Battery pack and pre-charging control method

Abstract

The invention discloses a battery pack and a pre-charging control method. The battery pack comprises a battery cell unit comprising at least one battery; the switch unit is configured to be connected with the battery cell unit so as to control charging and discharging of the battery cell unit; the power conversion unit is connected between the battery cell unit and the charging and discharging port of the battery pack; and the control unit is configured to enable the power conversion unit to perform charging pre-charging or discharging pre-charging when responding to the condition that the battery pack meets the preset pre-charging condition. According to the embodiment of the invention, charging pre-charging or discharging pre-charging is carried out on the battery cell unit through the power conversion unit, so that the pre-charging current of the battery cell unit is controlled, the pre-charging time of the battery cell unit is shortened, and the pre-charging efficiency of the battery pack is improved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a battery pack and a pre-charging control method. Background Art

[0002] When a lithium battery pack is connected to a load with a large input capacitance, it is easy to trigger overcurrent or short circuit protection. This is because the internal resistance of lithium batteries is usually relatively small. When the capacitive load is just connected to the battery pack, the current of the battery pack is the sum of the output voltage of the battery pack divided by the resistance of the entire circuit. The battery pack will generate a large current, thereby triggering the overcurrent or short circuit protection mechanism of the lithium battery pack. Therefore, it is necessary to set a pre-charging circuit to pre-charge the battery pack to limit the current when the battery pack is just connected to the load.

[0003] In the related art, the pre-charging circuit in the battery pack is usually composed of resistors and control switches. When the voltage difference between the battery pack voltage and the load voltage decreases, the pre-charging current also decreases, which will result in a longer pre-charging time for the battery pack and a lower pre-charging efficiency for the battery pack. Summary of the invention

[0004] The present application provides a battery pack and a pre-charging control method to reduce the pre-charging time of a battery cell unit and improve the pre-charging efficiency of the battery pack.

[0005] According to one aspect of the present application, a battery pack is provided, the battery pack comprising:

[0006] A battery cell unit, comprising at least one battery;

[0007] A switch unit, configured to be connected to the battery cell unit to control the charging and discharging of the battery cell unit;

[0008] A power conversion unit connected between the battery cell unit and the charging and discharging port of the battery pack; and

[0009] The control unit is configured to enable the power conversion unit to perform charging pre-charge or discharging pre-charge in response to the battery pack meeting a preset pre-charge condition.

[0010] Optionally, the power conversion unit includes a bidirectional power conversion circuit, the battery cell unit is connected to a first end of the bidirectional power conversion circuit, and a second end of the bidirectional power conversion circuit is connected to the charging and discharging port.

[0011] Optionally, the power conversion unit includes a charging conversion circuit and a discharging conversion circuit, the charging and discharging port includes a charging port and a discharging port, the charging conversion circuit is connected between the battery cell unit and the charging port, and the discharging conversion circuit is connected between the battery cell unit and the discharging port.

[0012] Optionally, the switch unit includes a charging switch unit and a discharging switch unit, and in response to the battery pack meeting a preset pre-charging condition, enabling the power conversion unit to perform charging pre-charging or discharging pre-charging includes:

[0013] In response to the battery pack being powered on, enabling the power conversion unit to perform pre-charging, and controlling the charging switch unit to be turned on after the pre-charging is completed; or,

[0014] The power conversion unit is enabled to perform discharge pre-charging, and the discharge switch unit is controlled to be turned on after the discharge pre-charging is completed.

[0015] Optionally, the switch unit includes a charging switch unit and a discharging switch unit, and in response to the battery pack meeting a preset pre-charging condition, enabling the power conversion unit to perform charging pre-charging or discharging pre-charging includes:

[0016] In response to determining that the battery pack is connected to an external charging device, acquiring the voltage of the charging and discharging port;

[0017] In response to the voltage difference between the charging and discharging port and the voltage of the battery cell being greater than or equal to a first preset voltage difference threshold, enabling the power conversion unit to perform pre-charging; or,

[0018] In response to the voltage difference between the charging and discharging port and the battery cell unit being less than a first preset voltage difference threshold, the charging switch unit is controlled to be turned on.

[0019] Optionally, the switch unit includes a charging switch unit and a discharging switch unit, and in response to the battery pack meeting a preset pre-charging condition, enabling the power conversion unit to perform charging pre-charging or discharging pre-charging includes:

[0020] In response to the battery pack needing to turn on the discharge switch unit, obtaining the voltage of the charge and discharge port;

[0021] In response to the voltage of the charge and discharge port being within a preset voltage range, the power conversion unit is enabled to perform discharge pre-charge.

[0022] Optionally, the switch unit includes a charging switch unit and a discharging switch unit, and after enabling the power conversion unit to perform pre-charging, the control unit is further configured to:

[0023] Periodically obtaining the voltage of the charging and discharging port;

[0024] In response to the voltage difference between the charging and discharging port and the battery cell unit being less than or equal to a preset charging voltage difference threshold, controlling the power conversion unit to be turned off and the charging switch unit to be turned on; or,

[0025] In response to the voltage difference between the charging and discharging port and the battery cell unit being greater than the preset charging voltage difference threshold, and the pre-charging time being greater than the preset pre-charging time, the power conversion unit is controlled to be turned off and the pre-charging is ended.

[0026] Optionally, the switch unit includes a charging switch unit and a discharging switch unit, and after enabling the power conversion unit to perform discharging pre-charging, the control unit is further configured to:

[0027] Periodically obtaining the voltage of the charging and discharging port;

[0028] In response to the voltage difference between the charge and discharge port and the battery cell being less than or equal to a preset discharge voltage difference threshold, controlling the power conversion unit to be turned off and the discharge switch unit to be turned on; or,

[0029] In response to the voltage difference between the charge and discharge port and the battery cell being greater than the preset discharge voltage difference threshold, and the discharge pre-charge time being greater than the preset discharge pre-charge time, the power conversion unit is controlled to be turned off and the discharge pre-charge is ended.

[0030] Optionally, after the charging and pre-charging are finished, the control unit is further configured to:

[0031] After a first preset time period, the power conversion unit is re-enabled for pre-charging.

[0032] Optionally, after the discharge pre-charging is finished, the control unit is further configured to:

[0033] After a second preset time period, the power conversion unit is re-enabled for discharge pre-charging.

[0034] According to another aspect of the present application, a pre-charge control method is also provided, the method being applied to a battery pack, the battery pack comprising:

[0035] A battery cell unit, comprising at least one battery;

[0036] A switch unit, configured to be connected to the battery cell unit to control the charging and discharging of the battery cell unit;

[0037] A power conversion unit connected between the battery cell unit and the charging and discharging port of the battery pack;

[0038] The method comprises:

[0039] In response to the battery pack satisfying a preset pre-charge condition, the power conversion unit is enabled to perform charge pre-charge or discharge pre-charge.

[0040] The battery pack of the embodiment of the present application includes: a battery cell unit having at least one battery; a switch unit configured to be connected to the battery cell unit to control the charging and discharging of the battery cell unit; a power conversion unit connected between the battery cell unit and the charging and discharging port of the battery pack; and a control unit configured to enable the power conversion unit to perform charging pre-charging or discharging pre-charging in response to the battery pack meeting a preset pre-charging condition. The embodiment of the present application controls the pre-charging current of the battery cell unit by using the power conversion unit to perform charging pre-charging or discharging pre-charging on the battery cell unit, thereby facilitating reducing the pre-charging time of the battery cell unit and improving the pre-charging efficiency of the battery pack.

[0041] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present application, nor is it intended to limit the scope of the present application. Other features of the present application will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 is a schematic diagram of a battery pack provided in an embodiment of the present application;

[0044] Figure 2 is a schematic diagram of another battery pack provided in an embodiment of the present application;

[0045] Figure 3 is a schematic diagram of another battery pack provided in an embodiment of the present application;

[0046] Figure 4 is a schematic diagram of another battery pack provided in an embodiment of the present application;

[0047] Figure 5 is a schematic diagram of another battery pack provided in an embodiment of the present application;

[0048] Figure 6 is a flow chart of a pre-charging control method provided in an embodiment of the present application;

[0049] Figure 7 is a flow chart of another pre-charging control method provided in an embodiment of the present application;

[0050] Figure 8 This is a flow chart of another pre-charging control method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0052] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0053] Figure 1 is a schematic diagram of a battery pack provided in an embodiment of the present application, Figure 2 is a schematic diagram of another battery pack provided in an embodiment of the present application. Figure 1 and Figure 2 The battery pack 100 includes: a battery cell unit 110, including at least one battery; a switch unit 120, configured to be connected to the battery cell unit 110 to control the charging and discharging of the battery cell unit 110; a power conversion unit 130, connected between the battery cell unit 110 and the charging and discharging port of the battery pack 100; and a control unit 140, configured to enable the power conversion unit 130 to perform charging pre-charging or discharging pre-charging in response to the battery pack 100 meeting a preset pre-charging condition.

[0054] Specifically, the battery pack 100 can be applied to a variety of electrical devices, such as automobiles or energy storage devices. The battery cell unit 110 is used for energy storage. The battery cell unit 110 is composed of at least one battery. When the battery cell unit 110 includes multiple batteries, the connection mode of the multiple batteries in the battery cell unit 110 can be series connection, parallel connection, or series-parallel connection. The battery pack 100 includes a first terminal P1 and a second terminal P2. According to the different settings of the battery cell unit 110 in the battery pack 100, the first terminal P1 and the second terminal P2 can both be used as the positive terminal or the negative terminal of the battery pack 100. For example, when the positive electrode of the battery cell unit 110 is connected to the first terminal P1, the first terminal P1 of the battery pack 100 is the positive terminal of the battery pack 100, and the second terminal P2 of the battery pack 100 is the negative terminal of the battery pack 100. The battery cell unit 110 is charged or discharged through the first terminal P1 and the second terminal P2 of the battery pack 100. In practical applications, the positive terminal of the battery pack 100 can be used as a charging and discharging port, or the negative terminal of the battery pack 100 can be used as a charging and discharging port. The switch unit 120 is connected in parallel with the power conversion unit 130. The power conversion unit 130 performs charging pre-charging or discharging pre-charging according to the enablement of the control unit 140. Among them, the control unit 140 can be a battery management system.

[0055] The control unit 140 controls the enabling of the power conversion unit 130 according to the voltage of the battery cell 110 and the voltage between the positive terminal and the negative terminal of the battery pack 100, thereby controlling the power conversion unit 130 to pre-charge the battery cell 110 or controlling the power conversion unit 130 to pre-discharge the battery cell 110.

[0056] It should be noted that the power conversion unit 130 can be a bidirectional power conversion circuit. When the power conversion unit 130 performs pre-discharging of the battery cell 110 under the enablement of the control unit 140, one end of the power conversion unit 130 connected to the battery cell 110 serves as the input of the power conversion unit 130, and one end of the power conversion unit 130 connected to the charge and discharge port serves as the output of the power conversion unit 130. When the power conversion unit 130 performs pre-charging of the battery cell 110 under the enablement of the control unit 140, one end of the power conversion unit 130 connected to the charge and discharge port serves as the input of the power conversion unit 130, and one end of the power conversion unit 130 connected to the charge and discharge port serves as the output of the power conversion unit 130.

[0057] When the power conversion unit 130 performs pre-charging or pre-discharging on the battery cell 110, the power conversion unit 130 first performs pre-charging with a preset current. During most of the pre-charging time, the power conversion unit 130 can operate in a constant current mode, and its rated current is significantly greater than the scheme of pre-charging using a pre-charging resistor, so the pre-charging efficiency is enhanced. After a certain period of pre-charging, the voltage difference between the voltage of the charging and discharging port and the voltage of the battery cell 110 will gradually decrease. When the voltage difference is less than or equal to the preset charging voltage difference threshold, the power conversion unit 130 will no longer perform pre-charging with a preset current. At this time, the pre-charging current of the power conversion unit 130 decreases as the voltage difference decreases. When the voltage difference is less than or equal to the safety voltage difference, the switch unit 120 is controlled to close, and the power conversion unit 130 is controlled to stop pre-charging the battery cell 110. Among them, the voltage of the charge and discharge port is the voltage between the positive terminal and the negative terminal of the battery pack 100, the preset current is the preset rated working current of the power conversion unit 130 during charging pre-charging or discharging pre-charging, and the preset charging voltage difference threshold is the voltage value that characterizes whether the voltage of the battery cell 110 is close to the voltage of the charge and discharge port. The preset current and the preset charging voltage difference threshold can be set according to actual needs.

[0058] Exemplarily, the power conversion unit 130 in this embodiment may be a bidirectional power conversion circuit. The battery cell unit 110 is connected to a first end of the bidirectional power conversion circuit, and a second end of the bidirectional power conversion circuit is connected to a charging and discharging port. When the power conversion unit 130 is a bidirectional power conversion circuit, the preset current of the power conversion unit 130 may be a rated current of the bidirectional power conversion circuit.

[0059] The battery pack of the embodiment of the present application includes: a battery cell unit 110 having at least one battery; a switch unit 120 configured to be connected to the battery cell unit 110 to control the charge and discharge of the battery cell unit 110; a power conversion unit 130 connected between the battery cell unit 110 and the charge and discharge port of the battery pack 100; and a control unit 140 configured to enable the power conversion unit 130 to perform charge pre-charge or discharge pre-charge in response to the battery pack 100 meeting a preset pre-charge condition. The embodiment of the present application performs charge pre-charge or discharge pre-charge on the battery cell unit 110 through the power conversion unit 130 to control the pre-charge current of the battery cell unit 110, which is conducive to reducing the pre-charge time of the battery cell unit 110 and improving the pre-charge efficiency of the battery pack 100.

[0060] Based on the above embodiment, optionally, refer to Figure 2 A relay switch S1 and a fuse FU may also be provided between the battery cell unit 110 and the charge and discharge port in the battery pack 100 to improve the safety of the battery pack 100 .

[0061] Figure 31 is a schematic diagram of another battery pack provided by an embodiment of the present application. Based on the above embodiment, optionally, the power conversion unit 130 includes a charging conversion circuit 131 and a discharging conversion circuit 132, and the charging and discharging ports include a charging port P11 and a discharging port P12. The charging conversion circuit 131 is connected between the battery cell unit 110 and the charging port P11, and the discharging conversion circuit 132 is connected between the battery cell unit 110 and the discharging port P12. Figure 3 It is shown that the charging conversion circuit 131 and the discharging conversion circuit 132 are connected to one electrode side of the battery cell unit. Optionally, the charging conversion circuit 131 and the discharging conversion circuit 132 can also be connected to different electrode sides of the battery cell unit respectively.

[0062] Specifically, when the battery cell 110 is pre-charged, the charging conversion circuit 131 performs pre-charge with a preset current, that is, the external charging device performs pre-charge on the battery cell 110 through the charging conversion circuit 131, reduces the voltage difference between the voltage of the battery cell 110 and the voltage of the charging and discharging port, and when the voltage difference is less than or equal to the preset charging voltage difference threshold, the charging conversion circuit 131 no longer performs pre-charge with the preset current, and at this time, the pre-charge current of the charging conversion circuit 131 decreases as the voltage difference decreases. When the voltage difference is less than or equal to the safety voltage difference, the control switch unit 120 is closed, and the control charging conversion circuit 131 stops pre-charging the battery cell 110 and switches to the normal charging circuit for charging.

[0063] Similarly, when the battery cell 110 is pre-charged for discharge, the discharge conversion circuit 132 performs pre-charged discharge with a preset current, that is, the battery cell 110 performs pre-charged discharge on an external load or device through the discharge conversion circuit 132, reducing the voltage difference between the voltage of the battery cell 110 and the voltage of the charge and discharge port, and when the voltage difference is less than or equal to the preset charge voltage difference threshold, the discharge conversion circuit 132 no longer performs pre-charge with a preset current, and at this time, the pre-charge current of the discharge conversion circuit 132 decreases as the voltage difference decreases. When the voltage difference is less than or equal to the safety voltage difference, the control switch unit 120 is closed, and the discharge conversion circuit 132 is controlled to stop pre-charging the battery cell 110 for discharge, and switch to the normal discharge circuit for discharge.

[0064] Figure 4 is a schematic diagram of another battery pack provided in an embodiment of the present application. Based on the above embodiment, optionally, refer to Figure 4A charging pre-charge switch S2 is also provided between the charging conversion circuit 131 and the battery cell unit 110, and a discharging pre-charge switch S3 is also provided between the discharging conversion circuit 132 and the battery cell unit 110. The charging pre-charge switch S2 and the discharging pre-charge switch S3 are both controlled by a control signal sent by the control unit 140. The control unit 140 enables or disables the charging conversion circuit 131 by controlling the conduction or disconnection of the charging pre-charge switch S2, and the control unit 140 enables or disables the discharging conversion circuit 132 by controlling the conduction or disconnection of the discharging pre-charge switch S3.

[0065] Figure 5 is a schematic diagram of another battery pack provided in an embodiment of the present application. Based on the above embodiment, optionally, refer to Figure 5 , the switch unit 120 includes a charging switch unit 121 and a discharging switch unit 122; in response to the battery pack 100 meeting a preset pre-charging condition, enabling the power conversion unit 130 to perform charging pre-charging or discharging pre-charging includes: in response to the battery pack 100 being powered on, enabling the power conversion unit 130 to perform charging pre-charging, and controlling the charging switch unit 121 to be turned on after the charging pre-charging is completed; or, enabling the power conversion unit 130 to perform discharging pre-charging, and controlling the discharging switch unit 122 to be turned on after the discharging pre-charging is completed.

[0066] Specifically, after the battery pack 100 is powered on, the battery pack 100 performs a self-test. The self-test content of the battery pack 100 may include, for example, the voltage of each battery in the battery cell unit 110, the temperature of each battery in the battery cell unit 110, the voltage of the battery cell unit 110, the ambient temperature and the current of the battery cell unit 110, and determines whether the corresponding protection will be triggered according to the built-in protection logic of the battery pack 100. When the self-test content of the battery pack 100 passes, the battery pack 100 self-test is successful, and the power conversion unit 130 can perform charging pre-charge or discharging pre-charge.

[0067] When the power conversion unit 130 completes the pre-charging or pre-discharging of the battery cell 110, it indicates that the voltage of the battery cell 110 is close to the voltage of the charging and discharging port of the battery pack 100. At this time, the battery cell 110 can withstand the impact of the voltage difference between the two, and the battery cell 110 does not need to be pre-charged by the power conversion unit 130. Therefore, when the power conversion unit 130 completes the pre-charging or pre-discharging of the battery cell 110, the charging switch unit 121 or the discharging switch unit 122 is turned on to allow the battery cell 110 to charge or discharge normally.

[0068] Based on the above embodiments, the switch unit 120 may optionally include a charging switch unit 121 and a discharging switch unit 122. The charging switch unit 121 and the discharging switch unit 122 may use solid-state switches, and typical solid-state switches include MOSFETs, IGBTs, GaN transistors, etc. Figures 1 to 4 For the embodiment shown, the charging switch unit 121 and the discharging switch unit 122 can be connected in series between the battery cell unit 110 and the charging and discharging port. Figure 5 In the illustrated embodiment, since the charging port and the discharging port are separately provided, the charging switch unit 121 is connected between the battery cell unit 110 and the charging port P11 , and the discharging switch unit 122 is connected between the battery cell unit 110 and the discharging port P12 .

[0069] Further, in response to the battery pack satisfying a preset pre-charge condition, enabling the power conversion unit 130 to perform pre-charging or pre-discharging includes: in response to determining that the battery pack 100 is connected to an external charging device, obtaining the voltage of the charging and discharging port; in response to the voltage difference between the charging and discharging port and the battery cell unit 110 being greater than or equal to a first preset voltage difference threshold, enabling the power conversion unit 130 to perform pre-charging; or, in response to the voltage difference between the charging and discharging port and the battery cell unit 110 being less than the first preset voltage difference threshold, controlling the charging switch unit 121 to be turned on.

[0070] Specifically, the power conversion unit 130 includes a charging conversion circuit 131 and a discharging conversion circuit 132. The first preset voltage difference threshold represents the maximum voltage difference that the battery cell 110 can withstand during the charging process. When the charging voltage difference is greater than or equal to the first preset voltage difference threshold, it indicates that the battery cell 110 cannot withstand the voltage difference. At this time, the power conversion unit 130 is required to pre-charge the battery cell 110 to reduce the voltage difference between the voltage of the battery cell 110 and the voltage of the external charging device; when the charging voltage difference is less than the first preset voltage difference threshold, it indicates that the voltage difference between the voltage of the battery cell 110 and the voltage of the external charging device is within the voltage difference range that the battery cell 110 can withstand. At this time, the power conversion unit 130 is not required to pre-charge the battery cell 110, and the charging switch unit 121 is directly turned on to charge the battery cell 110. Among them, the external charging device is connected to the battery pack 100 through the charging and discharging port and the charging and discharging port, so the voltage of the external charging device is the voltage of the charging and discharging port.

[0071] On the basis of the above embodiments, optionally, the switch unit 120 includes a charging switch unit 121 and a discharging switch unit 122. In response to the battery pack 100 satisfying a preset pre-charging condition, enabling the power conversion unit 130 to perform charging pre-charging or discharging pre-charging includes: in response to the battery pack 100 needing to turn on the discharging switch unit 122, obtaining the voltage of the charging and discharging port; in response to the voltage of the charging and discharging port being within a preset voltage range, enabling the power conversion unit 130 to perform discharging pre-charging.

[0072] Specifically, the preset voltage range is a preset voltage range for determining whether the battery cell 110 can be discharged. In practical applications, the preset voltage range can be set to zero to the rated voltage of the battery cell 110. When the voltage of the charge and discharge port is within the preset voltage range, it indicates that the external device connected to the charge and discharge port is correctly connected to the battery pack 100 (the positive pole of the battery pack 100 is connected to the positive pole of the external device, and the negative pole of the battery pack 100 is connected to the negative pole of the external device), and the battery cell 110 can discharge the external device; when the voltage of the charge and discharge port is outside the preset voltage range, it indicates that the external device connected to the charge and discharge port is incorrectly connected to the battery pack 100 (the positive pole of the battery pack 100 is connected to the negative pole of the external device, and the negative pole of the battery pack 100 is connected to the positive pole of the external device), or the voltage of the external device is greater than the rated voltage of the battery cell 110, and the battery cell 110 cannot discharge the external device. In this embodiment, whether the battery cell 110 can be discharged is determined by a preset voltage range to avoid the impact of the battery cell 110 caused by reverse connection of external devices or excessive voltage of external devices, thereby improving the safety of the battery pack 100.

[0073] On the basis of the above embodiments, optionally, the switch unit 120 includes a charging switch unit 121 and a discharging switch unit 122, and after enabling the power conversion unit 130 to perform pre-charging, the control unit 140 is further configured to: periodically obtain the voltage of the charging and discharging port; in response to the voltage difference between the charging and discharging port and the voltage of the battery cell unit 110 being less than or equal to a preset charging voltage difference threshold, control the power conversion unit 130 to be turned off and the charging switch unit 121 to be turned on; or, in response to the voltage difference between the charging and discharging port and the voltage of the battery cell unit 110 being greater than the preset charging voltage difference threshold, and the pre-charging time length being greater than the preset pre-charging time length, control the power conversion unit 130 to be turned off and the pre-charging to be ended.

[0074] Specifically, when the power conversion unit 130 performs pre-charging, the voltage of the battery cell 110 gradually rises, and the voltage difference between the charge and discharge port and the battery cell 110 gradually decreases. Due to the internal resistance of the battery cell 110, the voltage of the battery cell 110 cannot be completely consistent with the voltage of the charge and discharge port. Therefore, when the voltage difference between the charge and discharge port and the battery cell 110 is less than or equal to the preset charge voltage difference threshold, it is considered that the voltage of the battery cell 110 is the same as the voltage of the charge and discharge port. Among them, the preset charge voltage difference threshold is a voltage value that characterizes whether the voltage of the battery cell 110 is close to the voltage of the charge and discharge port.

[0075] The difference between the voltage of the charge and discharge port and the voltage of the battery cell 110 changes with the duration of the pre-charging of the power conversion unit 130. The longer the pre-charging duration of the power conversion unit 130 is, the smaller the difference between the voltage of the charge and discharge port and the voltage of the battery cell 110 is. Therefore, it is possible to determine whether the pre-charging of the battery cell 110 is successful based on the difference between the voltage of the charge and discharge port and the voltage of the battery cell 110.

[0076] When the voltage difference between the charge and discharge port and the voltage of the battery cell 110 is less than or equal to the preset charge voltage difference threshold, it means that the voltage of the battery cell 110 is the same as the voltage of the charge and discharge port, and the charge and pre-charge of the battery cell 110 is successful. At this time, the charging switch unit 121 is turned on, and the power conversion unit 130 is turned off. When the voltage difference between the charge and discharge port and the voltage of the battery cell 110 is greater than the set charge and discharge voltage difference threshold and the charge and pre-charge time of the power conversion unit 130 is greater than the preset discharge and pre-charge time, it means that the charge and pre-charge of the battery cell 110 has timed out, and the charge and pre-charge of the battery cell 110 has failed. At this time, the power conversion unit 130 is turned off and the charge and pre-charge ends. Among them, the preset charge and pre-charge time is the maximum time for the power conversion unit 130 to perform charge and pre-charge.

[0077] On the basis of the above embodiment, optionally, after the pre-charging is finished, the control unit 140 is further configured to: re-enable the power conversion unit 130 to perform the pre-charging after a first preset time period.

[0078] Specifically, the duration of pre-charging required for the battery cell 110 is positively correlated to the difference between the voltage of the charging and discharging port (the voltage of the external charging device) and the voltage of the battery cell 110. The greater the difference between the voltage of the charging and discharging port (the voltage of the external charging device) and the voltage of the battery cell 110, the longer the duration of pre-charging required for the battery cell 110. Therefore, within the preset pre-charging duration, there is a possibility that the battery cell 110 cannot complete the pre-charging. Therefore, after a delay of the first preset duration is performed on the basis of the failure of the pre-charging of the battery cell 110, the pre-charging of the battery cell 110 is performed again. In actual application, a preset number of pre-charging times can be set to limit the number of times the battery cell 110 is re-charged. When the number of pre-charging failures of the battery cell 110 is greater than the preset number of pre-charging times, the user is prompted that the pre-charging has failed, and the pre-charging of the battery cell 110 is terminated. Among them, the preset number of charging and pre-charging times is the maximum number of charging and pre-charging failures of the preset battery unit 110, and the first preset time is the time for re-charging and pre-charging after the preset charging and pre-charging failure of the battery unit 110. In actual application, the preset number of charging and pre-charging times and the first preset time can be set according to actual needs.

[0079] On the basis of the above embodiments, optionally, the switch unit 120 includes a charging switch unit 121 and a discharging switch unit 122, and after enabling the power conversion unit 130 to perform discharge pre-charging, the control unit 140 is further configured to: periodically obtain the voltage of the charging and discharging port; in response to the voltage difference between the charging and discharging port and the battery cell unit 110 being less than or equal to a preset discharge voltage difference threshold, control the power conversion unit 130 to be turned off and the discharge switch unit 122 to be turned on; or, in response to the voltage difference between the charging and discharging port and the battery cell unit 110 being greater than a preset discharge voltage difference threshold, and the discharge pre-charging time length being greater than a preset discharge pre-charging time length, control the power conversion unit 130 to be turned off and the discharge pre-charging to be ended.

[0080] Specifically, when the power conversion unit 130 performs discharge pre-charge, the voltage of the battery cell 110 gradually decreases, and the voltage difference between the charge and discharge port and the battery cell 110 gradually decreases. Due to the internal resistance of the battery cell 110, the voltage of the battery cell 110 cannot be completely consistent with the voltage of the charge and discharge port. Therefore, when the voltage difference between the charge and discharge port and the battery cell 110 is less than or equal to the preset discharge voltage difference threshold, it is considered that the voltage of the battery cell 110 is the same as the voltage of the charge and discharge port. Among them, the preset discharge voltage difference threshold is a voltage value that characterizes whether the voltage of the battery cell 110 is close to the voltage of the charge and discharge port.

[0081] The difference between the voltage of the charge and discharge port and the voltage of the battery cell 110 changes with the duration of the pre-discharge of the power conversion unit 130. The longer the pre-discharge of the power conversion unit 130 is, the smaller the difference between the voltage of the charge and discharge port and the voltage of the battery cell 110 is. Therefore, it is possible to determine whether the pre-discharge of the battery cell 110 is successful based on the difference between the voltage of the charge and discharge port and the voltage of the battery cell 110.

[0082] When the voltage difference between the charge and discharge port and the voltage of the battery cell 110 is less than or equal to the preset discharge voltage difference threshold, it means that the voltage of the battery cell 110 is the same as the voltage of the charge and discharge port, and the discharge pre-charge of the battery cell 110 is successful. At this time, the discharge switch unit 122 is turned on and the power conversion unit 130 is turned off. When the voltage difference between the charge and discharge port and the voltage of the battery cell 110 is greater than the preset discharge voltage difference threshold and the discharge pre-charge time of the power conversion unit 130 is greater than the preset discharge pre-charge time, it means that the discharge pre-charge of the battery cell 110 has timed out and the discharge pre-charge of the battery cell 110 has failed. At this time, the power conversion unit 130 is turned off and the discharge pre-charge ends. Among them, the preset discharge pre-charge time is the maximum time for the power conversion unit 130 to perform discharge pre-charge.

[0083] On the basis of the above embodiment, optionally, after the discharge pre-charging is finished, the control unit 140 is further configured to: after a second preset time period, re-enable the power conversion unit 130 to perform the discharge pre-charging.

[0084] Specifically, the discharge pre-charge duration required for the battery cell 110 is positively correlated to the size of the difference between the voltage of the charge and discharge port (the voltage of the external charging device) and the voltage of the battery cell 110. The greater the difference between the voltage of the charge and discharge port (the voltage of the external charging device) and the voltage of the battery cell 110, the longer the discharge pre-charge duration required for the battery cell 110. Therefore, within the preset discharge pre-charge duration, there is a possibility that the battery cell 110 cannot complete the discharge pre-charge. Therefore, after a delay of a second preset time period is performed on the basis of the failure of the discharge pre-charge of the battery cell 110, the discharge pre-charge of the battery cell 110 is performed again. In actual application, a preset discharge pre-charge number can be set to limit the number of times the battery cell 110 is re-discharged and pre-charged. When the number of discharge pre-charge failures of the battery cell 110 is greater than the preset discharge pre-charge number, the user is prompted with a discharge pre-charge failure, and the discharge pre-charge of the battery cell 110 is terminated. Among them, the preset number of discharge pre-charge times is the preset maximum number of discharge pre-charge failures of the battery cell 110, and the second preset time is the time for re-discharge pre-charge after the preset discharge pre-charge failure of the battery cell 110. In actual application, the preset number of discharge pre-charge times and the second preset time can be set according to actual needs.

[0085] The embodiment of the present application also provides a pre-charging control method. Figure 6is a flow chart of a pre-charge control method provided in an embodiment of the present application. The pre-charge control method is applied to the battery pack 100 provided in any of the above embodiments. The battery pack 100 includes: a battery cell unit 110, including at least one battery; a switch unit 120, configured to be connected to the battery cell unit 110 to control the charge and discharge of the battery cell unit 110; and a power conversion unit 130, connected between the battery cell unit 110 and the charge and discharge port of the battery pack 100. Figure 6 , the pre-charge control method comprises:

[0086] S110, in response to the battery pack meeting a preset pre-charge condition, enabling the power conversion unit to perform charge pre-charge or discharge pre-charge.

[0087] Specifically, the enabling of the power conversion unit is controlled according to the voltage of the battery cell and the voltage between the positive terminal and the negative terminal of the battery pack, thereby controlling the power conversion unit to pre-charge the battery cell unit or controlling the power conversion unit to pre-discharge the battery cell unit.

[0088] Wherein, when the power conversion unit performs pre-charging or discharging of the battery cell, the power conversion unit reduces the voltage difference between the voltage of the charge and discharge port and the voltage of the battery cell with a preset current, and when the voltage difference is less than or equal to the preset charging voltage difference threshold, the power conversion unit no longer performs pre-charging with the preset current, and at this time, the pre-charging current of the power conversion unit decreases as the voltage difference decreases. When the voltage difference is zero, the switch unit is closed, and the power conversion unit stops pre-charging the battery cell. Wherein, the voltage of the charge and discharge port is the voltage difference between the positive terminal and the negative terminal of the battery pack, the preset current is the preset starting current of the power conversion unit during pre-charging or pre-discharging, and the preset charging voltage difference threshold is the voltage value that characterizes whether the voltage of the battery cell is close to the voltage of the charge and discharge port. The preset current and the preset charging voltage difference threshold can be set according to actual needs.

[0089] Figure 7 is a flow chart of another pre-filling control method provided in an embodiment of the present application. Based on the above embodiment, optionally, refer to Figure 7 After enabling the power conversion unit to perform pre-charging, it is also determined whether to terminate the pre-charging, specifically including:

[0090] S120, periodically obtaining the voltage of the charging and discharging port.

[0091] Specifically, the voltage of the charge and discharge port is the voltage between the positive terminal and the negative terminal of the battery pack. The external device is connected to the battery cell unit through the positive terminal and the negative terminal of the battery pack, so the voltage of the charge and discharge port is the voltage of the external device. Exemplarily, the voltage of the charge and discharge port can be calculated by the potential of the positive terminal of the battery pack and the potential of the negative terminal of the battery pack. The difference between the potential of the positive terminal of the battery pack and the potential of the negative terminal of the battery pack is the voltage of the charge and discharge port.

[0092] S130, in response to the voltage difference between the charging and discharging port and the battery cell unit being less than or equal to a preset charging voltage difference threshold, controlling the power conversion unit to be turned off and the charging switch unit to be turned on; or, in response to the voltage difference between the charging and discharging port and the battery cell unit being greater than a preset charging voltage difference threshold, and the pre-charging time being greater than a preset pre-charging time, controlling the power conversion unit to be turned off and the pre-charging to be ended.

[0093] Specifically, when the voltage difference between the charge and discharge port and the voltage of the battery cell is less than or equal to the preset charge voltage difference threshold, it means that the voltage of the battery cell is the same as the voltage of the charge and discharge port, and the battery cell is successfully pre-charged. At this time, the charging switch unit is turned on and the power conversion unit is turned off. When the voltage difference between the charge and discharge port and the voltage of the battery cell is greater than the set discharge voltage difference threshold and the power conversion unit performs pre-charge charging for a longer time than the preset discharge pre-charge time, it means that the battery cell has timed out and the battery cell has failed to charge. At this time, the power conversion unit is turned off and the pre-charge charging ends. Among them, the preset pre-charge charging time is the maximum time for the power conversion unit to perform pre-charge charging.

[0094] Figure 8 is a flowchart of another pre-filling control method provided in an embodiment of the present application. Based on the above embodiment, optionally, refer to Figure 8 After enabling the power conversion unit to perform discharge pre-charge, it is also judged whether to end the discharge pre-charge, specifically including:

[0095] S140, periodically obtaining the voltage of the charging and discharging port.

[0096] Specifically, the voltage of the charge and discharge port is the voltage between the positive terminal and the negative terminal of the battery pack. The external device is connected to the battery cell unit through the positive terminal and the negative terminal of the battery pack, so the voltage of the charge and discharge port is the voltage of the external device. Exemplarily, the voltage of the charge and discharge port can be calculated by the potential of the positive terminal of the battery pack and the potential of the negative terminal of the battery pack. The difference between the potential of the positive terminal of the battery pack and the potential of the negative terminal of the battery pack is the voltage of the charge and discharge port.

[0097] S150, in response to the voltage difference between the charge and discharge port and the cell unit being less than or equal to a preset discharge voltage difference threshold, control the power conversion unit to be turned off and the discharge switch unit to be turned on; or, in response to the voltage difference between the charge and discharge port and the cell unit being greater than a preset discharge voltage difference threshold, and the discharge pre-charge time being greater than a preset discharge pre-charge time, control the power conversion unit to be turned off and the discharge pre-charge to be ended.

[0098] Specifically, when the voltage difference between the charge and discharge port and the voltage of the battery cell is less than or equal to the preset discharge voltage difference threshold, it means that the voltage of the battery cell is the same as the voltage of the charge and discharge port, and the discharge pre-charge of the battery cell is successful. At this time, the discharge switch unit is turned on and the power conversion unit is turned off. When the voltage difference between the charge and discharge port and the voltage of the battery cell is greater than the preset discharge voltage difference threshold and the discharge pre-charge time of the power conversion unit is greater than the preset discharge pre-charge time, it means that the discharge pre-charge of the battery cell has timed out and the discharge pre-charge of the battery cell has failed. At this time, the power conversion unit is turned off and the discharge pre-charge ends. Among them, the preset discharge pre-charge time is the maximum time for the power conversion unit to perform discharge pre-charge set in advance.

[0099] The above specific implementations do not constitute a limitation on the protection scope of this application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this application should be included in the protection scope of this application.

Claims

1. A battery pack, characterized in that: include: A battery cell unit, comprising at least one battery; A switch unit, configured to be connected to the battery cell unit to control the charging and discharging of the battery cell unit; A power conversion unit connected between the battery cell unit and the charging and discharging port of the battery pack; as well as The control unit is configured to enable the power conversion unit to perform charging pre-charge or discharging pre-charge in response to the battery pack meeting a preset pre-charge condition.

2. The battery pack according to claim 1, characterized in that: The power conversion unit includes a bidirectional power conversion circuit, the battery cell unit is connected to a first end of the bidirectional power conversion circuit, and a second end of the bidirectional power conversion circuit is connected to the charge and discharge port.

3. The battery pack according to claim 1, characterized in that: The power conversion unit includes a charging conversion circuit and a discharging conversion circuit, the charging and discharging port includes a charging port and a discharging port, the charging conversion circuit is connected between the battery cell unit and the charging port, and the discharging conversion circuit is connected between the battery cell unit and the discharging port.

4. The battery pack according to any one of claims 1 to 3, characterized in that: The switch unit includes a charging switch unit and a discharging switch unit, and in response to the battery pack meeting a preset pre-charging condition, enabling the power conversion unit to perform charging pre-charging or discharging pre-charging, including: In response to the battery pack being powered on, enabling the power conversion unit to perform pre-charging, and controlling the charging switch unit to be turned on after the pre-charging is completed; or, The power conversion unit is enabled to perform discharge pre-charging, and the discharge switch unit is controlled to be turned on after the discharge pre-charging is completed.

5. The battery pack according to any one of claims 1 to 3, characterized in that: The switch unit includes a charging switch unit and a discharging switch unit, and in response to the battery pack meeting a preset pre-charging condition, enabling the power conversion unit to perform charging pre-charging or discharging pre-charging, including: In response to determining that the battery pack is connected to an external charging device, acquiring the voltage of the charging and discharging port; In response to the voltage difference between the charging and discharging port and the voltage of the battery cell being greater than or equal to a first preset voltage difference threshold, enabling the power conversion unit to perform pre-charging; or, In response to the voltage difference between the charging and discharging port and the battery cell unit being less than a first preset voltage difference threshold, the charging switch unit is controlled to be turned on.

6. The battery pack according to any one of claims 1 to 3, characterized in that: The switch unit includes a charging switch unit and a discharging switch unit, and in response to the battery pack meeting a preset pre-charging condition, enabling the power conversion unit to perform charging pre-charging or discharging pre-charging, including: In response to the battery pack needing to turn on the discharge switch unit, obtaining the voltage of the charge and discharge port; In response to the voltage of the charge and discharge port being within a preset voltage range, the power conversion unit is enabled to perform discharge pre-charge.

7. The battery pack according to claim 1, characterized in that: The switch unit includes a charging switch unit and a discharging switch unit. After enabling the power conversion unit to perform pre-charging, the control unit is further configured to: Periodically obtaining the voltage of the charging and discharging port; In response to the voltage difference between the charging and discharging port and the battery cell unit being less than or equal to a preset charging voltage difference threshold, controlling the power conversion unit to be turned off and the charging switch unit to be turned on; or, In response to the voltage difference between the charging and discharging port and the battery cell unit being greater than the preset charging voltage difference threshold, and the pre-charging time being greater than the preset pre-charging time, the power conversion unit is controlled to be turned off and the pre-charging is ended.

8. The battery pack according to claim 1, characterized in that: The switch unit includes a charging switch unit and a discharging switch unit. After enabling the power conversion unit to perform discharging pre-charging, the control unit is further configured to: Periodically obtaining the voltage of the charging and discharging port; In response to the voltage difference between the charge and discharge port and the battery cell being less than or equal to a preset discharge voltage difference threshold, controlling the power conversion unit to be turned off and the discharge switch unit to be turned on; or, In response to the voltage difference between the charge and discharge port and the battery cell being greater than the preset discharge voltage difference threshold, and the discharge pre-charge time being greater than the preset discharge pre-charge time, the power conversion unit is controlled to be turned off and the discharge pre-charge is ended.

9. The battery pack according to claim 7, characterized in that: After the charging and pre-charging are finished, the control unit is further configured to: After a first preset time period, the power conversion unit is re-enabled for pre-charging.

10. The battery pack according to claim 8, characterized in that: After the discharge pre-charging is finished, the control unit is further configured to: After a second preset time period, the power conversion unit is re-enabled for discharge pre-charging.

11. A pre-filling control method, characterized in that: The method is applied to a battery pack, and the battery pack comprises: A battery cell unit, comprising at least one battery; A switch unit, configured to be connected to the battery cell unit to control the charging and discharging of the battery cell unit; A power conversion unit connected between the battery cell unit and the charging and discharging port of the battery pack; The method comprises: In response to the battery pack satisfying a preset pre-charge condition, the power conversion unit is enabled to perform charge pre-charge or discharge pre-charge.

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