Battery pack and energy storage system

Abstract

Provided are a battery pack and an energy storage system. The battery pack comprises a battery bank, a DC / DC converter, a controller and a voltage-stabilizing circuit, wherein the voltage-stabilizing circuit comprises a resistor, a capacitor, a first switch and a second switch; a positive-electrode port of the DC / DC converter and one end of the capacitor are connected to a positive electrode of the battery bank by means of the first switch, a negative-electrode port of the DC / DC converter and the other end of the capacitor are connected to a negative electrode of the battery bank by means of the resistor, and the negative-electrode port and the other end of the battery-side capacitor are connected to the negative electrode of the battery bank by means of the second switch; and the controller is used for controlling the turn-on of the first switch, controlling the turn-on of the second switch after a preset condition is met, and controlling the DC / DC converter, and a voltage across the two ends of the capacitor when the preset condition is met is greater than a voltage across the two ends of the capacitor when the preset condition is not met. Thus, a second switch is turned on after a preset condition is met, such that a control delay of a DC / DC converter can be reduced.

Description

Battery packs and energy storage systems

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on August 1, 2023, with application number 202310965046.6 and application name “Battery Pack and Energy Storage System”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of power technology, and in particular to a battery pack and an energy storage system. Background Art

[0003] In fields such as energy storage, a direct current to direct current (DC / DC) converter is usually configured in a battery pack to perform power conversion on the battery pack included in the battery through the DC / DC converter, for example, charging or discharging.

[0004] To prevent voltage fluctuations in the battery pack from damaging the DC / DC converter, a voltage stabilization circuit is usually installed in the battery pack. That is, the positive and negative ports of the DC / DC converter are connected to the two poles of the battery pack via the voltage stabilization circuit. The voltage stabilization circuit includes a capacitor, which is connected in parallel with the DC / DC converter at the two poles of the battery pack through the voltage stabilization circuit.

[0005] In order for the voltage stabilizing circuit to operate normally, before the DC / DC converter controls the battery, or in other words, before receiving a control instruction for controlling the DC / DC converter, the voltage stabilizing circuit needs to be turned on to allow the capacitor to be fully charged.

[0006] In the prior art, in order to ensure that the capacitor is reliably charged, it is necessary to turn on the voltage stabilizing circuit a long time in advance before controlling the DC / DC converter, resulting in a long control delay of the DC / DC converter.

[0007] Summary of the Invention

[0008] Embodiments of the present application provide a battery pack and an energy storage system that can reduce the control delay of a DC / DC converter.

[0009] In a first aspect, a battery pack is provided, comprising a battery pack, a DC / DC converter, a controller, and a voltage stabilizing circuit. The voltage stabilizing circuit comprises a resistor, a capacitor, a first switch, and a second switch. The positive terminal of the DC / DC converter and one end of the capacitor are connected to the positive terminal of the battery pack via the first switch, the negative terminal of the DC / DC converter and the other end of the capacitor are connected to the negative terminal of the battery pack via the resistor, and the negative terminal and the other end of the battery-side capacitor are connected to the negative terminal of the battery pack via the second switch. The controller is configured to control the first switch to close; after a preset condition is met, the controller controls the second switch to close, wherein after the preset condition is met, the voltage across the capacitor is greater than the voltage across the capacitor before the preset condition is met; and the controller controls the DC / DC converter according to the control instruction.

[0010] The preset condition is used to determine whether the voltage value across the capacitor satisfies the slow-start condition. In this case, "the voltage value across the capacitor satisfies the slow-start condition" or "the preset condition is satisfied" can be understood as: the voltage value of the capacitor increases to a level that can effectively stabilize and filter the current from the battery pack; "the voltage value across the capacitor does not satisfy the slow-start condition" or "the preset condition is not satisfied" can be understood as the voltage value of the capacitor does not meet the requirements for voltage stabilization and filtering. That is, in the embodiment of the present application, the determination of whether the preset condition is satisfied is equivalent to the determination of whether the voltage value across the capacitor satisfies the slow-start condition.

[0011] That is, when the preset conditions are met, the charged capacitor can effectively stabilize the current from the battery pack, thereby effectively protecting the DC / DC converter. Compared with the existing technology, this saves time waiting for the capacitor to complete charging, thereby reducing the control delay of the DC / DC converter.

[0012] In one implementation, the controller is further configured to receive a control instruction for the DC / DC converter, and control the first switch to be closed in response to the control instruction.

[0013] In the prior art, in order to protect the DC / DC converter, the controller needs to close the first switch and the second switch before receiving the control instruction for the DC / DC converter to complete the charging of the capacitor. Therefore, even though the DC / DC converter has not yet been controlled, the circuit between the DC / DC converter and the battery is already connected, causing additional loss of battery power. In contrast, the embodiment of the present application enables the controller to close the first switch and the second switch in sequence after receiving the control instruction for the DC / DC converter. After the first switch is closed, the capacitor can be charged under the protection of the resistor. After the second switch is closed, the current from the battery pack can be effectively stabilized by the charged capacitor, thereby effectively protecting the DC / DC converter. In addition, since the first switch and the second switch are disconnected before receiving the control instruction, the consumption of battery power can be reduced compared to the prior art.

[0014] In one implementation, the preset condition corresponds to the voltage across the capacitor, or in other words, the timing of closing the second switch is affected by the voltage across the capacitor. By detecting the voltage across the capacitor and immediately closing the second switch and performing power conversion on the battery pack after the voltage meets the preset condition, the delay between receiving the control instruction and completing the control can be reduced while effectively protecting the DC / DC converter, thereby further improving the practicality of the embodiment of the present application.

[0015] For example, the preset condition includes: the voltage value across the capacitor is greater than or equal to a first threshold; or

[0016] The preset condition includes: a difference between the voltage value of the battery pack and the voltage value across the capacitor is less than or equal to a second threshold.

[0017] In another implementation, the preset condition corresponds to a duration of time the first switch is closed. For example, the controller is further configured to start a timer after the first switch is closed, and control the second switch to close after the timer expires. The timer duration is greater than or equal to a first duration, which is the duration it takes for the voltage across the capacitor to change from zero to satisfy the slow-start condition. For example, the first duration can be determined through experiments or other methods.

[0018] That is, the preset condition includes: the time elapsed since the first switch is closed is greater than or equal to a third threshold.

[0019] Therefore, the determination of whether the voltage of the capacitor meets the slow-start condition can be converted into a determination of the timing duration from the start of the first switch being turned on, thereby reducing the cost and configuration space overhead caused by configuring the voltage detection device.

[0020] Furthermore, the controller is further configured to obtain a voltage value of the battery pack; and determine a threshold value in the preset condition according to the voltage value of the battery pack.

[0021] Due to the different battery voltages, the slow-start conditions that enable the capacitor to stabilize the current from the battery also change accordingly, that is, the threshold in the preset conditions also changes accordingly. Therefore, by determining the threshold in the preset conditions based on the battery voltage, the time delay between receiving the control instruction and completing the control can be further reduced.

[0022] It should be noted that the thresholds in the preset conditions listed above corresponding to the current voltage of the battery pack are only exemplary, and the present application is not limited thereto. For example, the thresholds in the preset conditions can also be determined based on the maximum voltage value of the battery pack.

[0023] In one possible implementation, the battery pack further includes an auxiliary power supply, which is used to supply power to the controller in response to the excitation signal, and the controller is further used to send a response instruction after the second switch is closed, wherein the response instruction is used to instruct to stop sending the excitation signal.

[0024] For example, the positive input terminal of the auxiliary power supply is connected to the positive electrode of the battery pack, the negative input terminal of the auxiliary power supply is connected to the negative electrode of the battery pack via the auxiliary power switch and the resistor in the voltage stabilizing circuit, and the output terminal of the auxiliary power supply is connected to the controller.

[0025] In this case, by turning off the auxiliary source switch in response to the instruction, the resistor can be disconnected, thereby reducing the power consumption generated by the resistor.

[0026] For another example, the auxiliary power supply has or is connected to a power supply independent of the battery, and the response instruction is used to instruct to cut off the connection between the auxiliary power circuit and the power supply.

[0027] The embodiment of the present application provides an auxiliary power supply to enable the controller to be powered, so that it can respond quickly when the DC / DC converter needs to be controlled, and successively close the first switch and the second switch to complete the control of the DC / DC converter.

[0028] In a second aspect, an energy storage system is provided, comprising one or more parallel battery clusters, each battery cluster comprising multiple battery packs, the multiple battery packs being connected in series, the battery pack comprising a battery pack, a DC / DC converter, a controller, and a voltage stabilization circuit. The voltage stabilization circuit comprises a resistor, a capacitor, a first switch, and a second switch. The positive terminal of the DC / DC converter and one end of the capacitor are connected to the positive terminal of the battery pack via the first switch, the negative terminal of the DC / DC converter and the other end of the capacitor are connected to the negative terminal of the battery pack via the resistor, and the negative terminal and the other end of the battery-side capacitor are connected to the negative terminal of the battery pack via the second switch. The controller is configured to control the first switch to close; after a preset condition is met, the controller controls the second switch to close, wherein after the preset condition is met, the voltage across the capacitor is greater than the voltage across the capacitor before the preset condition is met; and the controller controls the DC / DC converter according to the control instruction.

[0029] In one implementation, each battery pack includes an output positive electrode (denoted as Vdc+) and an output negative electrode (denoted as Vdc-), and the battery pack includes a power control positive electrode (denoted as Vbat+) and a power control negative electrode (denoted as Vbat-).

[0030] The DC / DC converter of each battery pack includes a first terminal and a second terminal.

[0031] In this case, "the positive port of the DC / DC converter and one end of the capacitor are connected to the positive pole of the battery pack via the first switch" can be understood as: the positive port of the first end of the DC / DC converter and one end of the capacitor are connected to Vbat+ of the battery pack via the first switch. "The negative port of the DC / DC converter and the other end of the capacitor are connected to the negative pole of the battery pack via the resistor, and the negative port and the other end of the battery-side capacitor are connected to the negative pole of the battery pack via the second switch" can be understood as: the negative port of the first end of the DC / DC converter and the other end of the capacitor are connected to Vbat- of the battery pack via the resistor, and the negative port of the first end of the DC / DC converter and the other end of the battery-side capacitor are connected to Vbat- of the battery pack via the second switch.

[0032] The energy storage system also includes a positive busbar Vbus+ and a negative busbar Vbus-, the positive port of the second end of the DC / DC converter of each battery pack is connected to Vbus+, and the negative port of the second end of the DC / DC converter of each battery pack is connected to Vbus-.

[0033] Multiple battery packs in a battery cluster are connected in series through Vdc+ and Vdc-, that is, the Vdc+ of each battery pack except the last battery pack is connected to the Vdc- of the adjacent battery pack.

[0034] In one implementation, the controller is further configured to receive a control instruction for the DC / DC converter, and control the first switch to be closed in response to the control instruction.

[0035] In another implementation, the preset condition corresponds to the voltage across the capacitor, or in other words, the timing of closing the second switch is affected by the voltage across the capacitor.

[0036] For example, the preset condition includes: the voltage value across the capacitor is greater than or equal to a first threshold; or

[0037] The preset condition includes: a difference between the voltage value of the battery pack and the voltage value across the capacitor is less than or equal to a second threshold.

[0038] In another implementation, the preset condition corresponds to a duration of time the first switch is closed. For example, the controller is further configured to start a timer after the first switch is closed, and control the second switch to close after the timer expires. The timer duration is greater than or equal to a first duration, which is the duration it takes for the voltage across the capacitor to change from zero to satisfy the slow-start condition. For example, the first duration can be determined through experiments or other methods.

[0039] That is, the preset condition includes: the time elapsed since the first switch is closed is greater than or equal to a third threshold.

[0040] Furthermore, the controller is further configured to obtain a voltage value of the battery pack; and determine a threshold value in the preset condition according to the voltage value of the battery pack.

[0041] It should be noted that the thresholds in the preset conditions listed above corresponding to the current voltage of the battery pack are only exemplary, and the present application is not limited thereto. For example, the thresholds in the preset conditions can also be determined based on the maximum voltage value of the battery pack.

[0042] In addition, the battery pack also includes an auxiliary power supply, which is used to supply power to the controller in response to the excitation signal, and the controller is also used to send a response instruction after the second switch is closed, and the response instruction is used to instruct to stop sending the excitation signal.

[0043] For example, the positive input terminal of the auxiliary power supply is connected to the positive pole Vbat+ of the battery pack, the negative input terminal of the auxiliary power supply is connected to the negative pole Vbat- of the battery pack via the auxiliary power switch and the resistor in the voltage stabilizing circuit, and the output terminal of the auxiliary power supply is connected to the controller.

[0044] For another example, the auxiliary power supply has or is connected to a power supply independent of the battery, and the response instruction is used to instruct to cut off the connection between the auxiliary power circuit and the power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG1 shows a schematic diagram of a power system provided by an embodiment of the present application;

[0046] FIG2 is a schematic diagram showing an example of an energy storage system provided in an embodiment of the present application;

[0047] FIG3 shows a schematic structure of a battery pack according to an embodiment of the present application;

[0048] FIG4 shows a schematic structure of another example of an energy storage system provided in an embodiment of the present application;

[0049] FIG5 shows a schematic flow chart of an example of a control process of a controller provided in an embodiment of the present application;

[0050] FIG6 shows a schematic structure of another example of a battery pack provided in an embodiment of the present application;

[0051] FIG7 shows a schematic structure of another example of a battery pack provided in an embodiment of the present application;

[0052] FIG8 shows a schematic structure of another example of a battery pack provided in an embodiment of the present application;

[0053] FIG9 shows a schematic flow chart of another example of a control process of a controller provided in an embodiment of the present application;

[0054] FIG10 shows a schematic flow chart of another example of the control process of the controller provided in an embodiment of the present application. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. It should be pointed out that "connection" in the embodiments of the present application refers to electrical connection, and the connection between two electrical elements may be a direct or indirect connection between the two electrical elements. For example, A is connected to B, which may be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical elements, such as A is connected to B, or A is directly connected to C, C is directly connected to B, and A and B are connected through C.

[0056] FIG1 is a schematic diagram of an application scenario of an embodiment of the present application. As shown in FIG1 , a power generation system in a power system generates alternating current (AC) or direct current (DC) and provides the AC power to an AC grid or an AC load. The power generation system can also provide the generated DC power to an energy storage system, which stores the electrical energy. When an AC load requires power, the energy storage system can output DC power, which is then processed by a direct current to alternating current (DC / AC) converter to obtain AC power, which is then provided to the AC load or AC grid.

[0057] The power generation system may be a new energy power generation system, such as a wind power generation system or a photovoltaic power generation system.

[0058] The power generation system includes a power generation module, which can generate direct current or alternating current. For example, the power generation module in a wind power generation system usually generates alternating current, while the power generation module in a photovoltaic power generation system usually generates direct current.

[0059] The power generation system also includes a voltage stabilization module, which stabilizes the voltage output by the power generation module. If the current output by the power generation module is alternating current (AC), the voltage stabilization module is also used to convert the AC power to direct current (DC). For example, the voltage stabilization module in a wind power generation system is typically an AC / DC converter, while the voltage stabilization module in a photovoltaic power generation system is typically a direct current to direct current (DC / DC) converter.

[0060] The power generation system also includes an inverter. Typically, the inverter is placed between the voltage stabilization module and the AC load (or AC grid), enabling direct current to alternating current conversion. The inverter can also be a DC / AC converter.

[0061] The DC side of an inverter receives DC power, while the AC side is connected to an AC load or AC grid. The inverter converts DC power from DC to AC power and then supplies the resulting AC power to the AC load or AC grid.

[0062] In addition, the DC end of the inverter is also connected to the energy storage system to output DC power to the energy storage system.

[0063] In addition, the inverter can also perform AC / DC conversion from the AC side to the DC side. For example, when the AC side is connected to the AC grid, it can convert the AC power input from the AC grid into DC power and provide it to the energy storage system.

[0064] As an example, in a photovoltaic power generation system, the inverter may be a DC / AC converter in a photovoltaic inverter.

[0065] A photovoltaic inverter is a specialized device designed for photovoltaic power generation systems. The core of photovoltaic power generation is the use of photovoltaic modules (i.e., solar panels) to convert solar energy into electrical energy. However, since photovoltaic modules can only generate direct current (DC), a photovoltaic inverter is required to convert DC to AC for easier transmission and utilization.

[0066] In an embodiment of the present application, the energy storage system includes one or more battery clusters, and when the energy storage system includes multiple battery clusters, the multiple battery clusters are connected in parallel. Figure 2 shows the structure of a battery cluster. As shown in Figure 2, a battery cluster is composed of multiple battery packs. Each battery pack includes a battery pack (PACK), a DC / DC converter, a controller and a voltage stabilizing circuit. There is a power connection (or electrical connection) between the DC / DC converter and the battery pack of each battery pack, and the DC / DC converter controls the power of the battery pack through the power link (or power connection), that is, charges or discharges. In addition, the DC / DC converters of each battery pack are connected to each other, for example, through a busbar, so that the flow of electricity between the battery packs of each battery pack can be achieved through each DC / DC converter. A communication link (or connection) exists between the controller and the DC / DC converter. The controller can send control signals to the DC / DC converter (e.g., the switching devices within the DC / DC converter) via this communication link to control the operation of the DC / DC converter and, in turn, the charging or discharging of the battery pack. The functions and connections of the various components within the battery pack are described in detail below with reference to Figure 3. Furthermore, the battery packs within the same battery cluster are connected in series, and this series connection is described in detail below with reference to Figure 4.

[0067] In one implementation, each battery pack may also include a battery management unit (BMU), and the energy storage system also includes a battery control unit (BCU). There is a communication link (or communication connection) between the BCU and the controller in each battery pack. The BCU sends control instructions to the controller through the communication link to implement the power control of the battery pack indicated by the control instruction through the controller and the DC / DC converter. There is a communication connection between the BCU and the BMU in each battery pack. The BMU is used to monitor the voltage, temperature and other information of the PACK and report the above information to the BCU. The BCU monitors the battery pack in the energy storage system based on the above information and generates control instructions, which are sent to the controller.

[0068] The PACK in the embodiment may be a single battery or a battery cluster composed of multiple batteries. Specifically, the battery may be a combination of one or more of a lead-carbon battery, a lithium iron phosphate battery, a ternary lithium battery, a sodium sulfur battery, and a flow battery.

[0069] FIG3 shows a schematic structure of a battery pack according to an embodiment of the present application. As shown in FIG3 , the battery pack includes a controller 140 , a DC / DC converter 110 , a voltage stabilization circuit, and a PACK. The voltage stabilization circuit includes a capacitor 120 , a resistor 130 , a first switch 150 , and a second switch 160 .

[0070] It should be noted that the battery pack provided in the embodiment of the present application may further include other modules or components according to actual needs. For example, the battery pack may further include the above-mentioned BMU.

[0071] The controller 140 has a signal transceiver (not shown in the figure) that can receive control instructions (e.g., control instructions from the BCU) and perform power conversion processing on the battery according to the control instructions. The controller 140 can be a general-purpose central processing unit (CPU), a general-purpose processor, a digital signal processing (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. The above-mentioned processor can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and the like.

[0072] For example, the first switch 150 and the second switch 160 may be switching devices such as relays, insulated gate bipolar transistors (IGBTs), or metal-oxide-semiconductor field-effect transistors (MOSs). Furthermore, in the embodiment of the present application, the controller 140 is capable of controlling the opening and closing of the first switch 150 and the second switch 160. For example, a communication connection is established between the controller 140 and the first switch 150 and the second switch 160, and the controller 140 may send a control signal to the first switch 150 and the second switch 160 via the communication connection to control the opening and closing of the first switch 150 and the second switch 160.

[0073] Next, the connection relationship (specifically, the power connection relationship) of the components in the battery pack will be described.

[0074] One end of the DC / DC converter 110 is connected to the battery pack, and the other end is connected to the busbar of the energy storage system. Thus, the DC / DC converter 110 can perform power conversion processing on the current input from the busbar and input the processed current into the battery pack, thereby charging the battery pack.

[0075] Furthermore, the DC / DC converter 110 can perform power conversion processing on the current input from the battery pack and input the processed current to the bus, thereby discharging the battery pack.

[0076] One end of the DC / DC converter 110, which is connected to the battery pack, includes a positive terminal 113 and a negative terminal 115. The positive terminal 113 is connected to the positive terminal of the battery pack via a first switch 150, and the negative terminal 115 is connected to the negative terminal of the battery pack via a second switch 160. Thus, a second circuit is formed. That is, in the second circuit, the DC / DC converter 110 and the capacitor 120 are connected in parallel and directly connected to the two poles of the battery pack.

[0077] One end of the capacitor 120 (referred to as end A for ease of understanding and explanation) is connected to the positive electrode of the PACK via the switch 150, and the other end of the capacitor 120 (referred to as end B for ease of understanding and explanation) is connected to the negative electrode of the PACK via the resistor 130. In addition, the end A of the capacitor 120 is connected to the positive terminal 113 of the DC / DC converter 110, and the end B of the capacitor 120 is connected to the negative terminal 115 of the DC / DC converter 110. Thus, a first circuit is formed. That is, in this first circuit, the DC / DC converter 110 and the capacitor 120 are connected in parallel and then in series with the resistor 130, and then connected to the two poles of the battery pack.

[0078] When the first switch 150 is closed and the second switch 160 is open, the first circuit is connected, the capacitor 120 is charged by the current from the battery, the voltage across the capacitor 120 increases, and under the current limiting effect (or shunting effect) of the resistor 130, the capacitor 120 and the first switch 150 will not be damaged by the excessive current from the battery.

[0079] When the first switch 150 is closed and the second switch 160 is closed, the second loop is turned on, and the capacitor 120 and the DC / DC converter 110 are connected in parallel to the two poles of the battery pack. Thus, the capacitor 120 can stabilize and filter the current from the PACK, thereby protecting the DC / DC converter 110.

[0080] Figure 4 illustrates an example of the connection relationship between battery packs having the structure shown in Figure 3 within an energy storage system. As shown in Figure 4 , each pack includes an output terminal for outputting direct current power, comprising a positive output electrode (Vdc+) and a negative output electrode (Vdc-). Furthermore, the packs are connected in series via Vdc+ and Vdc-.

[0081] Furthermore, each PACK includes a power control positive electrode Vbat+ and a power control negative electrode Vbat- for power control. In this case, the positive terminal 113 is connected to the PACK's Vbat+ via a first switch 150, and the negative terminal 115 is connected to the PACK's Vbat- via a second switch 160. Furthermore, one end A of capacitor 120 is connected to the PACK's Vbat+ via switch 150, and the end B of capacitor 120 is connected to the PACK's Vbat- via resistor 130. Furthermore, the end A of capacitor 120 is connected to the positive terminal 113 of DC / DC converter 110, and the end B of capacitor 120 is connected to the negative terminal 115 of DC / DC converter 110.

[0082] The busbars of the energy storage system include a positive busbar Vbus+ and a negative busbar Vbus-. One end of the DC / DC converter 110 used for connecting to the busbars includes a positive port 117 and a negative port 119. The positive port 117 is connected to Vbus+, and the negative port 119 is connected to Vbus-.

[0083] The control process of the controller 140 is described below with reference to FIG. 5 .

[0084] 5 shows a schematic flow chart 200 of the working process of the controller 140 provided in the present application. In the non-working state, the first switch 150 and the second switch 160 are both in an open state, or in other words, the first loop and the second loop are both in a non-conductive state.

[0085] In order to control the first switch 150 and the second switch 160 through the controller 140, the controller 140 needs to be powered. In one possible implementation, an independent power supply can be configured for the controller 140. In another possible implementation, as shown in FIG7 , an auxiliary power supply 170 powered by the PACK can be configured in the battery pack. The specific structure of the battery pack with the auxiliary power supply 170 and the power conversion process will be described in detail below with reference to FIG8 and FIG10 .

[0086] As shown in FIG. 5 , at S210 , the controller 140 controls the first switch 150 to be closed. At this time, the first loop is turned on, the capacitor 120 and the resistor 130 are connected in series between the two electrodes of the battery, and the capacitor 120 begins to charge under the current limiting effect of the resistor 130 .

[0087] In S220 , after determining that the preset condition is satisfied (or in other words, the capacitor 120 satisfies the slow-start condition), the controller 140 controls the second switch 160 to be closed. At this time, the second circuit is turned on.

[0088] The slow-start condition is used to protect capacitor 120 and first and second switches 150 and 160. Specifically, when capacitor 120 meets the slow-start condition, the voltage across capacitor 120 satisfies the following conditions: after second switch 160 is closed, capacitor 120, first and second switches 150 and 160 will not be damaged by excessive current from the battery. This preset condition and slow-start condition are described in detail below.

[0089] At S230 , the controller 140 controls the DC / DC converter 110 to implement a power conversion process of the PACK.

[0090] The following describes in detail how the controller 140 determines whether the capacitor 120 satisfies the slow-start condition (or in other words, whether the preset condition is satisfied).

[0091] Method 1

[0092] The preset condition is: whether the voltage across the capacitor 120 is greater than a first threshold.

[0093] Figure 6 shows a schematic structure of another example of a battery pack according to an embodiment of the present application. As shown in Figure 6, the battery pack further includes a first sensor 190, which is used to detect the voltage across the capacitor 120 (hereinafter, for ease of understanding and explanation, referred to as: V1).

[0094] The first sensor 190 is in communication with the controller 140 , so that the controller 140 can monitor V1 through the first sensor 190 .

[0095] Thus, when V1 satisfies V1≥a, the controller 140 determines that the capacitor 120 meets the slow-start condition and controls the second switch 160 to close. a represents the first threshold

[0096] For example, a can be the maximum voltage value of PACK.

[0097] Alternatively, a = m*b, where b is the maximum voltage of the PACK and m is a specified ratio. For example, when the maximum voltage b of the PACK is 200 V, the value of m can be 80% to 85%. Furthermore, the value of m is positively correlated with the value of b, meaning that the larger the value of b, the larger the value of m. For example, when the value of b is 1000 V, the value of m can be 90% to 95%.

[0098] In one implementation, the maximum voltage value of the PACK may be preset in the controller 140 .

[0099] In another implementation, a sensor for detecting the maximum voltage value of the PACK may be further provided in the battery pack, so that the controller 140 may obtain the maximum voltage value of the PACK from the sensor.

[0100] Method 2

[0101] The preset condition is: whether the difference between the maximum voltage value of the PACK and the voltage value across the capacitor 120 is less than or equal to a second threshold.

[0102] Similar to the method 1 , the controller 140 monitors V1 via the first sensor 190 .

[0103] Different from the method 1, when V1 satisfies b-V1≤c, the controller 140 determines that the capacitor 120 satisfies the slow-start condition and controls the second switch 160 to be closed.

[0104] Wherein, b represents the maximum voltage value of PACK, and c represents the second threshold value.

[0105] c is a preset constant. For example, c and b may have a proportional relationship. For example, when b is 200 V, the value of c may be 15%*b to 20%*b; when b is 1000 V, the value of c may be 5%*b to 10%*b.

[0106] Method 3

[0107] The preset condition is whether the voltage across the capacitor 120 reaches a specified ratio of the current voltage of the PACK.

[0108] Alternatively, the preset condition may also be understood as whether the voltage value across the capacitor 120 is greater than a first threshold, and the magnitude of the first threshold is a specified ratio of the current voltage value of the PACK.

[0109] Similar to the method 1 , the controller 140 monitors V1 via the first sensor 190 .

[0110] Different from the method 1, the controller 140 can also obtain the current voltage of the PACK (hereinafter, for ease of understanding and description, referred to as V2).

[0111] In one possible implementation, the battery pack further includes a second sensor (not shown) configured to detect the voltage V2 of the PACK. The second sensor is communicatively coupled to the controller 140, enabling the controller 140 to monitor V2 via the second sensor. The first sensor and the second sensor may be the same sensor or different sensors, and this is not particularly limited in this application.

[0112] In another possible implementation, the receiving device of the second sensor may receive a signal from an external sensor (not shown) for detecting the voltage of PACK, so that the controller 140 can analyze the signal and obtain V2.

[0113] Furthermore, the controller 140 may compare V1 and V2 (ie, an example of the first threshold), and when V1 ≥ k*V2, determine that the capacitor 120 meets the slow-start condition, and control the second switch 160 to be closed.

[0114] Compared with the solution of method 1, since the current voltage of the PACK may not be the maximum voltage, the slow-start condition is easier to meet in method 2. Therefore, compared with method 1, the time delay between receiving the control instruction and controlling the PACK based on the control instruction can be reduced, thereby further improving the practicality of the embodiment of the present application.

[0115] The value of k is described in detail below.

[0116] In one implementation, the value of k may be a fixed value, such as 80%.

[0117] Alternatively, the value of k corresponds to the maximum voltage of the PACK. For example, the greater the maximum voltage of the PACK, the greater the value of k. For example, when the maximum voltage of the PACK is 200V, the value of k may be 80%; when the maximum voltage of the PACK is 1000V, the value of k may be 90%.

[0118] In another implementation, the value of k corresponds to the current voltage of the PACK. For example, the greater the current voltage of the PACK, the greater the value of k. For example, when the current voltage of the PACK is 200V, the value of k may be 80%; when the current voltage of the PACK is 1000V, the value of k may be 90%.

[0119] By determining the k value based on the current voltage value of PACK, and then determining the threshold for determining whether capacitor 120 meets the slow-start condition, the delay between receiving the control instruction and controlling the PACK based on the control instruction can be further reduced, thereby further improving the practicality of the embodiment of the present application.

[0120] Method 4

[0121] The preset condition is: whether the difference between the current voltage value of the PACK and the voltage value across the capacitor 120 is less than or equal to a second threshold.

[0122] Similar to the method 3, the controller 140 monitors V1 through the first sensor 190 and obtains the current voltage V2 of the battery.

[0123] Different from the third approach, the controller 140 determines that the capacitor 120 meets the slow-start condition when determining that V2 - V1 ≤ t* V2, and controls the second switch 160 to be closed.

[0124] In this case, t*V2 represents the second threshold value.

[0125] The value of t is described in detail below.

[0126] In one implementation, the value of t may be a fixed value, such as 20%.

[0127] Alternatively, the value of t corresponds to the maximum voltage of the PACK. For example, the greater the maximum voltage of the PACK, the smaller the value of t. For example, when the maximum voltage of the PACK is 200V, the value of t may be 20%; when the maximum voltage of the PACK is 1000V, the value of k may be 10%.

[0128] In another implementation, the value of t corresponds to the current voltage of the PACK. For example, the greater the current voltage of the PACK, the smaller the value of t. For example, when the current voltage of the PACK is 200V, the value of t may be 20%; when the current voltage of the PACK is 1000V, the value of t may be 10%.

[0129] By determining the t value based on the current voltage value of PACK, and then determining the threshold for determining whether capacitor 120 meets the slow-start condition, the delay between receiving the control instruction and controlling the PACK based on the control instruction can be further reduced, thereby further improving the practicality of the embodiment of the present application.

[0130] Method 5

[0131] The preset condition is that the time elapsed since the first switch 150 is closed is greater than or equal to the third threshold.

[0132] FIG7 shows a schematic structure of another example of a battery pack according to an embodiment of the present application. As shown in FIG7 , the battery pack further includes a timer 180 .

[0133] Furthermore, the duration of the timer 180 is x, and the value of x is greater than or equal to the duration it takes for the voltage value 0 across the capacitor 120 to change to satisfy the slow-start condition (ie, an example of the third threshold).

[0134] In one implementation, the slow-start condition can be the condition described in Method 1 or Method 2 above. In this case, the first duration is a fixed value. Furthermore, the value of x can be obtained based on historical data or experiments. For example, the first duration is positively correlated with the maximum voltage of the PACK, i.e., the greater the maximum voltage of the PACK, the longer the first duration.

[0135] In another implementation, the slow-start condition may be the condition described in Method 3 or Method 4 above. In this case, the first duration may be determined based on the current voltage of the PACK. For example, the corresponding relationships between various durations and various voltages may be pre-stored in the controller 140. This correspondence may be obtained based on historical data or experiments. Thus, the controller 140 may determine the duration corresponding to the current voltage V2 of the PACK from the corresponding relationship as the first duration. For example, the first duration is positively correlated with the current voltage value of the battery, i.e., the higher the current voltage value of the battery, the longer the first duration.

[0136] Therefore, after controlling the first switch 150 to be closed, the controller 140 starts the timer 180 , and controls the second switch 160 to be closed after the timer 180 expires (at this time, the capacitor 120 meets the slow-start condition).

[0137] By determining the length of the timer based on the current voltage value of the PACK, the delay between receiving the control instruction and controlling the battery based on the control instruction can be reduced, thereby further improving the practicality of the embodiment of the present application.

[0138] As described above, by detecting whether the capacitor meets the preset conditions and conducting the second circuit when it is determined that the capacitor meets the preset conditions, the DC / DC converter can be controlled immediately after the capacitor can reliably perform voltage stabilization. Therefore, compared with the existing technology, the time required to wait for the capacitor to complete charging can be saved, thereby reducing the control delay of the DC / DC converter.

[0139] FIG9 shows a schematic flow 300 of the operation process of the controller 140 provided in the present application. Unlike the flow 400 shown in FIG5 , as shown in FIG9 , at S310, the controller 140 (e.g., from the BCU) receives a control instruction for controlling the operation of the DC / DC converter 110 to perform power conversion processing on the PACK. The power conversion processing can be various processes such as boosting and bucking, which are not particularly limited in the present embodiment.

[0140] In S320 , after receiving the control instruction, the controller 140 controls the first switch 150 to be closed.

[0141] The specific process from S330 to S340 is similar to the specific process from S220 to S230, and will not be described in detail here.

[0142] By enabling the controller 140 to sequentially connect the first and second circuits after receiving a control command for the battery, the resistor 130 in the first circuit can effectively protect the capacitor 120 and the first switch 150. Furthermore, the second circuit can be used to stabilize the current from the battery through the capacitor 120 and transmit it to the DC / DC converter 110, thereby effectively protecting the DC / DC converter 110, the first switch 150, and the second switch 160. Furthermore, because the first and second circuits are not connected before receiving the control command, battery power consumption can be reduced compared to the prior art. This reduces battery power consumption while protecting the DC / DC converter.

[0143] The structure of the battery pack and the power control process described above are only examples, and the embodiments of the present application are not limited thereto. Below, in conjunction with Figures 8 and 10, the specific structure of the battery pack with the auxiliary power supply 170 and the power conversion process are described in detail.

[0144] Figure 8 shows a schematic structure of a battery pack according to another embodiment of the present application. As shown in Figure 8 , the battery pack differs from the battery pack in Figure 1 in that an auxiliary power source 170 and an auxiliary power switch 171 are provided therein.

[0145] Auxiliary power supply 170 includes a positive input terminal 172, a negative input terminal 173, and an output terminal 174. Positive input terminal 172 is connected to the positive terminal Vbat+ of PACK, while negative input terminal 173 is connected to the negative terminal Vbat- of PCK via resistor 130, thereby forming a third loop. Auxiliary power supply 170 processes the current input from positive input terminal 172 and negative input terminal 173, such as by voltage stabilization, and outputs the processed current from output terminal 174. Output terminal 174 is connected to port 145 of the controller. In other words, the current output from output terminal 174 is supplied to controller 140 to operate controller 140.

[0146] For example, the auxiliary source switch 171 can be composed of a switching device such as a relay, an IGBT, or a MOS. Furthermore, in the embodiment of the present application, the auxiliary source switch 171 is controlled by an external device (e.g., a BCU). In one implementation, the external device and the auxiliary source switch 171 are directly connected in communication. In another implementation, the external device can communicate with the auxiliary source switch 171 through the BMU. Thus, the external device can send an excitation signal to the auxiliary source switch 171 through the above communication connection to control the opening and closing of the auxiliary source switch 171.

[0147] The control process of the controller in the battery pack of the structure shown in FIG8 will be described below with reference to FIG10.

[0148] Figure 10 shows a schematic flow chart of the operation process of another controller provided by the present application. In the non-operating state, the first switch 150 and the second switch 160 are both in the off state, and the auxiliary source switch 171 is in the off state, or in other words, the first circuit, the second circuit, and the third circuit are all in a non-conducting state.

[0149] As shown in Figure 10, in S410, the auxiliary source switch 171 receives an excitation signal and closes under the action of the excitation signal, thereby turning on the third circuit. Thus, the auxiliary power supply 170 receives the current from the PACK through the third circuit, performs processing such as voltage stabilization on the current, and inputs the processed current into the controller 140. The controller 140 is started under the power supply from the auxiliary power supply 170, so that it can receive control instructions through the signal transceiver. In one implementation, the auxiliary source switch 171 can be a normally closed switch and close when it receives a high-level signal. In this case, the excitation signal can be a high-level signal, and in order to keep the auxiliary source switch 171 in a closed state, the external device (e.g., BCU) needs to continuously output the excitation signal.

[0150] At S420 , the controller 140 receives a control instruction, where the control instruction is used to control the DC / DC converter 110 .

[0151] The specific process from S430 to S440 is similar to the specific process from S220 to S230, and will not be described in detail here.

[0152] In one possible implementation, at S450, after the first and second circuits are connected, the controller 140 can perform power conversion based on the power supplied by the PACK. In this case, the controller 140 can send a response instruction to the external device, instructing the external device to stop sending the excitation signal. When the excitation signal stops, the auxiliary source switch 171 is disconnected, thereby disconnecting the slow-start resistor 130. This prevents the slow-start resistor from consuming battery power, further improving the practicality of the battery pack according to the embodiment of the present application.

[0153] At 460 , the controller 140 controls the DC / DC converter according to the control command.

[0154] In addition, the battery pack in FIG8 can also be applied to the first sensor 190 and the timer 180 in FIG6 and FIG7 , and the application method is consistent with the embodiments in FIG6 and FIG7 , which will not be described in detail here.

[0155] It should be understood that the specific examples in the above embodiments are only intended to help those skilled in the art better understand the embodiments of the present application, and are not intended to limit the scope of the embodiments of the present application. It should also be understood that the order of the sequence numbers of the above processes does not necessarily indicate the order in which they are executed. The order in which the processes are executed should be determined by their functions and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0156] It should also be understood that in each embodiment, unless otherwise specified or there is any logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0157] Those skilled in the art should be aware that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is performed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0158] An embodiment of the present application further provides a computer-readable storage medium storing computer instructions for implementing the method executed by the controller in the above method embodiment.

[0159] For example, when the computer program is executed by a computer, the computer can implement the method performed by the controller in the above method embodiment.

[0160] An embodiment of the present application further provides a computer program product comprising instructions, which, when executed by a computer, enables the computer to implement the method executed by the controller in the above method embodiment.

[0161] The explanation of the relevant contents and beneficial effects of any of the above-mentioned devices can be referred to the corresponding method embodiments provided above, which will not be repeated here.

[0162] Those skilled in the art will appreciate that the units and steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel may use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of protection of this application.

[0163] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0164] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected according to actual needs to implement the solutions provided in this application.

[0165] In addition, each functional unit in each embodiment of the present application may be integrated into one unit, each unit may exist physically separately, or two or more units may be integrated into one unit.

[0166] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. For example, the computer can be a personal computer, a server, or a network device, etc. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)). For example, the aforementioned available medium may include, but is not limited to, various media that can store program code, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0167] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A battery pack, characterized in that: include: A battery pack, a DC / DC converter, a controller and a voltage stabilizing circuit, wherein the voltage stabilizing circuit includes a resistor, a capacitor, a first switch and a second switch, wherein the positive electrode port of the DC / DC converter and one end of the capacitor are connected to the positive electrode of the battery pack via the first switch, the negative electrode port of the DC / DC converter and the other end of the capacitor are connected to the negative electrode of the battery pack via the resistor, and the negative electrode port and the other end of the battery-side capacitor are connected to the negative electrode of the battery pack via the second switch, The controller is used to: Controlling the first switch to close; When a preset condition is met, the second switch is controlled to be closed, and the DC / DC converter is controlled. When the preset condition is met, the voltage across the capacitor is greater than the voltage across the capacitor when the preset condition is not met.

2. The battery pack according to claim 1, characterized in that: The preset condition includes any of the following conditions: The voltage value across the capacitor is greater than or equal to a first threshold; The difference between the voltage value of the battery pack and the voltage value across the capacitor is less than or equal to a second threshold value; The time elapsed since the first switch is closed is greater than or equal to a third threshold.

3. The battery pack according to claim 1 or 2, characterized in that: The controller is also used to: Obtaining a voltage value of the battery pack; The preset condition is determined according to the voltage value of the battery pack.

4. The battery pack according to any one of claims 1 to 3, characterized in that: The battery pack further includes an auxiliary power supply, the auxiliary power supply providing power to the controller in response to an excitation signal, and The controller is further configured to send a response instruction after the second switch is closed, wherein the response instruction is used to instruct to stop sending the excitation signal.

5. An energy storage system, characterized in that: include: One or more parallel battery clusters, each of which comprises a plurality of battery packs according to any one of claims 1 to 4, and the plurality of battery packs are connected in series.

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