CN117748660A

CN117748660A - Pre-charge control method, battery and battery management system

Info

Publication number: CN117748660A
Application number: CN202311728818.0A
Authority: CN
Inventors: 孙孝亮; 黄成成
Original assignee: If New Energy Technology Jiangsu Co ltd
Current assignee: If New Energy Technology Jiangsu Co ltd
Priority date: 2023-12-15
Filing date: 2023-12-15
Publication date: 2024-03-22
Anticipated expiration: 2043-12-15
Also published as: CN117748660B

Abstract

The embodiment of the invention discloses a pre-charge control method and a pre-charge control circuit, wherein the pre-charge control method is applied to a battery, and the battery comprises a battery unit, a pre-charge unit, a discharge unit and a discharge port; the pre-charging unit and the discharging unit are connected between the battery unit and the discharging port; the pre-charge control method comprises the following steps: controlling the battery unit to perform pre-charge and discharge through the pre-charge unit; periodically acquiring a first voltage of a discharge port; and controlling the pre-charge and discharge states of the battery cells according to the first voltage and the pre-charge time corresponding to the first voltage. The invention can adjust the pre-charging time according to the size of the load so as to improve the pre-charging efficiency and the carrying capacity of the battery.

Description

Pre-charge control method, battery and battery management system

Technical Field

The present invention relates to the field of precharge technologies, and in particular, to a precharge control method, a battery, and a battery management system.

Background

The load device, in particular the active load device, often contains a capacitive impedance component. When the lithium battery is used as a power supply to charge a capacitive load connected with cold start, the lithium battery has the characteristic of small internal resistance, so that transient current is large and short circuit is easy to cause. For the short-circuit protection mechanism of the lithium battery, devices such as a switching tube (such as a metal-oxide semiconductor field effect transistor MOSFET) and the like in the battery are easy to burn out after the short-circuit time is prolonged, otherwise, the cold start failure rate of the short-circuit time on some equipment with high capacitive impedance is greatly improved after the short-circuit time is shortened. For the reasons, a pre-charge loop is often built in the lithium battery, and the pre-charge loop is used for raising the voltage of an external capacitor before a discharge switch tube is started, and then the external capacitor is switched into a normal discharge loop to enter normal operation. The pre-charging circuit is used for controlling a proper power resistor to be connected in series in the MOS loop to limit the pre-charging current of the pre-charging loop, and forms a typical RC circuit with an external load.

Currently, the pre-charge strategy of the existing battery management system (Battery Management System, BMS) is relatively simple, i.e. the switch-in discharge loop works normally after waiting for a pre-charge fixed time. However, when the precharge current is small, since a fixed precharge time is adopted, if the external load capacitance is large, the precharge time is long and the precharge efficiency is low; when the precharge current is large, the precharge resistor requires a large power, resulting in severe heat generation and easy damage, and the occupation volume of the printed circuit board and the cost are remarkably increased. Because batteries often need to be adapted to a variety of different types of external loads, existing pre-charge strategies can cause problems in that the load cannot be cold started or the pre-charge time is too long, limiting the load carrying capacity of the battery.

Disclosure of Invention

The invention provides a pre-charge control method, a battery and a battery management system, which can adjust pre-charge time according to the size of a load so as to improve pre-charge efficiency and load capacity of the battery.

In a first aspect, the present invention provides a method for controlling pre-charge, the method being applied to a battery, the battery including a battery unit, a pre-charge unit, a discharge unit, and a discharge port; the pre-charging unit and the discharging unit are connected between the battery unit and the discharging port; the pre-charge control method comprises the following steps: controlling the battery unit to perform pre-charge and discharge through the pre-charge unit; periodically acquiring a first voltage of a discharge port; and controlling the pre-charge and discharge states of the battery cells according to the first voltage and the pre-charge time corresponding to the first voltage.

Optionally, the step of controlling the pre-charge and discharge states of the battery unit according to the first voltage and the pre-charge duration corresponding to the first voltage includes: controlling the battery unit to finish the pre-charge and discharge state and discharging through the discharge unit in response to the pre-charge time being smaller than the pre-charge time and the ratio of the first voltage to the output voltage of the battery unit being larger than or equal to a first set threshold; or, in response to the pre-charge time length being greater than or equal to the preset pre-charge time length and the ratio of the first voltage to the output voltage of the battery unit being less than a second set threshold, controlling the battery unit to enter a short circuit locking state; wherein the second set threshold is less than the first set threshold; or, in response to the fact that the pre-charging duration is equal to the preset pre-charging duration, the ratio of the first voltage to the output voltage of the battery unit is greater than or equal to the second set threshold value and less than the first set threshold value, the first voltage monotonically increases, the battery unit is controlled to finish the pre-charging and discharging state when the pre-charging duration is greater than the preset pre-charging duration, and the discharging unit discharges the battery unit; or, in response to the pre-charge duration being less than or equal to the preset pre-charge duration, the ratio of the first voltage to the output voltage of the battery unit 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, controlling the battery unit to finish the pre-charge and discharge state at the current moment, and discharging through the discharge unit.

Optionally, after the control of the battery cell to end the pre-charge and discharge state and discharge by the discharge cell, the pre-charge control method further includes: monitoring whether a short circuit event occurs in the discharge loop; in response to the occurrence of a short circuit event, short circuit protection is triggered, and the discharge unit is controlled to be turned off.

Optionally, the step of monitoring whether a short circuit event occurs in the discharge circuit includes: acquiring a discharge current in a discharge loop; and determining that a short circuit event occurs in the discharge loop in response to the discharge current being greater than or equal to the preset short circuit current threshold for a duration not less than the preset short circuit duration.

Optionally, after triggering the short-circuit protection in response to the occurrence of the short-circuit event and controlling to disconnect the discharge unit, the precharge control method further includes: accumulating the times of short circuit protection once; in response to the short-circuit protection times being less than or equal to the preset short-circuit protection times, the battery unit is controlled to be pre-charged and discharged through the pre-charging unit again; or, in response to the number of short-circuit protections being greater than the preset number of short-circuit protections, controlling the battery cell to enter a short-circuit locking state.

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

Optionally, the discharging unit includes a first switch, the pre-charging unit includes a second switch, and the step of controlling the battery unit to end the pre-charging and discharging through the discharging unit includes: the second switch is controlled to be turned off, and the first switch is controlled to be turned on.

Optionally, the discharging unit includes a first switch, the pre-charging unit includes a second switch, and the step of controlling the battery unit to enter the short circuit locking state includes: the first switch and the second switch are controlled to be turned off.

In a second aspect, the present invention provides a battery comprising: a battery unit; a discharge port for connecting an external load; the discharging unit and the pre-charging unit are connected between the battery unit and the discharging port, the discharging unit comprises a first switch, and the pre-charging unit comprises a second switch and a pre-charging resistor; the control unit is configured to control the battery unit to perform pre-charge and discharge through the pre-charge unit, periodically acquire the first voltage of the discharge port, and control the pre-charge and discharge state of the battery unit according to the first voltage and the pre-charge time corresponding to the first voltage.

In a third aspect, the present invention provides a battery management system including a storage unit storing a computer program, and a processing unit implementing the precharge control method of any one of the first aspects when the processing unit invokes the computer program.

According to the pre-charging control method provided by the embodiment of the invention, after a pre-charging function is started, the first voltage of the discharge port is monitored, and the pre-charging and discharging state of the battery unit is controlled through the first voltage and the pre-charging time corresponding to the first voltage, namely, 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 pre-charging degree is set, the pre-charging process can be finished in advance before the pre-charging time is set, and the pre-charging time is not required to be finished; when the pre-charging degree is very low, the actual short circuit is not required to be triggered, and the battery unit is directly controlled to enter a short circuit locking state, namely, the pre-charging control method of the embodiment can adjust the pre-charging time according to the size of the load so as to improve the pre-charging efficiency and the carrying capacity of the battery.

It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the invention or to delineate the scope of the invention. Other features of the present invention will become apparent from the description that follows.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural view of a battery according to an embodiment of the present invention;

FIG. 2 is a flowchart of a method for controlling priming according to an embodiment of the present invention;

FIG. 3 is a flow chart of yet another method for precharge control provided by an embodiment of the present invention;

FIG. 4 is a graph showing a ratio of a first voltage to an output voltage of a battery cell over time according to an embodiment of the present invention;

FIG. 5 is a flow chart of yet another method for precharge control provided by an embodiment of the present invention;

FIG. 6 is a flow chart of yet another method for precharge control provided by an embodiment of the present invention;

FIG. 7 is a flow chart of yet another method for precharge control provided by an embodiment of the present invention;

fig. 8 is a schematic view of a structure of a further battery according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a battery management system according to an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples are not representative of all implementations consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with some aspects of the present application as detailed in the accompanying claims.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element. It will be further understood that, as used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context indicates otherwise. Furthermore, the terms "or," "and/or," "including at least one of," and the like, as used herein, are to be construed as inclusive, or mean any one or any combination. An exception to this definition will occur only when a combination of elements, functions, steps or operations are in some way inherently mutually exclusive.

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 by these terms. These terms are only used to distinguish one parameter or module from another of the same type. For example, a first parameter may also be referred to as a second parameter, and similarly, a second parameter may also be referred to as a first parameter, without departing from the scope herein. The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrase "if determined" or "if detected (stated condition or event)" may be interpreted as "when determined" or "in response to determination" or "when detected (stated condition or event)" or "in response to detection (stated condition or event), depending on the context. Furthermore, components, features, and elements that are identically named in different embodiments of the present application may have the same meaning or may have different meanings, the particular meaning of which is to be determined by its interpretation in this particular embodiment or further in connection with the context of this particular embodiment.

It should be understood that, although the steps in the flowcharts in the embodiments of the present application are sequentially shown as indicated by arrows, these steps are not necessarily sequentially performed in the order indicated by the arrows. The steps are not strictly limited in order and may be performed in other orders, unless explicitly stated herein. Moreover, at least some of the steps in the figures may include multiple sub-steps or stages that are not necessarily performed at the same time, but may be performed at different times, the order of their execution not necessarily occurring in sequence, but may be performed alternately or alternately with other steps or at least a portion of the other steps or stages.

It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the claims.

In order to solve the problems in the prior art, the embodiments of the present application provide a pre-charge control method, a battery and a battery management system, and a battery to which the pre-charge control method provided in the embodiments of the present application may be applied is first described below. Fig. 1 is a schematic structural diagram of a battery according to an embodiment of the present invention, and as shown in fig. 1, the battery 1 includes a battery unit 11, a pre-charging unit 12, a discharging unit 13, and a discharging port 14; the precharge unit 12 and the discharge unit 13 are connected between the battery cell 11 and the discharge port 14.

The battery unit 11 may be a battery pack, and a plurality of unit cells are connected in series and parallel to form the battery unit 11, or only a single unit cell may form the battery unit 11. The battery 1, when connected to the load 2, is supplied with power by the battery unit 11. Alternatively, the load 2 may be any one of a inductive load, a resistive load, and a capacitive load. Illustratively, the load 2 may be equivalent to an effective capacitance Cb and an effective resistance R2 in parallel with the effective capacitance Cb.

The precharge unit 12 may include a precharge resistor and a precharge switching tube, and the precharge switching tube may enable the precharge unit 12 under the control of a control unit (not shown), thereby controlling the battery cell 11 to precharge and discharge.

The discharge unit 13 may include a discharge switching tube that may enable the discharge unit 13 under the control of the control unit, thereby controlling the battery cell to discharge through the discharge unit 13.

In some application scenarios, the battery charging device may further comprise a charging unit, and the charging unit at least comprises a charging switch tube. A charging unit may be connected in series with the discharging unit 13 between the battery unit 11 and the discharging port 14 for controlling the charging of the battery unit 13.

Fig. 2 is a flowchart of a precharge control method according to an embodiment of the present invention. The method of the present embodiment may be performed by a control unit of the battery (e.g., a battery management system BMS), which may be implemented in software and/or hardware, and may be integrated on devices such as an in-vehicle device, an energy storage device, an electric tool, and the like. As shown in fig. 2, the precharge control method includes:

S101, controlling the battery unit to conduct pre-charge and discharge through the pre-charge unit.

When the control unit of the battery is powered on, reset or activated, an initialization process is performed, and when the initialization is completed and the self-check of the system is not abnormal, the switching tube of the pre-charging unit 12 can be controlled to be turned on, and the switching tube of the discharging unit 13 can be controlled 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 and discharges the external load through the pre-charging unit 12.

S102, periodically acquiring a first voltage of the discharge port.

Wherein, periodicity refers to the lapse of a fixed time interval. The discharge port 14 includes a discharge port positive electrode 140 and a discharge port negative electrode 141. For example, the ground voltage of the negative electrode port of the discharge port 141 may be periodically sampled as the first voltage by the hardware sampling circuit, and the first voltage is acquired by the control module. The first voltage may be indicative of a degree of pre-charging of the battery 1 to the external load, the higher the first voltage, the higher the degree of pre-charging of the external load.

And S103, controlling the pre-charge and discharge states of the battery units according to the first voltage and the pre-charge time length corresponding to the first voltage.

The precharge duration corresponding to the first voltage indicates a duration from a time when the precharge is started (e.g., time t=0) to a time when the first voltage is acquired, and since the first voltage of the discharge port is periodically acquired, that is, each precharge duration may acquire one first voltage. Illustratively, the first precharge duration corresponds to a first voltage, the second precharge duration corresponds to a second first voltage, and so on, and the nth precharge duration corresponds to an nth first voltage, where N is a positive integer greater than or equal to 2. When the first precharge duration is 5s, that is, the first time when t=5s is reached, a first voltage corresponding to the first time may be obtained.

According to the first voltage and the pre-charge time corresponding to the first voltage, the pre-charge degree of the battery to the external load can be fed back, and then the pre-charge and discharge states of the battery are controlled according to different pre-charge degrees. For example, when the first voltage of the discharge port is still at a low level after a relatively long period of pre-charging, the external load currently connected to the battery is a large capacitive load, and if the pre-charging is disconnected and the discharge unit is connected to the circuit, the short-circuit protection is triggered, so that the pre-charging can be directly ended for this situation, and the battery can be short-circuit locked and protected. For another example, if the first voltage of the discharge port is precharged to a relatively high level in a relatively short time, the precharge may be terminated in advance to switch the discharge cell into the discharge circuit without waiting for the end of the set precharge period, and normal discharge control may be performed without risk of short circuit.

Further, controlling the pre-charge and discharge states of the battery cells according to the first voltage and the pre-charge duration corresponding to the first voltage may include:

and controlling the pre-charge and discharge states of the battery cells according to the relative magnitudes of the first voltage and the output voltage of the battery cells and the pre-charge time length corresponding to the first voltage.

Specifically, the battery 1 is further provided with a voltage sampling unit of a battery unit for sampling and acquiring an output voltage of the battery unit. The control unit also calculates the percentage of the first voltage and the output voltage of the battery unit after acquiring the first voltage of the discharge port, thereby reflecting the pre-charge degree. For example, taking the output voltage of the battery cell 11 as 14.4V as an example, if the first voltage is measured to be 8.8V, the current pre-charge degree is 8.8/14.4=61%.

Further, when the pre-charging duration is less than or equal to the preset pre-charging duration, the relative magnitude of the first voltage and the output voltage of the battery unit exceeds a first preset value, which indicates that the capacitance of the external load is smaller, and when the pre-charging degree exceeds a certain level, the pre-charging process can be finished in advance before the preset pre-charging duration, and the cut-in discharging unit enters a normal discharging state. Or after the preset pre-charging period, the relative magnitude of the first voltage and the output voltage of the battery unit is always smaller than a first preset value, which indicates that the external load capacitance is larger, and the battery unit can be controlled to enter a short-circuit locking state at the moment, namely, the external impedance abnormality can be identified in the pre-charging stage by the pre-charging control method of the embodiment, the battery unit is directly controlled to enter the short-circuit locking state, so that unnecessary impact of a battery circuit can be avoided, and the discharge unit is prevented from being damaged.

Fig. 3 is a flowchart of another method for controlling pre-charging according to an embodiment of the present invention, and fig. 4 is a graph of a ratio of a first voltage to an output voltage of a battery unit over time according to an embodiment of the present invention, and in combination with fig. 3 and fig. 4, the method specifically includes the steps of controlling a pre-charging and discharging state of the battery unit according to the first voltage and a pre-charging duration corresponding to the first voltage:

s1031, controlling the battery unit to finish the pre-charge and discharge state and discharging through the discharge unit in response to the pre-charge time being smaller than the pre-charge time and the ratio of the first voltage to the output voltage of the battery unit being larger than or equal to a first set threshold.

Specifically, the preset precharge duration t2 may be a duration of time for which the battery unit is normally discharged by switching into the discharging unit after the precharge is performed for a period of time in the conventional precharge process, and if the preset precharge duration t2 is set too short, many loads may fail in cold start due to insufficient precharge, and the load capacity is limited; the preset precharge period t2 is set too long, which may result in excessive power consumption. Therefore, the preset precharge period t2 may be determined according to different loads to which the battery may be adapted and empirical values obtained through a plurality of experiments. The preset precharge period may be 3s, for example. The first set threshold may also be determined from empirical values obtained from multiple trial simulations. Illustratively, the first set threshold may be any value from 60% -100%. Preferably, the first set threshold may be 80%, whereby the precharge period may be shortened, avoiding an increase in power consumption.

In some embodiments, step S1031 is a first working condition, and the first curve C1 in fig. 4 corresponds to the first working condition, that is, the first voltage monotonically rises to 80% of the output voltage of the battery unit in the period t1 of the pre-charging period t2, which indicates that the load capacitance is smaller and the pre-charging process can be ended before the pre-charging period, so that the battery unit can be controlled to enter the normal discharging state by switching into the discharging unit in advance.

S1032, controlling the battery unit to enter a short circuit locking state in response to the pre-charge time length being greater than or equal to the preset pre-charge time length and the ratio of the first voltage to the output voltage of the battery unit being less than a second set threshold.

Wherein the second set threshold is smaller than the first set threshold. Illustratively, the second set threshold may be any value from 0% -20%. Preferably, the second set threshold may be 10%, whereby more types of load can be brought into the load range of the battery as much as possible, improving the load carrying capacity of the battery.

In some embodiments, step S1032 is a second working condition, where the second curve C2 in fig. 4 corresponds to the second working condition, and when the pre-charging period t1 is greater than or equal to the preset pre-charging period t2, the first voltage rises by no more than 10% of the output voltage of the battery unit, which indicates that the load capacitance is large, and the battery unit is not required to be controlled to enter the short-circuit locking state after the short circuit is triggered, but is directly controlled to enter the short-circuit locking state for locking, so that the battery circuit can be prevented from bearing unnecessary short-circuit impact, and the switching tube in the discharging loop is protected.

S1033, in response to the fact that the pre-charging duration is equal to the preset pre-charging duration, the ratio of the first voltage to the output voltage of the battery unit is greater than or equal to the second set threshold value and less than the first set threshold value, the first voltage monotonically increases, and when the pre-charging duration is greater than the preset pre-charging duration, the battery unit is controlled to finish the pre-charging and discharging state, and discharging is conducted through the discharging unit.

In some embodiments, step S1033 is a third working condition, and the third curve C3 of fig. 4 corresponds to the third working condition, and since the first voltage monotonically increases, the corresponding first voltage is necessarily greater than the corresponding first voltage when the precharge duration t1 is greater than the preset precharge duration t2 and the precharge duration t1 is equal to the preset precharge duration t 2. Under certain conditions, the larger the first voltage is, the smaller the risk of short circuit at the output end of the battery unit is, so that the battery unit is controlled to finish the pre-charge and discharge state when the pre-charge time t1 is longer than the pre-charge time t2, and the discharge is carried out through the discharge unit, thereby being beneficial to reducing the risk of short circuit at the output end of the battery unit when the switch tube in the discharge unit is cut in. For the working condition, although the pre-charge degree of the external load does not exceed a first set threshold, the load carrying capacity and the adaptive load type of the battery can be obviously improved by considering the impact resistance capacity of the power device and matching with a subsequent short circuit detection mechanism.

S1034, in response to the pre-charge duration being less than or equal to the preset pre-charge duration, the ratio of the first voltage to the output voltage of the battery unit being greater than or equal to the second set threshold and less than the first set threshold, the first voltage at the current moment being less than the first voltage at the previous moment, the battery unit is controlled to finish the pre-charge and discharge state at the current moment, and the discharging is performed through the discharging unit.

In some embodiments, step S1034 is a fourth working condition, the fourth curve C4 of fig. 4 corresponds to the fourth working condition, before the preset pre-charging period t2, the ratio of the first voltage to the output voltage of the battery unit rises to a certain value and then changes to a decreasing trend (i.e. the first voltage at the current moment is smaller than the first voltage at the previous moment), and the reason for this working condition may be that the voltage of the discharge port of the battery is pulled down due to the start of the load device, then the battery unit is controlled to end the pre-charging and discharging state at the current moment, and the discharging unit discharges the battery unit to avoid the insufficient pre-charging power.

Fig. 5 is a flowchart of another pre-charge control method according to an embodiment of the present invention, where, as shown in fig. 5, after the control of the battery cell to end the pre-charge and discharge state and discharge through the discharge unit, the pre-charge control method further includes:

S104, monitoring whether a short circuit event occurs in the discharge loop.

Specifically, the discharging current in the discharging loop can be obtained through a hardware circuit, and the discharging current is compared with a preset short-circuit current threshold through a comparator and a corresponding level signal is output to the control unit; and starting timing after the control unit acquires the level signal, and determining that a short circuit event occurs in the discharge loop in response to the fact that the duration of the discharge current being greater than or equal to the preset short circuit current threshold value is not less than the preset short circuit duration.

The preset short-circuit current threshold is a preset maximum current value for determining that a short circuit exists in a discharge circuit of the battery. The preset short circuit current threshold may be 10A, for example. The preset short-circuit duration is a duration in which the discharge current is greater than or equal to a preset short-circuit current threshold. The preset short-circuit period may be 500 milliseconds, for example.

In practical applications, for the first, third and fourth conditions, after the switching to the discharging through the discharging unit, because the voltage difference still exists, a short circuit may still occur, or even though a short circuit does not occur, a large peak current fluctuation (for example, a current for charging the load by the battery at the moment of load access) may occur, so that the monitoring of the short circuit event of the battery after the switching of the discharging path is still required.

For the monitored discharge current, if the duration that the current exceeds the overcurrent protection value is shorter, the junction temperature of the power device (such as a switch) is not obviously improved, and the damage risk of the power device is lower. Therefore, by setting the duration that the discharge current is greater than or equal to the preset short-circuit current threshold value to be not less than the preset short-circuit duration, the occurrence of a short-circuit event in the discharge loop is determined, the reliability of battery load short-circuit diagnosis can be improved, and the occurrence of misjudgment is avoided. When it is detected that a short circuit event occurs in the discharge loop, step S105 is executed; when no short circuit event occurs in the discharge loop, the process returns to continue to step S104.

S105, in response to the occurrence of the short-circuit event, triggering short-circuit protection and controlling to disconnect the discharge unit.

Specifically, the control unit responds to the occurrence of a short circuit event to trigger short circuit protection, so that the short circuit protection of the battery unit is realized, and the battery unit, related components and the like are prevented from being damaged due to overlarge current.

Further, fig. 6 is a flowchart of still another method for controlling pre-charging according to an embodiment of the present invention, as shown in fig. 6, after triggering a short-circuit protection in response to occurrence of a short-circuit event and controlling to disconnect a discharge unit, the method for controlling pre-charging further includes:

S106, accumulating the times of short-circuit protection.

When the control unit detects that a short circuit event occurs, the short circuit protection times recorded by the control unit are increased by one on the basis of the original recorded short circuit protection times. Illustratively, when a first short circuit fault occurs, the number of times of the short circuit signals originally recorded is 0, and the current number of times of short circuit protection is recorded as 1; when the second short-circuit fault occurs, the original short-circuit protection times are 1, and the current short-circuit protection times are 2.

S1071, judging whether the short-circuit protection times are larger than preset short-circuit protection times.

The preset short-circuit protection times can be set according to actual conditions, and the embodiment of the invention is not limited to the preset short-circuit protection times. Preferably, the preset number of short-circuit protection is 3, so that both the pre-charging efficiency and the carrying capacity can be achieved.

Specifically, if the short-circuit protection times are smaller than or equal to the preset short-circuit protection times, the battery unit is controlled to be pre-charged and discharged through the pre-charging unit again so as to continuously raise the load voltage; and if the short-circuit protection times are greater than the preset short-circuit protection times, controlling the battery unit to enter a short-circuit locking state. Therefore, if the number of short-circuit protections is less than or equal to the preset number of short-circuit protections, step S1081 is performed; if the number of short-circuit protections is greater than the preset number of short-circuit protections, step S1082 is performed.

S1072, a preset short-circuit current threshold value and/or a preset short-circuit duration are/is adjusted.

Specifically, a short-circuit protection threshold is stored in the control unit, the short-circuit protection threshold comprises a preset short-circuit current threshold and a preset short-circuit duration, and when the judgment logic judges that the duration time of the current larger than the preset short-circuit current threshold exceeds the preset short-circuit duration, the short-circuit protection is determined to be needed. When a short circuit event is detected, the junction temperature of the power device already needs to execute stricter short circuit protection on the next precharge switching. Therefore, after each time of triggering the short-circuit protection, the preset short-circuit current threshold value can be adjusted downwards, or the preset short-circuit time length can be reduced, or the preset short-circuit current threshold value can be adjusted downwards and the preset short-circuit time length can be reduced at the same time, so that the next short-circuit protection is stricter and more effective. The first set short-circuit protection threshold may be, for example, 500a@150 μs, with each subsequent trigger of short-circuit protection having a threshold of 500a@100 μs and 500a@50 μs, respectively. When the preset number of short-circuit protections is exceeded, i.e. 3 times, the pre-charge is not switched back, and the battery cell is controlled to enter the short-circuit locking state (i.e. step S1082).

S1081, controlling the battery unit to perform pre-charge and discharge through the pre-charge unit.

Specifically, in the case of triggering short-circuit protection, as long as the preset short-circuit protection times are not exceeded, the discharging unit is still switched to the pre-charging unit to perform pre-charging and discharging, so that the voltage of an external load can be continuously raised through pre-charging repeatedly for a plurality of times.

S1082, controlling the battery unit to enter a short circuit locking state.

In the embodiment, the short circuit event monitoring is carried out on the working condition that the pre-charging is finished and the discharging unit is switched to discharge, and once the short circuit event occurs in the discharging circuit, the discharging circuit is immediately cut off, so that the power device is prevented from being damaged by short circuit risks; meanwhile, the voltage of the external load is continuously raised by repeatedly and continuously and rapidly switching the pre-charging loop, the capacity of the battery with capacitive load is improved under the condition of ensuring safety, and the battery adaptation rate is improved.

Fig. 7 is a flowchart of yet another pre-charging control method according to an embodiment of the present invention, as shown in fig. 7, where the pre-charging control method includes:

S102, periodically acquiring a first voltage of the discharge port.

S1031, controlling the battery unit to finish the pre-charge and discharge state and discharging through the discharge unit in response to the pre-charge time being smaller than the pre-charge time and the ratio of the first voltage to the output voltage of the battery unit being larger than or equal to a first set threshold. Or,

s1032, controlling the battery unit to enter a short circuit locking state in response to the pre-charge time length being greater than or equal to the preset pre-charge time length and the ratio of the first voltage to the output voltage of the battery unit being less than a second set threshold. Or,

s1033, in response to the fact that the pre-charging duration is equal to the preset pre-charging duration, the ratio of the first voltage to the output voltage of the battery unit is greater than or equal to the second set threshold value and less than the first set threshold value, the first voltage monotonically increases, and when the pre-charging duration is greater than the preset pre-charging duration, the battery unit is controlled to finish the pre-charging and discharging state, and discharging is conducted through the discharging unit. Or,

After ending the precharge and discharge state and discharging by the discharge unit, the following steps are continuously performed:

s104, monitoring whether a short circuit event occurs in the discharge loop.

When it is detected that a short circuit event occurs in the discharge circuit, step S105 is executed, and when it is detected that no short circuit event occurs in the discharge circuit, step S104 is executed again.

S106, accumulating the times of short-circuit protection.

If the number of short-circuit protection times is less than or equal to the preset number of short-circuit protection times, executing step S1072; if the number of short-circuit protections is greater than the preset number of short-circuit protections, step S1082 is performed.

S1082, controlling the battery unit to enter a short circuit locking state.

On the basis of the above embodiment, the discharging unit includes a first switch, the pre-charging unit includes a second switch, and the step of controlling the battery unit to end the pre-charging and discharging through the discharging unit includes: the second switch is controlled to be turned off, and the first switch is controlled to be turned on.

The step of controlling the battery cell to enter the short circuit locking state includes: the first switch and the second switch are controlled to be turned off.

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

It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps described in the present invention may be performed in parallel, sequentially, or in a different order, so long as the desired results of the technical solution of the present invention are achieved, and the present invention is not limited herein.

Fig. 8 is a schematic structural view of another battery according to an embodiment of the present invention, and as shown in fig. 8, the battery 1 includes: a battery cell 11; a discharge port 14 for connecting an external load 2; a discharging unit 13 and a pre-charging unit 12 connected between the battery unit 11 and the discharging port 14, the discharging unit 13 including a first switch K1, the pre-charging unit 12 including a second switch K2 and a pre-charging resistor R1; the control unit 15 is configured to control the battery unit 11 to perform pre-charge and discharge through the pre-charge unit 12, periodically acquire the first voltage of the discharge port 14, and control the pre-charge and discharge state of the battery unit according to the first voltage and the pre-charge period corresponding to the first voltage.

Wherein the first switch K1 and the second switch K2 are turned on or off according to the control of the control unit 15. It can be understood that when the first switch K1 is turned on, the discharge circuit of the battery unit 11 is turned on, and the supply current output by the battery unit 11 is returned to the negative terminal of the battery unit 11 after passing through the load 2 from the positive terminal and the first switch K1. When the second switch K2 is turned on and the first switch K1 is turned off, the pre-charging circuit of the battery unit 11 is turned on, and the power supply current output by the battery unit 11 is returned to the negative terminal of the battery unit 11 after passing through the load 2 from the positive terminal output and passing through the second switch K2. Optionally, the first switch K1 and the second switch K2 include, but are not limited to, MOS transistors.

The precharge resistor R1 may be implemented by a series resistor group composed of a plurality of resistors, wherein the number of resistors connected in series may be determined according to the size of the load, and the present invention is not particularly limited.

The control unit 15 may be electrically connected to the elements of the pre-charging unit 12 and the discharging unit 13, respectively, so as to control these elements. The control unit 15 may comprise a micro control unit. Optionally, the control unit 15 may comprise a single-chip microcomputer, a digital signal processor (Digital Signal Processor, DSP) or a field programmable gate array (Field Programmable Gate Array, FPGA).

Specifically, the control unit 15 controls the pre-charge-discharge state of the battery cell according to the relative magnitudes of the first voltage and the output voltage of the battery cell, and the pre-charge period corresponding to the first voltage. For example, the pre-charge state of the battery cell may be controlled according to a ratio or a difference of the first voltage to the battery cell. In an exemplary embodiment, when the pre-charging period is less than or equal to the preset pre-charging period, the relative magnitude of the first voltage and the output voltage of the battery unit exceeds the first preset value, which indicates that the capacitance of the external load is smaller, the pre-charging process may be finished in advance before the preset pre-charging period, and the cut-in discharging unit enters the normal state. Or after the preset pre-charging period, the relative magnitude of the first voltage and the output voltage of the battery unit is always smaller than a first preset value, which indicates that the external load capacitance is larger, and the battery unit can be controlled to enter a short-circuit locking state at the moment, namely, the external impedance abnormality can be identified in the pre-charging stage by the pre-charging control method of the embodiment, the battery unit is directly controlled to enter the short-circuit locking state, so that unnecessary impact of a battery circuit can be avoided, and the discharge unit is prevented from being damaged.

After the pre-charging function is started, the first voltage of the discharge port is monitored, and the pre-charging and discharging state of the battery unit is controlled through the first voltage and the pre-charging time length corresponding to the first voltage, namely, the pre-charging degree of the load is determined according to the first voltage and the pre-charging time length corresponding to the first voltage, and when the pre-charging degree is set, the pre-charging process can be finished in advance before the pre-charging time length is set, and the pre-charging time length is not required to be finished; when the pre-charging degree is very low, the actual short circuit is not required to be triggered, and the battery unit is directly controlled to enter a short circuit locking state, namely, the pre-charging control method of the embodiment can adjust the pre-charging time according to the size of the load so as to improve the pre-charging efficiency and the carrying capacity of the battery.

Alternatively, on the basis of the above embodiments, the control unit 15 includes a first operating condition state determining unit, a second operating condition state determining unit, a third operating condition state determining unit, and a fourth operating condition state determining unit.

The first working condition state determining unit is used for controlling the battery unit to finish the pre-charge and discharge state and discharging through the discharging unit in response to the pre-charge time length being smaller than the preset pre-charge time length and the ratio of the first voltage to the output voltage of the battery unit being larger than or equal to a first set threshold value.

The second working condition state determining unit is used for controlling the battery unit to enter a short circuit locking state in response to the fact that the pre-charging time length is greater than or equal to the preset pre-charging time length and the ratio of the first voltage to the output voltage of the battery unit is smaller than a second set threshold value; wherein the second set threshold is smaller than the first set threshold.

The third working condition state determining unit is used for responding to the fact that the pre-charging time length is equal to the preset pre-charging time length, the ratio of the first voltage to the output voltage of the battery unit is larger than or equal to a second set threshold value and smaller than the first set threshold value, the first voltage is monotonically increased, and when the pre-charging time length is larger than the preset pre-charging time length, the battery unit is controlled to finish the pre-charging and discharging state, and discharging is conducted through the discharging unit.

The fourth working condition state determining unit is used for controlling the battery unit to finish the pre-charge and discharge state at the current moment and discharging through the discharge unit in response to the fact that the pre-charge time is smaller than or equal to the preset pre-charge time, the ratio of the first voltage to the output voltage of the battery unit is larger than or equal to the second set threshold and smaller than the first set threshold, and the first voltage at the current moment is smaller than the first voltage at the last moment.

Optionally, on the basis of the above embodiments, the control unit 15 further includes a short-circuit event monitoring unit, where the short-circuit event monitoring unit is configured to monitor whether a short-circuit event occurs in the discharge circuit.

The control unit 15 further comprises a short-circuit event first response unit for triggering a short-circuit protection in response to the occurrence of a short-circuit event when the short-circuit event occurs, and controlling the opening of the discharge unit.

The short circuit event monitoring unit comprises a current acquisition unit and a short circuit event determining unit, wherein the current acquisition unit is used for acquiring the discharge current in the discharge loop. The short circuit event determining unit is used for determining that a short circuit event occurs in the discharge loop when the duration that the discharge current is greater than or equal to the preset short circuit current threshold value is not less than the preset short circuit duration.

Optionally, the control unit 15 further includes a short-circuit event second response unit, where the short-circuit event second response unit is configured to trigger short-circuit protection after the short-circuit event first response unit responds to occurrence of the short-circuit event, and control the discharge unit to be disconnected, and accumulate the number of times of short-circuit protection.

Optionally, the control unit 15 further includes a third response unit for a short-circuit event, where the third response unit for a short-circuit event is configured to re-control the battery unit to perform pre-charge and discharge through the pre-charge unit when the number of short-circuit protection is less than or equal to a preset number of short-circuit protection.

Optionally, the control unit 15 further includes a fourth response unit of a short circuit event, where the fourth response unit of the short circuit event is configured to control the battery unit to enter the short circuit locking state when the number of short circuit protections is greater than a preset number of short circuit protections.

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

Based on the same inventive concept, the embodiment of the invention also provides a battery management system. Fig. 9 is a schematic structural diagram of a battery management system according to an embodiment of the present invention, and as shown in fig. 9, the battery management system 3 includes a storage unit 901 and a processing unit 902, where the storage unit 901 stores a computer program, and the processing unit 902 implements the precharge control method in any of the foregoing embodiments when calling the computer program. Therefore, the battery management system also has the advantages of the pre-charge control method in the above embodiment, and the same points can be understood with reference to the explanation of the pre-charge control method, and will not be described in detail.

The foregoing embodiment numbers of the present application are merely for describing, and do not represent advantages or disadvantages of the embodiments.

In this application, the same or similar term concept, technical solution, and/or application scenario description will generally be described in detail only when first appearing, and when repeated later, for brevity, will not generally be repeated, and when understanding the content of the technical solution of the present application, etc., reference may be made to the previous related detailed description thereof for the same or similar term concept, technical solution, and/or application scenario description, etc., which are not described in detail later.

In this application, the descriptions of the embodiments are focused on, and the details or descriptions of one embodiment may be found in the related descriptions of other embodiments.

The technical features of the technical solutions of the present application may be arbitrarily combined, and for brevity of description, all possible combinations of the technical features in the above embodiments are not described, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the present application.

From the above description of the embodiments, it will be clear to those skilled in the art that the above-described embodiment method may be implemented by means of software plus a necessary general hardware platform, but of course may also be implemented by means of hardware, but in many cases the former is a preferred embodiment. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art in the form of a software product stored in a storage medium (e.g. ROM/RAM, magnetic disk, optical disk) as above, comprising several instructions for causing a terminal device (which may be a consumer or a network device, etc.) to perform the method of each embodiment of the present application.

The foregoing description is only of the preferred embodiments of the present application, and is not intended to limit the scope of the claims, and all equivalent structures or equivalent processes using the descriptions and drawings of the present application, or direct or indirect application in other related technical fields are included in the scope of the claims of the present application.

Claims

1. The pre-charge control method is characterized in that the pre-charge control method is applied to a battery, and the battery comprises a battery unit, a pre-charge unit, a discharge unit and a discharge port; the pre-charging unit and the discharging unit are connected between the battery unit and the discharging port; the pre-charge control method comprises the following steps:

controlling the battery unit to perform pre-charge and discharge through the pre-charge unit;

periodically acquiring a first voltage of the discharge port;

and controlling the pre-charge and discharge states of the battery cells according to the first voltage and the pre-charge time length corresponding to the first voltage.

2. The precharge control method according to claim 1, wherein the step of controlling the precharge state of the battery cell according to the first voltage and a precharge period corresponding to the first voltage includes:

Controlling the battery unit to finish a pre-charge and discharge state and discharging through the discharge unit in response to the pre-charge time being less than a preset pre-charge time and the ratio of the first voltage to the output voltage of the battery unit being greater than or equal to a first set threshold; or,

controlling the battery unit to enter a short circuit locking state in response to the pre-charge time length being greater than or equal to a preset pre-charge time length and the ratio of the first voltage to the output voltage of the battery unit being less than a second set threshold; wherein the second set threshold is less than the first set threshold; or,

responding to the fact that the pre-charging duration is equal to the preset pre-charging duration, the ratio of the first voltage to the output voltage of the battery unit is larger than or equal to the second set threshold value and smaller than the first set threshold value, the first voltage is monotonically increased, and when the pre-charging duration is larger than the preset pre-charging duration, the battery unit is controlled to end the pre-charging and discharging state, and discharging is conducted through the discharging unit; or,

and responding to the fact that the pre-charging time length is smaller than or equal to a preset pre-charging time length, the ratio of the first voltage to the output voltage of the battery unit is larger than or equal to the second set threshold value and smaller than the first set threshold value, the first voltage at the current moment is smaller than the first voltage at the last moment, and the battery unit is controlled to finish the pre-charging and discharging state at the current moment and is discharged through the discharging unit.

3. The precharge control method according to claim 2, wherein after controlling the battery cell to end the precharge and discharge state and discharge by the discharge cell, the precharge control method further comprises:

monitoring whether a short circuit event occurs in the discharge loop;

and in response to the occurrence of the short-circuit event, triggering short-circuit protection and controlling to disconnect the discharge unit.

4. A method of precharge control according to claim 3, wherein said step of monitoring the discharge circuit for the occurrence of a short circuit event comprises:

acquiring a discharge current in the discharge loop;

and determining that a short circuit event occurs in the discharge loop in response to the discharge current being greater than or equal to a preset short circuit current threshold for a duration not less than a preset short circuit duration.

5. The precharge control method according to claim 4, wherein after triggering a short-circuit protection in response to occurrence of a short-circuit event, controlling to turn off the discharge cell, the precharge control method further comprises:

accumulating the times of short circuit protection once;

in response to the short-circuit protection times being less than or equal to preset short-circuit protection times, re-controlling the battery unit to perform pre-charge and discharge through the pre-charge unit; or,

And controlling the battery unit to enter a short circuit locking state in response to the short circuit protection times being greater than the preset short circuit protection times.

6. The precharge control method according to claim 5, wherein after accumulating the number of times of short-circuit protection once, the precharge control method further comprises:

and adjusting the preset short-circuit current threshold value and/or the preset short-circuit time length.

7. The precharge control method according to any one of claims 2 to 6, wherein the discharge unit includes a first switch, the precharge unit includes a second switch, and the step of controlling the battery cell to end the precharge and discharge state and discharge by the discharge unit includes:

and controlling the second switch to be turned off and controlling the first switch to be turned on.

8. The precharge control method according to any one of claims 2 to 6, wherein the discharge unit includes a first switch, the precharge unit includes a second switch, and the step of controlling the battery cell to enter a short circuit lock state includes:

and controlling the first switch and the second switch to be turned off.

9. A battery, the battery comprising:

A battery unit;

a discharge port for connecting an external load;

the discharging unit comprises a first switch, and the pre-charging unit comprises a second switch and a pre-charging resistor;

the control unit is configured to control the battery unit to perform pre-charge and discharge through the pre-charge unit, periodically acquire the first voltage of the discharge port, and control the pre-charge and discharge state of the battery unit according to the first voltage and the pre-charge time corresponding to the first voltage.

10. A battery management system, characterized by comprising a storage unit storing a computer program and a processing unit implementing the precharge control method according to any one of claims 1 to 8 when the processing unit invokes the computer program.