Pre-charging circuit, charging device and unmanned aerial vehicle equipment

Abstract

The utility model discloses a kind of pre-charging circuit, charging device and unmanned aerial vehicle equipment. Among them, pre-charging circuit includes: battery pack, current limiting circuit, charging circuit and control unit;Control unit is used to divide the pre-charging voltage range of battery pack into first voltage range and second voltage range, detect the voltage of battery pack, if the voltage of battery pack meets first voltage range, then control to open current limiting circuit and charging circuit, if the voltage of battery pack meets second voltage range, then control to open charging circuit;Charging circuit, for output first pre-charging voltage, or, output second pre-charging voltage;Current limiting circuit, for generating variable current limiting current using the voltage difference between first pre-charging voltage and the voltage of battery pack, and using current limiting current to carry out first stage pre-charging to battery pack;Charging circuit is also used to generate variable charging current based on second pre-charging voltage, using charging current to carry out second stage pre-charging to battery pack.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a pre-charging circuit, a charging device, and a drone equipment. Background Technology

[0002] In related technologies, when the battery voltage drops below a safe threshold, a small current is needed for pre-charging to gradually restore the voltage to the normal charging range. However, current pre-charging circuits suffer from problems such as the pre-charging current failing to meet reasonable accuracy requirements and excessively long pre-charging times. Summary of the Invention

[0003] In view of this, the present invention aims to provide a pre-charging circuit, a charging device, and a drone equipment.

[0004] The technical solution of this utility model embodiment is implemented as follows:

[0005] This utility model embodiment provides a pre-charging circuit, which includes: a battery pack, a current limiting circuit, a charging circuit, and a control unit;

[0006] The control unit is used to divide the pre-charge voltage range of the battery pack into a first voltage range and a second voltage range, detect the voltage of the battery pack, and if the voltage of the battery pack meets the first voltage range, control the current limiting circuit and the charging circuit to be turned on; if the voltage of the battery pack meets the second voltage range, control the charging circuit to be turned on.

[0007] The charging circuit is configured to output a first pre-charge voltage when the voltage of the battery pack meets the first voltage range, or to output a second pre-charge voltage when the voltage of the battery pack meets the second voltage range; wherein the first pre-charge voltage is greater than the second pre-charge voltage.

[0008] The current limiting circuit is used to generate a variable current limiting current by utilizing the voltage difference between the first pre-charging voltage output by the charging circuit and the voltage of the battery pack, and to use the current limiting current to perform a first-stage pre-charging of the battery pack.

[0009] The charging circuit is further configured to generate a variable charging current based on the second pre-charging voltage, and use the charging current to perform a second-stage pre-charging of the battery pack to complete the pre-charging process; wherein the charging current is greater than the current limiting current.

[0010] Furthermore, according to at least one embodiment of the present invention, the pre-charging circuit further includes a first switch and a second switch; wherein, the positive terminal of the battery pack is connected to a first terminal of the current limiting circuit, the second terminal of the current limiting circuit is connected to a first terminal of the first switch, the second terminal of the first switch is connected to the positive terminal of the charging circuit, the first terminal of the second switch is connected to the positive terminal of the charging circuit, the second terminal of the second switch is connected to the positive terminal of the battery pack, the negative terminal of the battery pack is connected to the negative terminal of the charging circuit, and the control unit is connected to the first switch and the second switch respectively.

[0011] Furthermore, according to at least one embodiment of the present invention, the control unit is specifically configured to control the first switch to close and the second switch to open if the voltage of the battery pack meets the first voltage range, so as to control the current limiting circuit and the charging circuit to be turned on; and to control the first switch to open and the second switch to close if the voltage of the battery pack meets the second voltage range, so as to control the charging circuit to be turned on.

[0012] Furthermore, according to at least one embodiment of the present invention, the control unit is also connected to the charging circuit; the control unit is further configured to send a first signal to the charging circuit after controlling the first switch to close and controlling the second switch to open, wherein the first signal indicates a request for the charging circuit to output the first pre-charge voltage; or, after controlling the first switch to open and controlling the second switch to close, send a second signal to the charging circuit, wherein the second signal indicates a request for the charging circuit to output the second pre-charge voltage;

[0013] The charging circuit is specifically configured to receive the first signal sent by the control unit, respond to the first signal, and output the first pre-charge voltage; or, receive the second signal sent by the control unit, respond to the second signal, and output the second pre-charge voltage.

[0014] Furthermore, according to at least one embodiment of the present invention, the control unit is further configured to, after sending a first signal to the charging circuit, start a first timer, and if the first timer reaches a first preset threshold, control the stopping of the first stage of pre-charging; or, after sending a second signal to the charging circuit, start a second timer, and if the second timer reaches a second preset threshold, control the stopping of the second stage of pre-charging.

[0015] Furthermore, according to at least one embodiment of the present invention, the control unit is also used to detect the temperature of the current limiting circuit in real time during the first stage of pre-charging. If the temperature of the current limiting circuit is greater than or equal to a third preset threshold, the control unit controls the closing and opening time of the first switch according to a first duty cycle to control the working time and rest time of the current limiting circuit. The first duty cycle represents the ratio of the working time and rest time of the current limiting circuit.

[0016] Furthermore, according to at least one embodiment of the present invention, the first duty cycle has different values ​​when the battery pack is connected to different charging devices.

[0017] Furthermore, according to at least one embodiment of the present invention, the control unit is also used to detect the temperature of the battery pack in real time during the second stage of pre-charging. If the temperature of the battery pack is greater than or equal to a fourth preset threshold, the control unit controls the closing and opening time of the second switch according to a second duty cycle to control the working time and rest time of the charging circuit. The second duty cycle represents the ratio of the working time to the rest time of the charging circuit.

[0018] Furthermore, according to at least one embodiment of the present invention, the value of the second duty cycle is different when the battery pack is connected to different charging devices.

[0019] Furthermore, according to at least one embodiment of the present invention, the battery pack is composed of a first battery and a second battery connected in series; the control unit is further configured to, during the first stage pre-charging or the second stage pre-charging process, determine the sum of the voltage increment of the first battery and the voltage increment of the second battery within a preset time period to obtain a total voltage increment, determine the ratio of the voltage increment of the first battery to the total voltage increment within the preset time period to obtain a charge weight of the first battery, determine the ratio of the voltage increment of the second battery to the total voltage increment within the preset time period to obtain a charge weight of the second battery, determine whether the charge weight of the first battery or the second battery is greater than or equal to a preset weight value, and if it is determined that the charge weight of the first battery or the second battery is greater than or equal to the preset weight value, then control the stopping of the first stage pre-charging or the second stage pre-charging.

[0020] Furthermore, according to at least one embodiment of the present invention, the battery pack is composed of a first battery and a second battery connected in series; the control unit is further configured to, during the second stage of pre-charging, determine the sum of the voltage increment of the first battery and the voltage increment of the second battery within a preset time period to obtain the total voltage increment, determine the ratio of the voltage increment of the first battery to the total voltage increment within the preset time period to obtain the charge weight of the first battery, determine the ratio of the voltage increment of the second battery to the total voltage increment within the preset time period to obtain the charge weight of the second battery, determine whether the charge weight of the first battery or the second battery meets a preset weight range, and if it is determined that the charge weight of the first battery or the second battery meets the preset weight range, then control the pre-charging of the battery pack through the current limiting circuit until the charge weight of the first battery is equal to the charge weight of the second battery, and then control the pre-charging of the battery pack through the charging circuit.

[0021] Furthermore, according to at least one embodiment of the present invention, the control unit is also configured to detect the temperature of the battery pack during the second stage of pre-charging. If the temperature of the battery pack meets a first preset temperature range, the control unit controls the pre-charging of the battery pack through the charging circuit. If the temperature of the battery pack meets a second preset temperature range, the control unit controls the pre-charging of the battery pack through the current limiting circuit. The second preset temperature range is greater than the first preset temperature range.

[0022] This utility model provides a charging device, including the pre-charging circuit described in any of the above embodiments.

[0023] This utility model provides a drone device, including the charging device described above.

[0024] This utility model provides a pre-charging circuit, a charging device, and a drone device. The pre-charging circuit includes a battery pack, a current limiting circuit, a charging circuit, and a control unit. The control unit is used to divide the pre-charging voltage range of the battery pack into a first voltage range and a second voltage range, detect the voltage of the battery pack, and if the voltage of the battery pack meets the first voltage range, control the current limiting circuit and the charging circuit to be turned on; if the voltage of the battery pack meets the second voltage range, control the charging circuit to be turned on. The charging circuit is used to output a first pre-charging voltage when the voltage of the battery pack meets the first voltage range, and to output a second pre-charging voltage when the voltage of the battery pack meets the second voltage range; wherein the first pre-charging voltage is greater than the second pre-charging voltage. The current limiting circuit is used to generate a variable current limiting current using the voltage difference between the first pre-charging voltage output by the charging circuit and the voltage of the battery pack, and to perform a first-stage pre-charging of the battery pack using the current limiting current. The charging circuit is also used to generate a variable charging current based on the second pre-charging voltage, and to perform a second-stage pre-charging of the battery pack using the charging current to complete the pre-charging process; wherein the charging current is greater than the current limiting current.

[0025] By adopting the technical solution provided by this utility model embodiment, the pre-charge voltage range of the battery pack is divided into a first voltage range and a second voltage range. If the voltage of the battery pack meets the first voltage range, the current limiting circuit and the charging circuit are controlled to be turned on to use a small current, i.e., the current limiting current, for pre-charging to meet the accuracy requirements of the pre-charge current. If the voltage of the battery pack meets the second voltage range, the charging circuit is controlled to be turned on to use a large current, i.e., the charging current, for pre-charging to reduce the total pre-charge time. In this way, the problems of unreasonable accuracy of the pre-charge current and excessively long pre-charge time caused by using only the charging circuit or only the current limiting circuit for pre-charging in related technologies can be avoided. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the composition structure of the pre-charging circuit according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the specific composition and structure of the pre-charging circuit in an embodiment of this utility model;

[0028] Figure 3 This is a schematic diagram of the specific composition structure of the pre-charging circuit in the first stage pre-charging application of this utility model embodiment;

[0029] Figure 4 This is a schematic diagram of the specific composition and structure of the pre-charging circuit in the second stage pre-charging application of this utility model embodiment. Detailed Implementation

[0030] Before introducing the technical solutions of the embodiments of this utility model, the relevant technologies will be introduced first.

[0031] In related technologies, users should select battery types with suitable lifespans based on application scenarios and delay aging to the greatest extent possible through scientific management. For example, this includes reducing the risk of further damage after over-discharging and charging the battery with a small current. Battery pre-charging refers to the process of gradually restoring the voltage to the normal charging range when the battery voltage drops below a safe threshold; this stage aims to avoid chemical damage caused by deep discharge, ensure safety, and extend battery life. When the battery is in a discharged or dormant state, it needs to be activated and woken up through external means.

[0032] Current smart battery pre-charging solutions include the following two types:

[0033] The first technical solution controls the charging current through the charging module. However, due to the performance of the battery cell itself, the battery often requires a smaller current, such as less than 0.02C (equivalent to 100mA), when the voltage is low. The charging module cannot provide higher accuracy when the current is low, that is, the charging current output by the charging module cannot be less than 0.02C. This makes it unreasonable to use the charging module for pre-charging when the battery voltage is extremely low.

[0034] A charging module is an electronic system that converts an external power source (such as AC or DC) into controlled electrical energy output adapted for battery charging. Its core functions include voltage / current regulation, charging phase management, safety protection, and communication monitoring.

[0035] The second technical solution uses a current limiting module for current-limited pre-charging. Although the pre-charging current can be limited by the current limiting module, this solution will cause the pre-charging time to be too long, which may lead to a decrease in user experience due to the pre-charging time exceeding the preset time.

[0036] Here, a separate current limiting module is used for pre-charging. Although it can perform small-current pre-charging when the battery voltage is low, it cannot improve the pre-charging speed and the pre-charging time is too long. It also cannot adjust the pre-charging current according to the battery temperature, which is not good for battery life.

[0037] In summary, current pre-charging circuits have problems such as the pre-charging current failing to meet reasonable accuracy requirements, excessively long pre-charging time, and excessively high temperature of the current-limiting circuit inside the battery during pre-charging.

[0038] Based on this, in this embodiment of the present invention, the pre-charging circuit includes: a battery pack, a current limiting circuit, a charging circuit, and a control unit; the control unit is used to divide the pre-charging voltage range of the battery pack into a first voltage range and a second voltage range, detect the voltage of the battery pack, and if the voltage of the battery pack meets the first voltage range, control the current limiting circuit and the charging circuit to be turned on; if the voltage of the battery pack meets the second voltage range, control the charging circuit to be turned on; the charging circuit is used to output a first pre-charging voltage when the voltage of the battery pack meets the first voltage range, or output a second pre-charging voltage when the voltage of the battery pack meets the second voltage range; wherein, the first pre-charging voltage is greater than the second pre-charging voltage; the current limiting circuit is used to generate a variable current limiting current using the voltage difference between the first pre-charging voltage output by the charging circuit and the voltage of the battery pack, and use the current limiting current to perform a first-stage pre-charging of the battery pack; the charging circuit is also used to generate a variable charging current based on the second pre-charging voltage, and use the charging current to perform a second-stage pre-charging of the battery pack to complete the pre-charging process; wherein, the charging current is greater than the current limiting current.

[0039] See Figure 1 , Figure 1 This is a schematic diagram of the pre-charging circuit structure according to an embodiment of the present invention, as shown below. Figure 1 As shown, the pre-charging circuit includes: a battery pack 11, a current limiting circuit 12, a charging circuit 13, and a control unit 14;

[0040] The control unit 14 is used to divide the pre-charge voltage range of the battery pack 11 into a first voltage range and a second voltage range, detect the voltage of the battery pack 11, and if the voltage of the battery pack 11 meets the first voltage range, control the current limiting circuit 12 and the charging circuit 13 to be turned on; if the voltage of the battery pack 11 meets the second voltage range, control the charging circuit 13 to be turned on.

[0041] The charging circuit 13 is configured to output a first pre-charge voltage when the voltage of the battery pack 11 meets the first voltage range, or to output a second pre-charge voltage when the voltage of the battery pack 11 meets the second voltage range; wherein the first pre-charge voltage is greater than the second pre-charge voltage.

[0042] The current limiting circuit 12 is used to generate a variable current limiting current by utilizing the voltage difference between the first pre-charging voltage output by the charging circuit 13 and the voltage of the battery pack 11, and to use the current limiting current to perform a first-stage pre-charging of the battery pack 11.

[0043] The charging circuit 13 is further configured to generate a variable charging current based on the second pre-charging voltage, and use the charging current to perform a second-stage pre-charging of the battery pack 11 to complete the pre-charging process; wherein the charging current is greater than the current limiting current.

[0044] Here, the control unit 14 is specifically used to randomly select a first value from the pre-charge voltage range of the battery pack 11, and use the first value to divide the pre-charge voltage range into a first voltage range and a second voltage range; wherein, the first value is the maximum value of the first voltage range and the minimum value of the second voltage range.

[0045] Here, the pre-charge voltage range can be set according to the type of battery pack 11, and different types of battery packs 11 can correspond to different pre-charge voltage ranges.

[0046] Here, the voltage of the battery pack 11 satisfying the first voltage range can be understood as the current voltage of the battery pack 11 falling within the first voltage range, and the voltage of the battery pack 11 satisfying the second voltage range can be understood as the current voltage of the battery pack 11 falling within the second voltage range.

[0047] For example, assuming the pre-charge voltage range of the battery pack 11 is 3.5V to 5V, a first value, such as 4V, is randomly selected from the pre-charge voltage range of 3.5V to 5V. Using the first value, the pre-charge voltage range is divided into a first voltage range and a second voltage range. The first voltage range is 3.5V to 4.0V, and the second voltage range is 4.0V to 5.0V. The first value of 4V is the maximum value of the first voltage range and the minimum value of the second voltage range. When the voltage of the battery pack 11 meets the first voltage range of 3.5V to 4.0V, the current limiting circuit 12 and the charging circuit 13 are turned on (or described as being turned on), and a small current, i.e., a variable current (a current that varies in the range of 20 to 50mA), is used for the first stage of pre-charging. When the voltage of the battery pack 11 meets the second voltage range of 4.0V to 5.0V, the charging circuit 13 is turned on (or described as being turned on), and a large current, i.e., a variable charging current (a current that varies in the range of 100 to 200mA), is used for the second stage of pre-charging.

[0048] In some embodiments, the pre-charging circuit further includes a first switch and a second switch; wherein, the positive terminal of the battery pack 11 is connected to a first terminal of the current limiting circuit 12, the second terminal of the current limiting circuit 12 is connected to a first terminal of the first switch, the second terminal of the first switch is connected to the positive terminal of the charging circuit 13, the first terminal of the second switch is connected to the positive terminal of the charging circuit 13, the second terminal of the second switch is connected to the positive terminal of the battery pack 11, the negative terminal of the battery pack 11 is connected to the negative terminal of the charging circuit 13, and the control unit 14 is connected to the first switch and the second switch respectively.

[0049] In some embodiments, the control unit 14 is specifically configured to control the first switch to close and the second switch to open if the voltage of the battery pack 11 meets the first voltage range, so as to control the current limiting circuit 12 and the charging circuit 13 to be turned on; and to control the first switch to open and the second switch to close if the voltage of the battery pack 11 meets the second voltage range, so as to control the charging circuit 13 to be turned on.

[0050] In some embodiments, the control unit 14 is also connected to the charging circuit 13; the control unit 14 is further configured to send a first signal to the charging circuit 13 after controlling the first switch to close and controlling the second switch to open, wherein the first signal indicates a request for the charging circuit 13 to output the first pre-charge voltage; or, after controlling the first switch to open and controlling the second switch to close, send a second signal to the charging circuit 13, wherein the second signal indicates a request for the charging circuit 13 to output the second pre-charge voltage;

[0051] The charging circuit 13 is specifically used to receive the first signal sent by the control unit 14, respond to the first signal, and output the first pre-charge voltage; or, to receive the second signal sent by the control unit 14, respond to the second signal, and output the second pre-charge voltage.

[0052] In some embodiments, the control unit 14 is further configured to, after sending a first signal to the charging circuit 13, start a first timer, and if the first timer reaches a first preset threshold, control the stopping of the first stage of pre-charging; or, after sending a second signal to the charging circuit 13, start a second timer, and if the second timer reaches a second preset threshold, control the stopping of the second stage of pre-charging.

[0053] It should be noted that in this embodiment of the present invention, the first preset threshold and the second preset threshold may be the same or different.

[0054] In some embodiments, the control unit 14 is further configured to detect the temperature of the current limiting circuit 12 in real time during the first stage of pre-charging. If the temperature of the current limiting circuit 12 is greater than or equal to a third preset threshold, the control unit 14 controls the closing and opening time of the first switch according to the first duty cycle to control the working time and rest time of the current limiting circuit 12. The first duty cycle represents the ratio of the working time and rest time of the current limiting circuit 12.

[0055] In some embodiments, the first duty cycle may have different values ​​when the battery pack 11 is connected to different charging devices.

[0056] Specifically, it can include:

[0057] When the battery pack 11 is connected to a first type of charging device (such as a drone device, where the charging circuit 13 is located inside the drone device), due to heat dissipation within the first type of charging device, the use of the current-limiting circuit 12 during the first stage of pre-charging will cause a temperature rise in the current-limiting circuit 12. Therefore, based on the real-time detected temperature of the current-limiting circuit 12, a duty cycle method is adopted. That is, if the temperature of the current-limiting circuit 12 is greater than or equal to a third preset threshold, the closing and opening time of the first switch corresponding to the current-limiting circuit 12 is controlled according to the first duty cycle to control the working time and rest time of the current-limiting circuit 12. For example, the current-limiting circuit 12 is opened for 5 minutes (5 min) and closed for 10 minutes (10 min), thereby achieving the purpose of cooling the current-limiting circuit 12. Here, the first duty cycle represents the ratio of the working time and rest time of the current-limiting circuit 12, which is also the ratio of the closing time and opening time of the first switch.

[0058] When the battery pack 11 is connected to a second type of charging device (such as a charging management device, where the charging circuit 13 is located), the heat dissipation of this device is better than that of the first type of charging device. Based on the real-time detected temperature of the current limiting circuit 12, a duty cycle method is used. That is, if the temperature of the current limiting circuit 12 is greater than or equal to a third preset threshold, the closing and opening time of the first switch corresponding to the current limiting circuit 12 is controlled according to the first duty cycle to control the working time and rest time of the current limiting circuit 12. For example, the current limiting circuit 12 is turned on for 30 minutes (30 min) and turned off for 5 minutes (5 min), thereby achieving the purpose of cooling the current limiting circuit 12. Here, the first duty cycle represents the ratio of the working time and rest time of the current limiting circuit 12, which is also the ratio of the closing time and opening time of the first switch.

[0059] The first duty cycle value varies depending on the type of charging device connected to the battery pack 11.

[0060] In some embodiments, the control unit 14 is further configured to detect the temperature of the battery pack 11 in real time during the second stage of pre-charging. If the temperature of the battery pack 11 is greater than or equal to a fourth preset threshold, the control unit 14 controls the closing and opening time of the second switch according to the second duty cycle to control the working time and rest time of the charging circuit 13. The second duty cycle represents the ratio of the working time and rest time of the charging circuit 13.

[0061] In some embodiments, the second duty cycle may have different values ​​when the battery pack 11 is connected to different charging devices.

[0062] Specifically, it can include:

[0063] When the battery pack 11 is connected to a first type of charging device (such as a drone device, where the charging circuit 13 is located inside the drone device), the battery pack 11 will experience a temperature rise due to heat dissipation issues during the second stage of pre-charging using the charging circuit 13. Therefore, based on the real-time detected temperature of the battery pack 11, a duty cycle method is adopted. That is, if the temperature of the battery pack 11 is greater than or equal to a fourth preset threshold, the closing and opening times of the second switch corresponding to the charging circuit 13 are controlled according to the second duty cycle to control the working and resting times of the charging circuit 13. For example, the charging circuit 13 is turned on for 5 minutes (5 min) and turned off for 10 minutes (10 min), thereby achieving the purpose of cooling the battery pack 11. Here, the second duty cycle represents the ratio of the working and resting times of the charging circuit 13, which is also the ratio of the closing and opening times of the second switch.

[0064] When battery pack 11 is connected to a second type of charging device (such as a charging management device, where charging circuit 13 is located), this device has better heat dissipation conditions than the first type of charging device. Based on the real-time detected temperature of the battery pack, a duty cycle method is used. That is, if the temperature of battery pack 11 is greater than or equal to a fourth preset threshold, the closing and opening time of the charging switch corresponding to the charging circuit 13 module is controlled according to the second duty cycle to control the working time and rest time of the charging circuit 13. For example, the charging circuit 13 is turned on for 30 minutes (30 min) and turned off for 5 minutes (5 min), thereby achieving the purpose of cooling the battery pack. Here, the second duty cycle represents the ratio of the working time and rest time of the charging circuit 13, and is also the ratio of the closing time and opening time of the second switch.

[0065] The second duty cycle value varies depending on the type of charging device connected to the battery pack 11.

[0066] It should be noted that in this embodiment of the present invention, the third preset threshold and the fourth preset threshold may be the same or different.

[0067] In some embodiments, the battery pack 11 is composed of a first battery and a second battery connected in series; the control unit 14 is further configured to, during the first stage pre-charging or the second stage pre-charging process, determine the sum of the voltage increment of the first battery and the voltage increment of the second battery within a preset time period to obtain the total voltage increment, determine the ratio of the voltage increment of the first battery to the total voltage increment within the preset time period to obtain the charge weight of the first battery, determine the ratio of the voltage increment of the second battery to the total voltage increment within the preset time period to obtain the charge weight of the second battery, determine whether the charge weight of the first battery or the second battery is greater than or equal to a preset weight value, and if it is determined that the charge weight of the first battery or the second battery is greater than or equal to the preset weight value, then control the stopping of the first stage pre-charging or the second stage pre-charging.

[0068] Here, the control unit 14 detects the voltage increment of the first battery and the voltage increment of the second battery within the preset time, and sums the detected voltage increments of the first battery and the second battery within the preset time to obtain the total voltage increment.

[0069] Here, the power weight refers to the ratio of the voltage increment of the first battery to the total voltage increment, or the ratio of the voltage increment of the second battery to the total voltage increment, within the same time period. The total power increment is the sum of the voltage increments of the first battery and the second battery. For example, if the voltage increases of the first battery and the second battery are equal within the same time period, assuming they both increase by 5mV, then each accounts for 50% of the total voltage increment, and the two batteries are considered to be in a balanced state. If the voltage increases of the first battery and the second battery are not equal within the same time period, assuming the first battery increases by 5mV and the second battery increases by 10mV, then the second battery accounts for 66% of the total voltage increment, and the two batteries are considered to be in an unbalanced state.

[0070] Here, in the first stage of pre-charging and the second stage of pre-charging, if there is a serious imbalance in the first or second battery, for example, if the voltage increment of one cell accounts for a weight of more than or equal to a preset weight value such as 80% of the total voltage increment, then the first stage of pre-charging or the second stage of pre-charging will be stopped.

[0071] In some embodiments, the battery pack 11 is composed of a first battery and a second battery connected in series. The control unit 14 is further configured to, during the second stage of pre-charging, determine the sum of the voltage increment of the first battery and the voltage increment of the second battery within a preset time to obtain the total voltage increment, determine the ratio of the voltage increment of the first battery to the total voltage increment within the preset time to obtain the charge weight of the first battery, determine the ratio of the voltage increment of the second battery to the total voltage increment within the preset time to obtain the charge weight of the second battery, determine whether the charge weight of the first battery or the second battery meets a preset weight range, and if it is determined that the charge weight of the first battery or the second battery meets the preset weight range, then control the pre-charging of the battery pack 11 through the current limiting circuit 12 until the charge weight of the first battery is equal to the charge weight of the second battery, and then control the pre-charging of the battery pack 11 through the charging circuit 13.

[0072] Here, in the second stage of pre-charging, if there is a slight imbalance between the first battery and the second battery, for example, if the voltage increment of one battery accounts for a weight of 51% to 79% of the total voltage increment within a preset weight range, then the current limiting circuit 12 is switched to pre-charging until the pre-charge weight of the first battery and the second battery recovers to 50%, then the charging circuit 13 is switched to pre-charging.

[0073] In some embodiments, the control unit 14 is further configured to detect the temperature of the battery pack 11 during the second stage of pre-charging. If the temperature of the battery pack 11 meets a first preset temperature range, the control unit 14 controls the charging circuit 13 to pre-charge the battery pack 11. If the temperature of the battery pack 11 meets a second preset temperature range, the control unit 14 controls the current limiting circuit 12 to pre-charge the battery pack 11. The second preset temperature range is greater than the first preset temperature range.

[0074] For example, based on the detected temperature of the battery pack 11, the pre-charge mode is dynamically selected, that is, the module used for pre-charge is dynamically selected, and the pre-charge current is dynamically switched. For example, when the detected temperature of the battery pack 11 meets the first preset temperature range, such as when the temperature of the battery pack 11 is in the range of 25 to 35°C, the charging circuit 13 is selected for pre-charge; when the detected temperature of the battery pack 11 meets the second preset temperature range, such as when the temperature of the battery pack 11 is in the range of 35 to 45°C, the current limiting circuit 12 is selected for pre-charge.

[0075] The present invention has the following advantages:

[0076] (1) By dividing the pre-charge voltage range of the battery pack 11 into a first voltage range and a second voltage range, if the voltage of the battery pack 11 meets the first voltage range, the current limiting circuit 12 and the charging circuit 13 are controlled to be turned on so as to use a small current, i.e., the current limiting current, for pre-charging to meet the accuracy requirements of the pre-charge current; if the voltage of the battery pack 11 meets the second voltage range, the charging circuit 13 is controlled to be turned on so as to use a large current, i.e., the charging current, for pre-charging to reduce the total pre-charge time. In this way, the problems of unreasonable accuracy of the pre-charge current and excessively long pre-charge time caused by using only the charging circuit or only the current limiting circuit for pre-charging in related technologies can be avoided.

[0077] (2) After the battery pack 11 is connected to an external charging device, the switching ratio is dynamically switched according to the temperature of the current limiting circuit 12 detected in real time, so as to control the working time and rest time of the current limiting circuit 12 and achieve cooling of the current limiting circuit 12.

[0078] (3) After the battery pack 11 is connected to an external charging device, the switching ratio is dynamically switched according to the real-time temperature of the battery pack 11 to control the working time and rest time of the charging circuit 13, so as to cool down the battery pack 11.

[0079] (4) Based on the power weight ratio of the first battery and the second battery included in the battery pack 11, dynamically select the module to be used for pre-charging and switch the pre-charging state.

[0080] (5) It can dynamically select the module to be used for pre-charging according to the temperature of the battery pack 11, that is, dynamically adjust the pre-charging current to improve the battery life.

[0081] See Figure 2 , Figure 2 This is a schematic diagram of the specific composition and structure of the pre-charging circuit according to an embodiment of the present invention, as shown below. Figure 2 As shown, the pre-charging circuit includes:

[0082] Battery pack;

[0083] Rate limiting module R;

[0084] Charger module;

[0085] Battery control unit;

[0086] Precharge control switch;

[0087] Charging switch.

[0088] in,

[0089] The battery pack is the aforementioned battery pack 11, the current limiting module R is the aforementioned current limiting circuit 12, the charging module is the aforementioned charging circuit 13, the battery control unit is the aforementioned control unit 14, the pre-charge control switch is the aforementioned first switch, and the charging switch is the aforementioned second switch.

[0090] Here, the positive terminal of the battery pack (battery B+) is connected to the first terminal of the current limiting module R, the second terminal of the current limiting module R is connected to the first terminal of the pre-charge control switch, the second terminal of the pre-charge control switch is connected to the positive terminal of the charging module (battery P+), the first terminal of the charging switch is connected to the positive terminal of the charging module (battery P+), the second terminal of the charging switch is connected to the positive terminal of the battery pack (battery B+), the negative terminal of the battery pack (battery B-) is connected to the negative terminal of the charging module (battery P-), and the battery control unit is connected to the charging module, the pre-charge control switch, and the charging switch respectively.

[0091] Here, the battery pack is composed of cells BAT1 and BAT2 connected in series, and it is assumed that the pre-charge voltage range of the battery pack is 3.5V to 5V.

[0092] The battery control unit is used to divide the pre-charge voltage range of the battery pack into a first voltage range and a second voltage range, detect the voltage of the battery pack, and if the voltage of the battery pack meets the first voltage range, control the current limiting module R and the charging module to be turned on; if the voltage of the battery pack meets the second voltage range, control the charging module to be turned on.

[0093] Here, the battery control unit is specifically used to randomly select a first value, such as 4V, from the pre-charge voltage range of the battery pack, i.e., 3.5V to 5V, and use the first value to divide the pre-charge voltage range into a first voltage range and a second voltage range, wherein the first voltage range is 3.5 to 4.0V, the second voltage range is 4.0V to 5.0V, and the first value of 4V is the maximum value of the first voltage range and the minimum value of the second voltage range.

[0094] The battery control unit is specifically configured to, if the voltage of the battery pack meets the first voltage range, control the pre-charge control switch to close and control the charging switch to open, so as to control the current limiting module R and the charging charger module to start; if the voltage of the battery pack meets the second voltage range, control the pre-charge control switch to open and control the charging switch to close, so as to control the charging charger module to start.

[0095] Here, when the battery pack voltage V1 meets the first voltage range of 3.5V to 4.0V, the current limiting module R and the charging charger module are turned on, and a small current, i.e., a variable current (a current that varies in the range of 20 to 50mA), is used for the first stage of pre-charging.

[0096] Here, when the battery pack voltage V3 meets the second voltage range of 4.0V to 5.0V, the charging module is turned on (or described as being turned on), and a large current, i.e., a variable charging current (a current that varies in the range of 100 to 200mA), is used for the second stage of pre-charging.

[0097] The battery control unit is further configured to, after controlling the precharge control switch to close and the charging switch to open, send a first signal to the charging charger module, wherein the first signal indicates a request for the charging charger module to output the first precharge voltage; or, after controlling the precharge control switch to open and the charging switch to close, send a second signal to the charging charger module, wherein the second signal indicates a request for the charging charger module to output the second precharge voltage. The first precharge voltage is greater than the second precharge voltage.

[0098] Accordingly, the charging module is specifically used to receive the first signal sent by the battery control unit, and in response to the first signal, output the first pre-charge voltage; or, to receive the second signal sent by the battery control unit, and in response to the second signal, output the second pre-charge voltage.

[0099] Here, the external charging module is specifically used to receive the first signal sent by the battery control unit, namely the low-voltage pre-charge request, and in response to the first signal, output the first pre-charge voltage V2, such as the upper limit voltage of 8.6V for pre-charge, so that a voltage difference is formed on the current limiting module R.

[0100] Here, the external charging module is specifically used to receive the second signal sent by the battery control unit, namely the second low-voltage pre-charge request, respond to the second signal, output the second pre-charge voltage V4, such as 5.2V (at this time, the voltage only needs to be slightly larger than the voltage of the battery pack), and output the pre-charge current such as 100~200mA through its own device to perform the second stage of pre-charge, so as to achieve the purpose of the second low-voltage pre-charge.

[0101] The current limiting module R is used to generate a variable current limiting current by utilizing the voltage difference between the first pre-charge voltage output by the charging module and the voltage of the battery pack, and to use the current limiting current to perform a first-stage pre-charge of the battery pack.

[0102] The charging module is further configured to generate a variable charging current based on the second pre-charging voltage, and use the charging current to perform a second-stage pre-charging of the battery pack to complete the pre-charging process; wherein the charging current is greater than the current limiting current.

[0103] The battery control unit is further configured to, after sending a first signal to the charging charger module, start a first timer, and if the first timer reaches a first preset threshold, control the stopping of the first stage of pre-charging; or, after sending a second signal to the charging charger module, start a second timer, and if the second timer reaches a second preset threshold, control the stopping of the second stage of pre-charging.

[0104] Here, the battery control unit is also used to start a first timer after sending a first signal to the charging module. The battery control unit enters a pre-charge waiting state. If the first timer reaches a first preset threshold, or if the waiting time exceeds the first preset threshold, the battery control unit will shut down the first stage of pre-charge and wait for the next activation state.

[0105] Here, the battery control unit is also used to start a second timer after sending a second signal to the charging module, and the battery enters a pre-charge waiting state. If the second timer reaches a second preset threshold, or if the waiting time exceeds the second preset threshold, the battery control unit will shut down the second stage of pre-charge and wait for the next activation state.

[0106] Here, after the battery pack is connected to an external charging device, the battery control unit is also used to control the working time and rest time of the current limiting module R based on the real-time detected temperature of the current limiting module R, that is, to switch the pre-charge current state, which may specifically include:

[0107] When the battery pack is connected to a first type of charging device (such as a drone device, where the charging module is located inside the drone device), due to heat dissipation issues within the first type of charging device, the use of the current-limiting module R for pre-charging in the first stage will cause a temperature rise in the current-limiting module R. Therefore, based on the real-time detected temperature of the current-limiting module R, a duty cycle method is adopted. That is, if the temperature of the current-limiting module R is greater than or equal to a third preset threshold, the closing and opening time of the pre-charge control switch corresponding to the current-limiting module R is controlled according to the first duty cycle to control the working time and rest time of the current-limiting module R. For example, the current-limiting module R is turned on for 5 minutes (5 min) and turned off for 10 minutes (10 min), thereby achieving the purpose of cooling the current-limiting module R. Here, the first duty cycle represents the ratio of the working time and rest time of the current-limiting module R, which is also the ratio of the closing time and opening time of the pre-charge control switch.

[0108] When the battery pack is connected to a second type of charging device (such as a charging manager device, where the charging charger module is located within the charging manager device), this device has better heat dissipation conditions than the first type of charging device. Based on the real-time detected temperature of the current limiting module R, a duty cycle method is used. That is, if the temperature of the current limiting module R is greater than or equal to a third preset threshold, the closing and opening time of the pre-charge control switch corresponding to the current limiting module R is controlled according to the first duty cycle to control the working time and rest time of the current limiting module R. For example, the current limiting module R is turned on for 30 minutes (30 min) and turned off for 5 minutes (5 min), thereby achieving the purpose of cooling the current limiting module R. Here, the first duty cycle represents the ratio of the working time and rest time of the current limiting module R, which is also the ratio of the closing time and opening time of the pre-charge control switch.

[0109] The first duty cycle value varies depending on the type of charging device connected to the battery pack.

[0110] Here, the battery pack is connected to an external charging device. Based on the real-time detected temperature of the battery pack and a third temperature (the internal temperature of the charging device), the working time and rest time of the charging module are controlled, i.e., the pre-charge current state is switched. Specifically, this may include:

[0111] When the battery pack is connected to a first-type charging device (such as a drone device, where the charging module is located inside the drone device), the battery pack's temperature will rise during the second-stage pre-charging process due to heat dissipation issues within the first-type charging device. Therefore, based on the real-time detected battery pack temperature, a duty cycle method is used. Specifically, if the battery pack temperature is greater than or equal to a fourth preset threshold, the closing and opening times of the charging switch corresponding to the charging module are controlled according to a second duty cycle. This controls the working and resting times of the charging module; for example, the charging module is turned on for 5 minutes (5 min) and turned off for 10 minutes (10 min), thereby cooling the battery pack. The second duty cycle represents the ratio of the charging module's working and resting times, which is also the ratio of the charging switch's closing and opening times.

[0112] When the battery pack is connected to a second type of charging device (such as a charging management device, where the charging module is located within the charging management device), this device has better heat dissipation conditions than the first type of charging device. Based on the real-time detected temperature of the battery pack, a duty cycle method is used. That is, if the temperature of the battery pack is greater than or equal to a fourth preset threshold, the closing and opening time of the charging switch corresponding to the charging module is controlled according to the second duty cycle to control the working time and rest time of the charging module. For example, the charging module is turned on for 30 minutes and turned off for 5 minutes, thereby achieving the purpose of cooling the battery pack. Here, the second duty cycle represents the ratio of the working time and rest time of the charging module, and is also the ratio of the closing time and opening time of the charging switch.

[0113] The value of the second duty cycle varies depending on the type of charging equipment connected to the battery pack.

[0114] Here, the battery control unit is further configured to, during the first stage pre-charging or the second stage pre-charging process, determine the sum of the voltage increments of cell BAT1 and cell BAT2 within a preset time period to obtain the total voltage increment, determine the ratio of the voltage increment of cell BAT1 to the total voltage increment within the preset time period to obtain the charge weight of cell BAT1, determine the ratio of the voltage increment of cell BAT2 to the total voltage increment within the preset time period to obtain the charge weight of cell BAT2, determine whether the charge weight of cell BAT1 or cell BAT2 is greater than or equal to a preset weight value, and if it is determined that the charge weight of cell BAT1 or cell BAT2 is greater than or equal to the preset weight value, then control the stopping of the first stage pre-charging or the second stage pre-charging.

[0115] Here, the battery control unit detects the voltage increment of cell BAT1 and the voltage increment of cell BAT2 within the preset time, and sums the detected voltage increments of cell BAT1 and cell BAT2 within the preset time to obtain the total voltage increment.

[0116] Here, the power weight refers to the ratio of the voltage increment of cell BAT1 to the total voltage increment within the same time period, or the ratio of the voltage increment of cell BAT2 to the total voltage increment. The total power increment is the sum of the voltage increments of cell BAT1 and cell BAT2. For example, if cell BAT1 and cell BAT2 increase their voltage by the same amount within the same time period, assuming they both increase by 5mV, then each accounts for 50% of the total voltage increment, and the two cells are considered to be in a balanced state. If cell BAT1 and cell BAT2 increase their voltage by different amounts within the same time period, assuming cell BAT1 increases by 5mV and cell BAT2 increases by 10mV, then cell BAT2 accounts for 66% of the total voltage increment, and the two cells are considered to be in an unbalanced state.

[0117] Here, in the first stage of pre-charging and the second stage of pre-charging, if there is a serious imbalance between cell BAT1 and cell BAT2, for example, if the voltage increment of one cell accounts for a weight of more than or equal to a preset weight value such as 80% of the total voltage increment, then the first stage of pre-charging or the second stage of pre-charging will be stopped.

[0118] Here, the battery control unit is further configured to, during the second stage of pre-charging, determine the sum of the voltage increments of cell BAT1 and cell BAT2 within a preset time period to obtain the total voltage increment, determine the ratio of the voltage increment of cell BAT1 to the total voltage increment within the preset time period to obtain the charge weight of cell BAT1, determine the ratio of the voltage increment of cell BAT2 to the total voltage increment within the preset time period to obtain the charge weight of cell BAT2, determine whether the charge weight of cell BAT1 or cell BAT2 meets a preset weight range, and if it is determined that the charge weight of cell BAT1 or cell BAT2 meets the preset weight range, then control the pre-charging of the battery pack through the current limiting circuit until the charge weight of the first battery is equal to the charge weight of the second battery, and then control the pre-charging of the battery pack through the charging circuit.

[0119] Here, in the second stage of pre-charging, if there is a slight imbalance between cell BAT1 and cell BAT2, for example, if the voltage increment of one cell accounts for a weight of 51% to 79% of the total voltage increment within a preset weight range, then the current limiting module R is switched to pre-charging until the pre-charge weight of cell BAT1 and cell BAT2 is restored to 50%, then the charging module is switched to pre-charging.

[0120] Here, the battery control unit is also used to detect the temperature of the battery pack during the second stage of pre-charging. If the temperature of the battery pack meets the first preset temperature range, the battery pack is pre-charged through the charging module. If the temperature of the battery pack meets the second preset temperature range, the battery pack is pre-charged through the current limiting module R. The second preset temperature range is greater than the first preset temperature range.

[0121] For example, based on the detected temperature of the battery pack, the pre-charge mode is dynamically selected, that is, the module used for pre-charge is dynamically selected, and the pre-charge current is dynamically switched. For example, when the detected temperature of the battery pack meets the first preset temperature range, such as the temperature of the battery pack in the range of 25 to 35°C, the charging module is selected for pre-charge; when the detected temperature of the battery pack meets the second preset temperature range, such as the temperature of the battery pack in the range of 35 to 45°C, the current limiting module R is selected for pre-charge.

[0122] This example has the following advantages:

[0123] (1) By utilizing the combined action of the charging module and the current limiting module, the battery pack is pre-charged to reduce the pre-charging time. That is, the working state of the charging module and the current limiting module can be controlled according to the detected battery pack voltage to achieve dynamic selection of the pre-charging mode, i.e., dynamic switching between high pre-charging current and low pre-charging current, thereby reducing the pre-charging time.

[0124] Here, assuming the battery voltage is extremely low, such as 3.5–4.0V, the current limiting module R is selected for pre-charging. The pre-charging current is determined by the current limiting module R and varies in the range of approximately 20–50mA. The pre-charging time is denoted by t1. When the battery voltage is slightly higher, such as 4.0–5.0V, the charging module is selected for pre-charging. The pre-charging current is controlled by the charging module and varies in the range of approximately 100–200mA. The pre-charging time is denoted by t2. The total pre-charging time is t1 + t2.

[0125] It should be noted that if the charger module is used alone for pre-charging, the accuracy of the small current (20-50mA) cannot be met due to the limitations of device precision. If the current limiting module R is used alone for pre-charging, it can control the small current (20-50mA) for accurate pre-charging, but the pre-charging time will be longer, denoted by t3. Since t1+t2<t3, the technical solution provided by this embodiment can reduce the pre-charging time, thereby avoiding the problem of reduced user experience caused by excessively long pre-charging times in related technologies.

[0126] Here, a combination of a current limiting module R and a charging module is used to accurately control the magnitude of the pre-charging current when the battery pack voltage is low to meet accuracy requirements, and to minimize the pre-charging time.

[0127] (2) After the battery pack is connected to an external charging device, the switching ratio is dynamically switched according to the temperature of the current limiting module R detected in real time, so as to control the working time and rest time of the current limiting module R and achieve cooling of the current limiting module R.

[0128] (3) After the battery pack is connected to an external charging device, the switching ratio is dynamically switched according to the real-time detected temperature of the battery pack to control the working time and rest time of the charging charger module in order to cool down the battery pack.

[0129] (4) Based on the weight ratio of pre-charge amount of cell BAT1 and cell BAT2, switch the pre-charge state.

[0130] (5) It can dynamically select the module to be used for pre-charging according to the temperature of the battery pack, that is, dynamically adjust the pre-charging current to improve battery life.

[0131] See Figure 3 , Figure 3 This is a schematic diagram showing the specific composition of the pre-charging circuit in the first stage pre-charging application of this utility model embodiment, as shown below. Figure 3 As shown, the pre-charging circuit includes:

[0132] Battery pack;

[0133] Rate limiting module R;

[0134] Charger module;

[0135] Battery control unit;

[0136] Precharge control switch;

[0137] Charging switch.

[0138] in,

[0139] The battery pack is the aforementioned battery pack 11, the current limiting module R is the aforementioned current limiting circuit 12, the charging module is the aforementioned charging circuit 13, the battery control unit is the aforementioned control unit 14, the pre-charge control switch is the aforementioned first switch, the pre-charge control switch is in a closed state, and the charging switch is the aforementioned second switch, the charging switch is in a closed state.

[0140] Here, the positive terminal of the battery pack (battery B+) is connected to the first terminal of the current limiting module R, the second terminal of the current limiting module R is connected to the first terminal of the pre-charge control switch, the second terminal of the pre-charge control switch is connected to the positive terminal of the charging module (battery P+), the first terminal of the charging switch is connected to the positive terminal of the charging module (battery P+), the second terminal of the charging switch is connected to the positive terminal of the battery pack (battery B+), the negative terminal of the battery pack (battery B-) is connected to the negative terminal of the charging module (battery P-), and the battery control unit is connected to the charging module, the pre-charge control switch, and the charging switch respectively.

[0141] Here, the battery pack is composed of cells BAT1 and BAT2 connected in series, and it is assumed that the pre-charge voltage range of the battery pack is 3.5V to 5V.

[0142] The first stage of pre-charging process is explained below.

[0143] Here, when the voltage of the battery pack drops below the safety threshold and is within the pre-charge voltage range, such as 3.5V to 5V, pre-charging is required. At this time, an external means is needed to activate the battery pack, i.e., charge activation. After the battery is activated, the voltage data of the current battery pack itself will be read in real time. When the voltage of the battery pack is within the pre-charge voltage range, the battery control unit will pre-charge the battery pack.

[0144] The battery control unit is used to divide the pre-charge voltage range of the battery pack into a first voltage range and a second voltage range, detect the voltage of the battery pack, and if the voltage of the battery pack meets the first voltage range, control the current limiting module R and the charging module to be turned on.

[0145] The battery control unit is specifically used to randomly select a first value, such as 4V, from the pre-charge voltage range of 3.5V to 5V, and use the first value to divide the pre-charge voltage range into a first voltage range and a second voltage range. The first voltage range is 3.5V to 4.0V, the second voltage range is 4.0V to 5.0V, and the first value of 4V is the maximum value of the first voltage range and the minimum value of the second voltage range.

[0146] Here, in the first stage of pre-charging, when the battery pack voltage V1 meets the first voltage range of 3.5V to 4.0V, the pre-charging control switch is turned on and the charging switch is turned off, so as to turn on (or describe as turn on) the current limiting module R and the charging charger module, and use a small current for the first stage of pre-charging.

[0147] Here, the battery control unit is specifically used to turn on the pre-charge control switch and turn off the charging switch if the voltage of the battery pack meets the first voltage range, i.e., 3.5V to 4.0V. The battery control unit also sends a first signal to the external charging charger module at regular intervals through external information interaction. The first signal can also be described as a first low-voltage pre-charge request, and enters the pre-charge waiting state. The first signal represents a request for the charging charger module to output the first pre-charge voltage.

[0148] Here, the external charging module is specifically used to receive the first signal sent by the battery control unit, namely the low-voltage pre-charge request, and in response to the first signal, output the first pre-charge voltage V2, such as the upper limit voltage of 8.6V for pre-charge, so that a voltage difference is formed on the current limiting module R.

[0149] Here, the current limiting module R is specifically used to generate a current limiting current using the voltage difference, and to perform a first-stage pre-charge of the battery pack using the current limiting current.

[0150] Here, the voltage difference between the first pre-charge voltage output by the charger module and the voltage of the battery pack is expressed by Formula 1, as follows:

[0151] V2-V1=ΔV (1)

[0152] Wherein, V2 represents the first pre-charge voltage output by the charger module, V1 represents the voltage of the battery pack, and ΔV represents the voltage difference between the first pre-charge voltage output by the charger module and the voltage of the battery pack.

[0153] Here, the current-limiting current generated by the voltage difference is expressed by formula (2), as follows:

[0154] I=ΔV / R (2)

[0155] Where I represents the current limiting current (or can be described as the pre-charge current), ΔV represents the voltage difference between the first pre-charge voltage output by the charging module and the voltage of the battery pack, and R represents the value of the resistor in the current limiting module R.

[0156] Here, the battery control unit is also used to start a first timer after sending a first signal to the charging module. The battery control unit enters a pre-charge waiting state. If the first timer reaches a first preset threshold, and if the waiting time exceeds the first preset threshold t4, the battery control unit will shut down the first stage of pre-charge and wait for the next activation state.

[0157] See Figure 4 , Figure 4 This is a schematic diagram of the specific composition structure of the pre-charging circuit in the second stage pre-charging application of this utility model embodiment, as shown below. Figure 4 As shown, the pre-charging circuit includes:

[0158] Battery pack;

[0159] Rate limiting module R;

[0160] Charger module;

[0161] Battery control unit;

[0162] Precharge control switch;

[0163] Charging switch.

[0164] in,

[0165] The battery pack is the aforementioned battery pack 11, the current limiting module R is the aforementioned current limiting circuit 12, the charging module is the aforementioned charging circuit 13, the battery control unit is the aforementioned control unit 14, the pre-charge control switch is the aforementioned first switch, the pre-charge control switch is in the off state, and the charging switch is the aforementioned second switch, the charging switch is in the closed state.

[0166] Here, the positive terminal of the battery pack (battery B+) is connected to the first terminal of the current limiting module R, the second terminal of the current limiting module R is connected to the first terminal of the pre-charge control switch, the second terminal of the pre-charge control switch is connected to the positive terminal of the charging module (battery P+), the first terminal of the charging switch is connected to the positive terminal of the charging module (battery P+), the second terminal of the charging switch is connected to the positive terminal of the battery pack (battery B+), the negative terminal of the battery pack (battery B-) is connected to the negative terminal of the charging module (battery P-), and the battery control unit is connected to the charging module, the pre-charge control switch, and the charging switch respectively.

[0167] Here, the battery pack is composed of cells BAT1 and BAT2 connected in series, and it is assumed that the pre-charge voltage range of the battery pack is 3.5V to 5V.

[0168] The second stage of pre-charging process is explained below.

[0169] Here, when the voltage of the battery pack drops below the safety threshold and is within the pre-charge voltage range, such as 3.5V to 5V, pre-charging is required. At this time, an external means is needed to activate the battery pack, i.e., charge activation. After the battery is activated, the voltage data of the current battery pack itself will be read in real time. When the voltage of the battery pack is within the pre-charge voltage range, the battery control unit will pre-charge the battery pack.

[0170] The battery control unit is used to divide the pre-charge voltage range into a first voltage range and a second voltage range, detect the voltage of the battery pack, and if the voltage of the battery pack meets the second voltage range, control the charging module to be turned on.

[0171] The battery control unit is specifically used to randomly select a first value, such as 4V, from the pre-charge voltage range of 3.5V to 5V, and use the first value to divide the pre-charge voltage range into a first voltage range and a second voltage range. The first voltage range is 3.5V to 4.0V, the second voltage range is 4.0V to 5.0V, and the first value of 4V is the maximum value of the first voltage range and the minimum value of the second voltage range.

[0172] Here, in the second stage of pre-charging, when the battery pack voltage V3 meets the second voltage range of 4.0V to 5.0V, the pre-charging control switch is turned off and the charging switch is turned on to start (or describe as turn on) the charging charger module, and a current of 100 to 200mA is used for the second stage of pre-charging.

[0173] Here, the battery control unit is specifically used to control the pre-charge control switch to be turned off and the charging switch to be turned on when the voltage of the battery pack meets the second voltage range, i.e., 4.0V to 5.0V. The battery control unit also sends a second signal to the external charging module at regular intervals through external information interaction. The second signal can also be described as a second low-voltage pre-charge request, and enters a pre-charge waiting state. The second signal represents a request for the charging module to output the second pre-charge voltage.

[0174] Here, the external charging module is specifically used to receive the second signal sent by the battery control unit, namely the second low-voltage pre-charge request, respond to the second signal, output the second pre-charge voltage V4, such as 5.2V (at this time, the voltage only needs to be slightly larger than the voltage of the battery pack), and output the pre-charge current such as 100~200mA through its own device to perform the second stage of pre-charge, so as to achieve the purpose of the second low-voltage pre-charge.

[0175] Here, the battery control unit is also used to start a second timer after sending a second signal to the charging module, and the battery enters a pre-charge waiting state. If the second timer reaches a second preset threshold, and if the waiting time exceeds the second preset threshold t4, the battery control unit will shut down the second stage of pre-charge and wait for the next activation state.

[0176] Here, the battery control unit is also used to detect the temperature of the battery pack during the second stage of pre-charging. If the temperature of the battery pack meets the first preset temperature range, the battery pack is pre-charged through the charging module. If the temperature of the battery pack meets the second preset temperature range, the battery pack is pre-charged through the current limiting module R. The second preset temperature range is greater than the first preset temperature range.

[0177] For example, in the second stage of pre-charging, if the battery pack voltage V3 meets the second voltage range (4.0–5.0V), but the battery pack temperature is relatively high (e.g., if the battery pack temperature meets the second preset temperature range, such as 35°C–45°C), the pre-charging current needs to be reduced. In this case, the charging module is no longer used for the second stage of pre-charging; instead, the current limiting module R is used. That is, when the battery pack temperature is detected to meet the second preset temperature range (e.g., 35–45°C), the current limiting module R is selected for pre-charging.

Claims

1. A pre-charging circuit, characterized in that, The pre-charging circuit includes: a battery pack, a current limiting circuit, a charging circuit, and a control unit; The control unit is used to divide the pre-charge voltage range of the battery pack into a first voltage range and a second voltage range, detect the voltage of the battery pack, and if the voltage of the battery pack meets the first voltage range, control the current limiting circuit and the charging circuit to be turned on; if the voltage of the battery pack meets the second voltage range, control the charging circuit to be turned on. The charging circuit is configured to output a first pre-charge voltage when the voltage of the battery pack meets the first voltage range, or to output a second pre-charge voltage when the voltage of the battery pack meets the second voltage range; wherein the first pre-charge voltage is greater than the second pre-charge voltage. The current limiting circuit is used to generate a variable current limiting current using the voltage difference between the first pre-charge voltage and the voltage of the battery pack, and to use the current limiting current to perform a first-stage pre-charge of the battery pack. The charging circuit is further configured to generate a variable charging current based on the second pre-charging voltage, and use the charging current to perform a second-stage pre-charging of the battery pack to complete the pre-charging process; wherein the charging current is greater than the current limiting current.

2. The pre-charging circuit according to claim 1, characterized in that, The pre-charging circuit also includes a first switch and a second switch. The positive terminal of the battery pack is connected to the first terminal of the current limiting circuit, the second terminal of the current limiting circuit is connected to the first terminal of the first switch, the second terminal of the first switch is connected to the positive terminal of the charging circuit, the first terminal of the second switch is connected to the positive terminal of the charging circuit, the second terminal of the second switch is connected to the positive terminal of the battery pack, the negative terminal of the battery pack is connected to the negative terminal of the charging circuit, and the control unit is connected to the first switch and the second switch respectively.

3. The pre-charging circuit according to claim 2, characterized in that, The control unit is specifically configured to control the first switch to close and the second switch to open if the voltage of the battery pack meets the first voltage range, so as to control the current limiting circuit and the charging circuit to be turned on. If the voltage of the battery pack meets the second voltage range, the first switch is controlled to open and the second switch is controlled to close, so as to control the charging circuit to be turned on.

4. The pre-charging circuit according to claim 3, characterized in that, The control unit is also connected to the charging circuit; the control unit is further configured to send a first signal to the charging circuit after controlling the first switch to close and controlling the second switch to open, wherein the first signal indicates a request for the charging circuit to output the first pre-charge voltage; or, after controlling the first switch to open and controlling the second switch to close, send a second signal to the charging circuit, wherein the second signal indicates a request for the charging circuit to output the second pre-charge voltage; The charging circuit is specifically configured to receive the first signal sent by the control unit, respond to the first signal, and output the first pre-charge voltage; or, receive the second signal sent by the control unit, respond to the second signal, and output the second pre-charge voltage.

5. The pre-charging circuit according to claim 4, characterized in that, The control unit is further configured to, after sending a first signal to the charging circuit, start a first timer, and if the first timer reaches a first preset threshold, control the stopping of the first stage of pre-charging; or, after sending a second signal to the charging circuit, start a second timer, and if the second timer reaches a second preset threshold, control the stopping of the second stage of pre-charging.

6. The pre-charging circuit according to claim 2, characterized in that, The control unit is also used to detect the temperature of the current limiting circuit in real time during the first stage of pre-charging. If the temperature of the current limiting circuit is greater than or equal to a third preset threshold, the control unit controls the closing and opening time of the first switch according to the first duty cycle to control the working time and rest time of the current limiting circuit. The first duty cycle represents the ratio of the working time and rest time of the current limiting circuit.

7. The pre-charging circuit according to claim 6, characterized in that, The first duty cycle value varies depending on the charging device connected to the battery pack.

8. The pre-charging circuit according to claim 2, characterized in that, The control unit is also used to detect the temperature of the battery pack in real time during the second stage of pre-charging. If the temperature of the battery pack is greater than or equal to a fourth preset threshold, the control unit controls the closing and opening time of the second switch according to the second duty cycle to control the working time and rest time of the charging circuit. The second duty cycle represents the ratio of the working time and rest time of the charging circuit.

9. The pre-charging circuit according to claim 8, characterized in that, The second duty cycle value varies depending on the charging device connected to the battery pack.

10. The pre-charging circuit according to any one of claims 1 to 9, characterized in that, The battery pack is composed of a first battery and a second battery connected in series. The control unit is further configured to, during the first stage pre-charging or the second stage pre-charging process, determine the sum of the voltage increment of the first battery and the voltage increment of the second battery within a preset time period to obtain the total voltage increment, determine the ratio of the voltage increment of the first battery to the total voltage increment within the preset time period to obtain the charge weight of the first battery, determine the ratio of the voltage increment of the second battery to the total voltage increment within the preset time period to obtain the charge weight of the second battery, determine whether the charge weight of the first battery or the second battery is greater than or equal to a preset weight value, and if it is determined that the charge weight of the first battery or the second battery is greater than or equal to the preset weight value, then control the stopping of the first stage pre-charging or the second stage pre-charging.

11. The pre-charging circuit according to any one of claims 1 to 9, characterized in that, The battery pack is composed of a first battery and a second battery connected in series. The control unit is further configured to, during the second-stage pre-charging process, determine the sum of the voltage increments of the first battery and the second battery within a preset time period to obtain the total voltage increment; determine the ratio of the voltage increment of the first battery to the total voltage increment within the preset time period to obtain the charge weight of the first battery; determine the ratio of the voltage increment of the second battery to the total voltage increment within the preset time period to obtain the charge weight of the second battery; determine whether the charge weight of the first battery or the second battery meets a preset weight range; if it is determined that the charge weight of the first battery or the second battery meets the preset weight range, then control the pre-charging of the battery pack through the current-limiting circuit until the charge weight of the first battery is equal to the charge weight of the second battery, and then control the pre-charging of the battery pack through the charging circuit.

12. The pre-charging circuit according to any one of claims 1 to 9, characterized in that, The control unit is further configured to detect the temperature of the battery pack during the second stage of pre-charging. If the temperature of the battery pack meets the first preset temperature range, the control unit controls the pre-charging of the battery pack through the charging circuit. If the temperature of the battery pack meets the second preset temperature range, the control unit controls the pre-charging of the battery pack through the current limiting circuit. The second preset temperature range is greater than the first preset temperature range.

13. A charging device, characterized in that, Includes the pre-charge circuit as described in any one of claims 1 to 12.

14. A drone device, characterized in that, Includes the charging device as described in claim 13.

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