Energy storage charging and swapping system

Abstract

The present application discloses an energy storage charging and swapping system, comprising an AC / DC conversion unit connected to the power grid, a switch unit connected to the AC / DC conversion unit, an energy storage battery control unit connected to the switch unit, and a DC / DC conversion unit. The control unit is used to control the switch unit to connect the power grid to the energy storage battery during off-peak hours, thereby enabling the power grid to charge the energy storage battery. In non-off-peak hours, the control unit is used to control the switch unit to connect the energy storage battery to the power battery, thereby enabling the energy storage battery to supply power to the power battery. Since the control unit can control the energy storage battery to charge during off-peak hours and supply power to the power battery through the energy storage battery during non-off-peak hours, the charging and swapping system can choose to store the power grid's energy in the energy storage battery during off-peak hours, and supply power to the power battery through the energy storage battery during non-off-peak hours, thereby reducing the electricity cost of the energy storage charging and swapping system.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to an energy storage and charging system. Background Art

[0002] With the development of science and technology, new energy electric vehicles, as a model of clean energy use, have gradually become the focus of automobile industry and energy development, and have gradually become a more important part of human daily life.

[0003] Currently, charging and swapping systems for new energy electric vehicles rely primarily on power from the grid. However, because these systems cannot adapt to peak and valley electricity demand, they often rely on the grid to supply power to new energy electric vehicles during peak hours, leading to higher electricity costs.

[0004] It can be seen that how to reduce electricity costs is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to provide an energy storage charging and swapping system to reduce electricity costs.

[0006] To solve the above technical problems, the present application provides an energy storage charging and swapping system, comprising: an AC / DC conversion unit connected to a power grid, a switch unit connected to the AC / DC conversion unit, an energy storage battery connected to the switch unit, a control unit, and a DC / DC conversion unit;

[0007] The control unit is configured to control the switch unit to allow the power grid to charge the energy storage battery through the AC / DC conversion unit during a low-power period, wherein the output end of the AC / DC conversion unit can meet the charging demand of the energy storage battery;

[0008] The control unit is further configured to control the switch unit to allow the energy storage battery to charge the power battery through the DC / DC conversion unit during non-off-peak hours, wherein the output end of the DC / DC conversion unit can meet the charging requirements of the power battery.

[0009] Preferably, the control unit is further configured to control the switch unit to enable the AC / DC conversion unit of the power grid to charge the power battery when the energy storage battery does not meet a preset condition.

[0010] Preferably, the switch unit includes a first switch group and a second switch group, the first switch group is connected to the energy storage battery, and the second switch group is connected to the power battery.

[0011] Preferably, the energy storage battery includes a plurality of energy storage battery packs, the number of switches in the first switch group is multiple and corresponds one-to-one to each of the energy storage battery packs, the second end of each of the switches is respectively connected to each of the energy storage battery packs, and the first ends of each of the switches are connected to each other and then connected to the AC / DC conversion unit and the DC / DC conversion unit.

[0012] Preferably, the control unit is further configured to select a target energy storage battery pack that best matches the power battery according to preset parameters when the energy storage battery charges the power battery, and control the target energy storage battery pack to charge the power battery through the switch corresponding to the target energy storage battery pack in the first switch group.

[0013] Preferably, the AC / DC conversion unit and the DC / DC conversion unit are respectively connected to the control unit, and the control unit is further used to control the AC / DC conversion unit to work and control the DC / DC conversion unit not to work when the power grid charges the energy storage battery; and to control the AC / DC conversion unit not to work and control the DC / DC conversion unit to work when the energy storage battery charges the power battery.

[0014] Preferably, the preset parameters are one or more of the voltage of the energy storage battery, the voltage of the power battery, the discharge current of the energy storage battery, and the battery capacity of the energy storage battery.

[0015] Preferably, each switch in the first switch group is a bidirectional conduction switch.

[0016] Preferably, the preset condition is that the energy storage battery operates normally or the power of the energy storage battery meets the power requirement of the power battery.

[0017] Preferably, the charging requirement of the energy storage battery and / or the charging requirement of the power battery is specifically: outputting voltage and / or current according to the charging parameters required by the BMS.

[0018] The energy storage charging and swapping system provided in the present application includes an AC / DC conversion unit connected to the power grid, a switch unit connected to the AC / DC conversion unit, an energy storage battery control unit connected to the switch unit, and a DC / DC conversion unit. The control unit is used to control the switch unit to connect the power grid to the energy storage battery during the off-peak period, thereby enabling the power grid to charge the energy storage battery. In the non-off-peak period, the control unit is used to control the switch unit to connect the energy storage battery to the power battery, thereby enabling the energy storage battery to supply power to the power battery. Since the control unit can control the energy storage battery to charge during the off-peak period, and supply power to the power battery through the energy storage battery during the non-off-peak period, the charging and swapping system can choose to store the energy of the power grid in the energy storage battery during the off-peak period, and supply power to the power battery through the energy storage battery during the non-off-peak period, thereby reducing the electricity cost of the energy storage charging and swapping system.

[0019] In traditional electric vehicle energy storage and charging systems, all grid energy passes through the AC / DC converter unit to the busbar. Therefore, the AC / DC converter unit becomes a bottleneck for system reliability; if damaged, the system cannot function. This application, however, is a distributed system, where both the grid and the energy storage device provide power. Damage to any unit does not affect the normal operation of other units, making this solution more reliable.

[0020] Although existing technologies include energy storage devices, they have the following disadvantages: grid energy must undergo AC / DC conversion and then DC / DC conversion before reaching the energy storage battery. When the energy storage battery discharges, it must undergo two DC / DC conversions to deliver the stored energy to the battery that needs charging. This three-fold conversion results in low charging efficiency. However, the present invention uses AC / DC conversion to charge the energy storage battery, which then undergoes a single DC / DC conversion to charge the battery for battery swaps or electric vehicle power batteries, helping to improve system efficiency.

[0021] Compared with the existing technology, each rechargeable battery unit can save a set of DC / DC circuits, which is lower in cost.

[0022] The present invention uses a common AC / DC for charging the energy storage battery, thereby further reducing the system cost.

[0023] In traditional energy storage charging and swapping systems, all battery packs are connected in parallel when charging or discharging, requiring all cells in the pack to maintain the same voltage, resulting in high maintenance costs. However, in this invention, batteries are not connected in parallel, eliminating the need for battery screening and significantly reducing battery usage requirements (especially when using retired electric vehicle batteries). BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] Figure 1 A schematic structural diagram of an energy storage charging and swapping system provided in an embodiment of the present application;

[0026] Figure 2 A circuit diagram of an energy storage charging and swapping system provided in an embodiment of the present application;

[0027] Figure 3 A circuit diagram of a DC / DC conversion unit provided in an embodiment of the present application;

[0028] Figure 4 A circuit diagram of another energy storage charging and swapping system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0030] The core of this application is to provide an energy storage charging and swapping system to reduce electricity costs. The core of this application is also to provide a charging and swapping method, device and medium based on electric vehicles.

[0031] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0032] Figure 1 This is a schematic diagram of the structure of an energy storage charging and swapping system provided in an embodiment of the present application. Figure 1 As shown, the system includes: a switch unit 11 connected to the power grid, an energy storage battery 13 connected to the switch unit 11, and a control unit 15 connected to the switch unit 11.

[0033] The control unit 15 is used to control the switch unit 11 to allow the grid to charge the energy storage battery 13 during off-peak hours, and to control the switch unit 11 to allow the energy storage battery 13 to charge the power battery 14 during non-off-peak hours.

[0034] In the embodiment of the present application, the off-peak time period is the off-peak time period specified by the municipal government, and the off-peak time period is the off-peak time period specified by the municipal government. It is understandable that when the municipal regulations change, the off-peak time period and the off-peak time period may change accordingly.

[0035] It should be noted that at a battery swap station, power battery 14 refers to a battery that is quickly replaced for an electric vehicle; at a charging station, power battery 14 refers to the battery in the electric vehicle. Furthermore, energy storage battery 13 can be a brand new battery purchased separately or a retired power battery from an electric vehicle.

[0036] like Figure 1 As shown, the energy storage charging and swapping system also includes: an AC / DC conversion unit 10 and a DC / DC conversion unit 12. The input end of the AC / DC conversion unit 10 is connected to the power grid, the output end of the AC / DC conversion unit 10 is connected to the switch unit 11, the input end of the DC / DC conversion unit 12 is connected to the switch unit 11, and the output end of the DC / DC conversion unit 15 is connected to the power battery 14.

[0037] Then, the control unit 15 is used to control the switch unit 11 to allow the power grid to charge the energy storage battery 13 through the AC / DC conversion unit 10 during the off-peak period, and to control the switch unit 11 to allow the power storage battery 13 to charge the power battery 14 through the DC / DC conversion unit 12 during the non-off-peak period.

[0038] Among them, the AC / DC conversion unit 10 is used to convert the output alternating current of the power grid into direct current that can meet the charging requirements of the energy storage battery 13 when the power grid is charging the energy storage battery 13, so that the power grid supplies power to the energy storage battery 13 through the AC / DC conversion unit 10.

[0039] The DC / DC conversion unit 12 is used to convert the output DC power of the energy storage battery 13 into DC power that can meet the charging requirements of the power battery 14 when the energy storage battery 13 charges the power battery 14, so that the energy storage battery 13 charges the power battery 14 through the DC / DC conversion unit 12.

[0040] In order to prevent the AC / DC conversion unit 10 and the DC / DC conversion unit 15 from continuously working, resulting in unnecessary consumption of the grid input voltage, and at the same time to prevent the grid from supplying power to the power battery 14 when the energy storage battery 13 supplies power to the power battery 14, in a specific implementation, the control unit 15 can also be connected to the AC / DC conversion unit 10 and the DC / DC conversion unit 15, and is used to control the AC / DC conversion unit 10 to work and the DC / DC conversion unit 15 not to work when the energy storage battery 13 is connected to the grid, and to control the AC / DC conversion unit 10 not to work and to control the DC / DC conversion unit 15 to work when the energy storage battery 13 is connected to the power battery 14.

[0041] Figure 2 This is a circuit diagram of an energy storage charging and swapping system provided in an embodiment of the present application. Figure 2 As shown, the switch unit 11 includes a first switch group 20 and a second switch group 21. The first switch group 20 is connected to the energy storage battery 13, and the second switch group 21 is connected to the power battery 14.

[0042] In a specific implementation, the control module is used to control the AC / DC conversion unit 10 to start working, the first switch group 20 to close, and the second switch group 21 to disconnect during the off-peak period, thereby ensuring that the power grid charges the energy storage battery 13 through the AC / DC conversion unit 10; in the non-off-peak period, the control module is used to control the AC / DC conversion unit 10 to stop working, the first switch group 20 to close, and the second switch group 21 to disconnect, thereby ensuring that the energy storage battery 13 supplies power to the power battery 14 through the DC / DC conversion unit 12.

[0043] It should also be noted that in order to ensure that the first switch group 20 can connect the AC / DC conversion unit 10 and the energy storage battery 13, and can also connect the energy storage battery 13 and the DC / DC conversion unit 12, as a preferred embodiment, the switches in the first switch group 20 are all bidirectional conductive switches.

[0044] It is understandable that the switches included in the second switch group 21 can be bidirectional conduction switches or unidirectional conduction switches.

[0045] In addition, in a specific implementation, the AC / DC conversion unit 10 converts the input signal of the power grid into the input current or voltage of the energy storage battery 13 and / or the power battery 14 that meets the requirements of the battery management system (BMS).

[0046] Figure 3 This is a circuit diagram of a DC / DC conversion unit provided in an embodiment of the present application. Figure 3As shown, the DC / DC conversion unit includes a first inductor L1, a second inductor L2, a switch K1, a switch K2, a capacitor C, and a diode D1. The first end of the first inductor L1 is connected to the AC / DC conversion unit 10 and the first end of the second switch group 21, respectively. The second end of the first inductor L1 is connected to the first end of the switch K1 and the first end of the switch K2, respectively. The second end of the switch K1 is grounded. The second end of the switch K2 is connected to the first end of the second inductor L2 and the cathode of the diode D1, respectively. The anode of the diode D1 is grounded. The second end of the second inductor L2 is connected to the power battery, the first end of the capacitor C, and the second end of the second switch group 21, respectively. The second end of the capacitor C is grounded. In addition, in a specific implementation, the control unit 15 may also be connected to the third ends of the switches K1 and K2 to control the opening and closing of the switches K1 and K2.

[0047] It is understandable that Figure 3 This is a circuit diagram of a DC / DC conversion unit 12 provided based on a buck-boost circuit. The DC / DC conversion unit 12 can also be a separate boost circuit or a separate buck circuit.

[0048] The energy storage charging and swapping system provided in the embodiment of the present application includes an AC / DC conversion unit connected to the power grid, a switch unit connected to the AC / DC conversion unit, an energy storage battery control unit connected to the switch unit, and a DC / DC conversion unit. The control unit is used to control the switch unit to connect the power grid to the energy storage battery during the off-peak period, thereby enabling the power grid to charge the energy storage battery. In the non-off-peak period, the control unit is used to control the switch unit to connect the energy storage battery to the power battery, thereby enabling the energy storage battery to supply power to the power battery. Since the control unit can control the energy storage battery to charge during the off-peak period and supply power to the power battery through the energy storage battery during the non-off-peak period, the charging and swapping system can choose to store the energy of the power grid in the energy storage battery during the off-peak period, and supply power to the power battery through the energy storage battery during the non-off-peak period, thereby reducing the electricity cost of the energy storage charging and swapping system.

[0049] In traditional electric vehicle energy storage and charging systems, all grid energy passes through the AC / DC converter unit to the busbar. Therefore, the AC / DC converter unit becomes a bottleneck for system reliability; if damaged, the system cannot function. This application, however, is a distributed system, where both the grid and the energy storage device provide power. Damage to any unit does not affect the normal operation of other units, making this solution more reliable.

[0050] Although existing technologies include energy storage devices, they have the following disadvantages: grid energy must undergo AC / DC conversion and then DC / DC conversion before reaching the energy storage battery. When the energy storage battery discharges, it must undergo two DC / DC conversions to deliver the stored energy to the battery that needs charging. This three-fold conversion results in low charging efficiency. However, the present invention uses AC / DC conversion to charge the energy storage battery, which then undergoes a single DC / DC conversion to charge the battery for battery swaps or electric vehicle power batteries, helping to improve system efficiency.

[0051] Compared with the existing technology, each rechargeable battery unit can save a set of DC / DC circuits, which is lower in cost.

[0052] The present invention uses a common AC / DC for charging the energy storage battery, thereby further reducing the system cost.

[0053] In traditional energy storage charging and swapping systems, all battery packs are connected in parallel when charging or discharging, requiring all cells in the pack to maintain the same voltage, resulting in high maintenance costs. However, in this invention, batteries are not connected in parallel, eliminating the need for battery screening and significantly reducing battery usage requirements (especially when using retired electric vehicle batteries).

[0054] On the basis of the above embodiment, the control unit 15 is further configured to control the power grid to charge the power battery 14 through the switch unit 11 when the energy storage battery 13 does not meet the preset conditions.

[0055] The preset condition is that the energy storage battery 13 operates normally or the power of the energy storage battery 13 meets the power requirement of the power battery 14 .

[0056] It is understandable that when the power of the energy storage battery 13 cannot meet the demand for charging the power battery 14, or the energy storage battery 13 is malfunctioning, the control unit 15 can also control the switch unit 11 to allow the power grid to charge the power battery 14 through the AC / DC conversion unit 10 to ensure that the power battery 14 can be charged normally, thereby ensuring the user experience.

[0057] like Figure 2 As shown, based on the above embodiment, the energy storage battery 13 includes n energy storage battery packs (where n is a positive integer), the first switch group 20 includes multiple switches and corresponds one-to-one to each energy storage battery pack, the second end of each switch is respectively connected to each energy storage battery pack, and the first end of each switch is connected to each other and then connected to the AC / DC conversion unit 10 and the DC / DC conversion unit 12.

[0058] It can be understood that when all switches in the first switch group 20 are closed, the energy storage battery packs can be charged simultaneously.

[0059] In order to improve the working efficiency of the energy storage charging and swapping system, as a preferred embodiment, the control unit 15 is also used to select the target energy storage battery pack that best matches the power battery 14 according to preset parameters when the energy storage battery 13 charges the power battery 14, and control the target energy storage battery pack to charge the power battery 14 through the switch corresponding to the target energy storage battery pack in the first switch group 20.

[0060] It should be noted that the preset parameters are one or more of the voltage of the energy storage battery 13 , the voltage of the power battery 14 , the discharge current of the energy storage battery 13 , and the battery capacity of the energy storage battery 13 .

[0061] In addition, in order to further improve the working efficiency of the energy storage charging and swapping system, during the process of the energy storage battery 13 charging the power battery 14, the control unit 15 is also used to re-select the target energy storage battery pack that best matches the power battery 14 according to the preset parameters when the target energy storage battery does not meet the preset requirements.

[0062] It can be understood that, during the process of charging the power battery 14 from the energy storage battery 13, the power level of the target energy storage battery is monitored according to a preset period or in real time to see whether it meets the preset requirements. Once it does not meet the preset requirements, the energy storage battery that best matches the power battery 14 can be reselected. In a specific implementation, the preset requirement can be that the discharge time of the target energy storage battery does not reach the preset time, or that the voltage of the target energy storage battery is not lower than the preset voltage.

[0063] The energy storage charging and swapping system provided in the embodiment of the present application can ensure that the energy stored in the storage battery is sufficient for the use of the power battery because the energy storage battery includes multiple energy storage battery packs, thereby avoiding the problem of the stored power of the energy storage battery not meeting the power demand of the power battery during non-off-peak hours, and further reducing the electricity cost of the energy storage charging and swapping system.

[0064] Figure 4 This is a circuit diagram of another energy storage charging and swapping system provided in an embodiment of the present application. Figure 4 As shown, based on the above embodiment, the number of power batteries 14 is n (where n is a positive integer), wherein the number of DC / DC conversion units 12 matches the number of power batteries 14, the second end of each switch in the second switch group 21 is respectively connected to each power battery 14, the first end of each switch in the second switch group 21 is connected to the AC / DC conversion unit 10 after being connected to each other, and each DC / DC conversion unit 12 is connected in parallel with each switch in the second switch group 21.

[0065] In the embodiment of the present application, when the energy storage battery 13 charges the power battery 14 through the DC / DC conversion unit 12, the control unit 15 can simultaneously control multiple switches in the second switch group 21 to be closed, so as to realize simultaneous charging of multiple power batteries 14; when the power grid charges the power battery 14 through the AC / DC conversion unit 10, only one power battery 14 is charged in the same time period, that is, the control unit 15 only controls one switch in the second switch group 21 to be closed in the same time period.

[0066] It is understandable that, since the energy storage battery 13 can charge multiple power batteries 14 at the same time, the charging efficiency of the power battery 14 can be accelerated, and the speed at which the energy storage battery 13 supplies power to the power battery 14 is improved.

[0067] The above is a detailed introduction to an energy storage charging and swapping system provided by the present application. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of this application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of this application.

[0068] It should also be noted that, in this specification, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

Claims

1. An energy storage charging and swapping system, characterized in that: include: An AC / DC conversion unit connected to the power grid, a switch unit connected to the AC / DC conversion unit, an energy storage battery connected to the switch unit, a control unit, and a DC / DC conversion unit; grid energy passes through the AC / DC conversion unit to charge the energy storage battery, and the energy storage battery passes through the DC / DC conversion unit once more to charge the power battery; The control unit is configured to control the switch unit to allow the power grid to charge the energy storage battery through the AC / DC conversion unit during a low-power period, wherein the output end of the AC / DC conversion unit can meet the charging demand of the energy storage battery; The control unit is further configured to control the switch unit to enable the energy storage battery to charge the power battery through the DC / DC conversion unit during a non-off-peak period, wherein the output end of the DC / DC conversion unit can meet the charging demand of the power battery; Correspondingly, the switch unit includes a first switch group and a second switch group, the first switch group is connected to the energy storage battery, and the second switch group is connected to the power battery; Correspondingly, the energy storage battery includes a plurality of energy storage battery packs, the first switch group includes a plurality of switches corresponding one-to-one to each of the energy storage battery packs, the second end of each of the switches is connected to each of the energy storage battery packs, and the first ends of each of the switches are connected to each other and then to the AC / DC conversion unit and the DC / DC conversion unit; The control unit is configured to control the AD / DC conversion unit to start operating, close the first switch group, and disconnect the second switch group during off-peak hours, so that the energy storage battery is charged through the AC / DC conversion unit; and to control the AD / DC conversion unit to stop operating, close the first switch group, and disconnect the second switch group during off-peak hours, so that the energy storage battery is charged to the power battery through the DC / DC conversion unit. Correspondingly, the control unit is further configured to, when the energy storage battery is charging the power battery, select a target energy storage battery pack that best matches the power battery according to preset parameters, and control the target energy storage battery pack to charge the power battery through the switch corresponding to the target energy storage battery pack in the first switch group; During the process of charging the power battery from the energy storage battery, the control unit is also used to reselect the target energy storage battery pack that best matches the power battery according to the preset parameters when the target energy storage battery does not meet the preset requirements; Correspondingly, the AC / DC conversion unit and the DC / DC conversion unit are respectively connected to the control unit. The control unit is further configured to control the AC / DC conversion unit to operate and the DC / DC conversion unit to not operate when the power grid is charging the energy storage battery; and to control the AC / DC conversion unit to not operate and the DC / DC conversion unit to operate when the energy storage battery is charging the power battery. Correspondingly, when the energy storage battery charges the power battery through the DC / DC conversion unit, the control unit simultaneously controls multiple switches in the second switch group to close, so as to realize simultaneous charging of multiple power batteries; when the power grid charges the power battery through the AC / DC conversion unit, only one power battery is charged in the same time period, so that the control unit only controls one switch in the second switch group to close in the same time period.

2. The energy storage charging and swapping system according to claim 1, characterized in that: The control unit is further configured to control the switch unit to allow the power grid to charge the power battery through the AC / DC conversion unit when the energy storage battery does not meet a preset condition.

3. The energy storage charging and swapping system according to claim 1, characterized in that: The preset parameters are one or more of the voltage of the energy storage battery, the voltage of the power battery, the discharge current of the energy storage battery, and the battery capacity of the energy storage battery.

4. The energy storage charging and swapping system according to claim 1, characterized in that: Each switch in the first switch group is a bidirectional conducting switch.

5. The energy storage charging and swapping system according to claim 2, characterized in that: The preset condition is specifically that the energy storage battery operates normally or the power of the energy storage battery meets the power requirement of the power battery.

6. The energy storage charging and swapping system according to claim 1, characterized in that: The charging requirement of the energy storage battery and / or the charging requirement of the power battery is specifically: outputting voltage and / or current according to the charging parameters required by the BMS.

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