Pre-charging control method, battery, and battery management system

Abstract

A pre-charging control method, a battery, and a battery management system. The pre-charging control method is applied to a battery; the battery (1) comprises a battery cell (11), a pre-charging circuit (12), a discharging circuit (13), and a discharging port (14); the pre-charging circuit (12) and the discharging circuit (13) are connected between the battery cell (11) and the discharging port (14). The pre-charging control method comprises: controlling a battery cell to be pre-charged by means of a pre-charging circuit (S101); periodically acquiring a first voltage of a discharging port (S102); and on the basis of the first voltage and a pre-charging duration corresponding to the first voltage, controlling a pre-charging state of the battery cell (S103).

Description

Pre-charging control method, battery and battery management system

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 15, 2023, with application number 202311728818.0. The entire contents of the above application are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of pre-charging technology, for example, to a pre-charging control method, a battery, and a battery management system. Background Art

[0003] Load devices, such as active load devices, often contain capacitive impedance components. When a lithium battery is used as a power source to charge a capacitive load connected for cold start, the transient current is very large due to the low internal resistance of the lithium battery, which can easily cause a short circuit. For the short-circuit protection mechanism of the lithium battery, extending the short-circuit time can easily burn out the switching tube (such as the metal-oxide semiconductor field-effect transistor MOSFET) and other devices inside the battery. Conversely, shortening the short-circuit time will significantly increase the cold start failure rate of some devices with large capacitive impedance. For the above reasons, lithium batteries often have a built-in pre-charge circuit. Before turning on the discharge switch tube, the pre-charge circuit is used to raise the external capacitor voltage and then switch to the normal discharge circuit to enter normal operation. The pre-charge circuit is to control the MOS circuit by inserting a suitable power resistor in series to limit the pre-charge current of the pre-charge circuit, forming a typical RC circuit with the external load.

[0004] At present, the pre-charging strategy of the battery management system (BMS) in the related art is relatively simple, that is, it waits for a fixed pre-charging time and then switches to the discharge circuit to work normally. However, when the pre-charging current is small, due to the use of a fixed pre-charging time, if the external load capacitance is large, the pre-charging time is long and the pre-charging efficiency is low; when the pre-charging current is large, the power required by the pre-charging resistor is large, resulting in severe heat generation and easy damage, and the occupied volume and cost of the printed circuit board will increase significantly. Since batteries often need to adapt to a variety of different types of external loads, the pre-charging strategy in the related art will cause the load to be unable to start cold or the pre-charging time is too long, limiting the battery's load capacity. Summary of the Invention

[0005] The present application provides a pre-charging control method, a battery, and a battery management system, which can adjust the pre-charging time according to the size of the load to improve the pre-charging efficiency and the load capacity of the battery.

[0006] In a first aspect, the present application provides a pre-charging control method, which is applied to a battery, wherein the battery includes a battery cell, a pre-charging circuit, a discharge circuit, and a discharge port; the pre-charging circuit and the discharge circuit are connected between the battery cell and the discharge port; the pre-charging control method includes:

[0007] Controlling the battery unit to be pre-charged through the pre-charging circuit;

[0008] Periodically obtaining a first voltage of a discharge port;

[0009] The pre-charging state of the battery cell is controlled according to the first voltage and the pre-charging time corresponding to the first voltage.

[0010] Optionally, controlling the pre-charging state of the battery cell according to the first voltage and the pre-charging time corresponding to the first voltage includes:

[0011] In response to the pre-charging time being less than the preset pre-charging time and the ratio of the first voltage to the output voltage of the battery cell being greater than or equal to the first set threshold, controlling the battery cell to end the pre-charging state and discharge through the discharge circuit; or

[0012] In response to the pre-charging time being greater than or equal to the preset pre-charging time and the ratio of the first voltage to the output voltage of the battery cell being less than a second set threshold, controlling the battery cell to enter a short-circuit locking state; wherein the second set threshold is less than the first set threshold; or,

[0013] In response to the pre-charging time being equal to the preset pre-charging time, the ratio of the first voltage to the output voltage of the battery cell being greater than or equal to the second set threshold and less than the first set threshold, and the first voltage monotonically increasing, the battery cell is controlled to end the pre-charging state when the pre-charging time is greater than the preset pre-charging time, and discharge is performed through the discharge circuit; or

[0014] In response to the pre-charging time being less than or equal to the preset pre-charging time, the ratio of the first voltage to the output voltage of the battery cell being greater than or equal to the second set threshold and less than the first set threshold, and the first voltage at the current moment being less than the first voltage at the previous moment, the battery cell is controlled to end the pre-charging state at the current moment and discharge through the discharge circuit.

[0015] Optionally, after controlling the battery cell to end the pre-charging state and discharging through the discharge circuit, the pre-charging control method further includes:

[0016] Monitor whether there is a short circuit event in the discharge circuit;

[0017] In response to the occurrence of a short circuit event, the short circuit protection is triggered and the discharge circuit is controlled to be disconnected.

[0018] Optionally, monitoring whether a short circuit event occurs in the discharge circuit includes:

[0019] Obtaining the discharge current in the discharge circuit;

[0020] In response to the fact that the duration during which the discharge current is greater than or equal to the preset short-circuit current threshold is not less than the preset short-circuit duration, it is determined that a short-circuit event occurs in the discharge loop.

[0021] Optionally, in response to the occurrence of a short circuit event, after triggering the short circuit protection and controlling the disconnection of the discharge circuit, the pre-charge control method further includes:

[0022] Accumulate the number of short circuit protection times;

[0023] In response to the short-circuit protection number being less than or equal to the preset short-circuit protection number, re-controlling the battery unit to be pre-charged through the pre-charging circuit; or,

[0024] In response to the short circuit protection number being greater than a preset short circuit protection number, the battery unit is controlled to enter a short circuit locking state.

[0025] Optionally, after accumulating the number of short-circuit protection times, the pre-charging control method further includes: adjusting a preset short-circuit current threshold and / or a preset short-circuit duration.

[0026] Optionally, the discharge circuit includes a first switch, the pre-charge circuit includes a second switch, and controlling the battery cell to end the pre-charge state and discharge through the discharge circuit includes: controlling the second switch to turn off, and controlling the first switch to turn on.

[0027] Optionally, the discharge circuit includes a first switch, the pre-charge circuit includes a second switch, and controlling the battery cell to enter a short-circuit locking state includes: controlling the first switch and the second switch to be turned off.

[0028] In a second aspect, the present application provides a battery, comprising: a battery cell; a discharge port configured to connect to an external load; a discharge circuit and a pre-charging circuit connected between the battery cell and the discharge port, the discharge circuit comprising a first switch, the pre-charging circuit comprising a second switch and a pre-charging resistor; a control unit configured to control the battery cell to be pre-charged through the pre-charging circuit, periodically obtain a first voltage of the discharge port, and control the pre-charging state of the battery cell according to the first voltage and the pre-charging time corresponding to the first voltage.

[0029] In a third aspect, the present application provides a battery management system, including a storage unit and a processing unit, wherein the storage unit stores a computer program, and the processing unit implements any pre-charging control method of the first aspect when calling the computer program.

[0030] The pre-charging control method provided in the embodiment of the present application, after starting the pre-charging function, simultaneously monitors the first voltage of the discharge port, and controls the pre-charging state of the battery cell through the first voltage and the pre-charging time corresponding to the first voltage, that is, the pre-charging degree of the load is determined according to the first voltage and the pre-charging time corresponding to the first voltage, and when the set pre-charging degree is reached, the pre-charging process can be terminated in advance before the preset pre-charging time without waiting until the preset pre-charging time ends; when the pre-charging degree is very low, there is no need to trigger an actual short circuit, and the battery cell can be directly controlled to enter a short-circuit locking state, that is, the pre-charging control method of this embodiment can adjust the pre-charging time according to the size of the load to improve the pre-charging efficiency and the load capacity of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] FIG1 is a schematic structural diagram of a battery provided in an embodiment of the present application;

[0033] FIG2 is a flow chart of a pre-charging control method provided in an embodiment of the present application;

[0034] FIG3 is a flow chart of another pre-charging control method provided in an embodiment of the present application;

[0035] FIG4 is a graph showing a ratio of a first voltage to an output voltage of a battery cell varying over time, provided by an embodiment of the present application;

[0036] FIG5 is a flow chart of another pre-charging control method provided in an embodiment of the present application;

[0037] FIG6 is a flow chart of another pre-charging control method provided in an embodiment of the present application;

[0038] FIG7 is a flow chart of another pre-charging control method provided in an embodiment of the present application;

[0039] FIG8 is a schematic structural diagram of another battery provided in an embodiment of the present application;

[0040] FIG9 is a schematic structural diagram of a battery management system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0042] It should be noted that, in this article, the term "comprise", "include" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not clearly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, the elements limited by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device comprising the element. It should be further understood that, as used in this article, the singular forms "one", "an" and "the" are intended to also include plural forms, unless there is an opposite indication in the context. Furthermore, the terms "or", "and / or", "including at least one of the following" etc. used in this article can be interpreted as inclusive, or mean any one or any combination. Only when the combination of elements, functions, steps or operations is inherently mutually exclusive in some way, will the exception to this definition occur.

[0043] It should be understood that although the terms first, second, third, etc. may be used herein to describe various parameters or modules, these parameters or modules should not be limited to these terms. These terms are only used to distinguish parameters or modules of the same type from each other. For example, without departing from the scope of this article, the first parameter may also be referred to as the second parameter, and similarly, the second parameter may also be referred to as the first parameter. Depending on the context, the words "if" and "if" as used herein can be interpreted as "at ... time" or "when ... time" or "in response to determination" or "in response to detection". Similarly, depending on the context, the phrase "if it is determined" or "if detection (statement condition or event)" can be interpreted as "when determination" or "in response to determination" or "when detection (statement condition or event)" or "in response to detection (statement condition or event)". In addition, the components, features, and elements with the same name in different embodiments of the present application may have the same meaning or may have different meanings, and their specific meanings need to be determined by their explanation in this specific embodiment or further in conjunction with the context in this specific embodiment.

[0044] It should be understood that although the various steps in the flowcharts in the embodiments of the present application are shown in sequence as indicated by the arrows, these steps are not necessarily performed in sequence in the order indicated by the arrows. Unless otherwise specified herein, the execution of these steps is not strictly limited in order and may be performed in other orders. Moreover, at least a portion of the steps in the figure may include multiple sub-steps or multiple stages, which are not necessarily performed at the same time but may be performed at different times, and their execution order is not necessarily performed in sequence but may be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0045] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the scope of rights of the present application.

[0046] Embodiments of the present application provide a pre-charging control method, a battery, and a battery management system. Below, a battery to which the pre-charging control method provided in the embodiments of the present application can be applied is first introduced.

[0047] Figure 1 is a structural schematic diagram of a battery provided in an embodiment of the present application. As shown in Figure 1, the battery 1 includes a battery cell 11, a pre-charging circuit (also referred to as a pre-charging unit) 12, a discharge circuit (also referred to as a discharge unit) 13 and a discharge port 14; the pre-charging circuit 12 and the discharge circuit 13 are connected between the battery cell 11 and the discharge port 14.

[0048] The battery unit 11 can be a battery pack, formed by connecting several single cells in series or in parallel, or it can be formed by a single single cell. When the battery 1 is connected to the load 2, the battery unit 11 supplies power to the load. Optionally, the load 2 can be any of an inductive load, a resistive load, or a capacitive load. For example, the load 2 can be equivalent to an effective capacitor Cb and an effective resistor R2 connected in parallel with the effective capacitor Cb.

[0049] The pre-charging circuit 12 may include a pre-charging resistor and a pre-charging switch tube. The pre-charging switch tube enables the pre-charging circuit 12 under the control of a control unit (not shown), thereby controlling the battery cell 11 to perform pre-charging and discharging (pre-charging). The pre-charging and discharging process can be understood as the process of discharging the battery to the outside, or as the process of charging an external load. In this application, the above process is summarized as pre-charging.

[0050] The discharge circuit 13 may include a discharge switch tube. Under the control of the control unit, the discharge switch tube enables the discharge circuit 13, thereby controlling the battery cell to discharge through the discharge circuit 13. In some application scenarios, a charging unit may also be included, and the charging unit may include at least a charging switch tube. The charging unit can be connected in series with the discharge circuit 13 between the battery cell 11 and the discharge port 14 to control the charging of the battery cell 13.

[0051] The above-mentioned pre-charge switch tube, discharge switch tube and charging switch tube can all be composed of one or more solid-state switches connected in parallel. Typical solid-state switches include MOSFET (metal-oxide semiconductor field-effect transistor), IGBT (insulated gate bipolar transistor), GaN (gallium nitride) transistor and other switching devices.

[0052] Figure 2 is a flow chart of a pre-charging control method provided in an embodiment of the present application. The method of this embodiment can be executed by a battery control unit (such as a battery management system BMS), which can be implemented in software and / or hardware and can be integrated into devices such as vehicle-mounted equipment, energy storage equipment, power tools, etc. As shown in Figure 2, the pre-charging control method includes:

[0053] S101 , controlling the battery unit to be pre-charged through the pre-charging circuit.

[0054] Among them, when the battery control unit is powered on, reset or activated, it will perform an initialization process. When the initialization is completed and the system self-test is normal, it can control the switch tube of the pre-charge circuit 12 to be turned on and the switch tube of the discharge circuit 13 to be turned off. When an external load is connected to the discharge port 14 of the battery 1, the battery unit 11 pre-charges the external load through the pre-charge circuit 12.

[0055] S102: Periodically obtain a first voltage of a discharge port.

[0056] Here, periodicity refers to a fixed time interval. The discharge port 14 includes a positive discharge port 140 and a negative discharge port 141. For example, a hardware sampling circuit can periodically sample the voltage of the negative terminal of the discharge port 141 relative to ground as a first voltage, and the control module can obtain this first voltage. The first voltage can represent the degree of pre-charge of the external load by the battery 1. A higher first voltage indicates a higher degree of pre-charge of the external load.

[0057] S103 : Control the pre-charging state of the battery cell according to the first voltage and the pre-charging time corresponding to the first voltage.

[0058] Among them, the pre-charge duration corresponding to the first voltage represents the duration from the moment of starting pre-charging (such as t=0) to the moment of obtaining the first voltage. Since the first voltage of the discharge port is periodically obtained, a first voltage can be obtained for each pre-charge duration. Exemplarily, the first pre-charge duration corresponds to the first first voltage, the second pre-charge duration corresponds to the second first voltage, and so on. The Nth pre-charge duration corresponds to the Nth first voltage, where N is a positive integer greater than or equal to 2. When the first pre-charge duration is 5s, that is, when the first moment of t=5s is reached, the first first voltage corresponding to the first moment can be obtained.

[0059] According to the first voltage and the pre-charge time corresponding to the first voltage, the degree of pre-charging of the battery to the external load can be fed back, and then the pre-charging state of the battery can be controlled according to different pre-charging degrees. For example, when the first voltage of the discharge port is still at a low level after a considerable period of pre-charging, it means that the external load currently connected to the battery is a large capacitive load. At this time, if the pre-charging is disconnected and the discharge circuit is connected to the loop, the short-circuit protection will be triggered. Therefore, in this case, the pre-charging can be ended directly and the battery can be short-circuit locked for protection. For another example, if the first voltage of the discharge port is pre-charged to a relatively high level in a relatively short time, there is no need to wait until the set pre-charging time is over. The pre-charging can be ended in advance and the discharge circuit can be cut into the discharge loop to perform normal discharge control without the risk of short circuit.

[0060] The pre-charging control method provided in the embodiment of the present application, after starting the pre-charging function, simultaneously monitors the first voltage of the discharge port, and controls the pre-charging state of the battery cell through the first voltage and the pre-charging time corresponding to the first voltage, that is, the pre-charging degree of the load is determined according to the first voltage and the pre-charging time corresponding to the first voltage, and when the set pre-charging degree is reached, the pre-charging process can be terminated in advance before the preset pre-charging time without waiting until the preset pre-charging time ends; when the pre-charging degree is very low, there is no need to trigger an actual short circuit, and the battery cell can be directly controlled to enter a short-circuit locking state, that is, the pre-charging control method of this embodiment can adjust the pre-charging time according to the size of the load to improve the pre-charging efficiency and the load capacity of the battery.

[0061] Optionally, controlling the pre-charging state of the battery unit according to the first voltage and the pre-charging time corresponding to the first voltage may include:

[0062] The pre-charging state of the battery cell is controlled according to the relative magnitude of the first voltage and the output voltage of the battery cell, and the pre-charging time corresponding to the first voltage.

[0063] Specifically, battery 1 is also equipped with a battery cell voltage sampling unit for sampling and obtaining the output voltage of the battery cell. After obtaining the first voltage at the discharge port, the control unit also calculates the percentage of the first voltage to the output voltage of the battery cell, thereby reflecting the pre-charge degree. For example, if the output voltage of battery cell 11 is 14.4V, if the measured first voltage is 8.8V, the current pre-charge degree is 8.8 / 14.4 = 61%.

[0064] Optionally, if the relative magnitude of the first voltage and the output voltage of the battery cell exceeds a first preset value while the pre-charge duration is less than or equal to a preset pre-charge duration, indicating that the capacitance of the external load is small and the pre-charge degree has exceeded a certain level, the pre-charge process can be terminated in advance before the preset pre-charge duration, and the discharge circuit can be switched to enter a normal discharge state. Alternatively, if the relative magnitude of the first voltage and the output voltage of the battery cell is always less than the first preset value after the preset pre-charge duration, indicating that the capacitance of the external load is large, the battery cell can be controlled to enter a short-circuit lockout state. That is, the pre-charge control method of this embodiment can identify external impedance anomalies during the pre-charge stage and directly control the battery cell to enter a short-circuit lockout state, thereby avoiding unnecessary impacts on the battery circuit and protecting the discharge circuit from damage.

[0065] FIG3 is a flow chart of another pre-charging control method provided by an embodiment of the present application, and FIG4 is a graph showing a ratio of a first voltage to an output voltage of a battery cell varying over time provided by an embodiment of the present application. In conjunction with FIG3 and FIG4 , controlling the pre-charging state of the battery cell according to the first voltage and the pre-charging time corresponding to the first voltage specifically includes:

[0066] S1031. In response to the pre-charging time being less than the preset pre-charging time and the ratio of the first voltage to the output voltage of the battery cell being greater than or equal to a first set threshold, control the battery cell to end the pre-charging state and discharge through the discharge circuit.

[0067] Specifically, the preset pre-charge time t2 can be the time it takes for the discharge circuit to discharge the battery cell normally after a period of pre-charging in the conventional pre-charging process. If the preset pre-charge time t2 is set too short, it may cause many loads to fail to cold start due to insufficient pre-charging, and the load capacity will be limited; if the preset pre-charge time t2 is set too long, it will cause excessive power consumption. Therefore, the preset pre-charge time t2 can be determined based on the different loads that the battery may be adapted to and the empirical values ​​obtained through multiple tests. For example, the preset pre-charge time can be 3s. The first set threshold can also be determined by the empirical value obtained from multiple test simulations. For example, the first set threshold can be any value between 60% and 100%. Optionally, the first set threshold can be 80%, thereby shortening the pre-charge time and avoiding increased power consumption.

[0068] In some embodiments, step S1031 is the first operating condition, and the first curve C1 in Figure 4 corresponds to the first operating condition. That is, when the pre-charging time t1 is less than the preset pre-charging time t2, the first voltage monotonically rises to 80% of the output voltage of the battery cell, indicating that the load capacitance is small and the pre-charging process can be ended before the preset pre-charging time. Therefore, the discharge circuit can be cut in advance to control the battery cell to enter a normal discharge state.

[0069] S1032: In response to the pre-charging time being greater than or equal to the preset pre-charging time and the ratio of the first voltage to the output voltage of the battery cell being less than a second set threshold, control the battery cell to enter a short-circuit locking state.

[0070] The second set threshold is lower than the first set threshold. For example, the second set threshold can be any value between 0% and 20%. Alternatively, the second set threshold can be 10%, thereby allowing as many types of loads as possible to fall within the battery's load range, thereby improving the battery's load capacity.

[0071] In some embodiments, step S1032 is the second operating condition, and the second curve C2 in Figure 4 corresponds to the second operating condition. When the pre-charging time t1 is greater than or equal to the preset pre-charging time t2, the first voltage rise never exceeds 10% of the output voltage of the battery cell, indicating that the load capacitance is large, and there is no need to trigger a short circuit and then control the battery cell to enter a short-circuit locking state. Instead, the battery cell is directly controlled to enter a short-circuit locking state and locked, which can prevent the battery circuit from suffering unnecessary short-circuit shocks and protect the switch tube in the discharge circuit.

[0072] S1033. In response to the pre-charging time being equal to the preset pre-charging time, and the ratio of the first voltage to the output voltage of the battery cell being greater than or equal to the second set threshold and less than the first set threshold, and the first voltage monotonically increasing, the battery cell is controlled to end the pre-charging state when the pre-charging time is greater than the preset pre-charging time, and discharge is performed through the discharge circuit.

[0073] In some embodiments, step S1033 is a third operating condition, and the third curve C3 of Figure 4 corresponds to the third operating condition. Since the first voltage increases monotonically, the first voltage corresponding to when the pre-charge time t1 is greater than the preset pre-charge time t2 must be greater than the first voltage corresponding to when the pre-charge time t1 is equal to the preset pre-charge time t2. Under certain conditions, the greater the first voltage, the lower the risk of a short circuit at the output end of the battery cell. Therefore, when the pre-charge time t1 is greater than the preset pre-charge time t2, the battery cell is controlled to end the pre-charge state and discharge through the discharge circuit, which is beneficial to reducing the risk of a short circuit at the output end of the battery cell when the switch tube in the discharge circuit is cut in. For this operating condition, although the pre-charge degree of the external load does not exceed the first set threshold, considering the impact resistance of the power device itself, combined with the subsequent short-circuit detection mechanism, the load capacity of the battery and the type of load that can be adapted can be significantly improved.

[0074] S1034. In response to the pre-charging time being less than or equal to the preset pre-charging time, and the ratio of the first voltage to the output voltage of the battery cell being greater than or equal to the second set threshold and less than the first set threshold, and the first voltage at the current moment being less than the first voltage at the previous moment, the battery cell is controlled to end the pre-charging state at the current moment and discharge through the discharge circuit.

[0075] In some embodiments, step S1034 is the fourth operating condition, and the fourth curve C4 of Figure 4 corresponds to the fourth operating condition. Before the preset pre-charging time t2, the ratio of the first voltage to the output voltage of the battery cell rises to a certain value and then turns to a downward trend (that is, the first voltage at the current moment is less than the first voltage at the previous moment). The reason for this operating condition may be that the load device is started, causing the voltage of the battery discharge port to be pulled down. In this case, the battery cell is controlled to end the pre-charging state at the current moment and discharge through the discharge circuit to avoid insufficient pre-charging power.

[0076] FIG5 is a flow chart of another pre-charging control method provided by an embodiment of the present application. As shown in FIG5 , after controlling the battery cell to end the pre-charging state and discharge through the discharge circuit, the pre-charging control method further includes:

[0077] S104: Monitor whether a short circuit event occurs in the discharge circuit.

[0078] Specifically, the discharge current in the discharge circuit can be obtained through the hardware circuit, and the discharge current can be compared with the preset short-circuit current threshold through the comparator and the corresponding level signal can be output to the control unit; the control unit starts timing after obtaining the level signal, and determines that a short-circuit event has occurred in the discharge circuit in response to the discharge current being greater than or equal to the preset short-circuit current threshold for a period of time that is not less than the preset short-circuit duration.

[0079] The preset short-circuit current threshold is a preset maximum current value for determining a short circuit in the battery's discharge circuit. Exemplarily, the preset short-circuit current threshold may be 10A. The preset short-circuit duration is the duration during which the discharge current is greater than or equal to the preset short-circuit current threshold. Exemplarily, the preset short-circuit duration may be 500 milliseconds.

[0080] In actual applications, for the first, third, and fourth operating conditions mentioned above, after switching to discharge through the discharge circuit, a short circuit may still occur because the voltage difference still exists. Or, even if no short circuit occurs, a large peak current fluctuation may be generated (for example, the current of the battery charging the load at the moment the load is connected). Therefore, it is still necessary to monitor the battery for short-circuit events after switching the discharge path.

[0081] For the monitored discharge current, if the duration that the current exceeds the overcurrent protection value is short, the junction temperature of the power device (such as the switch) will not be significantly increased, and the risk of power device damage is low. Therefore, by setting the duration that the discharge current is greater than or equal to the preset short-circuit current threshold to be no less than the preset short-circuit duration, determining whether a short-circuit event has occurred in the discharge circuit can improve the reliability of battery load short-circuit diagnosis and avoid the occurrence of misjudgments. When a short-circuit event is detected in the discharge circuit, step S105 is executed; when no short-circuit event is detected in the discharge circuit, the process returns to step S104.

[0082] S105 , in response to the occurrence of a short-circuit event, triggering short-circuit protection and controlling the disconnection of the discharge circuit.

[0083] Specifically, the control unit triggers short-circuit protection in response to the occurrence of a short-circuit event, thereby implementing short-circuit protection for the battery cell and preventing the battery cell and related components from being damaged by excessive current.

[0084] FIG6 is a flow chart of another pre-charging control method provided by an embodiment of the present application. As shown in FIG6 , in response to the occurrence of a short circuit event, after the short circuit protection is triggered and the discharge circuit is disconnected, the pre-charging control method further includes:

[0085] S106. Accumulate the number of short-circuit protection times.

[0086] When the control unit detects a short circuit, the control unit adds one to the original recorded short circuit protection count. For example, when a short circuit occurs for the first time, the original recorded short circuit signal count is 0, and the current short circuit protection count is 1. When a short circuit occurs for the second time, the original recorded short circuit protection count is 1, and the current short circuit protection count is 2.

[0087] S1071. Determine whether the number of short-circuit protection times is greater than the preset number of short-circuit protection times.

[0088] Among them, the preset short circuit protection times can be set according to actual conditions, and the embodiment of the present application does not limit this. Optionally, the preset short circuit protection times are 3 times, thereby taking into account both pre-charging efficiency and load capacity.

[0089] Specifically, if the short-circuit protection count is less than or equal to the preset short-circuit protection count, the battery cell is re-controlled to be pre-charged through the pre-charging circuit to continue raising the load voltage; if the short-circuit protection count is greater than the preset short-circuit protection count, the battery cell is controlled to enter a short-circuit lock state. Therefore, if the short-circuit protection count is less than or equal to the preset short-circuit protection count, step S1081 is executed; if the short-circuit protection count is greater than the preset short-circuit protection count, step S1082 is executed.

[0090] S1072: Adjust the preset short-circuit current threshold and / or the preset short-circuit duration.

[0091] Specifically, a short-circuit protection threshold is stored in the control unit. The short-circuit protection threshold includes a preset short-circuit current threshold and a preset short-circuit duration. The judgment logic is that when the duration of the current greater than the preset short-circuit current threshold exceeds the preset short-circuit duration, it is determined that short-circuit protection is required. When a short-circuit event is detected, the junction temperature of the power device at this time already requires stricter short-circuit protection for the next pre-charge switching. Therefore, after each short-circuit protection is triggered, the preset short-circuit current threshold can be lowered, or the preset short-circuit duration can be reduced, or the preset short-circuit current threshold can be lowered and the preset short-circuit duration can be reduced at the same time, so that the next short-circuit protection is more stringent and effective. For example, the short-circuit protection threshold set for the first time can be 500A@150μs, and the thresholds for each subsequent triggering of short-circuit protection are 500A@100μs and 500A@50μs respectively. When the preset number of short-circuit protection times is exceeded, that is, 3 times, the pre-charge is no longer switched back, and the battery cell is controlled to enter a short-circuit lock state (i.e., step S1082).

[0092] S1081. Control the battery unit to perform pre-charging through the pre-charging circuit.

[0093] Specifically, in the case of triggering short-circuit protection, as long as the preset short-circuit protection times are not exceeded, the battery will still switch to the pre-charging circuit for pre-charging after disconnecting the discharge circuit. In this way, the voltage of the external load can be continuously raised through pre-charging several times. This strategy can significantly improve the battery's ability to carry capacitive loads and improve the battery adaptability.

[0094] S1082. Control the battery unit to enter a short-circuit locking state.

[0095] In this embodiment, short-circuit events are monitored for the working condition of switching to the discharge circuit for discharge after the pre-charging is completed. Once a short-circuit event occurs in the discharge circuit, the discharge circuit is immediately cut off to avoid the risk of short-circuit damage to the power device. At the same time, the voltage of the external load is continuously raised by repeatedly switching the pre-charging circuit quickly, thereby improving the battery's ability to carry capacitive loads while ensuring safety and improving the battery adaptation rate.

[0096] FIG7 is a flow chart of another pre-charging control method provided in an embodiment of the present application. As shown in FIG7 , the pre-charging control method includes:

[0097] S101 , controlling the battery unit to be pre-charged through the pre-charging circuit.

[0098] S102: Periodically obtain a first voltage of a discharge port.

[0099] S1031: In response to the pre-charging time being less than the preset pre-charging time and the ratio of the first voltage to the output voltage of the battery unit being greater than or equal to the first set threshold, control the battery unit to end the pre-charging state and discharge through the discharge circuit. Or,

[0100] S1032: In response to the pre-charging time being greater than or equal to the preset pre-charging time and the ratio of the first voltage to the output voltage of the battery cell being less than a second set threshold, control the battery cell to enter a short-circuit locking state. Or,

[0101] S1033: In response to the pre-charging time being equal to the preset pre-charging time, the ratio of the first voltage to the output voltage of the battery cell being greater than or equal to the second set threshold and less than the first set threshold, and the first voltage monotonically increasing, control the battery cell to end the pre-charging state when the pre-charging time is greater than the preset pre-charging time, and discharge the battery cell through the discharge circuit. Or,

[0102] S1034. In response to the pre-charging time being less than or equal to the preset pre-charging time, and the ratio of the first voltage to the output voltage of the battery cell being greater than or equal to the second set threshold and less than the first set threshold, and the first voltage at the current moment being less than the first voltage at the previous moment, the battery cell is controlled to end the pre-charging state at the current moment and discharge through the discharge circuit.

[0103] After the pre-charge state is completed and the discharge is completed through the discharge circuit, the following steps are continued:

[0104] S104: Monitor whether a short circuit event occurs in the discharge circuit.

[0105] When it is detected that a short circuit event occurs in the discharge circuit, step S105 is executed. When it is detected that no short circuit event occurs in the discharge circuit, the process returns to step S104.

[0106] S105 , in response to the occurrence of a short-circuit event, triggering short-circuit protection and controlling the disconnection of the discharge circuit.

[0107] S106. Accumulate the number of short-circuit protection times.

[0108] S1071. Determine whether the number of short-circuit protection times is greater than the preset number of short-circuit protection times.

[0109] If the short-circuit protection times are less than or equal to the preset short-circuit protection times, step S1072 is executed; if the short-circuit protection times are greater than the preset short-circuit protection times, step S1082 is executed.

[0110] S1072: Adjust the preset short-circuit current threshold and / or the preset short-circuit duration.

[0111] S1081. Control the battery unit to perform pre-charging through the pre-charging circuit.

[0112] S1082. Control the battery unit to enter a short-circuit locking state.

[0113] Based on the above embodiment, the discharge circuit includes a first switch, the pre-charging circuit includes a second switch, and controlling the battery cell to end the pre-charging state and discharge through the discharge circuit includes: controlling the second switch to turn off, and controlling the first switch to turn on.

[0114] Controlling the battery unit to enter a short-circuit locking state includes: controlling the first switch and the second switch to be turned off.

[0115] In the above embodiment, the first switch and the second switch may be any one of a MOS tube, an IGBT tube, and a triode.

[0116] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this application can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of this application can be achieved. This is not limited herein.

[0117] Figure 8 is a structural schematic diagram of another battery provided in an embodiment of the present application. As shown in Figure 8, the battery 1 includes: a battery cell 11; a discharge port 14, for connecting an external load 2; a discharge circuit 13 and a pre-charging circuit 12, connected between the battery cell 11 and the discharge port 14, the discharge circuit 13 includes a first switch K1, and the pre-charging circuit 12 includes a second switch K2 and a pre-charging resistor R1; a control unit 15, configured to control the battery cell 11 to be pre-charged through the pre-charging circuit 12, periodically obtain a first voltage of the discharge port 14, and control the pre-charging state of the battery cell according to the first voltage and the pre-charging time corresponding to the first voltage.

[0118] The first switch K1 and the second switch K2 are turned on or off according to the control of the control unit 15. It is understood that when the first switch K1 is turned on, the discharge circuit of the battery cell 11 is connected, and the power supply current output by the battery cell 11 is output from the positive terminal, passes through the load 2, passes through the first switch K1, and returns to the negative terminal of the battery cell 11. When the second switch K2 is turned on and the first switch K1 is turned off, the pre-charge circuit of the battery cell 11 is connected, and the power supply current output by the battery cell 11 is output from the positive terminal, passes through the load 2, passes through the second switch K2, and returns to the negative terminal of the battery cell 11. Optionally, the first switch K1 and the second switch K2 include but are not limited to MOS transistors.

[0119] The pre-charging resistor R1 can be implemented by a series resistor group consisting of multiple resistors, wherein the number of resistors connected in series can be determined according to the size of the load, and this application does not make any specific limitation.

[0120] The control unit 15 can be electrically connected to components such as the pre-charge circuit 12 and the discharge circuit 13, respectively, to control these components. The control unit 15 may include a microcontroller. Optionally, the control unit 15 may include a single-chip microcomputer, a digital signal processor (DSP) or a field programmable gate array (FPGA).

[0121] Specifically, the control unit 15 controls the pre-charge state of the battery cell according to the relative size of the first voltage and the output voltage of the battery cell, and the pre-charge time corresponding to the first voltage. For example, the pre-charge state of the battery cell can be controlled according to the ratio or difference between the first voltage and the battery cell. Exemplarily, when the pre-charge time is less than or equal to the preset pre-charge time, the relative size of the first voltage and the output voltage of the battery cell has exceeded the first preset value, indicating that the capacitance of the external load is small, and the pre-charge process can be ended in advance before the preset pre-charge time, and the discharge circuit can be switched to enter the normal state. Alternatively, after the preset pre-charge time, the relative size of the first voltage and the output voltage of the battery cell is always less than the first preset value, indicating that the external load capacitance is large. At this time, the battery cell can be controlled to enter the short-circuit locking state, that is, the pre-charge control method of this embodiment can identify the external impedance abnormality in the pre-charge stage, and directly control the battery cell to enter the short-circuit locking state, which can avoid unnecessary impact on the battery circuit and protect the discharge circuit from damage.

[0122] The battery provided in the embodiment of the present application, after starting the pre-charging function, simultaneously monitors the first voltage of the discharge port, and controls the pre-charging state of the battery cell through the first voltage and the pre-charging time corresponding to the first voltage, that is, the pre-charging degree of the load is determined according to the first voltage and the pre-charging time corresponding to the first voltage, and when the set pre-charging degree is reached, the pre-charging process can be terminated in advance before the preset pre-charging time, without waiting until the preset pre-charging time ends; when the pre-charging degree is very low, there is no need to trigger an actual short circuit, and the battery cell can be directly controlled to enter a short-circuit locking state, that is, the pre-charging control method of this embodiment can adjust the pre-charging time according to the size of the load to improve the pre-charging efficiency and the load capacity of the battery.

[0123] Optionally, based on the above embodiments, the control unit 15 includes a first operating state determination unit, a second operating state determination unit, a third operating state determination unit and a fourth operating state determination unit.

[0124] The first operating condition determination unit is used to control the battery cell to end the pre-charging state and discharge through the discharge circuit in response to the pre-charging time being less than the preset pre-charging time and the ratio of the first voltage to the output voltage of the battery cell being greater than or equal to the first set threshold.

[0125] The second operating condition determination unit is used to control the battery cell to enter a short-circuit locking state in response to the pre-charging time being greater than or equal to the preset pre-charging time and the ratio of the first voltage to the output voltage of the battery cell being less than a second set threshold; wherein the second set threshold is less than the first set threshold.

[0126] The third operating condition determination unit is used to respond to the fact that the pre-charging time is equal to the preset pre-charging time, the ratio of the first voltage to the output voltage of the battery cell is greater than or equal to the second set threshold and less than the first set threshold, and the first voltage monotonically increases, and control the battery cell to end the pre-charging state when the pre-charging time is greater than the preset pre-charging time, and discharge through the discharge circuit.

[0127] The fourth operating condition determination unit is used to control the battery cell to end the pre-charging state at the current moment and discharge through the discharge circuit in response to the pre-charging time being less than or equal to the preset pre-charging time, the ratio of the first voltage to the output voltage of the battery cell being greater than or equal to the second set threshold and less than the first set threshold, and the first voltage at the current moment being less than the first voltage at the previous moment.

[0128] Optionally, based on the above embodiments, the control unit 15 further includes a short-circuit event monitoring unit, which is used to monitor whether a short-circuit event occurs in the discharge circuit.

[0129] The control unit 15 further includes a short-circuit event first response unit, which is configured to trigger short-circuit protection and control disconnection of the discharge circuit in response to the occurrence of the short-circuit event.

[0130] The short-circuit event monitoring unit includes a current acquisition unit and a short-circuit event determination unit. The current acquisition unit is configured to acquire the discharge current in the discharge circuit. The short-circuit event determination unit is configured to determine that a short-circuit event has occurred in the discharge circuit when the discharge current is greater than or equal to a preset short-circuit current threshold for a period not less than a preset short-circuit duration.

[0131] Optionally, the control unit 15 further includes a second short-circuit event response unit, which is configured to trigger short-circuit protection in response to the occurrence of a short-circuit event by the first short-circuit event response unit, and control the disconnection of the discharge circuit to accumulate the number of short-circuit protection times.

[0132] Optionally, the control unit 15 further includes a third short-circuit event response unit, which is configured to re-control the battery cell to be pre-charged through the pre-charging circuit when the number of short-circuit protection times is less than or equal to a preset number of short-circuit protection times.

[0133] Optionally, the control unit 15 further includes a fourth short-circuit event response unit, which is configured to control the battery unit to enter a short-circuit locking state when the number of short-circuit protection times is greater than a preset number of short-circuit protection times.

[0134] Optionally, the control unit 15 further includes a short-circuit parameter adjustment unit, which is configured to adjust a preset short-circuit current threshold and / or a preset short-circuit duration after accumulating the number of short-circuit protection times.

[0135] Based on the same inventive concept, an embodiment of the present application also provides a battery management system. Figure 9 is a structural diagram of a battery management system provided by an embodiment of the present application. As shown in Figure 9, the battery management system 3 includes a storage unit 901 and a processing unit 902. The storage unit 901 stores a computer program, and the processing unit 902 implements the pre-charging control method in any of the above-mentioned embodiments when calling the computer program. Therefore, the battery management system also has the effect of the pre-charging control method in the above-mentioned embodiment. The similarities can be understood by referring to the above explanation of the pre-charging control method, which will not be repeated below.

[0136] The serial numbers of the above embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0137] In this application, the same or similar terminology, technical solutions and / or application scenario descriptions are generally only described in detail the first time they appear. When they appear again later, they are generally not repeated for the sake of brevity. When understanding the technical solutions and other contents of this application, for the same or similar terminology, technical solutions and / or application scenario descriptions that are not described in detail later, you can refer to the previous relevant detailed descriptions.

[0138] In this application, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0139] The various technical features of the technical solution of this application can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0140] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the relevant technology can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as above, and includes a number of instructions for enabling a terminal device (which can be an electrical device or a network device, etc.) to execute the method of each embodiment of the present application.

Claims

1. A pre-charging control method, applied to a battery, wherein the battery comprises a battery cell, a pre-charging circuit, a discharging circuit and a discharging port; the pre-charging circuit and the discharging circuit are connected between the battery cell and the discharging port; The pre-charge control method comprises: Controlling the battery unit to be pre-charged through the pre-charging circuit; Periodically acquiring a first voltage of the discharge port; The pre-charging state of the battery cell is controlled according to the first voltage and the pre-charging time corresponding to the first voltage.

2. The pre-charge control method according to claim 1, wherein: The controlling the pre-charging state of the battery unit according to the first voltage and the pre-charging time corresponding to the first voltage includes: In response to the pre-charging time being less than a preset pre-charging time and the ratio of the first voltage to the output voltage of the battery cell being greater than or equal to a first set threshold, controlling the battery cell to end the pre-charging state and discharge through the discharge circuit; or, In response to the pre-charging time being greater than or equal to a preset pre-charging time and the ratio of the first voltage to the output voltage of the battery cell being less than a second set threshold, controlling the battery cell to enter a short-circuit locking state; wherein the second set threshold is less than the first set threshold; or, In response to the pre-charging time being equal to the preset pre-charging time, and the ratio of the first voltage to the output voltage of the battery cell being greater than or equal to the second set threshold and less than the first set threshold, and the first voltage monotonically increasing, when the pre-charging time is greater than the preset pre-charging time, the battery cell is controlled to end the pre-charging state and discharge through the discharge circuit; or, In response to the pre-charging time being less than or equal to the preset pre-charging time, and the ratio of the first voltage to the output voltage of the battery cell being greater than or equal to the second set threshold and less than the first set threshold, and the first voltage at the current moment is less than the first voltage at the previous moment, the battery cell is controlled to end the pre-charging state at the current moment and discharge through the discharge circuit.

3. The pre-charging control method according to claim 2, after controlling the battery unit to end the pre-charging state and discharge through the discharge circuit, further comprising: Monitor whether there is a short circuit event in the discharge circuit; In response to the occurrence of a short circuit event, the short circuit protection is triggered, and the discharge circuit is controlled to be disconnected.

4. The pre-charge control method according to claim 3, wherein: The monitoring of whether a short circuit event occurs in the discharge circuit includes: Obtaining a discharge current in the discharge circuit; In response to the time duration during which the discharge current is greater than or equal to the preset short-circuit current threshold being not less than the preset short-circuit time duration, it is determined that a short-circuit event occurs in the discharge loop.

5. The pre-charge control method according to claim 4, after triggering the short circuit protection in response to the occurrence of the short circuit event and controlling the disconnection of the discharge circuit, further comprises: Accumulate the number of short-circuit protection times; In response to the short-circuit protection number being less than or equal to a preset short-circuit protection number, re-controlling the battery unit to be pre-charged through the pre-charging circuit; or, In response to the short circuit protection number being greater than the preset short circuit protection number, the battery unit is controlled to enter a short circuit locking state.

6. The pre-charge control method according to claim 5, after accumulating the number of short-circuit protection times, further comprising: The preset short-circuit current threshold and / or the preset short-circuit duration are adjusted.

7. The pre-charge control method according to any one of claims 2 to 6, wherein: The discharge circuit includes a first switch, the pre-charge circuit includes a second switch, and the control of the battery unit to end the pre-charge state and discharge through the discharge circuit includes: The second switch is controlled to be turned off, and the first switch is controlled to be turned on.

8. The pre-charge control method according to any one of claims 2 to 6, wherein: The discharge circuit includes a first switch, the pre-charge circuit includes a second switch, and the controlling the battery unit to enter a short-circuit locking state includes: The first switch and the second switch are controlled to be turned off.

9. A battery comprising: Battery cells; A discharge port configured to connect an external load; A discharge circuit and a pre-charge circuit are connected between the battery unit and the discharge port, the discharge circuit comprises a first switch, and the pre-charge circuit comprises a second switch and a pre-charge resistor; A control unit is configured to control the battery cell to be pre-charged through the pre-charging circuit, periodically obtain the first voltage of the discharge port, and control the pre-charging state of the battery cell according to the first voltage and the pre-charging time corresponding to the first voltage.

10. A battery management system, comprising a storage unit and a processing unit, wherein the storage unit stores a computer program, and the processing unit implements the pre-charging control method according to any one of claims 1 to 8 when calling the computer program.

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