Charging and discharging device, control method and device, battery device, and storage medium

Abstract

The present disclosure provides a charging and discharging device, a control method and device, a battery device, and a storage medium. The charging and discharging device includes a processor, a voltage measuring unit, a current limiting unit, and a switch unit. The processor controls the connection status of the current limiting unit and the switch unit based on the voltage measured by the voltage measuring unit to achieve charging and discharging of the battery unit through at least one of the current limiting unit and the switch unit. This embodiment provides a fast charging solution.

Description

Technical Field

[0001] The embodiments of the present invention relate to, but are not limited to, a charging and discharging device, a charging and discharging control method and device, a battery device, and a storage medium. Background Art

[0002] Lithium batteries offer the advantages of long cycle life, compact size, light weight, and high-current, rapid charge and discharge capabilities. However, fully leveraging these characteristics to generate corresponding economic value has proven challenging in the industry. In particular, the safety issue of overcurrent, which is prone to occur during charging, has always been a key challenge for lithium battery management systems. Existing lithium battery management systems in the industry approach charging safety passively, focusing on battery protection and employing only passive overcurrent protection measures.

[0003] Traditional separate lithium-ion batteries utilize charge and discharge protection measures and are relatively large. During charging, especially at the initial low voltage, they are prone to high currents and even overcurrent. To prevent the cascading safety risks associated with continued overcurrent, the battery management system activates overcurrent protection, disconnecting the charging circuit and halting charging. This approach not only shortens battery life but also severely impacts charging performance, resulting in charging failures, excessively long charging times, and even battery damage. Summary of the Invention

[0004] At least one embodiment of the present invention provides a charging and discharging device, a charging and discharging control method and device, a battery device, and a storage medium to improve charging efficiency.

[0005] At least one embodiment of the present invention provides a charging and discharging device, comprising: a processor, a voltage measuring unit, a current limiting unit, and a switch unit, wherein: the current limiting unit and the switch unit are connected in parallel and then connected in series with a battery cell to be charged and discharged; the processor is connected to the voltage measuring unit, the current limiting unit, and the switch unit; the voltage measuring unit is connected to both ends of the battery cell; and the voltage measuring unit is connected to both ends of a power supply for charging the battery cell, wherein:

[0006] The voltage measuring unit is used to measure the voltage across the battery unit and the voltage across the power supply;

[0007] The processor is configured to control the access states of the current limiting unit and the switch unit according to the voltage measured by the voltage measuring unit so as to realize charging and discharging of the battery unit through at least one of the current limiting unit and the switch unit;

[0008] The current limiting unit is configured to close or open a current-limited charging branch based on control of the processor;

[0009] The switch unit is configured to close or open a charging branch with unlimited current based on control of the processor.

[0010] At least one embodiment of the present invention provides a battery device, comprising: the charging and discharging device and a battery cell according to any one embodiment.

[0011] At least one embodiment of the present invention provides a charge and discharge control method, which is applied to the charge and discharge device described in any embodiment, comprising:

[0012] Obtaining a first voltage across the battery unit and a second voltage across the power supply;

[0013] According to the first voltage and the second voltage, the access states of the current limiting unit and the switch unit are controlled to realize the charging and discharging of the battery unit through at least one of the current limiting unit and the switch unit.

[0014] At least one embodiment of the present invention provides a charge and discharge control device, including a memory and a processor, wherein the memory stores a program, and when the program is read and executed by the processor, the charge and discharge control method described in any embodiment is implemented.

[0015] At least one embodiment of the present invention provides a computer-readable storage medium, which stores one or more programs. The one or more programs can be executed by one or more processors to implement the charge and discharge control method described in any embodiment.

[0016] Compared with the related art, in at least one embodiment of the present invention, a current limiting unit and a current-unlimited switching unit are provided, and the current-limited current limiting unit or the current-unlimited switching unit is selected for charging according to the voltage, providing a large-current charging solution and improving the charging efficiency.

[0017] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the structures particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0019] Figure 1 This is a schematic diagram of a simple rechargeable battery system in the related art;

[0020] Figure 2ais a schematic diagram of a battery device provided by one embodiment of the present invention;

[0021] Figure 2b This is a schematic diagram of a battery device provided by one embodiment of the present invention (with a current measurement unit added);

[0022] Figure 2c This is a schematic diagram of a battery device provided by one embodiment of the present invention (with voltage measurement unit detailed);

[0023] Figure 3 This is a schematic diagram of a battery device provided by one embodiment of the present invention (with an additional cell measurement unit);

[0024] Figure 4 1 is a schematic diagram of a charge and discharge control method provided by one embodiment of the present invention;

[0025] Figure 5 1 is a schematic diagram of a battery device provided by an embodiment of the present invention (switching unit implementation method 1);

[0026] Figure 6 1 is a schematic diagram of a battery device provided by an embodiment of the present invention (switching unit implementation method 2);

[0027] Figure 7 1 is a schematic diagram of a battery device provided by an embodiment of the present invention (switching unit implementation method three);

[0028] Figure 8 1 is a schematic diagram of a current limiting unit provided by an embodiment of the present invention;

[0029] Figure 9 1 is a schematic diagram of a voltage measurement unit provided by an embodiment of the present invention;

[0030] Figure 10 is a schematic diagram of a current measurement unit provided by an embodiment of the present invention;

[0031] Figure 11 is a flow chart of a charge and discharge control method provided by one embodiment of the present invention;

[0032] Figure 12 is a flow chart of a charge and discharge control method provided by another embodiment of the present invention;

[0033] Figure 13 Schematic diagram of a charge and discharge control device provided by one embodiment of the present invention;

[0034] Figure 14 It is a schematic diagram of a storage medium provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of the present application can be combined with each other in any manner.

[0036] The steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions. Also, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be performed in an order different from that shown here.

[0037] The relevant technical solution in the industry is to connect the current limiting module in series in the charge and discharge circuit, so that the current limiting work is always carried out during the charge and discharge process, such as Figure 1 This is shown in the simplified rechargeable battery system in Figure 1. While this solution solves the overcurrent problem during the charging phase, the current limiting module consumes a lot of power, resulting in significant charge and discharge losses, low efficiency, and high cost. Furthermore, it cannot be applied in applications requiring high-current, fast charging and discharging. This significantly wastes the economic value of lithium batteries' high-current, fast-charging characteristics, effectively limiting charge and discharge at low currents and failing to fully utilize the advantages of high-current fast charging. Currently, no effective solution has been proposed to the problem of low charge and discharge efficiency when rechargeable batteries are not overcurrent-controlled.

[0038] Figure 2a Schematic diagram of a battery device provided by one embodiment of the present invention. Figure 2a As shown, an embodiment of the present invention provides a battery device, including: a battery cell U1 and a charging and discharging device, wherein the charging and discharging device includes a processor U2, a voltage measuring unit D1, a current limiting unit U3, and a switch unit U4. The current limiting unit U3 is connected in parallel with the switch unit U4, and after being connected in parallel with the switch unit U4, the current limiting unit U3 is connected in series with the battery cell U1 and the power supply Y1 for charging the battery cell. The processor U2 is connected to the voltage measuring unit D1, the current limiting unit U3, and the switch unit U4. The voltage measuring unit D1 is connected to both ends of the battery cell U1, and the voltage measuring unit D1 is connected to both ends of the power supply Y1. A load device RL can be connected between the two ends A and B of the power supply Y1 ( Figure 2a (not shown), wherein the battery unit U1 and the power supply Y1 can supply power to the load device RL. When the power supply Y1 is not disconnected, the load device RL is powered by Y1. When the power supply Y1 is disconnected, the battery unit U1 supplies power to the load device RL.

[0039] The voltage measuring unit D1 is used to measure the voltage across the power source Y1 and the voltage across the battery unit U1;

[0040] The processor U2 is configured to control the voltage measuring unit D1, and control the access status of the current limiting unit U3 and the switch unit U4 according to the voltage measured by the voltage measuring unit D1, so as to realize the charging and discharging of the battery unit U1 through at least one of the current limiting unit U3 and the switch unit U4;

[0041] The current limiting unit U3 is used to be closed or opened based on the control of the processor U2, and provides a current-limited charging branch when closed; when opened, the current limiting unit U3 is equivalent to being disconnected from the circuit.

[0042] The switch unit U4 is used to provide a charging branch with unlimited current, and close or open the charging branch with unlimited current based on the control of the processor U2.

[0043] This embodiment provides a solution that selects different charging modes based on the battery cell voltage and power supply voltage, offering a high-current charging solution and enabling fast charging. By controlling the current-limiting branch and the fast-charging branch to alternate between charging and discharging, this embodiment improves battery charge and discharge efficiency, reduces losses, and saves charging time and energy, while ensuring that the battery does not overcharge. This achieves the economic benefits of rechargeable battery safety, low cost, and high charging efficiency.

[0044] The battery unit U1 includes at least one battery. The battery is, for example, a lithium battery. The battery unit U1 serves as a backup power source and includes, but is not limited to, lithium iron phosphate batteries, ternary lithium batteries, lithium cobalt oxide batteries, and other lithium batteries.

[0045] In one embodiment, the current limiting unit U3 is, for example, a power conversion unit composed of components and circuits with a maximum current limiting function. The current limiting unit U3 is used to limit the charging current and solve the problem of overcurrent.

[0046] In one embodiment, the switch unit U4 is, for example, a switch element or a combination of switch elements having a unidirectional current control function. Specifically, the switch unit U4 may include only one switch, or multiple switches, or a combination of multiple switches and multiple diodes.

[0047] In one embodiment, the processor U2 compares the voltage of the power source Y1 and the battery unit U1, and controls the access status of the current limiting unit U3 and the switch unit U4 according to the comparison result. Specifically, the processor U2 controls the access status of the current limiting unit U3 and the switch unit U4 according to the voltage measured by the voltage measuring unit D1 to realize the charging and discharging of the battery unit U1 through at least one of the current limiting unit U3 and the switch unit U4, including:

[0048] When the difference between the voltage of the power source Y1 and the voltage of the battery unit U1 is greater than or equal to a first threshold value U0, the charging branch of the switch unit U4 is disconnected, and the current limiting unit U3 is closed to charge the battery unit U1 through the current limiting unit U3; this is the current limiting charging state;

[0049] When the difference between the voltage of the power source Y1 and the voltage of the battery unit U1 is less than the first threshold value U0, the current limiting unit U3 is disconnected and the charging branch of the switch unit U4 is closed to charge the battery unit U1 through the switch unit. This is the non-current limiting charging state, or the fast charging state.

[0050] The first threshold value can be set as needed, or determined through experiments.

[0051] In another embodiment, Figure 2b As shown, the battery device further includes a current measuring unit D2, a shunt D3, the current measuring unit D2 is connected to the shunt D3 and the processor U2, and the shunt D3 is connected to the charge and discharge branch of the battery unit U1 ( Figure 2b The figure is for illustration only and can be connected to other locations as long as it can detect the charging and discharging currents.

[0052] The current measuring unit D2 is used to measure the discharge current or charging current of the battery unit U1;

[0053] The processor U2 is further configured to control the access status of the current limiting unit U3 and the switch unit U4 according to the discharge current or the charge current measured by the current measuring unit D2 so as to realize the charging and discharging of the battery unit through at least one of the current limiting unit U3 and the switch unit U4.

[0054] In one embodiment, the processor U2 controls the access state of the current limiting unit U3 and the switch unit U4 according to the discharge current or the charging current measured by the current measuring unit D2 to realize the charging and discharging of the battery unit through at least one of the current limiting unit U3 and the switch unit U4, including:

[0055] When the current limiting unit U3 is disconnected, the charging branch of the switch unit U4 is closed, and the current measured by the current measuring unit D2 is greater than or equal to the second threshold value Imax, the charging branch of the switch unit U4 is disconnected and the current limiting unit U3 is closed. That is, when in the fast charging state, the current is detected. If the current is too high, the charging state is switched back to the current limiting state. If the current is less than the second threshold value, the fast charging state is maintained.

[0056] In one embodiment, the processor U2 is further configured to adjust the current value of the current limiting unit U3 after the current limiting unit U3 is closed. This method controls the current value in the circuit so that the charging current does not exceed the current limit ILm. The current limiting unit U3 is a switching circuit that acts as a secondary bypass in parallel with the main circuit charging and discharging switches. The current limiting unit U3 includes, but is not limited to, a DC power conversion circuit, a current limiting board, a buck circuit, a buck-boost circuit, etc. It uses PWM to control the on / off of the MOSFET (metal oxide semiconductor field effect transistor) in the current limiting branch, thereby controlling the charging current and achieving low-current limited charging.

[0057] In one embodiment, the switch unit U4 is further configured to provide a unidirectional discharge branch based on the control of the processor U2. For example, a branch consisting of a diode and a switch element connected in series, where the diode conducts in the direction of the discharge current of the battery cell. It should be noted that the components of the charging branch and the unidirectional discharge branch in the switch unit U4 may overlap, that is, the two may share the same components.

[0058] In one embodiment, the processor U2 is further configured to initially close the unidirectional discharge branch of the switch unit U4 (before charging or comparing the voltages of the power source Y1 and the battery unit U1). This provides a discharge branch so that if the power source Y1 loses power, the battery unit U1 can promptly supply power to the load device RL, avoiding interruptions. This state is known as the online non-floating charge state, in which the charging branch of the switch unit U4 and the current limiting unit U3 are both disconnected.

[0059] In one embodiment, the processor U2 is further configured to, when the battery cell U1 is fully charged, disconnect the charging branch of the switch unit U4, close the unidirectional discharge branch of the switch unit U4, and disconnect the current limiting unit U3. This embodiment promptly disconnects the battery cell U1 after charging is complete, thereby preventing overcharging of the battery cell U1. Whether the battery cell U1 is fully charged can be determined by whether the voltage across the battery cell U1 and the charging current have reached preset thresholds. At this point, the battery cell U1 enters an online non-floating charging state.

[0060] In one embodiment, the processor U2 is further configured to disconnect the charging branch of the switch unit U4 and the current limiting unit U3 when the power source Y1 is powered off and the current measured by the current measuring unit D2 is less than a third threshold value Imin. After the power source Y1 is powered off, discharge occurs through the unidirectional discharge branch. The third threshold value can be set as needed. This is applicable when the current required by the load RL is relatively low. At this point, the battery enters an online non-floating charge state.

[0061] In one embodiment, the processor U2 is further configured to disconnect the current limiting unit U3 and close the charging branch of the switch unit U4 when the power supply Y1 is powered off and the current measured by the current measuring unit D2 is greater than a third threshold value Imin. After the power supply Y1 is powered off, discharge occurs through the unidirectional discharge branch and the charging branch of the switch unit U4. This state is defined as the discharge-charge state, which is logically consistent with the fast charge state and can be freely converted, thus achieving high-rate charge and discharge.

[0062] In one embodiment, the switch unit U4 includes:

[0063] A first switch, a second switch, and a first diode, wherein the first diode and the second switch are connected in series, the first switch is connected in parallel at both ends of the series branch formed by the first diode and the second switch, and the conductive direction of the first diode is the discharge current direction of the battery cell; in this case, the charging branch is the circuit formed by the first switch, and the discharging branch is the circuit formed by the second switch and the first diode;

[0064] or,

[0065] A first switch and a second switch are connected in series, and a first diode is connected in parallel at both ends of the first switch, and the conductive direction of the first diode is the discharge current direction of the battery cell; in this case, the charging branch is the circuit composed of the first switch, and the discharging branch is the circuit composed of the first switch and the first diode;

[0066] or,

[0067] A first switch and a second switch are connected in series, a first diode is connected in parallel at both ends of the first switch, and a second diode is connected in parallel at both ends of the second switch, and the conduction direction of the first diode is the discharge current direction of the battery cell, and the conduction direction of the second diode is the charging current direction for charging the battery cell.

[0068] It should be noted that the switch unit may also include only the first switch. In addition, the first switch and the second switch may be replaced by more switches, and the first diode and the second diode may be replaced by more diodes.

[0069] In one embodiment, if Figure 2c As shown, the voltage measuring unit D1 includes a first voltage measuring unit D1-1 and a second voltage measuring unit D1-2; wherein, the first voltage measuring unit D1-1 is connected to both ends of the battery unit U1 for detecting the voltage of the battery unit U1, and the second voltage measuring unit D1-2 is connected to both ends of the power supply Y1 for detecting the voltage of the power supply Y1.

[0070] In one embodiment, if Figure 3As shown, the charging and discharging device further includes a cell measurement unit D4, which is connected to the battery unit U1 and the processor U2, wherein:

[0071] The cell measurement unit D4 is used to measure the cell voltage and cell temperature in the battery unit U1;

[0072] The processor U2 is further configured to control the connection status of the current limiting unit U3 and the switch unit U4 based on the cell voltage and the cell temperature. For example, when the cell voltage or the cell temperature is too high, charging is stopped, i.e., the current limiting unit U3 is disconnected, the charging branch of the switch unit U4 is disconnected, and the discharging branch of the switch unit U4 may also be disconnected.

[0073] like Figure 4 As shown, an embodiment of the present invention provides a charge and discharge control method, which is applied to the above-mentioned charge and discharge device, including:

[0074] Step 401, obtaining a first voltage across the battery cell and a second voltage across the power supply;

[0075] Step 402: Control the access status of the current limiting unit and the switch unit according to the first voltage and the second voltage to realize charging and discharging of the battery unit through at least one of the current limiting unit and the switch unit.

[0076] In one embodiment, controlling the access states of the current limiting unit and the switch unit according to the first voltage and the second voltage to realize charging and discharging of the battery unit through at least one of the current limiting unit and the switch unit includes:

[0077] When the voltage difference between the power source and the battery cell is greater than or equal to a first threshold value U0, the charging branch of the switch unit is disconnected, and the current limiting unit is closed to charge the battery cell through the current limiting unit;

[0078] When the voltage difference between the power source and the battery unit is less than the first threshold value U0, the current limiting unit is disconnected, and the charging branch of the switch unit is closed to charge the battery unit through the switch unit.

[0079] In one embodiment, the method further includes: obtaining a charging current or a discharging current of the battery cell;

[0080] According to the charging current or the discharging current, the access states of the current limiting unit and the switch unit are controlled to realize the charging and discharging of the battery unit through at least one of the current limiting unit and the switch unit.

[0081] In one embodiment, controlling the access state of the current limiting unit and the switch unit according to the charging current or the discharging current to realize charging and discharging of the battery unit through at least one of the current limiting unit and the switch unit includes:

[0082] When the current limiting unit is disconnected, the charging branch of the switch unit is closed, and the discharge current is greater than or equal to a second threshold, the charging branch of the switch unit is disconnected and the current limiting unit is closed.

[0083] In one embodiment, the method further comprises, initially, closing a unidirectional discharge branch of the switch unit.

[0084] In one embodiment, the method further includes: when the battery unit is fully charged, disconnecting the charging branch of the switch unit, closing the unidirectional discharging branch of the switch unit, and disconnecting the current limiting unit.

[0085] In one embodiment, the method further includes, when the power source is powered off, disconnecting the current limiting unit and closing the charging branch of the switch unit.

[0086] In one embodiment, the method further includes, when the power supply is cut off and the discharge current is less than a third threshold, disconnecting the current limiting unit and disconnecting the charging branch of the switch unit.

[0087] In one embodiment, the method further includes, when the power supply is cut off and the discharge current is greater than a third threshold, disconnecting the current limiting unit and closing the charging branch of the switch unit.

[0088] In other embodiments, multiple power sources Y1 , multiple load devices RL, and multiple battery devices may be included.

[0089] In one embodiment, the switch unit U4 can be controlled to have a conductive direction consistent with the current direction required by the circuit in which it is located, and can perform both unidirectional discharge and bidirectional charge and discharge.

[0090] In one embodiment, the method further includes, when the power source Y1 is powered off, controlling the charging branch of the switch unit U4 to close and the current limiting unit U3 to disconnect.

[0091] In one embodiment, the method further includes, when the power source Y1 is powered off, closing the unidirectional discharge branch of the switch unit U4 , disconnecting the charging branch of the switch unit U4 , and disconnecting the current limiting unit U3 .

[0092] Figure 5 A battery device is provided. In this embodiment, the charging branch is separated from the discharging branch. For other units except the switch unit U4, please refer to the previous embodiment. Figure 5 As shown, in this embodiment, the switch unit U4 includes a first switch S1 and a second switch S2. A unidirectional limit is added to the discharge branch, that is, the discharge branch also includes a first diode B1, wherein the first diode B1 is connected in series with the second switch S2, and the first switch S1 is connected in parallel at both ends of the series branch formed by the first diode B1 and the second switch S2. The conductive direction of the diode B1 is consistent with the current direction of the branch in which it is located (the discharge branch), that is, the discharge current direction of the battery unit U1. In this embodiment, the charging branch is a circuit composed of the first switch S1, and the discharging branch is a circuit composed of the second switch S2 and the first diode B1.

[0093] It should be noted that, in another embodiment, the switch unit U4 only includes the first switch S1.

[0094] based on Figure 5 In the circuit shown, in order to ensure the safety and maintenance of the battery unit U1, the processor U2 is further configured to control the second switch S2 to be closed before comparing the voltage values of the power source Y1 with the battery unit U1.

[0095] In another embodiment, in order to ensure that the battery cell is charged safely without overcurrent, the processor U2 controls the current limiting unit U3 and the first switch S1 to charge the battery cell U1 according to the comparison result, including:

[0096] If the voltage difference between the power source Y1 and the battery unit U1 is greater than or equal to a first threshold value U0, the processor controls the first switch S1 to be disconnected, the second switch S2 to be closed, and the current limiting unit U3 to be turned on;

[0097] If the voltage difference between the power source Y1 and the battery unit U1 is less than a first threshold value U0 , the processor controls the first switch S1 to be closed, the second switch S2 to be opened, and the current limiting unit U3 to be opened.

[0098] In another embodiment, to ensure that the current of the battery unit U1 does not overflow, the device also performs current monitoring. Specifically, if the voltage difference between the power source Y1 and the battery unit U1 is less than a first threshold value U0, after controlling the first switch S1 to close, the processor U2 further detects the charging current value I and compares the charging current value I with a second threshold value Imax. If the charging current value I is greater than or equal to the second threshold value Imax, the processor U2 controls the first switch S1 to open, the second switch S2 to close, and the current limiting unit U3 to turn on.

[0099] In one embodiment, the processor U2 is further configured to adjust the current of the current limiting unit U3 after the current limiting unit U3 is turned on, so as to control the current value in the loop.

[0100] In one embodiment, the processor U2 is further configured to, after controlling the first switch S1 to close, control the first switch S1 to open, the second switch S2 to close, and the current limiting unit U3 to open to stop charging when the battery unit U1 is fully charged.

[0101] In one embodiment, the processor U2 is further configured to control the first switch S1 to be closed and the current limiting unit U3 to be disconnected when the power source Y1 is powered off.

[0102] In one embodiment, the processor U2 is further configured to, when the power source Y1 is powered off, control the first switch S1 to be opened and the second switch S2 to be closed, so as to discharge the battery unit U1.

[0103] The entire charging and discharging process of the aforementioned battery device is described below. Initially, the current limiting unit U3 is disconnected, the first switch S1 is disconnected, and the second switch S2 is closed. At the start of charging, the voltage difference between the power source Y1 and the battery cell U1 is greater than or equal to the first threshold U0. At this point, the current limiting unit U3 is closed, and the first switch is closed. Charging continues until the voltage difference between the power source Y1 and the battery cell U1 is less than the first threshold U0. At this point, the current limiting unit U3 is disconnected, the first switch S1 is closed, and charging is continued through the branch containing the first switch S1 (if the current is too high, charging is switched back to using the current limiting unit U3) until the battery cell U1 is fully charged. At this point, the first switch S1 and the current limiting unit U3 are disconnected. If the power source Y1 loses power, the battery cell U1 provides power. At this point, the first switch S1 can be closed, and the current limiting unit U3 remains disconnected.

[0104] In another embodiment, if the voltage difference between power source Y1 and battery cell U1 is greater than or equal to a first threshold value U0, current limiting unit U3 is closed, and first switch S1 is closed. Charging continues until the voltage difference between power source Y1 and battery cell U1 is less than the first threshold value U0. At this point, current limiting unit U3 is disconnected, first switch S1 is closed, and charging is performed through the branch containing first switch S1 (if the current is too high, charging is switched back to current limiting unit U3). If power source Y1 loses power at any time before the battery is fully charged, current limiting unit S3 is disconnected, and first switch S1 may or may not be closed. This decision is based on comparing the current in the circuit with a third threshold value. If the current in the circuit is greater than or equal to the third threshold value, first switch S1 is closed. It should be noted that second switch S2 remains closed during this process. If the discharge current is too high or other abnormalities occur, first switch S1 and second switch S2 may be disconnected.

[0105] One embodiment of the present invention provides another battery device. Figure 6As shown, the switch unit U4 includes a first switch S1 and a second switch S2, which are connected in series. A unidirectional limiter is added to the discharge branch. That is, the discharge branch of the circuit also includes a first diode B1, wherein the first diode B1 is connected in parallel with the first switch S1, and the conductive direction of the first diode B1 is consistent with the current direction of the branch in which it is located (i.e., the discharge current direction of the battery unit U1). After the battery unit U1 is fully charged, further charging is not allowed. The first switch S1 is opened, the second switch S2 is closed, and the discharge current is monitored and discharged through the diode B1 and the discharge switch S3. When a high current discharge is required, the processor U2 controls the closing of the first switch S1 and the second switch S2 to discharge. In this embodiment, the charging branch is a circuit formed by the first switch S1 and the second switch S2, and the discharge branch is a circuit formed by the first diode B1 and the second switch S2.

[0106] Another embodiment of the present invention provides a battery device. Figure 7 As shown, for other units except the switch unit U4, please refer to the previous embodiment. In this embodiment, the switch unit U4 includes a first switch S1 and a second switch S2, wherein the second switch S2 is connected in series with the first switch S1, and the series branch of the second switch S2 and the first switch S1 is connected in parallel with the current limiting unit U3. A unidirectional limit is added to the discharge branch, that is, the switch unit U4 also includes a first diode B1 and a second diode B2, wherein the first diode B1 is connected in parallel with the first switch S1, and the second diode B2 is connected in parallel with the second switch S2. The conductive direction of the first diode B1 and the second diode B2 is consistent with the current direction of the branch in which they are located, that is, the conductive direction of the first diode B1 is the discharge current direction of the battery unit U1, and the conductive direction of the second diode B2 is the charging current direction of the battery unit U1. After the battery is fully charged, further charging is not allowed. The first switch S1 is disconnected and the second switch S2 is closed. The discharge current is monitored and discharged through the first diode B1 and the second switch S2. When a small current transition charge is required, the processor U2 controls the first switch S1 to be closed and the second switch S2 to be disconnected for charging. When a large current discharge is required, the processor U2 controls the first switch S1 to be closed and the second switch S2 to be closed for discharging.

[0107] It should be noted that Figures 5 to 7 The device shown can also be added Figure 3 The cell measurement unit D4 is shown. In addition, Figures 5 to 7 The switch unit provided in the illustrated embodiment can be applied in any embodiment of the present application.

[0108] Below Figure 5 The illustrated embodiment is further described in detail.

[0109] like Figure 5 As shown, a current-limiting unit U3 is connected in parallel across a switch unit U4, forming a loop switch controlled by processor U2. This loop switch, along with battery unit U1 and power supply Y1, is connected in series to form a battery charging circuit. When power supply Y1 is disconnected, this loop switch, along with battery unit U1 and load RL, forms a battery discharging circuit. Processor U2 is responsible for detecting and sampling voltage, current, and temperature, and for controlling and managing the safe and reliable operation of the battery units. This device primarily includes, but is not limited to, the following components (enclosed in the dashed box): battery unit U1, processor U2, first switch S1, second switch S2, current-limiting unit U3, voltage measurement unit D1, current measurement unit D2, and shunt D3.

[0110] Battery unit U1 comprises several lithium battery cells (or cells) connected in series and parallel. The charge and discharge status of battery unit U1 is controlled by a circuit switch, which includes a switch unit U4 and a current-limiting unit U3, connected in parallel across switch unit U4. The discharge branch consists of a first diode B1 for reverse charge protection connected in series with a second switch S2. The first switch S1 is connected in parallel across the discharge branch, forming switch unit U4. The first switch S1, second switch S2, and current-limiting unit U3 in the circuit switch are all controlled by processor U2.

[0111] During battery charging, processor U2 detects the voltage Uy of power source Y1 in real time through voltage measurement unit D1-1, and the voltage Ub of battery cell U1 in real time through voltage measurement unit D1-2. When the voltage difference △V between Uy and Ub (△V = Uy - Ub) is greater than or equal to a first threshold value U0 (i.e., △V >= U0), indicating a large voltage difference and a risk of overcurrent, processor U2 controls first switch S1 to open, second switch S2 to close, and current limiting unit U3 to operate. Battery cell U1 is charged with a relatively low current through current limiting unit U3, thereby preventing overcurrent. When the voltage difference △V is less than the first threshold value U0 (i.e., △V < U0), indicating a small voltage difference and a potential risk of overcurrent, processor U2 controls first switch S1 to close, current limiting unit U3 to disconnect, and battery cell U1 is charged with a relatively high current through first switch S1. If the battery is being charged through the first switch S1, the processor U2 detects through the shunt D3 that the loop current I exceeds the second threshold value Imax, i.e., I>Imax. The processor U2 then controls the first switch S1 to open, the second switch S2 to close, and the current limiting unit U3 to start current-limited charging or discharging. When the power supply Y1 is powered off, charging stops, and the processor U2 controls the first switch S1 to close, the second switch S2 to close, the current limiting unit U3 to open and stop working, and the discharging process is started. The first switch S1 is a high-current branch, and the circuit formed by the second switch S2 is a low-current branch. This solution can prevent overcurrent in the battery cell while ensuring charging efficiency.

[0112] The current limiting unit and the switch unit in this example are in parallel, and there are two charging modes to choose from during the charging process. The processor detects the circuit voltage and current in real time, and compares the voltage difference and current with the preset threshold value to reasonably select whether to charge in a fast charging mode or a current limiting charging mode, providing a fast charging solution. In addition, overcurrent protection is achieved through the current limiting charging mode. The current limiting unit is controlled by the processor so that it can exit the charging circuit at the right time and start the switch unit charging at the same time, ensuring a larger current charging, shortening the charging time, and thus solving the problem of low charging efficiency. This method is simple and reliable, cost-effective, and easy to implement.

[0113] In the above embodiment:

[0114] (1) The positive electrode of the battery cell is connected to the positive electrode of the power supply as a common ground terminal. The power supply Y1 and the load device RL are used to describe the application scenario of the present invention; the power supply Y1 is used to charge the battery and power the load device RL, and the load device RL is the equivalent load of the actual power device.

[0115] It should be noted that, in another embodiment, the negative electrode of the battery unit is connected to the negative electrode of the power supply, and the negative electrode is used as a common ground terminal.

[0116] (2) Current limiting units such as BUCK circuits are implemented, such as Figure 8 The figure shows an embodiment of a buck circuit, which controls the output current by adjusting PWM. The circuit includes: one end of a first capacitor C1 is connected to the drain of a MOS transistor M1; a PWM signal is input to the gate of the MOS transistor M1; the source of the MOS transistor M1 is connected to the cathode of a third diode B3; the other end of the first capacitor C1 is connected to the cathode of the third diode B3; one end of an inductor L1 is connected to the cathode of the third diode; the other end of the inductor L1 is connected to one end of a second capacitor C2; and the other end of the second capacitor C2 is connected to the anode of the third diode B3.

[0117] (3) The first voltage measuring unit D1-1 detects the busbar negative electrode voltage, that is, the power supply voltage Uy, and the second voltage measuring unit D1-2 detects the battery cell negative electrode voltage, that is, the battery cell voltage Ub; Figure 9 The figure shows an embodiment of a voltage measurement unit, including: one end of a resistor R1 is a first voltage input end, the other end of the resistor R1 is connected to the inverting input end of an operational amplifier P1, one end of a resistor R2 is connected to the inverting input end of the operational amplifier P1, and the other end of the resistor R2 is connected to the output end of the operational amplifier P1; one end of a resistor R3 is a second voltage input end, the other end of the resistor R3 is connected to the non-inverting input end of the operational amplifier P1, one end of a resistor R4 is connected to the non-inverting input end of the operational amplifier P1, and the other end of the resistor R4 is grounded.

[0118] The voltage Vout at the output of the operational amplifier P1 is equal to (VI+)-(VI-))*R2 / R1, which is then restored to a digital voltage value by the ADC. The first voltage measurement unit D1-1 can be used Figure 9 The voltage measurement unit shown in the figure can be realized by the second voltage measurement unit D1-2. Figure 9 The voltage measurement unit implementation shown.

[0119] (4) The current measuring unit D2 is used to detect the loop current, that is, the charging or discharging current I; the shunt D3 is used to sample the loop current, and the shunt D3 includes but is not limited to a Hall sensor, a current transformer, a shunt, a resistance detection, etc. Figure 10 FIG. 1 shows an embodiment of a current measurement unit D2, comprising: a resistor R5 having one end serving as a first current input terminal, the other end of which is connected to the inverting input terminal of an operational amplifier P2; a resistor R6 having one end serving as a first current input terminal, the other end of which is connected to the inverting input terminal of the operational amplifier P2; a resistor R7 having one end serving as a second current input terminal, the other end of which is connected to the non-inverting input terminal of the operational amplifier P2; a resistor R8 having one end serving as a first current input terminal, the other end of which is connected to the non-inverting input terminal of the operational amplifier P2; and a resistor R8 having one end serving as a first current input terminal, the other end of which is connected to the non-inverting input terminal of the operational amplifier P2.

[0120] The output of the output end of the transport amplifier P2 is IBout = ((IB+) - (IB-)) * R4 / R3, and then restored to a digital current value by the ADC.

[0121] (5) The first switch S1 and the second switch S2 can be any controlled switching characteristic components, including but not limited to contactors, relays, MOSFET tubes, IGBTs (Insulated Gate Bipolar Transistors), etc.

[0122] (6) The first threshold, the second threshold, and the third threshold are all control parameters in the processor, and the parameters can be set or preset by software.

[0123] like Figure 11 As shown, use Figure 5 The method for charging and discharging a battery cell of the battery device includes:

[0124] Step 1101: Before battery charging begins, the processor U2 determines whether there is a system fault or protection alarm; if not, execute step 1103; if so, execute step 1102;

[0125] Step 1102: disconnect the current limiting unit U3, disconnect the switch unit U4, and end;

[0126] Step 1103: Close the second switch S2 to connect the discharge circuit and ensure the ability to discharge at any time.

[0127] Step 1104: The processor U2 uses the voltage measurement unit D1-1 to detect the voltage Uy of the power supply Y1 in real time, and uses the voltage measurement unit D1-2 to detect the voltage Ub of the battery unit U1 in real time. The processor U2 compares the pressure difference △V between Uy and Ub with the first threshold U0 to control the charging method. If the pressure difference △V (△V = Uy - Ub) between Uy and Ub is greater than or equal to the first threshold U0, that is, △V >= U0, execute Step 1105. If the pressure difference △V is less than the first threshold U0, that is, △V < U0, execute Step 1106.

[0128] Step 1105: When there is a risk of overcurrent charging due to excessive pressure difference, the processor U2 controls the first switch S1 to open and closes the current limiting unit U3. The battery unit U1 is charged with current limiting through the current limiting unit U3.

[0129] Among them, the current limiting unit U3 is a power conversion switch circuit. The processor U2 controls the on and off of the MOS transistor in the current limiting unit U3 in a PWM manner. It controls the output current of the current limiting unit U3 by adjusting the duty cycle of the PWM waveform in real time, and controls the current in the current limiting unit U3 within a preset threshold range to prevent overcurrent charging. In another embodiment, the current limiting unit U3 can also be a functional unit with an independent output current limiting function. The processor U2 issues a current limiting command to the current limiting unit U3, and the current limiting unit U3 performs output current limiting charging according to the current limiting command to achieve the goal of non-overcurrent charging.

[0130] Step 1106: When the pressure difference is small and there is no risk of overcurrent charging, the processor U2 controls the first switch S1 to close and the current limiting unit U3 to open. The battery unit U1 is charged through the first switch S1, and larger current charging can be performed to achieve the goal of fast charging of the battery.

[0131] Step 1107: When in the state of charging through the first switch S1, the processor U2 detects the loop current I through the current measurement unit D2 and judges whether the loop current I exceeds the second threshold Imax. If I > Imax, execute Step 1105; if I < Imax, execute Step 1108.

[0132] Step 1108: Continue charging through the first switch S1.

[0133] Step 1109: When the power supply Y1 is powered off, the charging stops. Since the second switch S2 is already closed, the discharge starts immediately. When the processor U2 determines that the discharge state is enabled by detecting the busbar voltage Uy and the discharge current I, it immediately controls the first switch S1 to close, disconnects the current limiting unit U3, and starts the discharge process.

[0134] It should be noted that, in other embodiments, when the power supply Y1 is cut off during charging through the current limiting unit U3, charging stops, the processor U2 immediately controls the first switch S1 to close, the current limiting unit U3 is disconnected, the current limiting unit U3 stops working, and discharge is started.

[0135] The technical solution of this example can prevent the battery cells from overcharging while ensuring charging efficiency.

[0136] like Figure 12 As shown, use Figure 7 The method for charging and discharging a battery cell of the battery device includes:

[0137] Step 1201: Set the first threshold U0 and the second threshold Imax parameters in the processor U2;

[0138] Step 1202: After the processor U2 is powered on and initialized, the system protection mechanism and fault are detected. If no protection or serious fault is detected, the process goes to step 1204; otherwise, the process goes to step 1203.

[0139] Step 1203: disconnect the current limiting unit U3, disconnect the switch unit U4, and end;

[0140] Step 1204, closing the second switch S2 to ensure discharge capability;

[0141] In step 1205, the processor U2 detects the power supply voltage Uy in real time through the voltage measurement unit D1-1 and the battery cell voltage Ub in real time through the voltage measurement unit D1-2. The processor U2 compares the voltage difference △V between the power supply voltage and the battery voltage with a preset voltage difference value; if △V < U0, the processor executes step 1206; if △V > U0, the processor executes step 1207;

[0142] When the power supply Y1 is powered on and battery charging is started, the processor U2 calculates and determines in real time the voltage difference △V between the power supply voltage and the battery voltage and the first threshold U0, and controls the working mode of the first switch S1, the second switch S2 and the current limiting unit U3 according to the comparison result.

[0143] In step 1206, the processor U2 controls the first switch S1 to be opened and the current limiting unit U3 to be closed. The battery cell is charged with current limiting by the current limiting unit U3. During the current limiting charging process, the battery voltage increases with charging, and the voltage difference ΔV gradually changes accordingly. Therefore, it is necessary to re-compare ΔV and U0, and execute step 1205.

[0144] Step 1207: The processor U2 controls the first switch S1 to be closed and the current limiting unit U3 to be disconnected, i.e., the current limiting unit U3 does not work, and the battery unit is charged through the switch unit U4, and step 1208 is executed.

[0145] In step 1208, the processor controls the current measurement unit D2 to operate, detect the current I in real time, compare it with the second threshold value Imax, and control the current limiting unit U3 and the switch unit U4 based on the comparison result. If the processor U2 detects that the loop current I is greater than or equal to the second threshold value Imax during the charging process, step 1206 is executed. If I is less than the second threshold value Imax, step 1209 is executed.

[0146] In another embodiment, when the loop current I is greater than or equal to the second threshold value Imax and lasts for a predetermined time, step 1206 is executed;

[0147] When charging is enabled and current limiting is enabled, processor U2 uses PWM to control the on / off switching of the MOS transistor in the current limiting unit U3 branch. It then adjusts the PWM waveform duty cycle in real time to control the output current of current limiting unit U3, keeping the current in the current limiting branch within a specified threshold range, thereby preventing overcurrent during charging. Alternatively, current limiting unit U3 can be a functional unit with an independent output current limiting function. Processor U2 issues a current limiting command to current limiting unit U3, which then automatically performs output current limiting charging.

[0148] Step 1209 , determining whether the battery cell has entered a fully charged state (current I and voltage Ub have reached a preset threshold value). If so, executing step 1210 ; otherwise, re-determining whether the battery cell has entered a fully charged state.

[0149] In step 1210, processor U2 controls the first switch S1 to open and the second switch S2 to close, entering a state where the battery can be discharged but not charged. When the battery is fully charged, simply disconnecting the charging branch prevents floating charge without affecting discharge, ensuring that the discharge branch is always online.

[0150] When the first switch S1 is opened and the second switch S2 is closed, the system is in a dischargeable but not rechargeable state, the power supply Y1 is powered off, the battery unit U1 starts discharging, and the processor U2 detects that the discharge current I is greater than a preset threshold (such as a third threshold), and immediately closes the first switch S1 to ensure normal discharge.

[0151] In another embodiment, when the battery cell is in current-limited charging, the power source Y1 is disconnected and charging stops. The processor U2 immediately controls the first switch S1 to close and the current-limiting unit U3 to disconnect, so that the current-limiting unit U3 stops working and discharge starts.

[0152] like Figure 13 As shown, an embodiment of the present invention provides a charge and discharge control device 130, including a memory 1310 and a processor 1320. The memory 1310 stores a program, and when the program is read and executed by the processor 1320, it implements the charge and discharge control method described in any embodiment.

[0153] like Figure 14 As shown, an embodiment of the present invention provides a computer-readable storage medium 140, wherein the computer-readable storage medium 140 stores one or more programs 141, and the one or more programs 141 can be executed by one or more processors to implement the charge and discharge control method described in any embodiment.

[0154] Those skilled in the art will appreciate that all or some of the steps, systems, and functional modules / units in the methods, systems, and devices disclosed above may be implemented as software, firmware, hardware, or any combination thereof. In hardware implementations, the division between functional modules / units described above does not necessarily correspond to the division between physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on computer-readable media, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is well known to those skilled in the art, the term computer storage media encompasses both volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, as is well known to those skilled in the art, communication media typically embodies computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A charging and discharging device, characterized in that: include: A processor, a voltage measuring unit, a current limiting unit, and a switch unit, wherein: the current limiting unit and the switch unit are connected in parallel and connected in series with the battery unit to be charged and discharged and the power supply for charging the battery unit; the processor is connected to the voltage measuring unit, the current limiting unit, and the switch unit; the voltage measuring unit is connected to both ends of the battery unit; and the voltage measuring unit is connected to both ends of the power supply; wherein: The voltage measuring unit is used to measure the voltage across the battery cell and the voltage across the power supply; the processor is used to control the access state of the current limiting unit and the switch unit according to the voltage measured by the voltage measuring unit to realize charging and discharging of the battery cell through at least one of the current limiting unit and the switch unit; wherein, the processor controls the access state of the current limiting unit and the switch unit according to the voltage measured by the voltage measuring unit to realize charging and discharging of the battery cell through at least one of the current limiting unit and the switch unit, including: When the difference between the voltage of the power source and the voltage of the battery cell is greater than or equal to a first threshold, the charging branch of the switch unit is disconnected, and the current limiting unit is closed to charge the battery cell through the current limiting unit; when the difference between the voltage of the power source and the voltage of the battery cell is less than the first threshold, the current limiting unit is disconnected, and the charging branch of the switch unit is closed to charge the battery cell through the switch unit; The current limiting unit is configured to be closed or opened based on the control of the processor, and to provide a current-limited charging branch when closed; The switch unit is used to provide a charging branch with unlimited current, and close or open the charging branch with unlimited current based on the control of the processor; The charging and discharging device further includes a current measuring unit and a shunt, wherein the current measuring unit is connected to the shunt and the processor, and the shunt is connected in series with the battery unit; The current measuring unit is used to measure the discharge current or charging current of the battery unit; The processor is further configured to control, according to the discharge current or the charging current measured by the current measuring unit, the access state of the current limiting unit and the switch unit so as to realize the charging and discharging of the battery unit through at least one of the current limiting unit and the switch unit; The processor controls the access state of the current limiting unit and the switch unit according to the discharge current or the charge current measured by the current measuring unit to realize the charging and discharging of the battery unit through at least one of the current limiting unit and the switch unit, including: When the current limiting unit is disconnected, the charging branch of the switch unit is closed, and the current measured by the current measuring unit is greater than or equal to a second threshold, the charging branch of the switch unit is disconnected and the current limiting unit is closed; The processor is further configured to adjust the current value of the current limiting unit after the current limiting unit is closed; The switch unit is further configured to provide a unidirectional discharge branch based on the control of the processor.

2. The charge and discharge device according to claim 1, wherein: The processor is further configured to initially close the unidirectional discharge branch of the switch unit.

3. The charge and discharge device according to claim 1, wherein: The processor is further configured to, when the battery unit is fully charged, disconnect the charging branch of the switch unit, close the unidirectional discharge branch of the switch unit, and disconnect the current limiting unit.

4. The charge and discharge device according to claim 1, wherein: The processor is further configured to, when the power supply is cut off, disconnect the charging branch of the switch unit, disconnect the current limiting unit, and close the unidirectional discharge branch of the switch unit.

5. The charge and discharge device according to claim 1, wherein: The processor is further configured to, when the power supply is cut off, disconnect the current limiting unit and close the charging branch of the switch unit.

6. The charge and discharge device according to claim 1, wherein: The processor is further configured to: When the power supply is cut off and the current measured by the current measuring unit is greater than a third threshold, the current limiting unit is disconnected and the charging branch of the switch unit is closed.

7. The charge and discharge device according to claim 1, wherein: The switch unit includes: a first switch, a second switch, and a first diode, wherein the first diode and the second switch are connected in series, the first switch is connected in parallel at both ends of a series branch formed by the first diode and the second switch, and a conductive direction of the first diode is a discharge current direction of the battery cell; or, A first switch and a second switch connected in series, and a first diode connected in parallel at both ends of the first switch, wherein the conductive direction of the first diode is the discharge current direction of the battery cell; or, A first switch and a second switch are connected in series, a first diode is connected in parallel at both ends of the first switch, and a second diode is connected in parallel at both ends of the second switch, and the conduction direction of the first diode is the discharge current direction of the battery cell, and the conduction direction of the second diode is the charging current direction for charging the battery cell.

8. The charge and discharge device according to claim 1, wherein: The voltage measuring unit includes a first voltage measuring unit and a second voltage measuring unit, wherein the first voltage measuring unit is connected to both ends of the battery unit, and the second voltage measuring unit is connected to both ends of the power supply, wherein: The first voltage measuring unit is used to measure the voltage across the battery unit; The second voltage measuring unit is used to measure the voltage across the power supply.

9. The charge-discharge device according to any one of claims 1 to 8, characterized in that: The charging and discharging device further includes a cell measurement unit, which is connected to the battery unit and the processor, wherein: The battery cell measurement unit is used to measure the battery cell voltage and battery cell temperature in the battery unit; The processor is further configured to control the access status of the current limiting unit and the switch unit according to the battery cell voltage and the battery cell temperature.

10. A battery device, characterized in that: include: The charging and discharging device and battery cell according to any one of claims 1 to 9.

11. A charge and discharge control method, characterized in that: The charging and discharging device according to any one of claims 1 to 9 comprises: Obtaining a first voltage across the battery unit and a second voltage across the power supply; Controlling the access states of the current limiting unit and the switch unit according to the first voltage and the second voltage so as to realize charging and discharging of the battery cell through at least one of the current limiting unit and the switch unit; wherein, controlling the access states of the current limiting unit and the switch unit according to the first voltage and the second voltage so as to realize charging and discharging of the battery cell through at least one of the current limiting unit and the switch unit includes: when the difference between the voltage of the power supply and the voltage of the battery cell is greater than or equal to a first threshold, disconnecting the charging branch of the switch unit and closing the current limiting unit to charge the battery cell through the current limiting unit; when the difference between the voltage of the power supply and the voltage of the battery cell is less than the first threshold, disconnecting the current limiting unit and closing the charging branch of the switch unit to charge the battery cell through the switch unit; Obtaining a charging current or a discharging current of the battery cell; According to the charging current or discharging current, controlling the access state of the current limiting unit and the switch unit to realize charging and discharging of the battery unit through at least one of the current limiting unit and the switch unit; The step of controlling the access states of the current limiting unit and the switch unit according to the charging current or the discharging current to realize charging and discharging of the battery unit through at least one of the current limiting unit and the switch unit includes: When the current limiting unit is disconnected, the charging branch of the switch unit is closed, and the discharge current is greater than or equal to a second threshold, the charging branch of the switch unit is disconnected and the current limiting unit is closed; After the current limiting unit is closed, the current value of the current limiting unit is adjusted.

12. The charge and discharge control method according to claim 11, wherein: The method further includes, initially, closing the unidirectional discharge branch of the switch unit.

13. The charge and discharge control method according to claim 11, wherein: The method further includes: when the battery unit is fully charged, disconnecting the charging branch of the switch unit, closing the unidirectional discharge branch of the switch unit, and disconnecting the current limiting unit.

14. The charge and discharge control method according to any one of claims 11 to 13, characterized in that: The method further includes, when the power supply is cut off, disconnecting the current limiting unit, disconnecting the charging branch of the switch unit, and closing the unidirectional discharge branch of the switch unit.

15. The charge and discharge control method according to any one of claims 11 to 13, characterized in that: The method further includes, when the power source is powered off, disconnecting the current limiting unit and closing the charging branch of the switch unit.

16. The charge and discharge control method according to any one of claims 11 to 13, characterized in that: The method further includes, when the power source is cut off and the discharge current of the battery unit is greater than a third threshold, disconnecting the current limiting unit and closing the charging branch of the switch unit.

17. A charge and discharge control device, characterized in that: The device comprises a memory and a processor, wherein the memory stores a program, and when the program is read and executed by the processor, the charge and discharge control method according to any one of claims 11 to 16 is implemented.

18. A computer-readable storage medium, characterized in that The computer-readable storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the charge and discharge control method according to any one of claims 11 to 16.

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