Battery control method and device

Abstract

The present invention discloses a battery control method and device. The method includes: obtaining a first minimum cell voltage among the cell voltages corresponding to multiple batteries included in a battery pack; when the battery pack is in an undervoltage state, determining a target undervoltage level corresponding to the battery pack from multiple preset undervoltage levels based on the first minimum cell voltage; obtaining the current temperature, current state of charge, and current discharge power of the battery pack; determining a target discharge power of the battery pack based on the target undervoltage level, current temperature, and current state of charge; and adjusting the current discharge power of the battery pack to the target discharge power. The present invention solves the technical problem of frequent power loss in battery packs, which exists in related technologies.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and in particular to a battery control method and device. Background Art

[0002] With the widespread use of new energy vehicles, higher requirements are being placed on the estimation and control of the allowable discharge power of power batteries themselves. The method in the related art estimates the allowable discharge power of power batteries by combining the maximum and minimum temperatures of the battery pack with the SOC (State of Charge), which is highly dependent on the estimated SOC. However, when the SOC value is too high, the allowable discharge power estimated based on the SOC will be too high, causing the allowable discharge power of the power battery to exceed the actual discharge capacity of the power battery itself, causing the minimum power battery cell voltage to trigger over-discharge failure, resulting in a high frequency of power loss during driving.

[0003] To address the above-mentioned problems, no effective solutions have been proposed so far. Summary of the Invention

[0004] The embodiments of the present invention provide a battery control method and device to at least solve the technical problem of frequent power loss of a battery pack existing in the related art.

[0005] According to one aspect of an embodiment of the present invention, a battery control method is provided, comprising: obtaining a first minimum cell voltage among the cell voltages corresponding to a plurality of batteries included in a battery pack; when the battery pack is in an undervoltage state, determining a target undervoltage level corresponding to the battery pack from a plurality of preset undervoltage levels based on the first minimum cell voltage; obtaining a current temperature, a current state of charge, and a current discharge power of the battery pack; determining a target discharge power of the battery pack based on the target undervoltage level, the current temperature, and the current state of charge; and adjusting the current discharge power of the battery pack to the target discharge power.

[0006] According to another aspect of an embodiment of the present invention, a battery control device is provided, including: a voltage determination module for obtaining a first minimum cell voltage among the cell voltages corresponding to a plurality of batteries included in a battery pack; an undervoltage determination module for determining, when the battery pack is in an undervoltage state, a target undervoltage level corresponding to the battery pack from a plurality of preset undervoltage levels based on the first minimum cell voltage; an acquisition module for obtaining a current temperature, a current state of charge, and a current discharge power of the battery pack; a power determination module for determining a target discharge power of the battery pack based on the target undervoltage level, the current temperature, and the current state of charge; and an adjustment module for adjusting the current discharge power of the battery pack to the target discharge power.

[0007] In an embodiment of the present invention, a hierarchical control method is adopted. The method obtains the first minimum cell voltage among the cell voltages corresponding to the multiple batteries included in the battery pack; when the battery pack is in an undervoltage state, determines the target undervoltage level corresponding to the battery pack from multiple preset undervoltage levels based on the first minimum cell voltage; obtains the current temperature, current state of charge, and current discharge power of the battery pack; determines the target discharge power of the battery pack based on the target undervoltage level, the current temperature, and the current state of charge; and adjusts the current discharge power of the battery pack to the target discharge power. This achieves the purpose of hierarchical control of the battery pack, improves battery control accuracy, and reduces the frequency of power loss, thereby resolving the technical problem of frequent power loss in battery packs existing in related technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0009] Figure 1 is a flow chart of an optional battery control method provided according to an embodiment of the present invention;

[0010] Figure 2 is a flow chart of an optional battery control method provided according to an embodiment of the present invention;

[0011] Figure 3 A comparative diagram of an optional battery control method provided according to an embodiment of the present invention

[0012] Figure 4 is a schematic diagram of an optional battery control device provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0013] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0014] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0015] With the widespread use of new energy vehicles, higher requirements are being placed on the estimation and control of the allowable discharge power of the power battery itself. The current mainstream method is to estimate the allowable discharge power of the power battery by combining the maximum and minimum temperatures of the battery pack with the SOC. The solution disclosed in patent application number 201210317949.5 is highly dependent on the estimated results of the SOC. Since the SOC is a representation of the remaining battery capacity through calculation, it is difficult for the current mainstream calculation methods such as Kalman filtering to be very accurate. However, when the SOC value is too large, the allowable discharge power estimated based on the SOC will be too large. The allowable discharge power of the power battery will exceed the actual discharge capacity of the power battery itself. In the related art, when the power battery is under a continuous, dynamic high-power discharge condition, the minimum power battery cell voltage triggers over-discharge failure, which in turn triggers an undervoltage fault, resulting in power loss during driving.

[0016] In response to the above problems, an embodiment of the present invention provides a method embodiment of battery control. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0017] Figure 1 is a flow chart of a battery control method according to an embodiment of the present invention. Figure 1 As shown, the method includes the following steps:

[0018] Step S102, obtaining a first minimum cell voltage among cell voltages corresponding to a plurality of batteries included in the battery pack;

[0019] It is understood that a battery pack includes multiple batteries (also called single cells). When the battery pack is charging, due to differences in the internal resistance parameters of each single cell or different resistance voltage dividers of the connecting row, the single cell voltages corresponding to the multiple single cells are not exactly the same. Therefore, even if the total voltage of the battery pack is not undervoltage, the single cell voltage of multiple batteries may be too low, that is, the battery is over-discharged. To prevent damage to the battery pack due to over-discharge, it is necessary to determine the smallest single cell voltage among the single cell voltages corresponding to the multiple batteries in the battery pack as the first minimum single cell voltage.

[0020] In an optional embodiment, after obtaining the first minimum cell voltage among the cell voltages corresponding to the multiple batteries included in the battery pack, the method further includes: when the first minimum cell voltage is less than the voltage upper limit corresponding to any level among the multiple undervoltage levels, determining a first duration during which the first minimum cell voltage is less than the voltage upper limit of any level; determining a candidate undervoltage level among the multiple undervoltage levels in which the first minimum cell voltage is less than the corresponding voltage upper limit and greater than the corresponding voltage lower limit; determining a target duration corresponding to the candidate undervoltage level among the preset multi-level undervoltage durations, wherein the multi-level undervoltage durations correspond to the multiple undervoltage levels; and determining that the battery pack is in an undervoltage state when the first duration is greater than or equal to the target duration.

[0021] It can be understood that after determining the first minimum cell voltage, it is also necessary to determine whether the battery pack is undervoltage and the degree of undervoltage based on the first minimum cell voltage. In order to achieve refined control of the battery pack, the undervoltage level and the corresponding undervoltage duration are determined according to the size of the first minimum cell voltage. Since the first minimum cell voltage is less than the voltage upper limit corresponding to any level among the multiple undervoltage levels, it is considered that undervoltage may exist, and it is necessary to determine the first duration of the above situation. After determining the candidate undervoltage level in which the first minimum cell voltage is less than the corresponding voltage upper limit and greater than the corresponding voltage lower limit among the multiple undervoltage levels, and after determining the candidate undervoltage level corresponding to the battery pack among the multiple undervoltage levels, it is necessary to determine whether the battery pack is in an undervoltage state according to the corresponding target undervoltage duration. Through the above processing, a graded undervoltage countermeasure for the battery pack can be implemented.

[0022] It should be noted that when the battery output power is high, the battery voltage will drop. For example, when an electric vehicle is outputting high power, the battery voltage drops, which may cause the smallest single cell in the battery pack to directly trigger over-discharge protection, resulting in power loss. To avoid frequent power loss, whether to trigger over-discharge is determined based on the undervoltage level of the smallest single cell voltage and the duration of the undervoltage. For ease of understanding, let's use a specific example. For example, if the single cell voltage range is 2.65V (volts) to 3.6V, three undervoltage levels are set from least severe to most severe. The first undervoltage level is 2.55V to 2.6V, corresponding to the first undervoltage duration of 3s. The second undervoltage level is 2.45V to 2.55V, corresponding to the second undervoltage duration of 1s. The third undervoltage level is 2.3V to 2.45V, corresponding to the second undervoltage duration of 200ms. When the single cell voltage is 2.5V, it is in the second undervoltage level, and the first undervoltage duration of the single cell is 200ms. The battery pack is not in an undervoltage state, and there is no need to trigger undervoltage protection. When the first duration is 1 second or longer, it can be determined that the battery pack is in an undervoltage state.

[0023] Step S104, when the battery pack is in an undervoltage state, determining a target undervoltage level corresponding to the battery pack from a plurality of preset undervoltage levels based on the first minimum cell voltage;

[0024] It can be understood that when the battery pack is in an undervoltage state, the severity of the undervoltage is judged based on the first minimum cell voltage, and the target undervoltage level corresponding to the battery pack is determined.

[0025] Step S106, obtaining the current temperature, current state of charge, and current discharge power of the battery pack;

[0026] It can be understood that the current temperature, current state of charge, and current discharge power of the battery pack are obtained to determine whether the state of the battery pack requires undervoltage protection measures.

[0027] Step S108, determining a target discharge power of the battery pack based on the target undervoltage level, the current temperature, and the current state of charge;

[0028] It can be understood that the target discharge power of the battery pack is determined based on the target undervoltage level, current temperature, and current state of charge. This is because excessive discharge power will cause the voltage to drop to the point of battery over-discharge. The target discharge power is obtained to avoid power loss in the event of battery over-discharge.

[0029] In an optional embodiment, the target discharge power of the battery pack is determined based on the target undervoltage level, the current temperature, and the current state of charge, including: determining a predetermined undervoltage coefficient corresponding to the target undervoltage level; determining the current state of the battery pack based on the current temperature and the current state of charge; determining the instantaneous discharge power and the rated discharge power corresponding to the current state, wherein the instantaneous discharge power is the maximum discharge power allowed by the battery pack within a predetermined time; and determining the target discharge power based on the predetermined undervoltage coefficient, the instantaneous discharge power, and the rated discharge power.

[0030] It can be understood that the predetermined undervoltage coefficient corresponding to the target undervoltage level is determined. Based on the current temperature and the current state of charge, the current state of the battery pack is determined. This is to determine the instantaneous discharge power and rated discharge power corresponding to the current state. The instantaneous discharge power is the maximum discharge power allowed by the battery pack within a predetermined time. Generally speaking, the instantaneous discharge power will be greater than the rated discharge power. Based on the predetermined undervoltage coefficient, the instantaneous discharge power, and the rated discharge power, the target discharge power is determined. Through the above processing, the target discharge power for adjusting the battery power is determined based on the target undervoltage level, which is conducive to minimizing direct undervoltage protection and causing loss of power.

[0031] It should be noted that batteries, especially chemical batteries, are greatly affected by temperature due to their chemical properties. For example, lithium-ion batteries may not be able to discharge normally at low temperatures, and the power will drop significantly. This is because the ion exchange rate of battery components such as the electrolyte is reduced. Therefore, it is necessary to determine the current state of the battery pack based on the current temperature and the current state of charge. Determine the instantaneous discharge power and rated discharge power corresponding to the above current state. It should be noted that the above instantaneous discharge power can also be regarded as pulse discharge power, that is, the maximum output power allowed by the battery in a short time. However, if the instantaneous discharge power is used for output for a long time, it will damage the life of the battery. The above rated discharge power is the power that can be output for a long time at the current temperature and state of charge.

[0032] In an optional embodiment, the target discharge power is determined based on the predetermined undervoltage coefficient, the instantaneous discharge power, and the rated discharge power, including: determining a first discharge power based on the predetermined undervoltage coefficient and the instantaneous discharge power; and selecting the larger power value between the first discharge power and the rated discharge power as the target discharge power.

[0033] It can be understood that the first discharge power is calculated based on the predetermined undervoltage coefficient and the instantaneous discharge power, and the larger one between the first discharge power and the rated discharge power is selected as the target discharge power.

[0034] Optionally, the first discharge power may be of multiple types, for example, the product of a predetermined undervoltage coefficient and the instantaneous discharge power. The instantaneous discharge power may also be adjusted in stages according to the predetermined undervoltage coefficient, and so on.

[0035] Step S110 , adjusting the current discharge power of the battery pack to the target discharge power.

[0036] In an optional embodiment, the above-mentioned adjusting the current discharge power of the above-mentioned battery pack to the above-mentioned target discharge power includes: determining the target downward adjustment slope corresponding to the above-mentioned target undervoltage level, wherein the above-mentioned target downward adjustment slope is used to characterize the reduction rate of the battery pack power; and using the above-mentioned target downward adjustment slope to adjust the above-mentioned current discharge power to the above-mentioned target discharge power.

[0037] It can be understood that the grading countermeasures for the degree of undervoltage also include the speed of adjustment. When the undervoltage condition is not serious, the power can be slowly reduced, that is, the slope of the decline is relatively gentle, but if the undervoltage is serious and the power is about to be cut off, it is necessary to perform the reduction immediately, that is, the slope of the decline is very steep. Because it is necessary to determine the corresponding target reduction slope according to the target undervoltage level, the current discharge power is adjusted to the target discharge power according to the target reduction slope. Through the above processing, it is possible to achieve different power adjustment rates and more refined processing of undervoltage control.

[0038] In an optional embodiment, after adjusting the current discharge power of the battery pack to the target discharge power, the method further includes: obtaining the second minimum cell voltage among the cell voltages corresponding to the multiple batteries included in the battery pack; determining the power recovery threshold corresponding to the target undervoltage level; and determining whether to maintain control of the battery pack adjusted to the target discharge power based on the second minimum cell voltage and the power recovery threshold.

[0039] As you can understand, to prevent the cell voltage from dropping to undervoltage protection, the output power is limited and regulated to the target discharge power. After dropping to the target discharge power, the cell voltage may rebound, at which point it is necessary to determine whether to restore the battery's power output. The decision to maintain control of the battery pack at the target discharge power is made based on the second minimum cell voltage and the power recovery threshold. This process adaptively handles the dynamic changes in the battery pack, avoiding the problem of battery pack output rigidity caused by power control.

[0040] In an optional embodiment, the above-mentioned determination of whether to maintain the control of adjusting the above-mentioned battery pack to the above-mentioned target discharge power based on the above-mentioned second minimum cell voltage and the above-mentioned power recovery threshold includes: judging whether the above-mentioned second minimum cell voltage is greater than or equal to the above-mentioned power recovery threshold, wherein the above-mentioned power recovery threshold is greater than the above-mentioned first minimum cell voltage; if the above-mentioned second minimum cell voltage is greater than or equal to the above-mentioned power recovery threshold, determining the second duration during which the above-mentioned second minimum cell voltage is greater than or equal to the above-mentioned power recovery threshold; determining the preset target recovery duration corresponding to the above-mentioned target undervoltage level; and determining to release the control of maintaining the above-mentioned battery pack adjusted to the above-mentioned target discharge power when the above-mentioned second duration is greater than or equal to the above-mentioned target recovery duration.

[0041] It is understood that to avoid inappropriate power recovery caused by voltage fluctuations or fluctuations in the voltage acquisition signal, not only is it necessary for the second minimum cell voltage to be greater than or equal to the power recovery threshold (this is the voltage threshold for power recovery), but it is also necessary to determine the second duration of the second minimum cell voltage being greater than or equal to the power recovery threshold. The target recovery duration corresponding to the target undervoltage level is determined. If the second duration is greater than or equal to the target recovery duration, it is considered that the control of maintaining the battery pack adjusted to the target discharge power can be released.

[0042] In an optional embodiment, after the above determination to release the control of maintaining the battery pack adjusted to the above target discharge power, the above method further includes: determining the target upward slope corresponding to the above target undervoltage level, wherein the above target upward slope is used to characterize the increase rate of the battery pack power; at the sampling moment after the adjustment is released, determining the sampling state corresponding to the above battery pack and the instantaneous discharge power corresponding to the sampling state; and using the above target upward slope, adjusting the target discharge power to the instantaneous discharge power corresponding to the above sampling state.

[0043] It is understandable that after the power limit of the battery pack is released, the corresponding increase rate also needs to be adopted. Generally speaking, the more severe the undervoltage is, the slower the corresponding power increase rate is, and the worse the acceleration performance of the vehicle is, but it is beneficial to ensure that the power battery does not frequently report power failures due to undervoltage. Therefore, it is necessary to determine the target increase rate corresponding to the target undervoltage level. Since the instantaneous discharge power allowed by the battery pack is limited by temperature and state of charge, it is necessary to obtain the sampling time after the adjustment is released, determine the sampling state corresponding to the battery pack, and then determine the instantaneous discharge power corresponding to the sampling state. The target increase rate is used to adjust the target discharge power until the instantaneous discharge power corresponding to the sampling state is reached.

[0044] In an optional embodiment, after determining the target undervoltage level corresponding to the above-mentioned battery pack, the above-mentioned method also includes: when the voltage upper limit corresponding to the above-mentioned target undervoltage level is less than or equal to the preset cut-off threshold, the above-mentioned current discharge power of the above-mentioned battery pack is reset to zero.

[0045] It can be understood that when the voltage upper limit corresponding to the target undervoltage level is less than or equal to the preset cut-off threshold, it is considered that the undervoltage level of the battery pack is already very serious, which may cause damage to the battery pack. Continuing to output power will lead to safety hazards. It is considered that power must be cut off, and the current discharge of the battery pack is reset to zero to cut off the power output of the battery pack.

[0046] It should be noted that due to the characteristics of batteries, severe undervoltage can cause irreversible damage, potentially posing a safety hazard or even rendering the battery pack useless. These consequences are more serious than a loss of power output, and therefore require a power outage. It is generally believed that the battery in this situation has reached its capacity limit or has failed, and even if the cell voltage recovers, the fault cannot be cleared and automatically recovered.

[0047] In an optional embodiment, when the voltage upper limit corresponding to the target undervoltage level is less than or equal to the first undervoltage level, the first discharge power is determined based on the predetermined undervoltage coefficient and the instantaneous discharge power; and the larger power value between the first discharge power and the rated discharge power is selected as the target discharge power.

[0048] In an optional embodiment, after determining the instantaneous discharge power and rated discharge power corresponding to the current state, the method further includes: if the voltage upper limit corresponding to the target undervoltage level is less than or equal to the voltage upper limit corresponding to the second undervoltage level, then using the instantaneous discharge power as the target discharge power; if the voltage upper limit corresponding to the target undervoltage level is less than or equal to the voltage upper limit corresponding to the third undervoltage level, then using the preset protection discharge power as the target discharge power. The voltage upper limit corresponding to the first undervoltage level is greater than the voltage upper limit corresponding to the second undervoltage level, the voltage upper limit corresponding to the second undervoltage level is greater than the voltage upper limit corresponding to the third undervoltage level, and the protection discharge power is lower than either the instantaneous discharge power or the rated discharge power.

[0049] Through the above steps, the battery pack can be controlled in a hierarchical manner, the battery control accuracy can be improved, and the technical effect of reducing the frequency of power loss can be achieved, thereby solving the technical problem of frequent power loss of battery packs existing in related technologies.

[0050] Based on the above embodiments and optional embodiments, the present invention proposes an optional implementation method, the application scenario of which is to perform hierarchical undervoltage correction power control processing on the power battery of an electric vehicle. Figure 2FIG. 1 is a flow chart of an optional battery control method provided according to an embodiment of the present invention, and the following steps are described in detail.

[0051] Step S1: Obtain the voltage values ​​of all cells in the power battery and determine the minimum cell voltage value V of the power battery. min .

[0052] Step S2, determine the minimum cell voltage value V min Is it less than the preset undervoltage threshold set {V Q1 、V Q2 ,...V Q6}, the above judgment corresponds to Figure 2 Condition 1. Determine the minimum cell voltage value V min Less than the preset undervoltage threshold set {V Q1 、V Q2 ,...V Q6} Whether the duration of any value reaches the preset undervoltage protection time of each level {t Q1 , t Q2 ,...t Q6}, the above judgment corresponds to Figure 2 Condition 2 in the above table. Among them, the undervoltage thresholds of each level correspond to the undervoltage protection time of each level.

[0053] It should be noted that each level of undervoltage threshold can be set to different thresholds according to different temperature ranges. This specific implementation only takes the method of setting a voltage threshold as an example, that is, each level of undervoltage level only sets one undervoltage threshold in the entire temperature range. The preset first-level undervoltage threshold is V Q1 , preset secondary undervoltage threshold V Q2 , the first level of undervoltage is the lowest level, and then the levels increase step by step, and so on. In this embodiment, the preset V Q1 is about 3.0V, V Q3 This is the minimum value of the normal operating voltage range.

[0054] Step S3, determine the undervoltage level of the power battery. If both conditions 1 and 2 are met, it is determined that the power battery is in an undervoltage state. It is further necessary to determine which undervoltage level it is in and implement a power reduction strategy corresponding to the undervoltage level. Otherwise, the power battery maintains the current discharge power.

[0055] Figure 3 This is a comparison diagram of an optional battery control method provided by an embodiment of the present invention, which obtains the real-time temperature value T and real-time SOC value of the power battery. Figure 3 The allowable discharge power of the power battery is obtained, including the instantaneous discharge power (also known as pulse discharge power) P10s In this embodiment, the predetermined time is 10s, that is, P is allowed to be used within 10s. 10s Discharge output, and rated discharge power (i.e., the power that can be continuously discharged in the current state) P 持续 .in, Figure 3 The specific values ​​are for illustration only and are not limiting.

[0056] Step S4, execute the current undervoltage level processing mode, and use the downward adjustment slope K corresponding to the undervoltage level. Qi Reduce the power to the target discharge power and adjust the slope K downward Qi It is a negative value, 0>K Q1 ≥K Q2 ≥K Q3 ≥K Q4 ≥K Q5 ≥K Q6 , usually the slope K Qi The smoother it is, the less impact it has on the vehicle's drivability and power. i represents the undervoltage level. It should be noted that since it is a negative value, K Q6 Represents the slope compared to K Q5 Smoother, and so on, K Q1 The downward adjustment rate is the largest and steepest.

[0057] In the embodiment of the present invention, Table 1 is a schematic diagram of undervoltage levels, with a total of 6 undervoltage levels preset. Q1…… V Q6 is the undervoltage threshold from level 1 to level 6, t Q1…… t Q6 K is the duration of undervoltage protection from level 1 to level 6. Q1…… K Q6 Power reduction rate from level 1 to level 6, V H1…… V H5 The voltage recovery thresholds for levels 1 to 5 are 0, and t H1…… t H5 is the voltage recovery time from level 1 to level 5, and the sixth level recovery time is 0, K H1…… K H5 The power recovery rate is from level 1 to level 5, and the power recovery rate of level 6 is 0.

[0058] Table 1

[0059]

[0060] The first three undervoltage levels correspond to the power reduction processing mode, and the target discharge power is determined. The target discharge power is P 10s , P 持续 The largest one, namely Max(predetermined undervoltage coefficient*P 10s , P 持续The value range of the preset undervoltage coefficient is (0,1). The specific value is obtained based on the test calibration of the vehicle's power level. The preset undervoltage coefficient for each level can be different. The lower the undervoltage level, the higher the preset undervoltage coefficient, which minimizes the impact on vehicle power.

[0061] The fourth level of undervoltage is handled in a power reduction mode. There is no fault response and only DTC (Diagnostic Trouble Code) is recorded. The target discharge power is P 持续 .

[0062] The fifth level of undervoltage corresponds to a power reduction processing mode with a fault response. The fault response methods include lighting up the vehicle lights, prompting the driver, recording the DTC (fault code), and setting the target discharge power to a predetermined protective discharge power, such as 7kW (kilowatts).

[0063] The sixth level of undervoltage corresponds to a power reduction processing mode. The fault response methods include lighting up the vehicle lights, prompting the driver, recording the DTC (fault code), and adjusting the target discharge power to 0kW, that is, the power battery does not output power.

[0064] Step S5: When the discharge power is reduced to the target power, according to the battery discharge characteristics, the minimum cell voltage value V min There may be a rebound. Determine the minimum single cell voltage value V min Is it greater than the voltage recovery threshold corresponding to the current undervoltage level? The above judgment corresponds to Figure 2 Condition 3. Determine the minimum cell voltage value V min The duration greater than the current voltage recovery threshold is greater than the corresponding voltage recovery time t Hi The above judgment corresponds to Figure 2 Condition 4. The voltage recovery thresholds at each level correspond to the voltage recovery times at each level.

[0065] Each voltage recovery threshold can be set to different thresholds according to different temperature ranges. This specific embodiment only takes the method of setting a voltage threshold as an example, and each undervoltage level only sets one voltage recovery threshold in the full temperature range. The preset first-level voltage recovery threshold is V H1 , the preset secondary voltage recovery threshold V H2 , and so on. In the embodiment of the present invention, V is preset Hi =V Qi +0.3V, it can be understood that the i-th level voltage recovery threshold is 0.3V higher than the undervoltage threshold corresponding to the i-th level undervoltage level.

[0066] Step S6: When conditions 3 and 4 are met at the same time, the power battery triggers the voltage recovery power recovery mode, and the discharge power is at a slope K corresponding to the current undervoltage level. Hi Restore to permissible power P 10s , otherwise the power battery maintains the target discharge power.

[0067] Power recovery rate slope K Qi is a positive value, K h1 ≥K h2 ≥K h3 ≥K h4 ≥K h5 >0, usually the higher the undervoltage level, the higher the power recovery slope K hi The smaller it is, the worse the acceleration performance of the vehicle will be, but it can ensure that the power battery will not frequently undervoltage and interrupt the power failure.

[0068] It should be noted that the corresponding processing mode for the sixth level undervoltage level is due to the minimum single cell voltage value V min If the voltage is too low, vehicle manufacturers and battery manufacturers generally believe that the battery has reached its limit or a battery failure has occurred, and the driver cannot continue driving. The target discharge power drops to 0. Even if conditions three and four are met and the voltage is restored, the fault cannot be automatically cleared and the power recovery rate remains 0.

[0069] The above optional implementation method achieves at least the following effects: under a continuous, dynamic high-power discharge condition, the power battery reduces the frequent over-discharge failures triggered by the minimum power battery cell voltage, thereby solving the problem of frequent power loss during driving due to unnecessary undervoltage failures.

[0070] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0071] This embodiment also provides a battery control device for implementing the above-mentioned embodiments and preferred embodiments. Details already described will not be repeated. As used below, the terms "module" and "device" may refer to a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation using hardware, or a combination of software and hardware, is also possible and contemplated.

[0072] According to an embodiment of the present invention, there is also provided an embodiment of a device for implementing a battery control method. Figure 4 is a schematic diagram of a battery control device according to an embodiment of the present invention. Figure 4As shown, the battery control device includes: a voltage determination module 402, an undervoltage determination module 404, an acquisition module 406, a power determination module 408, and a regulation module 410. The device is described below.

[0073] The voltage determination module 402 is configured to obtain a first minimum cell voltage among cell voltages corresponding to a plurality of batteries included in the battery pack;

[0074] an undervoltage determination module 404, connected to the voltage determination module 402, for determining, when the battery pack is in an undervoltage state, a target undervoltage level corresponding to the battery pack from among a plurality of preset undervoltage levels based on the first minimum cell voltage;

[0075] an acquisition module 406 , connected to the undervoltage determination module 404 , configured to acquire the current temperature, current state of charge, and current discharge power of the battery pack;

[0076] a power determination module 408 , connected to the acquisition module 406 , configured to determine a target discharge power of the battery pack based on the target undervoltage level, the current temperature, and the current state of charge;

[0077] The regulating module 410 is connected to the power determining module 408 and is configured to regulate the current discharge power of the battery pack to the target discharge power.

[0078] In a battery control device provided by an embodiment of the present invention, a voltage determination module 402 is configured to obtain a first minimum cell voltage among the cell voltages corresponding to the multiple batteries included in the battery pack; an undervoltage determination module 404 is connected to the voltage determination module 402 and, when the battery pack is in an undervoltage state, determines a target undervoltage level corresponding to the battery pack from a plurality of preset undervoltage levels based on the first minimum cell voltage; an acquisition module 406 is connected to the undervoltage determination module 404 and configured to obtain the current temperature, current state of charge, and current discharge power of the battery pack; a power determination module 408 is connected to the acquisition module 406 and configured to determine a target discharge power of the battery pack based on the target undervoltage level, current temperature, and current state of charge; and an adjustment module 410 is connected to the power determination module 408 and configured to adjust the current discharge power of the battery pack to the target discharge power. This achieves the purpose of hierarchical control of the battery pack, improves battery control accuracy, and reduces the frequency of power loss, thereby resolving the technical problem of frequent power loss in battery packs existing in the related art.

[0079] It should be noted that the above modules can be implemented by software or hardware. For example, for the latter, it can be implemented in the following ways: the above modules can be located in the same processor; or the above modules can be located in different processors in any combination.

[0080] It should be noted that the voltage determination module 402, undervoltage determination module 404, acquisition module 406, power determination module 408, and adjustment module 410 described above correspond to steps S102 to S110 in the embodiment. The examples and application scenarios implemented by these modules and corresponding steps are the same, but are not limited to the contents disclosed in the above embodiment. It should be noted that the above modules, as part of the device, can be run in a computer terminal.

[0081] It should be noted that the optional or preferred implementation of this embodiment can be found in the relevant description in the embodiment, which will not be repeated here.

[0082] The above-mentioned battery control device may further include a processor and a memory, wherein the voltage determination module 402, the undervoltage determination module 404, the acquisition module 406, the power determination module 408, the adjustment module 410, etc. are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to implement corresponding functions.

[0083] The processor includes a kernel, which retrieves the corresponding program unit from memory. There can be one or more kernels. Memory may include non-permanent memory in a computer-readable medium, random access memory (RAM), and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory includes at least one memory chip.

[0084] An embodiment of the present invention provides a non-volatile storage medium on which a program is stored. When the program is executed by a processor, a battery control method is implemented.

[0085] An embodiment of the present invention provides an electronic device comprising a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, the following steps are implemented: obtaining a first minimum cell voltage among the cell voltages corresponding to a plurality of batteries included in a battery pack; when the battery pack is in an undervoltage state, determining a target undervoltage level corresponding to the battery pack from a plurality of preset undervoltage levels based on the first minimum cell voltage; obtaining the current temperature, current state of charge, and current discharge power of the battery pack; determining a target discharge power of the battery pack based on the target undervoltage level, the current temperature, and the current state of charge; and adjusting the current discharge power of the battery pack to the target discharge power. The device herein may be a server, a PC, or the like.

[0086] The present invention also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program initialized with the following method steps: obtaining a first minimum cell voltage among the cell voltages corresponding to a plurality of batteries included in a battery pack; when the battery pack is in an undervoltage state, determining a target undervoltage level corresponding to the battery pack from a plurality of preset undervoltage levels based on the first minimum cell voltage; obtaining the current temperature, current state of charge, and current discharge power of the battery pack; determining the target discharge power of the battery pack based on the target undervoltage level, the current temperature, and the current state of charge; and adjusting the current discharge power of the battery pack to the target discharge power.

[0087] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0088] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0089] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0090] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0091] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0092] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0093] Computer-readable media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0094] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0095] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0096] The above are merely embodiments of the present invention and are not intended to limit the present invention. It will be apparent to those skilled in the art that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are intended to be included within the scope of the claims of the present invention.

Claims

1. A battery control method, characterized in that: include: Obtaining a first minimum cell voltage among cell voltages corresponding to a plurality of batteries included in the battery pack; When the battery pack is in an undervoltage state, determining a target undervoltage level corresponding to the battery pack from a plurality of preset undervoltage levels based on the first minimum cell voltage; Obtaining the current temperature, current state of charge, and current discharge power of the battery pack; determining a target discharge power of the battery pack based on the target undervoltage level, the current temperature, and the current state of charge; adjusting the current discharge power of the battery pack to the target discharge power; Among them, determining the target discharge power of the battery pack based on the target undervoltage level, the current temperature, and the current state of charge includes: determining a predetermined undervoltage coefficient corresponding to the target undervoltage level; determining the current state of the battery pack based on the current temperature and the current state of charge; determining the instantaneous discharge power and rated discharge power corresponding to the current state, wherein the instantaneous discharge power is the maximum discharge power allowed by the battery pack within a predetermined time; determining a first discharge power based on the predetermined undervoltage coefficient and the instantaneous discharge power; and selecting the larger power value between the first discharge power and the rated discharge power as the target discharge power.

2. The method according to claim 1, characterized in that After obtaining the first minimum cell voltage among the cell voltages corresponding to the plurality of batteries included in the battery pack, the method further includes: When the first minimum cell voltage is less than a voltage upper limit corresponding to any level among the multiple undervoltage levels, determining a first duration during which the first minimum cell voltage is less than the voltage upper limit of any level; determining, from the plurality of undervoltage levels, a candidate undervoltage level in which the first minimum cell voltage is less than a corresponding voltage upper limit and greater than a corresponding voltage lower limit; Determining a target duration corresponding to the candidate undervoltage level from a preset multi-level undervoltage duration, wherein the multi-level undervoltage duration corresponds to the multiple undervoltage levels; When the first duration is greater than or equal to the target duration, it is determined that the battery pack is in an undervoltage state.

3. The method according to claim 1, characterized in that The adjusting the current discharge power of the battery pack to the target discharge power includes: Determining a target downward adjustment slope corresponding to the target undervoltage level, wherein the target downward adjustment slope is used to represent a downward adjustment rate of battery pack power; The target downward adjustment slope is adopted to adjust the current discharge power to the target discharge power.

4. The method according to any one of claims 1 to 3, characterized in that After adjusting the current discharge power of the battery pack to the target discharge power, the method further includes: Obtaining a second minimum cell voltage among cell voltages corresponding to a plurality of batteries included in the battery pack; Determining a power recovery threshold corresponding to the target undervoltage level; Based on the second minimum cell voltage and the power recovery threshold, it is determined whether to maintain control of the battery pack to adjust to the target discharge power.

5. The method according to claim 4, characterized in that The determining, based on the second minimum cell voltage and the power recovery threshold, whether to maintain control of adjusting the battery pack to the target discharge power includes: determining whether the second minimum cell voltage is greater than or equal to the power recovery threshold, wherein the power recovery threshold is greater than the first minimum cell voltage; If the second minimum cell voltage is greater than or equal to the power recovery threshold, determining a second duration of time during which the second minimum cell voltage is greater than or equal to the power recovery threshold; Determine a preset target recovery time corresponding to the target undervoltage level; When the second duration is greater than or equal to the target recovery duration, it is determined to release the control of maintaining the battery pack adjusted to the target discharge power.

6. The method according to claim 5, characterized in that After determining to release the control of maintaining the battery pack at the target discharge power, the method further includes: Determining a target upward slope corresponding to the target undervoltage level, wherein the target upward slope is used to represent an upward adjustment rate of battery pack power; At the sampling moment after the regulation is released, determining a sampling state corresponding to the battery pack and an instantaneous discharge power corresponding to the sampling state; The target increasing slope is used to adjust the target discharge power to the instantaneous discharge power corresponding to the sampling state.

7. The method according to any one of claims 1 to 3, characterized in that After determining the target undervoltage level corresponding to the battery pack, the method further includes: When the voltage upper limit corresponding to the target undervoltage level is less than or equal to a preset cut-off threshold, the current discharge power of the battery pack is reset to zero.

8. A battery control device, characterized in that: include: a voltage determination module, configured to obtain a first minimum cell voltage among cell voltages corresponding to a plurality of batteries included in the battery pack; an undervoltage determination module, configured to determine, when the battery pack is in an undervoltage state, a target undervoltage level corresponding to the battery pack from among a plurality of preset undervoltage levels based on the first minimum cell voltage; an acquisition module, configured to acquire the current temperature, current state of charge, and current discharge power of the battery pack; a power determination module, configured to determine a target discharge power of the battery pack based on the target undervoltage level, the current temperature, and the current state of charge; an adjusting module, configured to adjust the current discharge power of the battery pack to the target discharge power; Among them, the power determination module is also used to determine the predetermined undervoltage coefficient corresponding to the target undervoltage level; determine the current state of the battery pack based on the current temperature and the current state of charge; determine the instantaneous discharge power and rated discharge power corresponding to the current state, wherein the instantaneous discharge power is the maximum discharge power allowed by the battery pack within a predetermined time; determine the first discharge power based on the predetermined undervoltage coefficient and the instantaneous discharge power; select the larger power value between the first discharge power and the rated discharge power as the target discharge power.

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