power from the fixed battery to the removable battery, sets the fixed battery and the removable battery group at the same voltage, and connects the fixed battery and the removable battery group in parallel to drive the drive system.

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