Power supply system

Abstract

Provided is a power supply system which includes a detachable battery that can be attached to and detached from a drive system, and which has little power loss. This power supply system is provided with: a fixed battery fixed to a drive system that is driven by power; a detachable battery pack that can be attached to and detached 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 power from either or both of the fixed battery and the detachable battery pack.

Description

Technical Field

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

[0002] Patent document 1 discloses a power storage system in which a plurality of battery packs are connected in parallel and each includes a chargeable and dischargeable battery, a converter that changes the discharge current and charge current of the battery, and a battery pack control unit that detects the state of the battery and controls the converter, and at least some of the battery packs are loadable and removable.

[0003] When a high-voltage battery and a low-voltage battery are connected in parallel, a large current flows as an equalization current. However, in the configuration of Patent Document 1, since the battery pack has a converter, the voltage difference between the batteries can be adjusted to prevent the large current from flowing.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-025791 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the configuration of Patent Document 1, the converter functions as a resistor to equalize the current from the high-voltage battery, thereby preventing a large current from flowing, resulting in a large power loss. In addition, since the battery pack has the converter, the weight increases, the portability decreases, and the configuration becomes complicated, resulting in an increase in cost.

[0009] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a power supply system including a detachable battery that can be attached to and detached from a drive system and has a small power loss.

[0010] Technical solutions to solve problems

[0011] The power supply system disclosed in the present invention comprises: a fixed battery fixed to a drive system driven by electric power; a detachable battery pack that can be loaded and unloaded relative to 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 switches to power from either or both of the fixed battery and the detachable battery pack to drive the drive system.

[0012] Effects of the Invention

[0013] According to the present disclosure, it is possible to realize a power supply system including a detachable battery that is detachable from a drive system and having a small power loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic configuration diagram of a power supply system according to an embodiment.

[0015] Description of Reference Numerals

[0016] 1: Power supply system;

[0017] 2: Drive the load;

[0018] 3: Fixed battery;

[0019] 4: Removable battery pack;

[0020] 5: DCDC converter;

[0021] 7: ECU;

[0022] 41, 42: removable batteries;

[0023] 61, 62, 63: voltage monitoring unit;

[0024] SW1~SW6: switch;

[0025] 100: Vehicles. DETAILED DESCRIPTION

[0026] The power supply system according to the embodiment of the present disclosure will be described with reference to the drawings. The components of the following embodiment include components that can be easily replaced by those skilled in the art or are substantially the same.

[0027] (Implementation Method)

[0028] [Composition of the power supply system]

[0029] Figure 1 : is a schematic diagram of the power supply system of the embodiment. Figure 1 As shown, in a vehicle 100 serving as a driving system, a power supply system 1 for supplying power to a driving load 2 includes a fixed battery 3, a detachable battery pack 4, a DCDC converter 5, voltage monitoring units 61 to 63 serving as detection units, an ECU (Electronic Control Unit) 7 serving as a control unit, switches SW1 and SW2 serving as first switches, and switches SW3 to SW6 serving as second switches.

[0030] The vehicle 100 is, for example, an electric vehicle (BEV) or a plug-in hybrid electric vehicle (PHEV), but is not limited to a vehicle as long as it is a drive system that can be driven by electric power supplied from the power supply system 1 .

[0031] The drive load 2 is a motor mounted on the vehicle 100 .

[0032] The fixed battery 3 is fixed to the vehicle 100, but can also be replaced. The fixed battery 3 is, for example, a battery pack composed of 12 battery cells connected in series, but the number of battery cells is not particularly limited. In addition, the following description assumes that "the voltage of each battery cell is equal", but battery cells with different voltages can also be used. When the voltage of each battery cell is equal, the voltage of the fixed battery 3 is proportional to the number of battery cells. In addition, the fixed battery 3 can drive the drive load 2 with the power of the fixed battery 3 alone.

[0033] The detachable battery pack 4 is connected in parallel with the fixed battery 3, and has two detachable batteries 41 and 42 that can be attached and detached (installed and removed) relative to the vehicle 100. The voltage of each detachable battery of the detachable battery pack 4 is a value obtained by dividing the voltage of the fixed battery 3 by an integer, and the voltage of the detachable batteries 41 and 42 is approximately half of the voltage of the fixed battery 3. In this case, the detachable batteries 41 and 42 are, for example, battery packs formed by connecting six battery cells in series. In addition, the detachable battery pack 4 can drive the driving load 2 with the power of the detachable battery pack 4 alone.

[0034] The DCDC converter 5 converts the voltage from the stationary battery 3 and supplies electric power to the detachable battery 41 or the detachable battery 42 .

[0035] 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 detachable battery 41. The voltage monitoring unit 63 detects the voltage state of the detachable battery 42. The voltage monitoring units 61 to 63 are, for example, voltmeters or ammeters, and any configuration is sufficient as long as it can detect the voltage states of the fixed battery 3 and the detachable battery pack 4. The voltage monitoring units 61 to 63 are provided on the vehicle 100 side, and the voltage monitoring unit 62 can be provided on the detachable battery 41 side, and the voltage monitoring unit 63 can be provided on the detachable battery 42 side. By providing the voltage monitoring units 62 and 63 on the vehicle 100 side, the weight of the detachable battery 41 and the detachable battery 42 can be reduced to improve portability, and the configuration of the detachable battery 41 and the detachable battery 42 can be simplified to reduce costs. In this case, a configuration for detecting the voltage states of the detachable battery 41 and the detachable battery 42 is provided on the charger side that charges the detachable battery 41 and the detachable battery 42 .

[0036] ECU7 is composed of information processing devices such as microcomputers including CPU (Central Processing Unit), FPGA (Field-Programmable Gate Array), ROM (Read Only Memory), and RAM (Random Access Memory). ECU7 comprehensively controls the electrical operation of each part of the vehicle 100. ECU7 is configured to perform calculations using input data, pre-stored data, and programs, and output the calculation results as control command signals. In addition, ECU7 selects a detachable battery to be supplied with power from the fixed battery 3 based on the detection results of the voltage monitoring units 61 to 63. In addition, ECU7 supplies power from the fixed battery 3 to the detachable battery 41 or the detachable battery 42, sets the fixed battery 3 and the detachable battery pack 4 to the same voltage, and connects the fixed battery 3 and the detachable battery pack 4 in parallel to drive the vehicle 100.

[0037] The switches SW1 and SW2 switch the vehicle 100 to drive the vehicle 100 by using the electric power from either or both of the stationary battery 3 and the detachable battery pack 4 .

[0038] The switches SW3 to SW6 switch the detachable battery that supplies power from the DCDC converter 5. The switches SW3 to SW6 are provided on the vehicle 100 side, the switches SW3 and SW4 can be provided on the detachable battery 41 side, and the switches SW5 and SW6 can be provided on the detachable battery 42 side. By providing the switches SW3 to SW6 on the vehicle 100 side, the weight of the detachable battery 41 and the detachable battery 42 can be reduced to improve portability, and the configuration of the detachable battery 41 and the detachable battery 42 can be simplified to reduce costs.

[0039] According to the power supply system 1 described above, the detachable battery 41 and the detachable battery 42 are included in the vehicle 100, and the circuit for supplying power from the detachable battery pack 4 to the driving load 2 does not include a converter, so the power loss is small.

[0040] Furthermore, according to the power supply system 1 , the detachable battery 41 and the detachable battery 42 do not include a converter, so that the weight of each detachable battery is reduced and portability is improved, and the configuration can be simplified and the cost can be reduced.

[0041] In addition, according to the power supply system 1, by dividing the detachable battery pack 4 into the detachable battery 41 and the detachable battery 42, the weight of each detachable battery is reduced, the portability is improved, and the operation of removing and carrying becomes easy. Therefore, the detachable battery 41 and the detachable battery 42 can be flexibly used as an auxiliary power source during a disaster or outdoor activities.

[0042] In addition, the voltage of each detachable battery of the detachable battery group 4 can be a value obtained by dividing the voltage of the fixed battery 3 by an integer. For example, when the integer is 3, the detachable battery group 4 has three detachable batteries. In this case, each detachable battery is a battery pack composed of four battery cells connected in series. By setting it as such a structure, the portability of the detachable battery can be further improved.

[0043] [Vehicle driving method based on electric power supply system]

[0044] When the vehicle 100 is driven by the power supply system 1, the ECU 7 preferentially uses the power of the detachable battery pack 4 to drive the vehicle 100. Since each detachable battery of the detachable battery pack 4 can be replaced with a charged detachable battery, the vehicle 100 can be used continuously for a long time by preferentially using the power of the detachable battery pack 4. In addition, when the power of the detachable battery pack 4 is exhausted, the weight of the vehicle 100 can be reduced by removing the detachable battery 41 and the detachable battery 42, and the power economy can be improved by driving the vehicle 100 with the power from the fixed battery 3. In addition, although the life of the detachable battery 41 and the detachable battery 42 is shortened first by preferentially using the power of the detachable battery pack 4, the battery life of the vehicle 100 can be prolonged because the detachable battery is replaceable.

[0045] In addition, when the voltages of the detachable battery 41 and the detachable battery 42 are different, the detachable battery with a low capacity reaches the discharge stop voltage, and the other detachable batteries become unusable. Therefore, the ECU 7 selects the detachable battery with a low capacity as the detachable battery to be supplied with power from the fixed battery 3 based on the detection results of the voltage monitoring units 61 to 63. And, by charging the detachable battery with a low capacity to the same capacity as the detachable battery with a high capacity using the power from the fixed battery 3, the detachable battery group 4 can be used for a long time.

[0046] When the detachable battery 41 and the detachable battery 42 have different voltages and the vehicle 100 is driven by the detachable battery pack 4 , the stationary battery 3 assists the output of the low-capacity detachable battery, and the vehicle 100 can be driven by the detachable battery pack 4 .

[0047] In addition, the ECU 7 supplies power from the fixed battery 3 to the detachable battery 41 or the detachable battery 42, sets the fixed battery 3 and the detachable battery pack 4 to the same voltage, and connects the fixed battery 3 and the detachable battery pack 4 in parallel to drive the vehicle 100. First, by setting the fixed battery 3 and the detachable battery pack 4 to the same voltage, it is possible to prevent a large current from flowing as an equalization current. Then, by connecting the fixed battery 3 and the detachable battery pack 4 in parallel to drive the vehicle 100, it is possible to suppress heat generation and efficiently drive the vehicle 100, and the vehicle 100 can be used continuously for a long time.

[0048] [Method of charging the power supply system]

[0049] When charging the fixed battery 3 and the detachable battery pack 4 from the vehicle 100, the ECU 7 charges the fixed battery 3 with priority. Since each detachable battery of the detachable battery pack 4 can be replaced with a charged detachable battery, the vehicle 100 can be used continuously for a long time by charging the fixed battery 3 with priority. In addition, by charging the fixed battery 3 with priority, even in a state where the voltages of the detachable battery 41 and the detachable battery 42 are different, the vehicle 100 can be driven by the detachable battery pack 4 by supplying power from the fixed battery 3 to the detachable battery with a low capacity, and the vehicle 100 can be used continuously for a long time.

[0050] When charging the detachable battery pack 4 from the vehicle 100 , the ECU 7 preferentially charges the detachable battery with a low total voltage or a small charging capacity. This can reduce the voltage difference of the detachable batteries and enable the vehicle 100 to be driven for a long time by the detachable battery pack 4 .

[0051] In the embodiment, an example is described in which the ECU 7 selects a detachable battery to be supplied with power from the fixed battery 3 based on the detection results of the voltage monitoring units 61 to 63, but the DCDC converter 5 may also have a function of selecting a detachable battery to be supplied with power from the fixed battery 3 based on the detection results of the voltage monitoring units 61 to 63. Similarly, the DCDC converter 5 may also have a part of the functions of the ECU 7.

[0052] Further effects and variations can be easily derived by those skilled in the art. Thus, the broader technical solutions of the present invention are not limited to the specific detailed and representative embodiments shown and described above. Therefore, various changes can be made without departing from the spirit or scope of the concept of the general invention defined by the attached claims and their equivalents.

Claims

1. A power supply system comprising: Stationary batteries are fixed to the drive system that uses electricity for driving; a detachable battery pack that can be detached from the drive system, is connected in parallel to the fixed battery, and has a plurality of detachable batteries connected in series; and The first switch switches the driving system to be driven by power from one or both of the fixed battery and the detachable battery pack.

2. The power supply system according to claim 1, comprising: a DCDC converter that converts a voltage from the fixed battery to supply electric power to any of the detachable batteries; and The second switch switches the detachable battery to which the DCDC converter supplies power.

3. The power supply system according to claim 1, comprising: A detection unit detects voltage states of the fixed battery and the detachable battery.

4. The power supply system according to claim 3, comprising: A control unit selects the detachable battery to which electric power is supplied from the fixed battery based on the detection result of the detection unit.

5. The power supply system according to claim 4, The control unit supplies power from the fixed battery to the selected detachable battery, makes the fixed battery and the detachable battery group have the same voltage, and connects the fixed battery and the detachable battery group in parallel to drive the drive system.

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