TWI531135B - System and method for charge and discharge - Google Patents

Description

Charge and discharge system and method thereof

The present invention relates to a charging and discharging system and a method thereof, and more particularly to charging a first battery or a second battery by a charging circuit, and making the electric quantity sufficient to drive a load, and simultaneously A control unit controls the first battery or the second battery to perform a selective discharge mode or a simultaneous discharge mode charge and discharge system for a load and a method thereof.

At present, there is only one vehicle battery in a general drive vehicle, but after using it for a period of time, the battery power of the vehicle will be exhausted, so that the passenger can not continue driving in the middle of the road and the use is inconvenient.

However, in order to improve the use of the above-mentioned vehicle battery for a period of time, the power is gradually lost and the driving cannot be continued, and a new vehicle battery must be replaced. Therefore, as shown in the figure 9, there is a generator (A). Connected to a charging circuit (B), the charging circuit (B) is electrically connected to a vehicle battery (C), the vehicle battery (C) is electrically connected to a discharging circuit (D), and the discharging circuit (D) is electrically Connecting a load (E), and the load (E) is electrically connected to the generator (A) to form a charge and discharge electrical circuit, and further generating electricity by the generator (A) The charging circuit (B) charges the vehicle battery (C), and further discharges the power of the vehicle battery (C) to a load (E) by the discharge circuit (D) to generate power for the vehicle. The generator (A) can generate electric power by the power, and thus circulates, but the battery (C) of the vehicle performs charging and discharging processes at the same time, which often damages the vehicle battery (C) itself, and Since the service life is reduced, it is still necessary to replace the battery (C) of the vehicle from time to time, which causes inconvenience in use.

According to the shortcomings of the above-mentioned prior art, the battery charging and discharging structure of the conventional driving vehicle is as in the case of the Republic of China New Patent Publication No. M410676 "Electric Vehicle with Power Generation Function", which includes a vehicle body including At least one driving device; two car batteries, which are correspondingly disposed in the car body, and are respectively electrically connected to the driving device, and one of the car batteries is supplied with power of the driving device; a judgment control circuit electrically connected to the Between the driving device and the vehicle battery, and the determining control circuit can switch to be in a state to be charged when the remaining battery power of the driving device power is lower than a preset value, and simultaneously switch another battery battery for The device power should be driven; and a charging device electrically connected to the determination control circuit and can be charged when the battery of the vehicle is lower than the preset suitable value and is in a state to be charged.

In addition, the Republic of China New Patent Announcement No. M381547 "Electric Vehicle Power Supply Device" uses a solar power module, a wind power module, a manual power generation module, or a mains power supply device to charge a battery that is rectified. After the circuit and the voltage stabilizing circuit, the detecting circuit is used to determine the power of the first battery and the second battery, to charge the battery with a smaller power, and the battery with a larger power is supplied to the electric vehicle. When the battery in use is about to run out, the detection circuit will automatically switch to the battery that has been charged to continue to supply power.

However, the above-mentioned conventional ones have the following disadvantages that still need to be improved:

1. The judgment control circuit of the "electric vehicle with power generation function" determines that one of the batteries switches to a state to be charged if its electric quantity is lower than a preset appropriate value, and simultaneously switches another battery to supply the drive. The device is powered, but this is not the case when the power of the driving device is supplied by another battery, and the power generated by the driving device is converted into electric power to be stored on the battery to be charged, so that it is still inconvenient in use.

2. It is known that the charging device of the "electric vehicle with power generation function" mainly charges the battery by burning fuel or by using solar energy. However, if the fuel is burned, it will have environmental concerns. If it passes through the solar energy, it cannot be fast. Charge the battery.

3. It is known that "electric vehicles with power generation functions" cannot be further charged by the charging device when the fuel is exhausted or the solar energy cannot be converted. Therefore, the electric vehicle still has a disadvantage of being inoperable.

4. It is known that the "electric vehicle power supply device" cannot supply the electric power required for the electric vehicle when it is started or when it requires a large amount of power.

Accordingly, the inventors of the present invention have innovated and developed in order to improve the disadvantages disclosed in the above various conventional embodiments, and further proposed a charging and discharging system and method thereof, the charging and discharging system comprising: a power supply end for outputting a power; a unit electrically connected to the power supply end to receive the power and perform rectification; a control unit electrically connected to the rectifying unit for controlling a switching charging mode, a selective discharging mode or a simultaneous discharging mode; a load is electrically connected to the control unit, wherein the load is a power device, and the power device is used to drive or control a carrier, and the power device is connected to the power supply end. Converting the power generated by the power device into electric power and supplying the power to the power supply end; a first battery; a second battery connected to the control unit in parallel with the first battery; in the charging mode, The control unit controls the power input to the power supply terminal to be input to the first battery or/and the second battery to be charged, and the power of the first battery and the second battery is sufficient to drive When the load is moved and the load reaches a first preset value, the control unit controls switching and performs the selected discharge mode, causing the first battery and the second battery to be selectively discharged to drive the a load, when the amount of power of the first battery and the second battery is sufficient to drive the load and the load reaches a second preset value, The control unit controls switching and performs the simultaneous discharge mode to simultaneously discharge the first battery and the second battery to drive the load.

Further comprising a charging circuit, the charging circuit is electrically connected to the rectifying unit and the control unit, respectively, and a discharging circuit, wherein the discharging circuit is electrically connected to the load and the control unit, respectively a battery and the second battery system are respectively connected in parallel between the charging circuit and the discharging circuit, wherein the charging circuit is controlled by the control unit to perform the charging mode, and the discharging circuit is controlled by the foregoing control unit Controlling the selection of the discharge mode or the simultaneous discharge mode.

The power supply end is one of a power generation device or a utility power.

The control unit includes a detection circuit, and the detection circuit detects that the first battery or/and the second battery contain less than a set value, and supplies the external power The power generating device operates the power required to perform the charging mode by the control unit to charge the power to the first battery or/and the second battery.

Further, a switch group is electrically connected to the control unit, and the detecting circuit detects that the power of the first battery and the second battery is insufficient to drive the load, and the switch is controlled by the control unit. The group disconnects a circuit between the first battery, the second battery, and the discharge circuit.

The switch group further includes a first switch disposed between the charging circuit and the first battery, a second switch disposed between the charging circuit and the second battery, and a second switch a third switch between the discharge circuit and the first battery, a fourth switch disposed between the discharge circuit and the second battery, the first switch, the second switch, and the The third switch and the fourth open relationship are respectively electrically connected to the control unit, and the control unit is configured to control disconnection of the circuit of the first switch and the second switch from the charging circuit, and control The third switch and the fourth switch are disconnected from a circuit of the discharge circuit.

In addition, the present invention provides a charging and discharging method, comprising the steps of: respectively connecting a first battery and a second battery between a power supply end and a load; and performing a charging mode by a control unit for controlling the power supply The power of the terminal is input to the first battery or/and the second battery to be charged; when the amount of power of the first battery and the second battery is sufficient to drive the load and the load reaches a first preset value, The control unit performs a selective discharge mode, and controls the first battery and the second battery to selectively discharge to drive the load; the power of the first battery and the second battery is sufficient to drive the load and the load reaches a second The preset value causes the control unit to perform a simultaneous discharge mode, and controls the first battery to simultaneously discharge with the second battery to drive the load, wherein the load is a power device, and the power device is used To drive or control a carrier, the power device is connected to the power supply terminal, and converts power generated by the power device into power and supplied to the power supply terminal.

When the control unit performs the selected discharge mode, the control unit further includes a limiting condition, and the control unit controls the first when the power of the power supply terminal is input to the first battery by the charging circuit according to the limiting condition. The battery stops discharging to the load, or the power at the power supply terminal controls the second battery to stop discharging to the load when the power is input to the second battery by the charging circuit.

When the detecting unit includes a detecting circuit that detects that the first battery or/and the second battery contains less than a set value, the control unit operates by supplying an external power to the power supply terminal. The required power is performed by the control unit and the power is charged to the first battery or/and the second battery.

The detecting circuit detects that the first battery and the second battery are insufficient to drive the load, so that a switch group controls the first battery, the second battery, and the The circuit between the discharge circuits is broken.

The effect of the invention is:

1. The present invention mainly includes a first battery and a second battery. In the system of the present invention, the first battery and the second battery can be electrically connected to the discharge circuit of the first battery and the second battery. The power of the battery is respectively discharged to a load, and the power generated by the load causes one of the power terminals connected to the load to generate power, and the power is charged to the first battery or the first battery or lower Two batteries to achieve the effect of continuous cycle charge and discharge of the entire system.

2. The present invention does not require the use of additional fuel, and therefore is environmentally friendly, and the present invention can quickly utilize the power of the first battery or the second battery to generate power for the load due to the continuous cycle of charge and discharge.

3. The present invention can continuously operate a driving vehicle (such as an electric vehicle) due to continuous cycle charging and discharging.

4. The present invention can further switch the control unit control to a simultaneous discharge mode when the vehicle is started, or when a large load requires immediate and large power, to simultaneously discharge the first battery or the second by the discharge circuit. The battery's power is discharged to the load and the load is energized.

5. The invention can detect whether the power of the first battery or the second battery is lower than a preset value by using a detecting circuit included in the control unit, and if it is lower than the preset value, the charging circuit can be further The power generated by the power supply terminal is charged to the first battery or the second battery to ensure that the power of the first battery or the second battery remains in a non-zero state.

6. The present invention utilizes a first battery and a second battery for charging and discharging. Since charging and discharging are not performed on the same battery, the service life of the first battery and the second battery of the present invention can be further improved.

(1) ‧‧‧Power supply

(2) ‧‧‧Rectifier unit

(3) ‧‧‧Charging circuit

(4) ‧‧‧First battery

(5) ‧‧‧second battery

(6)‧‧‧ switch group

(61) ‧ ‧ first switch

(62) ‧‧‧second switch

(63) ‧ ‧ third switch

(64)‧‧‧fourth switch

(7) ‧‧‧Control unit

(71)‧‧‧Detection circuit

(8)‧‧‧Discharge circuit

(9) ‧‧‧load

(10) ‧‧‧External power

(N1)‧‧‧ first node

(N2) ‧‧‧second node

(A)‧‧‧ Generator

(B) ‧‧‧Charging circuit

(C) ‧ ‧ car battery

(D)‧‧‧Discharge circuit

(E) ‧ ‧ load

[First figure] is a block diagram of the system of the present invention.

[Second figure] is a flow chart of the steps of the present invention.

[Third image] is a schematic diagram of one of the flow states of the present invention.

[Fourth figure] is a schematic diagram of one of the flow states of the present invention.

[Fifth figure] is a schematic diagram of one of the flow states of the present invention.

[Sixth Diagram] is a schematic diagram of one of the flow states of the present invention.

[Seventh figure] is a schematic diagram of one of the flow states of the present invention.

[Embodiment 8] is a block diagram of a system in another state of the present invention.

[Ninth diagram] is a block diagram of a conventional one.

The technical features and the enhancements of the present invention are clearly shown in conjunction with the preferred embodiments of the following drawings. First, please refer to the first figure, wherein the first figure is a block diagram of the system of the present invention, and the present invention The main embodiment is used in a driving vehicle, such as an electric vehicle, which comprises a power supply end (1), a rectifying unit (2), a charging circuit (3), a first battery (4), and a second a battery (5), a switch group (6), a first switch (61), a second switch (62), a third switch (63), a fourth switch (64), and a control unit (7) a detecting circuit (71), a discharging circuit (8) and a load (9), wherein the power supply end (1) can be a power generating device or a mains power, mainly used to generate power, and In an embodiment, the power supply end (1) is a generator, and the present invention can further apply the generator to an idler of the driving vehicle, wherein the driving vehicle makes the hair when driving The motor generates electricity, and the rectifying unit (2) is electrically connected to the power supply end (1), and the rectifying unit (2) is mainly provided by the power supply end (1). And performing rectification to obtain a relatively stable current, and the charging circuit (3) is electrically connected to the rectifying unit (2). In the embodiment, the first battery (4) and the first The two batteries (5) are respectively a battery for a vehicle, wherein the switch group (6) is electrically connected to the control The unit (7) includes the first switch (61), the second switch (62), the third switch (63), and the fourth switch (64), and in the embodiment, the first The battery (4), the second battery (5) and the control unit (7) are respectively connected in parallel, and the first battery (4), the second battery (5) and the control unit (7) are two The end of the first battery (4) is electrically connected to the charging circuit (3) and the discharging circuit (8), and one end of the first battery (4) is charged by the first switch (61) The circuit (3) is electrically connected, and the other end is electrically connected to the discharge circuit (8) by the third switch (63), and the second end of the second battery (5) is terminated by The second switch (62) is electrically connected to the charging circuit (3), and the other end is electrically connected to the discharging circuit (8) by the fourth switch (64), wherein the charging The circuit (3) is formed with a first node (N1) at one end of the first switch (61), the second switch (62) and the control unit (7), and the discharge circuit (8) is connected to the first The third switch (63), the fourth switch (64) and the other end of the control unit (7) form a second node (N2) That is, the first node (N1) is connected to the charging circuit (3), the second node (N2) is connected to the discharging circuit (8), and the discharging circuit (8) is electrically connected. The load (9) is configured to form an electrical circuit, wherein the control unit (7) is configured to control switching a charging mode, a selective discharging mode, or a simultaneous discharging mode, wherein the charging circuit (3) The charging mode is controlled by the aforementioned control unit (7), and the discharging circuit (8) is controlled by the control unit (7) to perform the selected discharging mode or the simultaneous discharging mode, in the charging In the mode, the control unit (7) controls the power input of the power supply terminal (1) to the first battery (4) or/and the second battery (5) to be charged, and when the first battery (4) The control unit (7) controls switching and performs the selection when the amount of power of the second battery (5) is sufficient to drive the load (9) and the load (9) reaches a first predetermined value a discharge mode, and selectively discharging the first battery (4) and the second battery (5) to drive the load (9), and additionally when the first battery (4) and the first The second battery (5) is sufficient to drive the load (9) and the load (9) reaches a second At a preset value, the control unit (7) controls switching and performs the simultaneous discharge mode, and simultaneously discharges the first battery (4) and the second battery (5) to drive the load (9) The first preset value refers to the amount of power contained in the first battery (4) or the second battery (5) is sufficient to drive the load (9) and the load can be easily driven (9) a preset value; and the second preset value means that the first battery (4) or the second battery (5) contains a sufficient amount of power to drive the load (9) but cannot be easily The preset value when the load (9) is driven.

Furthermore, referring to the second figure, the charging and discharging method of the present invention comprises the following steps: First, a first battery is connected in parallel between a power supply end (1) and a load (9). 4) and a second battery (5), wherein the first battery (4) and the second battery (5) are respectively a vehicle battery.

Then, a charging mode is executed by a control unit (7), and the power of the power supply terminal (1) is controlled to be input to the first battery (4) or/and the second battery (5) to be charged.

When the first battery (4) and the second battery (5) are sufficiently charged to drive the load (9) and the load (9) reaches a first preset value, the control unit (7) is caused to perform a selection. Discharging mode, and controlling the first battery (4) and the second battery (5) to selectively discharge to drive the load (9), wherein the first preset value refers to the first battery (4) Or the second battery (5) contains a sufficient amount of power to drive the load (9) and can easily drive the load (9).

When the first battery (4) and the second battery (5) are sufficiently charged to drive the load (9) and the load (9) reaches a second preset value, the control unit (7) is executed simultaneously. a discharge mode, and controlling the first battery (4) to simultaneously discharge with the second battery (5) to drive the load (9), wherein the second preset value refers to the first battery (4) or The second battery (5) contains a sufficient amount of power to drive the load (9) but cannot easily drive the load (9).

Furthermore, referring to the third and fourth figures, first, the first switch (61), the second switch (62), the third switch (63), and the fourth switch (64) are respectively used. The first battery (4) and the second battery (5) are connected in parallel to the control unit (7), and the first battery (4), the second battery (5) and the control unit are (7) one end is electrically connected to the charging circuit (3), and the other end is electrically connected to the discharging circuit (8), and in the embodiment, the load (9) is an electric device, The power device is used to drive or control a vehicle, and the power device is connected to the power supply end (1), thereby converting the power generated by the power device into electric power and supplying the power to the power supply end (1) And forming an electrical circuit as shown in the third figure, and further detecting the first battery (4) and the detecting circuit (71) included in the control unit (7) The electric quantity contained in the second battery (5) is, in this embodiment, the electric quantity of the first battery (4) and the second battery (5) is sufficient to drive the load (9). The load (9) reaches a first pre- In the case of a value, the control unit (7) controls the switching and performs the selected discharge mode such that the first battery (4) and the second battery (5) are selectively discharged, that is, the first battery ( 4) discharging or discharging the second battery (5) and driving the load (9). In this embodiment, the control unit (7) controls the first switch (61), the second The switch (62) and the fourth switch (64) are turned off, and further controlling the third switch (63) to be turned on, as shown in the fourth figure, that is, by using the first battery (4) The discharge circuit (8) discharges to drive the load (9), and the load (9) generates a power and transmits to the power supply terminal (1).

Furthermore, as shown in FIG. 5, after the first battery (4) is discharged for a period of time, at this time, the detecting circuit (71) included in the control unit (7) detects the respectively The amount of electricity contained in the first battery (4) and the second battery (5), and knowing that the amount of electricity of the first battery (4) will be insufficient to drive the load (9), so the control unit ( 7) The third switch (63) is first turned off to prevent the first battery (4) from being continuously discharged, and then further Steps enable the first switch (61) and the fourth switch (64) to be turned on, that is, the first switch (61) and the fourth switch (64) are turned on, and the second switch (62) and the third switch (63) are turned off. That is, the load (9) can be immediately discharged by the electric quantity of the second battery (5), and the power supply end (1) is generated by the load (9). The generated electric power is supplied to the first battery (4) to be charged to achieve the purpose of circulating charging and discharging.

Furthermore, referring to the sixth figure, when the second battery (5) is discharged for a period of time, at this time, the detecting circuit (71) included in the control unit (7) detects the respectively The amount of electricity contained in the first battery (4) and the second battery (5), and knowing that the amount of electricity of the second battery (5) is insufficient to drive the load (9), at this time, the The power of a battery (4) is sufficient to drive the load (9), so the control unit (7) first controls the fourth switch (64) to be disconnected to avoid the second battery. (5) continuing to be in a discharged state, further turning off the first switch (61), interrupting charging of the first battery (4), and further respectively causing the second switch (62) and the third switch (63) conducting, that is, immediately discharging the electric quantity of the first battery (4) and driving the load (9), and further generating power by the load (9) The power supply terminal (1) is powered to the second battery (5) to be charged to achieve the purpose of circulating charge and discharge.

It should be further noted that the patterns of the fourth to sixth figures of the drawing are the charging and discharging cycle system of the present invention, mainly by one of the batteries [the first battery (4) or the second battery (5)] The control unit (7) controls the first battery (4) and the second battery (5) when the amount of power is sufficient to drive the load (9) and the load (9) reaches the first predetermined value. Selecting a discharge to drive the load (9) [discharge] and causing the load (9) to generate power to supply the power supply terminal (1) to the first battery (4) or the second battery to be charged ( 5) [Charging] to achieve the purpose of cyclic charging and discharging.

It is to be noted that, in the charging and discharging process of the present invention, the detecting circuit (71) simultaneously detects the amount of electricity contained in the first battery (4) and the second battery (5). When the amount of electricity contained in the first battery (4) is lower than a set value of the amount of power contained in the second battery (5), the control unit (7) controls the first switch (61) and the The circuit between the charging circuit (3) is turned on, and the circuit between the fourth switch (64) and the discharging circuit (8) is turned on, that is, the first switch (61) and the fourth switch (64) being turned on, the second switch (62) and the third switch (63) being disconnected [as shown in the fifth figure], further causing the first battery (4) to be in a charging state, and the The second battery (5) is in a discharged state; if the second battery (5) is discharged due to the amount of electricity contained in the first battery (4) being charged, at a set value, The control unit (7) controls a circuit disconnection between the first switch (61) and the charging circuit (3), and controls the second switch (62) and the charging circuit (3) The circuit between the two is turned on The circuit between the four switch (64) and the discharge circuit (8) is open, and the circuit between the third switch (63) and the discharge circuit (8) is controlled to be turned on, as shown in the sixth figure, further The first battery (4) is in a discharging state, and the second battery (5) is in a charging state, so that the effect of immediate charging and discharging can be further achieved.

Furthermore, referring to the seventh figure, if the present invention requires a large power of one of the driving vehicles, in the embodiment, the large powertrain is a driving force required to start the vehicle or a large load. The required power [climbing] may further detect the first battery (4) and the second battery (5) by the detecting circuit (71) included in the control unit (7). The amount of electricity contained, when the amount of electricity of the first battery (4) and the second battery (5) is sufficient to drive the load (9) and the load (9) reaches a second preset value, The control unit (7) controls the switching and performs the simultaneous discharge mode, that is, controls the second switch (62) and the fourth switch (64) to be turned on, and the first switch (61) and Disconnecting the third switch (63) to simultaneously discharge the first battery (4) and the second battery (5) to drive the load (9), thereby using the first power The power contained in the pool (4) and the second battery (5) easily drives the load (9) [the large power required by the load (9): the power required to drive the vehicle to start or the Driving the vehicle to power the climber].

Furthermore, as shown in the eighth figure, there is further an external power (10) connected to a power supply end (1), thereby driving the power supply end (1) to generate electricity, if the first battery (4) and the When the amount of electricity contained in the second battery (5) is insufficient to drive the load (9), an external power can be further generated by the external power (10) to connect the external power (10). The power supply terminal (1) generates electric power, and the power generated by the power supply terminal (1) can be further rectified by the rectifying unit (2), and then electrically connected by the rectifying unit (2). The circuit (3) charges the first battery (4) or/and the second battery (5) to be charged, and connects the first battery (4) and the second battery (5) When the detecting circuit (71) of the control unit (7) of the terminal detects the amount of power [the amount of electricity of the first battery (4) and the second battery (5)] is sufficient to drive the load (9), As shown in the foregoing description and in conjunction with the fourth to sixth figures, the continuous charging and discharging of the cycle is achieved, so that the driving vehicle does not have an unusable effect.

It is further noted that when the first battery (4) and the second battery (5) are insufficient to drive the load (9), the control unit (7) controls the first The switch (61) and the second switch (62) are turned on, and the third switch (63) and the fourth switch (64) are turned off, that is, the first battery (4) and the second battery are controlled. (5) The line disconnection from the discharge circuit (8) mainly prevents the first battery (4) and the second battery (5) from being over-discharged to cause damage to the battery, so The control unit (7) controls the first switch (61) and the second switch (62) to be turned on, and the third switch (63) and the fourth switch (64) are turned off to further protect the first battery ( 4) and the second battery (5), and The service life is extended, and at this time, the first battery (4) to be charged or/and the second battery (5) can still be charged [as shown in the eighth figure].

In view of the foregoing description of the embodiments, the operation and the use of the present invention and the effects of the present invention are fully understood, but the above described embodiments are merely preferred embodiments of the present invention, and the invention may not be limited thereto. Included within the scope of the present invention are the scope of the present invention.

(1) ‧‧‧Power supply

(2) ‧‧‧Rectifier unit

(3) ‧‧‧Charging circuit

(4) ‧‧‧First battery

(5) ‧‧‧second battery

(6)‧‧‧ switch group

(61) ‧ ‧ first switch

(62) ‧‧‧second switch

(63) ‧ ‧ third switch

(64)‧‧‧fourth switch

(7) ‧‧‧Control unit

(71)‧‧‧Detection circuit

(8)‧‧‧Discharge circuit

(9) ‧‧‧load

(N1)‧‧‧ first node

(N2) ‧‧‧second node

Claims (10)

A charging and discharging system includes: a power supply end for outputting a power; a rectifying unit electrically connected to the power supply end to receive the power and perform rectification; and a control unit electrically connecting the rectification a unit for controlling a switching one charging mode, a selective discharging mode or a simultaneous discharging mode; a load electrically connected to the control unit, wherein the load is a power device, and the power device is used Driving or controlling a vehicle, the power device is connected to the power supply end, thereby converting power generated by the power device into power and supplied to the power supply terminal; a first battery; a second battery; The first battery is respectively connected in parallel to the control unit; in the charging mode, the control unit controls the power input from the power supply terminal to the first battery or/and the second battery to be charged, in the When a battery and the second battery are sufficiently charged to drive the load and the load reaches a first preset value, the control unit controls switching and performs the selected discharge mode, so that the first Selecting a discharge from the battery and the second battery to drive the load, and when the amount of power of the first battery and the second battery is sufficient to drive the load and the load reaches a second preset value, The control unit controls switching and performs the simultaneous discharge mode to simultaneously discharge the first battery and the second battery to drive the load. The charging and discharging system of claim 1, further comprising a charging circuit, wherein the charging circuit is electrically connected to the rectifying unit and the control unit, respectively, and a discharging circuit, wherein the discharging circuit is respectively Electrically connecting the load to the control unit, the first battery and the second battery system are respectively connected between the charging circuit and the discharging circuit, wherein the charging circuit is controlled by the control unit The charging mode, and the discharging circuit is controlled by the control unit to perform the selected discharging mode or the simultaneous discharging mode. The charging and discharging system of claim 2, wherein the power supply end is one of a power generating device or a commercial power. The charging and discharging system of claim 3, wherein the control unit includes a detecting circuit, and the detecting circuit detects a quantity of the first battery or/and the second battery When the value is lower than a set value, the power required for the operation of the power generating device is supplied with an external power, and the charging mode is executed by the control unit to charge the power to the first battery or/and the Said second battery. The charging and discharging system of claim 4, wherein a switch group is electrically connected to the control unit, and the detecting circuit detects that the first battery and the second battery are insufficient to drive During the load, the switch unit is controlled by the control unit to open a circuit between the first battery, the second battery, and the discharge circuit. The charging and discharging system of claim 5, wherein the switch group further comprises a first switch disposed between the charging circuit and the first battery, a charging circuit and the a second switch between the second battery, a third switch disposed between the discharge circuit and the first battery, and a fourth switch disposed between the discharge circuit and the second battery, The first switch, the second switch, the third switch, and the fourth open relationship are electrically connected to the control unit, and the control unit is configured to control the first switch and the first The two switches are disconnected from the circuit of the charging circuit, and the third switch and the fourth switch are controlled to be disconnected from the circuit of the discharging circuit. A charging and discharging method includes the steps of: paralleling a first battery and a second battery between a power supply end and a load; and performing a charging mode by a control unit for controlling power input to the power supply end The first battery or/and the second battery to be charged; the amount of power in the first battery and the second battery is sufficient to drive the load and the load reaches a first preset value And causing the control unit to perform a selective discharge mode, and controlling the first battery and the second battery to be selectively discharged to drive the load; the power of the first battery and the second battery is sufficient to drive the load and the load When the second preset value is reached, the control unit is configured to perform a simultaneous discharge mode, and control the first battery to be simultaneously discharged with the second battery to drive the load, wherein the load is a power device, The power device is for driving or controlling a vehicle, and the power device is connected to the power supply end, and converts power generated by the power device into power and supplies the power to the power supply terminal. The charging and discharging method of claim 7, wherein the control unit further includes a limiting condition when the selective discharging mode is executed, and the control unit uses the power at the power supply end according to the limiting condition. Controlling that the first battery stops discharging to the load when the charging circuit is input to the first battery, or controlling the second battery to stop discharging when the power of the power supply terminal is input to the second battery by the charging circuit To the load. The charging and discharging method of claim 7, wherein the detecting unit includes a detecting circuit detecting that the first battery or/and the second battery contain less than one And setting a value, supplying an electric power required for the power supply terminal to operate by an external power, and performing the charging mode by the control unit and charging the electric power to the first battery or/and the second battery . The charging and discharging method of claim 9, wherein the detecting circuit detects that the first battery and the second battery are insufficient to drive the load, thereby causing a switch group Controlling an open circuit between the first battery, the second battery, and the discharge circuit.