DCR detection method and device, EMS, BMS and energy storage system

Abstract

The invention provides a DCR detection method and device, an EMS, a BMS and an energy storage system. The DCR of a battery pack can be effectively detected. The detection method is used for detecting the DCR of a battery pack, the battery pack is connected with a PCS, the detection method is executed by an energy management system, and the detection method comprises the following steps: controlling the PCS to charge and discharge the battery pack; wherein the information of the voltage and the current of the battery pack in the charging and discharging process is used for determining the target DCR of the battery pack.

Description

Technical Field

[0001] The present application relates to the field of batteries, and particularly to a method and device for detecting direct current resistance (DCR), an energy management system (EMS), a battery management system (BMS), and an energy storage system. Background Art

[0002] Energy storage systems usually have requirements such as high voltage and large capacity. Therefore, a large number of batteries are required in the energy storage system to be connected in series and parallel to form products such as electric cabinets or containers, and energy interaction with the power grid is carried out through a power conversion system (PCS). Each PCS can be connected to multiple battery packs, and multiple battery packs are connected in parallel to the power grid through the PCS. The current difference in each branch is caused by the difference in DCR of the battery packs on the parallel branches, which further causes the current imbalance between multiple paralleled containers, increasing the overcurrent risk of the battery packs. Therefore, it is necessary to detect the DCR of the battery packs. How to effectively detect the DCR of the batteries has become an urgent problem to be solved. Summary of the Invention

[0003] Embodiments of the present application provide a method and device for detecting DCR, an EMS, a BMS, and an energy storage system, which can effectively detect the DCR of a battery pack.

[0004] In a first aspect, a method for detecting DCR is provided for detecting the DCR of a battery pack, where the battery pack is connected to a PCS. The detection method includes: controlling the PCS to charge and discharge the battery pack; determining the target DCR of the battery pack according to the voltage and current information of the battery pack.

[0005] This method is executed by the EMS, for example.

[0006] In the embodiments of the present application, by controlling the PCS to charge and discharge the battery pack and using the voltage and current information of the battery pack during the charge and discharge process, the DCR of the battery pack can be dynamically obtained.

[0007] In some possible implementation manners, the target DCR is determined according to the current of the battery pack and the change amount of the voltage of the battery pack within a target duration.

[0008] Within the target duration, by controlling the PCS to charge and discharge the battery pack and according to the current of the battery pack and the change amount of the voltage of the battery pack within the target duration, the DCR of the battery pack can be effectively calculated, realizing the on-line test of the DCR of the battery pack.

[0009] For example, the target DCR is the ratio of the change amount of the voltage of the battery pack within the target duration to the current of the battery pack.

[0010] In some possible implementations, controlling the PCS to charge and discharge the battery pack includes: when the battery pack is in a static state, controlling the PCS to charge and discharge the battery pack.

[0011] When there is no charge and discharge demand from the power grid, that is, when the battery pack is in a static state, controlling the PCS to charge and discharge the battery pack to perform DCR detection can reduce the impact of DCR detection on the ongoing charge and discharge process between the power grid and the battery pack.

[0012] In some possible implementations, when the battery pack is in a static state, controlling the PCS to charge and discharge the battery pack includes: determining whether the duration of the battery pack in the static state is greater than or equal to the target duration; when the duration of the battery pack in the static state is greater than or equal to the target duration, controlling the PCS to charge and discharge the battery pack.

[0013] Reserving a sufficient duration, i.e., the target duration, for detecting the DCR of the battery pack can reduce the situation of DCR detection interruption caused by the suddenly started charge and discharge process between the power grid and the battery pack.

[0014] For example, determining whether the duration of the battery pack in the static state is greater than or equal to the target duration includes: obtaining a display interface; in response to a user's operation on the display interface, determining whether the duration of the battery pack in the static state is greater than or equal to the target duration.

[0015] In some possible implementations, the detection method further includes: receiving information on the target duration sent by the battery management system of the battery pack, where the target duration is determined according to state parameters of the battery pack, and the state parameters include at least one of the SOC, SOH, and temperature of the battery pack.

[0016] According to at least one of the state parameters of the battery pack, such as SOC, SOH, and temperature, etc., the DCR of the battery pack under this state parameter can be detected more accurately, improving the accuracy of the detection result.

[0017] In some possible implementations, the detection method further includes: obtaining the historical DCR of the battery pack, where the historical DCR includes the initial DCR of the battery pack and / or the DCR of the battery pack detected within a historical time; correcting the target DCR according to the historical DCR to obtain the corrected DCR of the battery pack.

[0018] Combining the historical DCR data of the battery pack to correct the online detected DCR can improve the accuracy of DCR detection.

[0019] In a second aspect, a method for detecting the DCR of a battery pack is provided, which is used to detect the DCR of the battery pack. The battery pack is connected to a PCS. The detection method includes: during the process of the EMS controlling the PCS to charge and discharge the battery pack, obtaining the voltage and current information of the battery pack; determining the target DCR of the battery pack according to the voltage and current information of the battery pack.

[0020] This method is executed by the BMS of the battery pack, for example.

[0021] In the embodiments of the present application, by controlling the PCS to charge and discharge the battery pack and using the voltage and current information of the battery pack during the charge and discharge process, the DCR of the battery pack can be dynamically obtained.

[0022] In some possible implementation manners, determining the target DCR of the battery pack according to the voltage information and current information of the battery pack includes: determining the target DCR according to the current of the battery pack and the change amount of the voltage of the battery pack within a target time period.

[0023] Within the target time period, by controlling the PCS to charge and discharge the battery pack and according to the current of the battery pack and the change amount of the voltage of the battery pack within the target time period, the DCR of the battery pack can be effectively calculated, and the online test of the DCR of the battery pack can be realized.

[0024] For example, determining the target DCR according to the current of the battery pack and the change amount of the voltage of the battery pack within a target time period includes: determining the ratio between the change amount of the voltage of the battery pack within the target time period and the current of the battery pack as the target DCR of the battery pack.

[0025] In some possible implementation manners, the detection method further includes: determining the target time period according to the state parameters of the battery pack, where the state parameters include at least one of the SOC, SOH, and temperature of the battery pack.

[0026] According to at least one of the state parameters of the battery pack, such as SOC, SOH, and temperature, etc., the DCR of the battery pack under this state parameter can be detected more accurately, and the accuracy of the detection result can be improved.

[0027] In some possible implementation manners, determining the target time period according to the state parameters of the battery pack includes: when the battery pack is in a stationary state, determining the target time period according to the state parameters of the battery pack.

[0028] When there is no charge and discharge demand in the power grid, that is, when the battery pack is in a static state, controlling the PCS to charge and discharge the battery pack to detect DCR can reduce the impact of DCR detection on the ongoing charge and discharge process between the power grid and the battery pack.

[0029] In some possible implementation manners, the detection method further includes: sending information of the target duration to an energy management system, so that the energy management system determines whether the duration of the battery pack in the static state is greater than or equal to the target duration; when the duration of the battery pack in the static state is greater than or equal to the target duration, determining the target DCR of the battery pack according to information of the voltage and current of the battery pack.

[0030] Reserving a sufficient duration, that is, the target duration, to detect the DCR of the battery pack can reduce the situation of DCR detection interruption caused by a suddenly started charge and discharge process between the power grid and the battery pack.

[0031] In some possible implementation manners, the detection method further includes: obtaining the historical DCR of the battery pack, where the historical DCR includes the initial DCR of the battery pack and / or the DCR of the battery pack detected within a historical time; correcting the target DCR according to the historical DCR to obtain the corrected DCR of the battery pack.

[0032] Combining the historical DCR data of the battery pack to correct the online detected DCR can improve the accuracy of DCR detection.

[0033] In a third aspect, a DCR detection device is provided for detecting the DCR of a battery pack, where the battery pack is connected to a PCS, and the detection device includes: a charge and discharge module for controlling the PCS to charge and discharge the battery pack; where information of the voltage and current of the battery pack during the charge and discharge process is used for the BMS to determine the target DCR of the battery pack.

[0034] The detection device can be applied to an EMS, for example.

[0035] In some possible implementation manners, the target DCR is determined according to the current of the battery pack and the change amount of the voltage of the battery pack within the target duration.

[0036] In some possible implementation manners, the target DCR is the ratio of the change amount of the voltage of the battery pack within the target duration to the current of the battery pack.

[0037] In some possible implementation manners, the charge and discharge module is specifically configured to control the PCS to charge and discharge the battery pack when the battery pack is in a static state.

[0038] In some possible implementation manners, the charge and discharge module is specifically configured to determine whether the duration for which the battery pack is in a stationary state is greater than or equal to the target duration; and in the case where the duration for which the battery pack is in a stationary state is greater than or equal to the target duration, control the PCS to charge and discharge the battery pack.

[0039] In some possible implementation manners, the detection device further includes a processing module, and the processing module is configured to obtain a display interface; and in response to an operation of a user on the display interface, determine whether the duration for which the battery pack is in a stationary state is greater than or equal to the target duration.

[0040] In some possible implementation manners, the detection device further includes a transceiver module, and the transceiver module is configured to receive information about the target duration sent by the battery management system of the battery pack, where the target duration is determined according to state parameters of the battery pack, and the state parameters include at least one of the SOC, SOH, and temperature of the battery pack.

[0041] In some possible implementation manners, the processing module is further configured to: obtain the historical DCR of the battery pack, where the historical DCR includes the initial DCR of the battery pack and / or the DCR of the battery pack detected within a historical time; and correct the target DCR according to the historical DCR to obtain the corrected DCR of the battery pack.

[0042] In a fourth aspect, a DCR detection device is provided for detecting the DCR of a battery pack, where the battery pack is connected to a PCS, and the detection device includes: an acquisition module configured to obtain information about the voltage and current of the battery pack during the process of the EMS controlling the PCS to charge and discharge the battery pack; and a processing module configured to determine the target DCR of the battery pack according to the information about the voltage and current of the battery pack.

[0043] The detection device can be applied to, for example, a BMS.

[0044] In some possible implementation manners, the processing module is specifically configured to determine the target DCR according to the current of the battery pack and the change amount of the voltage of the battery pack within the target duration.

[0045] In some possible implementation manners, the processing module is specifically configured to determine the ratio between the change amount of the voltage of the battery pack within the target duration and the current of the battery pack as the target DCR of the battery pack.

[0046] In some possible implementation manners, the processing module is further configured to determine the target duration according to the state parameters of the battery pack, where the state parameters include at least one of the state of charge (SOC), state of health (SOH), and temperature of the battery pack.

[0047] In some possible implementation manners, the processing module is specifically configured to determine the target duration according to the state parameters of the battery pack when the battery pack is in a static state.

[0048] In some possible implementation manners, the detection device further includes a transceiver module, configured to send the information of the target duration to an energy management system, so that the energy management system determines whether the duration of the battery pack in the static state is greater than or equal to the target duration; the processing module is specifically configured to determine the target DC resistance (DCR) of the battery pack according to the information of the voltage and current of the battery pack when the duration of the battery pack in the static state is greater than or equal to the target duration.

[0049] In some possible implementation manners, the processing module is further configured to obtain the historical DCR of the battery pack, where the historical DCR includes the initial DCR of the battery pack and / or the DCR of the battery pack detected during the historical time; correct the target DCR according to the historical DCR to obtain the corrected DCR of the battery pack.

[0050] In a fifth aspect, an energy management system (EMS) is provided, including a memory and a processor, where the memory is configured to store instructions, and the processor is configured to read the instructions and execute the DCR detection method according to the first aspect or any possible implementation manner of the first aspect based on the instructions.

[0051] In a sixth aspect, a battery management system (BMS) is provided, including a memory and a processor, where the memory is configured to store instructions, and the processor is configured to read the instructions and execute the DCR detection method according to the second aspect or any possible implementation manner of the second aspect based on the instructions.

[0052] In a seventh aspect, an energy storage system is provided, including: a plurality of battery packs connected in parallel; the EMS according to the fifth aspect or any possible implementation manner of the fifth aspect; the BMS according to the sixth aspect or any possible implementation manner of the sixth aspect; and a power conversion system (PCS) connected between the plurality of battery packs and the power grid. Description of the Drawings

[0053] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments of the present application. Obviously, the following described drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the drawings.

[0054] Figure 1 It is a schematic diagram of a possible energy storage system according to an embodiment of the present application.

[0055] Figure 2 It is a schematic flowchart of a method for detecting DCR according to an embodiment of the present application.

[0056] Figure 3 It is a schematic flowchart of a method for detecting DCR according to another embodiment of the present application.

[0057] Figure 4 It is a schematic diagram of the architecture of an energy storage system according to an embodiment of the present application.

[0058] Figure 5 It is a schematic diagram of the principle of DCR calculation according to an embodiment of the present application.

[0059] Figure 6 It is a process interaction diagram of a method for detecting DCR according to an embodiment of the present application.

[0060] Figure 7 It is a schematic flowchart of a possible test method for the initial DCR of a battery cell.

[0061] Figure 8 is Figure 2 and 3 A flowchart of a possible specific implementation manner of the method for detecting DCR shown in

[0062] Figure 9 It is a schematic block diagram of a device for detecting DCR according to an embodiment of the present application.

[0063] Figure 10 It is a schematic block diagram of a device for detecting DCR according to another embodiment of the present application.

[0064] Figure 11 It is a schematic block diagram of the EMS according to an embodiment of the present application.

[0065] Figure 12 It is a schematic block diagram of the BMS according to an embodiment of the present application. Detailed implementation manners

[0066] The following further describes in detail the implementation manners of the present application in conjunction with the accompanying drawings and embodiments. The detailed descriptions and drawings of the following embodiments are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0067] Since energy storage systems usually have requirements such as high voltage and large capacity, a large number of batteries are required in the energy storage system to be connected in series and parallel to form products such as electrical cabinets or containers, and energy interaction is carried out with the power grid through a power control system (PCS). Among them, the PCS is used to realize the conversion between the AC signal of the power grid and the DC signal of the energy storage system.

[0068] As an example, as Figure 1 shown, each PCS can be connected to one or more battery packs, and multiple battery packs are connected in parallel to the power grid through the PCS, so as to charge or discharge with the power grid. The battery pack can be, for example, a battery product such as an electrical cabinet or a container. The electrical cabinet can be regarded as a battery product formed by battery clusters. Therefore, the electrical cabinet described in the embodiments of the present application can also be called a battery cluster, and multiple electrical cabinets can be assembled to form battery products such as containers. Each battery cluster includes a plurality of electrical boxes connected in series and / or in parallel, and each electrical box includes a plurality of battery cells connected in series and / or in parallel.

[0069] During the production process of battery cells, their DCR is affected by various factors, resulting in differences in DCR among different battery cells, and further resulting in large differences in the DCR of battery products such as electrical cabinets or containers formed by assembling battery cells. After the battery pack is connected in parallel to the power grid through the PCS, the difference in DCR of the battery packs on the parallel branches causes current differences in each branch, and further causes uneven current sharing among the multiple parallel-connected battery packs. Therefore, it is necessary to detect the DCR of the battery pack.

[0070] For this reason, the present application provides a DCR detection solution, which controls the PCS to charge and discharge the battery pack, and uses the voltage and current information of the battery pack during the charge and discharge process to obtain the DCR of the battery pack.

[0071] Figure 2 and Figure 3 shows the DCR detection method of the embodiments of the present application. This method is used to detect the DCR of the battery pack, and the battery pack is connected to the PCS. Among them, Figure 2 the DCR detection method 100 shown can be executed by, for example, an energy management system (EMS), etc. Figure 3The DCR detection method 200 shown, for example, can be executed by a battery management system (BMS) of a battery pack. Of course, where possible, the BMS can execute some of the operations performed by the EMS below, and the EMS can also execute some of the operations performed by the BMS below.

[0072] As Figure 2 shown, the DCR detection method 100 of the embodiments of the present application may include some or all of the following steps.

[0073] In step 110, the EMS determines to detect the DCR of the battery pack.

[0074] In step 120, the EMS controls the PCS connected to the battery pack to charge and discharge the battery pack.

[0075] The charge and discharge here may mean that the power grid charges the battery pack through the PCS, or the battery pack discharges to the power grid through the PCS.

[0076] For example, when the EMS determines to detect the DCR of the battery pack, it controls the PCS connected to the battery pack to charge and discharge the battery pack. Among them, the voltage and current information of the battery pack during the charge and discharge process is used to determine the target DCR of the battery pack.

[0077] As Figure 3 shown, the DCR detection method 200 of the embodiments of the present application may include some or all of the following steps.

[0078] In step 210, during the process of the EMS controlling the PCS to charge and discharge the battery pack, the BMS obtains the voltage and current information of the battery pack.

[0079] In step 220, the BMS determines the target DCR of the battery pack according to the voltage and current information of the battery pack.

[0080] For example, during the process of the PCS charging and discharging the battery pack, the BMS collects the voltage and current information of the battery pack, and determines the target DCR of the battery pack according to the voltage and current information of the battery pack. Optionally, the EMS can issue an instruction to instruct the BMS to collect voltage and current and calculate DCR.

[0081] In this way, by controlling the PCS to charge and discharge the battery pack and using the voltage and current information of the battery pack during the charge and discharge process, the DCR of the battery pack can be dynamically obtained.

[0082] The PCS serves as a medium between the alternating current (AC) side connected to the power grid and the direct current (DC) side of the battery pack. For example, it may include a bidirectional AC / DC converter. As an example, as Figure 4 shown in the architecture of the energy storage system, battery pack 1, battery pack 2, ……, battery pack n are respectively connected to the PCS through corresponding power units 1, power unit 2, ……, power unit n. The power units include, for example, switches, etc., to achieve the cut-in and cut-out of the DC side, and the BMS, PCS, and EMS are used to mobilize and control the energy of the entire system. In addition, other modules such as a display module can be configured to achieve corresponding functions. In the embodiments of the present application, by controlling the PCS to charge and discharge the battery pack, that is, the battery pack is charged and discharged through the PCS during corresponding periods in the actual use process, such as idle periods, and by using the information of the voltage and current of the battery pack during the charge and discharge process, the online detection of DCR can be achieved. Optionally, the detection result of DCR can also be uploaded to a local database or a cloud server through communication methods such as WIFI, Bluetooth, 4G, and 5G to store and update the DCR of the battery pack.

[0083] The battery pack in the embodiments of the present application can be, for example, an electric box, an electric cabinet, or a container, etc., or other parallel units connected to the power grid in parallel through the PCS. The DCR of these battery packs can all be detected online through the DCR detection method 100 of the embodiments of the present application.

[0084] In some embodiments, in step 220, the BMS can determine the target DCR of the battery pack according to the current of the battery pack and the change amount of the voltage of the battery pack within the target duration. For example, the BMS can determine the ratio between the change amount of the voltage of the battery pack within the target duration and the current of the battery pack as the target DCR of the battery pack.

[0085] Among them, the target duration is used to detect the DCR of the battery pack. For example, it can be the duration for the PCS to charge and discharge the battery pack. Within this target duration, by charging and discharging the battery pack through the PCS and according to the current of the battery pack and the change amount of the voltage of the battery pack within the target duration, the DCR of the battery pack can be effectively calculated, and the online test of the DCR of the battery pack can be achieved.

[0086] For example, as Figure 5As shown, the EMS controls the PCS to charge or discharge the battery pack. Taking the charging of the battery pack as an example, the PCS charges the battery pack with a current I for a target duration ΔT. The voltage of the battery pack at the start of charging is U0, and the voltage of the battery pack after reaching the target duration ΔT is U. The change in voltage ΔU of the battery pack within the target duration ΔT is ΔU = U - U0. According to the change in voltage ΔU and the current I, the target DCR of the battery pack is determined as ΔU / I = (U - U0) / I.

[0087] Since the embodiments of the present application need to charge or discharge the battery pack through the PCS for a target duration, in some embodiments, in step 120, it is necessary to control the PCS to charge and discharge the battery pack when the battery pack is in a static state.

[0088] The battery pack is in a static state, or in a static working condition, that is, there is no need for charge and discharge between the power grid and the battery pack. At this time, the PCS is controlled to charge and discharge the battery pack to detect the DCR. In this way, it is possible not to affect the normal charge and discharge process of the battery pack to meet the power grid demand, and reduce the impact of DCR detection on the ongoing charge and discharge process between the power grid and the battery pack.

[0089] Optionally, in step 110, the EMS can determine whether the static duration of the battery pack, that is, the duration when the battery pack is in a static state, is greater than or equal to the target duration, and determine to detect the DCR of the battery pack when the duration when the battery pack is in a static state is greater than or equal to the target duration.

[0090] That is to say, in step 120, when the duration when the battery pack is in a static state is greater than or equal to the target duration, the EMS controls the PCS to charge and discharge the battery pack.

[0091] Since it is necessary to utilize the change in voltage of the battery pack within the target duration and sufficient duration, that is, the target duration, needs to be reserved to detect the DCR of the battery pack, before performing DCR detection, it is necessary to determine whether the duration during which the battery pack can be in a static state is greater than or equal to the target duration, so as to utilize the PCS to detect the DCR of the battery pack, thereby reducing the situation of DCR detection interruption caused by the suddenly started charge and discharge process between the power grid and the battery pack.

[0092] In some embodiments, the BMS can determine the target duration according to the state parameters of the battery pack. Among them, the state parameters include, for example, at least one of the SOC, SOH, and temperature of the battery pack. In this way, it is possible to more accurately detect the DCR of the battery pack under the state parameters, and improve the accuracy of the detection results.

[0093] Among them, SOC can, for example, represent the ratio between the current remaining capacity of the battery and its maximum capacity or rated capacity; SOH can, for example, represent the percentage of the battery's capacity to its factory capacity, which is used to measure the aging state of the battery, that is, the degree of performance degradation of the battery during use.

[0094] Generally, the target duration can be set within 1 minute, for example. Optionally, the target duration can be determined according to the SOC, SOH of the battery pack, and the current temperature of the battery pack, etc. For example, for a battery pack at 25°C, with an SOC of 25% and a BCL SOH, the battery pack is discharged for 30 seconds through the PCS, and the DCR of the battery pack is determined according to the ratio between the change in the voltage of the battery pack within 30 seconds of discharge and the discharge current of the battery pack; for another example, for a battery pack at 25°C, with an SOC of 25% and an EOL SOH of 70%, the battery pack is discharged for 30 seconds through the PCS, and the DCR of the battery pack is determined according to the ratio between the change in the voltage of the battery pack within 30 seconds of discharge and the discharge current of the battery pack. Generally, the DCR of a battery pack with a BOL SOH of 100% is less than that of a battery pack with an EOL SOH of 70%. For the battery packs with the above state parameters, their DCR is approximately at the milliohm level.

[0095] Optionally, the BMS can determine the target duration when the battery pack is in a static state and send the target duration to the EMS. Correspondingly, the EMS receives the target duration sent by the BMS and determines whether the duration of the battery pack in the static state is greater than or equal to the target duration, and then judges whether to perform DCR detection on the battery pack.

[0096] For example, as Figure 6 shown in the process interaction diagram between the EMS and the BMS.

[0097] In step 201, the BMS determines the target duration for DCR detection.

[0098] For example, the target duration is determined according to the current state parameters of the battery pack such as SOC, SOH, and temperature, etc. Or directly use a pre-set target duration.

[0099] In step 202, the BMS sends the target duration to the EMS.

[0100] In step 203, the EMS receives the target duration.

[0101] In step 204, the EMS determines whether the duration of the battery pack in the static state is greater than or equal to the target duration.

[0102] In step 205, when the duration for which the battery pack is in a stationary state is greater than or equal to the target duration, the EMS controls the PCS to charge and discharge the battery pack.

[0103] In step 206, during the process of the PCS charging and discharging the battery pack, the BMS acquires information on the voltage and current of the battery pack.

[0104] In step 207, the BMS determines the target DCR of the battery pack based on the information on the voltage and current of the battery pack.

[0105] It can be understood that the EMS determines whether the duration for which the battery pack is in a stationary state is greater than or equal to the target duration to ensure that the battery pack can be stationary for a sufficient duration for DCR detection, and the sufficient duration should be greater than or equal to the target duration.

[0106] Specifically, when the EMS determines that the battery pack is in a stationary state, the BMS determines the target duration required for DCR detection. The BMS sends the information on the target duration to the EMS so that the EMS can determine whether there is a need for charging and discharging in the power grid within the target duration. If the EMS determines or the user determines that there is no need for charging and discharging in the power grid within the target duration, the test condition is met, and the DCR of the battery pack can be detected based on the above method. That is to say, first, it is judged whether there is sufficient time for detecting the DCR of the battery pack to reduce the occurrence of the situation where the DCR test process is forced to charge and discharge by the power grid. If there is sufficient time for testing the DCR of the battery pack, the DCR is detected within the predetermined time. At this time, the EMS can control the PCS to charge or discharge the battery pack with a certain current. During this process, the BMS detects the change amount of the voltage and the current of the battery pack within the target duration and calculates the DCR of the battery pack based on the voltage change amount and the current.

[0107] In the embodiment of the present application, the EMS can determine whether the duration for which the battery pack is in a stationary state is greater than the target duration in the following two ways. On the one hand, the EMS can judge whether there is a need for charging and discharging in the power grid within the target duration; or, on the other hand, the EMS can provide the target duration to the user through, for example, a human-computer interaction system, etc., and the user can confirm it. For example, the EMS can acquire a display interface, and in response to the operation of the user on the display interface, determine whether the duration for which the battery pack is in a stationary state is greater than or equal to the target duration. The user can inform the EMS whether the battery pack can currently be stationary for more than the target duration by performing corresponding operations on the display interface, such as determining or canceling, etc.

[0108] In some embodiments, the detection method 100 or the detection method 200 may further include: obtaining the historical DCR of the battery pack; correcting the target DCR of the battery pack obtained in the above steps according to the historical DCR of the battery pack to obtain the corrected DCR of the battery pack.

[0109] That is to say, the historical DCR data of the battery pack can also be combined to correct the online-detected DCR, which can improve the accuracy of DCR detection.

[0110] If the historical DCR of the battery pack is not stored in the database or cloud platform, then the target DCR of the battery pack can be used as the final detection result, for example, as a judgment condition for uneven current flow, etc. If the historical DCR of the battery pack is stored in the database or cloud platform, then corresponding data processing can be performed according to the historical DCR data and the target DCR to obtain the updated DCR as the final detection result, for example, as a judgment condition for uneven current flow, etc.

[0111] Combined with the historical DCR, it can effectively judge whether the target DCR obtained by online detection has abnormal conditions such as outliers, so that when the target DCR deviates from the normal range due to environmental factors or factors such as forced charge and discharge of the power grid, it can be discovered in time. Or, the target DCR can be adjusted according to the change trend of the historical DCR to make up for the influence of factors such as the use and environment of the battery pack on the DCR.

[0112] The historical DCR includes the initial DCR of the battery pack and / or the DCR of the battery pack detected within the historical time. The DCR of the battery pack detected within the historical time can be, for example, the target DCR of the battery pack detected by charging and discharging the battery pack using the PCS within the historical time. The initial DCR of the battery pack can be calculated according to the initial DCRs of each battery cell in the battery pack. Among them, the initial DCR of the battery cell can be the DCR obtained by the battery cell passing through the DCR test process on the production line.

[0113] As an example, as Figure 7 shown, a possible test method for the initial DCR of the battery cell. The initial DCR of the battery cell usually refers to the DCR obtained by testing the battery cell on the production line. As Figure 7 shown, the battery cells on the production line usually need to go through processes such as formation, aging, measuring the coefficient K at room temperature, DCR test and capacity test, and DCR grouping. Among them, in the DCR test process, the battery cell with a certain SOC can be charged for a certain period of time, for example, the battery cell can be charged at a constant current for 30 s when the SOC of the battery cell is 20%, and based on a principle similar to Figure 5 to calculate the DCR of the battery cell, and this DCR can be used as the initial DCR of the battery cell.

[0114] Figure 8 This is a possible specific implementation of the DCR detection method according to an embodiment of the present application. Figure 8 The method shown can be executed by the EMS and the BMS.

[0115] As Figure 8 shown, in step 1001, the EMS pre-judges whether the battery pack is in a static state.

[0116] In step 1002, when the battery pack is in a static state, the BMS determines the target duration ΔT for detecting the DCR.

[0117] In step 1003, the BMS sends the target duration ΔT to the EMS, and after it is confirmed by the EMS or the user that the duration of the battery pack in the static state is greater than the target duration, the DCR detection starts.

[0118] In step 1004, the EMS controls the PCS to charge and discharge the battery pack at a certain charge and discharge rate.

[0119] In step 1005, the BMS detects the voltage change amount ΔU and the current I of the battery pack within the target duration ΔT, and calculates the target DCR.

[0120] For example, the target DCR = ΔU / I.

[0121] In step 1006, the BMS uploads the target DCR to the EMS.

[0122] In step 1007, the EMS determines whether there is a historical DCR of the battery pack in the database.

[0123] If the target DCR of the battery pack is not stored in the database, step 1008 is executed; if the target DCR of the battery pack is stored in the database, step 1009 is executed.

[0124] In step 1008, it is determined that the detection result is the target DCR.

[0125] The BMS can use the target DCR as the final detection result, for example, as a judgment condition for uneven current distribution, etc.

[0126] In step 1009, the target DCR is processed according to the historical DCR of the battery pack to obtain the corrected DCR.

[0127] In step 1010, the EMS determines that the detection result is the corrected DCR, and can feedback the corrected DCR to the BMS.

[0128] The BMS can use the corrected DCR as the final detection result, for example, as a judgment condition for uneven current distribution, etc.

[0129] It can be seen that during the actual application process of the battery, during the idle time when there is no charging or discharging demand from the power grid, the PCS is used to charge and discharge the battery pack, and based on the information of the voltage and current of the battery pack during the charging and discharging process, the target DCR of the battery pack is determined, and the target DCR can be processed in combination with historical DCR data to obtain the corrected DCR, thus accurately realizing the online detection of DCR.

[0130] The above has described in detail the method for detecting DCR of the embodiments of the present application. Next, in combination with Figure 9 and Figure 10 the detection device for DCR of the embodiments of the present application will be described in detail. The technical features described in the method embodiments are applicable to the following device embodiments.

[0131] Figure 9 FIG. is a schematic block diagram of a detection device for DCR according to an embodiment of the present application. The detection device is used to detect the DCR of a battery pack, and the battery pack is connected to a PCS. As Figure 9 shown, the detection device 300 includes a charge and discharge module 310.

[0132] Among them, the charge and discharge module 210 is used to control the PCS to charge and discharge the battery pack; among them, the information of the voltage and current of the battery pack during the charge and discharge process is used to determine the target DCR of the battery pack.

[0133] In some embodiments, the target DCR is determined according to the current of the battery pack and the change amount of the voltage of the battery pack within the target duration.

[0134] In some embodiments, the target DCR of the battery pack is the ratio between the change amount of the voltage of the battery pack within the target duration and the current of the battery pack.

[0135] In some embodiments, the charge and discharge module 310 is specifically configured to control the PCS to charge and discharge the battery pack when the battery pack is in a static state.

[0136] In some embodiments, the charge and discharge module 310 is specifically configured to determine whether the duration for which the battery pack is in a static state is greater than or equal to the target duration; when the duration for which the battery pack is in a static state is greater than or equal to the target duration, control the PCS to charge and discharge the battery pack.

[0137] In some embodiments, as Figure 9 shown, the detection device 300 further includes a processing module 320, which is used to obtain a display interface; in response to an operation of a user on the display interface, determine whether the duration for which the battery pack is in a static state is greater than or equal to the target duration.

[0138] In some embodiments, the detection device 300 further includes a transceiver module 330 configured to receive information on a target duration sent by the battery management system of the battery pack, where the target duration is determined according to the state parameters of the battery pack, and the state parameters include at least one of the SOC, SOH, and temperature of the battery pack.

[0139] In some embodiments, the processing module 320 is further configured to: obtain the historical DCR of the battery pack, where the historical DCR includes the initial DCR of the battery pack and / or the DCR of the battery pack detected within a historical time period; correct the target DCR according to the historical DCR to obtain the corrected DCR of the battery pack.

[0140] It should be understood that for the specific manner of DCR detection by the detection device 300 and the beneficial effects produced, reference may be made to the description of the relevant steps performed by the EMS in the method embodiments. For the sake of simplicity, it will not be elaborated here.

[0141] Figure 10 is a schematic block diagram of a DCR detection device according to another embodiment of the present application. The detection device is configured to detect the DCR of a battery pack, and the battery pack is connected to a PCS. As Figure 10 shown, the detection device 400 includes an acquisition module 410 and a processing module 420.

[0142] Among them, the acquisition module 410 is configured to obtain information on the voltage and current of the battery pack during the charging and discharging of the battery pack by the PCS; the processing module 420 is configured to determine the target DCR of the battery pack according to the information on the voltage and current of the battery pack.

[0143] In some embodiments, the processing module 420 is specifically configured to determine the target DCR according to the current of the battery pack and the change amount of the voltage of the battery pack within the target duration.

[0144] In some embodiments, the processing module 420 is specifically configured to determine the ratio between the change amount of the voltage of the battery pack within the target duration and the current of the battery pack as the target DCR of the battery pack.

[0145] In some embodiments, the processing module 420 is further configured to determine the target duration according to the state parameters of the battery pack, and the state parameters include at least one of the SOC, SOH, and temperature of the battery pack.

[0146] In some embodiments, the processing module 420 is specifically configured to determine the target duration according to the state parameters of the battery pack when the battery pack is in a stationary state.

[0147] In some embodiments, the detection device 400 further includes a transceiver module 430 configured to send information on a target duration to an energy management system, so that the energy management system determines whether the duration for which the battery pack is in a stationary state is greater than or equal to the target duration; the processing module 420 is specifically configured to, when the duration for which the battery pack is in a stationary state is greater than or equal to the target duration, determine a target DCR of the battery pack according to information on the voltage and current of the battery pack.

[0148] In some embodiments, the processing module 420 is further configured to obtain a historical DCR of the battery pack, where the historical DCR includes an initial DCR of the battery pack and / or a DCR of the battery pack detected within a historical period; and correct the target DCR according to the historical DCR to obtain a corrected DCR of the battery pack.

[0149] It should be understood that the specific manner of performing DCR detection by the detection device 400 and the beneficial effects achieved can be referred to the description of the relevant steps performed by the BMS in the method embodiments. For the sake of simplicity, details are not described herein again.

[0150] An embodiment of the present application further provides a computer-readable storage medium for storing a computer program, which, when executed by a computing device, enables the computing device to implement the DCR detection method described in any of the foregoing embodiments. Optionally, the computer program may be a computer program in an EMS or a BMS.

[0151] An embodiment of the present application further provides an EMS 500. For example, as Figure 11 shown, the EMS 500 includes a processor 510 and a memory 520. The memory 520 is configured to store instructions, and the processor 510 is configured to read the instructions and execute the method 100 of various embodiments of the present application based on the instructions. The memory 520 may be a separate device independent of the processor 510 or integrated in the processor 510.

[0152] Optionally, as Figure 11 shown, the EMS 500 may further include a transceiver 530, and the processor 510 may control the transceiver 530 to communicate with other devices. For example, information, data, or instructions may be sent to devices such as a BMS and a PCS, or information, data, or instructions sent by devices such as a BMS and a PCS may be received.

[0153] An embodiment of the present application further provides a BMS 600. For example, as Figure 12As shown, the BMS 600 includes a processor 610 and a memory 620. Among them, the memory 620 is used to store instructions, and the processor 610 is used to read the instructions and execute the method 200 of various embodiments of the present application based on the instructions. Among them, the memory 620 can be a separate device independent of the processor 610, or can be integrated in the processor 610.

[0154] Optionally, as Figure 12 shown, the BMS 600 may further include a transceiver 630, and the processor 610 can control the transceiver 630 to communicate with other devices. For example, information, data or instructions can be sent to devices such as the EMS and PCS, or information, data or instructions sent by devices such as the EMS and PCS can be received.

[0155] An embodiment of the present application further provides an energy storage system, which includes a plurality of battery packs connected in parallel, the EMS and BMS described in any of the above embodiments, and a PCS connected between the battery packs and the power grid.

[0156] It should be understood that the processor in the embodiments of the present application may be an integrated circuit chip with signal processing capabilities. In the implementation process, the steps of the above method embodiments can be completed by the integrated logic circuit in the hardware of the processor or the instructions in the form of software. The above processor can be a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. It can implement or execute the various methods, steps and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor can be a microprocessor or any conventional processor, etc. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as being executed and completed by the hardware decoding processor, or executed and completed by the combination of the hardware and software modules in the decoding processor. The software module can be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. This storage medium is located in the memory, and the processor reads the information in the memory and combines its hardware to complete the steps of the above method. <{

[0157] In addition, the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable ROM (PROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memories of the systems and methods described herein are intended to include, but are not limited to, these and any other suitable types of memories.

[0158] It should be noted that, on the premise of no conflict, the various embodiments described in the present application and / or the technical features in each embodiment can be combined with each other arbitrarily, and the technical solutions obtained after the combination should also fall within the protection scope of the present application.

[0159] In various embodiments of the present application, the magnitudes of the sequence numbers of the respective steps do not imply the order of execution. The order of execution of the respective steps should be determined by their functions and internal logics, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0160] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0161] In several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling, direct coupling, or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the devices or units can be in electrical, mechanical, or other forms.

[0162] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiments of the present application.

[0163] Although the present application has been described with reference to the preferred embodiments, various improvements can be made to it and components therein can be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for detecting a DC resistance, characterized in that, For detecting the DC resistance of a battery pack, the battery pack is connected to a power control system, and the detection method is executed by an energy management system. The detection method includes: Controlling the power control system to charge and discharge the battery pack; During the charging and discharging process, the voltage and current information of the battery pack is used by the battery management system to determine the target DC resistance of the battery pack.

2. The detection method according to claim 1, wherein The target DC resistance is determined based on the current of the battery pack and the change in the voltage of the battery pack within a target time period.

3. The detection method according to claim 2, wherein The target DC resistance is the ratio of the change in the voltage of the battery pack within the target time period to the current of the battery pack.

4. The detection method according to claim 2 or 3, characterized in that, The controlling the power control system to charge and discharge the battery pack includes: When the battery pack is in a static state, controlling the power control system to charge and discharge the battery pack.

5. The detection method according to claim 4, characterized in that, The when the battery pack is in a static state, controlling the power control system to charge and discharge the battery pack includes: Determining whether the duration of the battery pack in the static state is greater than or equal to the target time period; When the duration of the battery pack in the static state is greater than or equal to the target time period, controlling the power control system to charge and discharge the battery pack.

6. The detection method according to claim 5, wherein The determining whether the duration of the battery pack in the static state is greater than or equal to the target time period includes: Obtaining a display interface; In response to the user's operation on the display interface, determining whether the duration of the battery pack in the static state is greater than or equal to the target time period.

7. The detection method according to any one of claims 2 to 6, characterized in that, The detection method further includes: Receiving the information of the target time period sent by the battery management system of the battery pack, where the target time period is determined based on the state parameters of the battery pack, and the state parameters include at least one of the state of charge, health state, and temperature of the battery pack.

8. The detection method according to any one of claims 1 to 7, characterized in that The detection method further includes: Obtaining the historical DC resistance of the battery pack, where the historical DC resistance includes the initial DC resistance of the battery pack and / or the DC resistance of the battery pack detected within a historical time; Correcting the target DC resistance based on the historical DC resistance to obtain the corrected DC resistance of the battery pack.

9. A method for detecting a DC resistance, characterized in that, For detecting the DC resistance of a battery pack, the battery pack is connected to a power control system, and the detection method is executed by the battery management system of the battery pack. The detection method includes: During the process of the energy management system controlling the power control system to charge and discharge the battery pack, obtaining the voltage and current information of the battery pack; Based on the voltage and current information of the battery pack, determining the target DC resistance of the battery pack.

10. The detection method according to claim 9, characterized in that, The based on the voltage information and current information of the battery pack, determining the target DC resistance of the battery pack includes: Based on the current of the battery pack and the change in the voltage of the battery pack within a target time period, determining the target DC resistance.

11. The detection method according to claim 10, wherein, The based on the current of the battery pack and the change in the voltage of the battery pack within a target time period, determining the target DC resistance includes: Determine the ratio between the change in the voltage of the battery pack within the target duration and the current of the battery pack as the target DC resistance of the battery pack.

12. The detection method according to claim 10 or 11, characterized in that, The detection method further includes: Determine the target duration according to the state parameters of the battery pack, where the state parameters include at least one of the state of charge, health state, and temperature of the battery pack.

13. The detection method according to claim 12, wherein The determining the target duration according to the state parameters of the battery pack includes: When the battery pack is in a static state, determine the target duration according to the state parameters of the battery pack.

14. The detection method according to claim 13, characterized in that, The detection method further includes: Send the information of the target duration to the energy management system, so that the energy management system determines whether the duration of the battery pack in the static state is greater than or equal to the target duration; When the duration of the battery pack in the static state is greater than or equal to the target duration, determine the target DC resistance of the battery pack according to the information of the voltage and current of the battery pack.

15. The detection method according to any one of claims 9 to 14, characterized in that, The detection method further includes: Obtain the historical DC resistance of the battery pack, where the historical DC resistance includes the initial DC resistance of the battery pack and / or the DC resistance of the battery pack detected within a historical time; Correct the target DC resistance according to the historical DC resistance to obtain the corrected DC resistance of the battery pack.

16. A detection device for DC resistance, characterized in that, The detection device is applied to an energy management system for detecting the DC resistance of a battery pack. The battery pack is connected to a power control system. The detection device includes: A charge and discharge module for controlling the power control system to charge and discharge the battery pack; Wherein, the information of the voltage and current of the battery pack during the charge and discharge process is used by the battery management system to determine the target DC resistance of the battery pack.

17. The detection device according to claim 16, characterized in that, The target DC resistance is determined according to the current of the battery pack and the change in the voltage of the battery pack within the target duration.

18. The detection device according to claim 17, wherein The target DC resistance is the ratio between the change in the voltage of the battery pack within the target duration and the current of the battery pack.

19. The detection device according to claim 17 or 18, characterized in that, The charge and discharge module is specifically used for When the battery pack is in a static state, control the power control system to charge and discharge the battery pack.

20. The detection device according to claim 19, characterized in that, The charge and discharge module is specifically used for Determine whether the duration of the battery pack in the static state is greater than or equal to the target duration; When the duration of the battery pack in the static state is greater than or equal to the target duration, control the power control system to charge and discharge the battery pack.

21. The detection device according to claim 20, wherein The detection device further includes a processing module, and the processing module is used for Obtain a display interface; In response to an operation of the user on the display interface, determine whether the duration of the battery pack in the static state is greater than or equal to the target duration.

22. The detection device according to any one of claims 17 to 21, characterized in that The detection device further includes a transceiver module, and the transceiver module is used for Receive the information of the target duration sent by the battery management system of the battery pack, where the target duration is determined according to the state parameters of the battery pack, and the state parameters include at least one of the state of charge, health state, and temperature of the battery pack.

23. The detection device according to any one of claims 16 to 22, characterized in that The detection device further includes a processing module, and the processing module is configured to acquire the historical DC resistance of the battery pack, where the historical DC resistance includes the initial DC resistance of the battery pack and / or the DC resistance of the battery pack detected within a historical time period; correct the target DC resistance according to the historical DC resistance to obtain the corrected DC resistance of the battery pack.

24. A detection device for DC resistance, characterized in that, The detection device is applied to a battery management system for detecting the DC resistance of a battery pack. The battery pack is connected to a power control system. The detection device includes: a collection module configured to acquire information on the voltage and current of the battery pack during the process of the energy management system controlling the power control system to charge and discharge the battery pack; a processing module configured to determine the target DC resistance of the battery pack according to the information on the voltage and current of the battery pack.

25. The detection device according to claim 24, wherein Specifically, the processing module is configured to determine the target DC resistance according to the current of the battery pack and the change amount of the voltage of the battery pack within a target time period.

26. The detection device according to claim 25, characterized in that, Specifically, the processing module is configured to determine the ratio between the change amount of the voltage of the battery pack within the target time period and the current of the battery pack as the target DC resistance of the battery pack.

27. The detection device according to claim 25 or 26, characterized in that, The processing module is further configured to determine the target time period according to the state parameters of the battery pack, where the state parameters include at least one of the state of charge, health state, and temperature of the battery pack.

28. The detection device according to claim 27, characterized in that, Specifically, the processing module is configured to determine the target time period according to the state parameters of the battery pack when the battery pack is in a stationary state.

29. The detection device according to claim 28, wherein, The detection device further includes a transceiver module The transceiver module is configured to send information on the target time period to the energy management system, so that the energy management system determines whether the duration of the battery pack in the stationary state is greater than or equal to the target time period; Specifically, the processing module is configured to determine the target DC resistance of the battery pack according to the information on the voltage and current of the battery pack when the duration of the battery pack in the stationary state is greater than or equal to the target time period.

30. The detection device according to claim 29, characterized in that, The processing module is further configured to acquire the historical DC resistance of the battery pack, where the historical DC resistance includes the initial DC resistance of the battery pack and / or the DC resistance of the battery pack detected within a historical time period; correct the target DC resistance according to the historical DC resistance to obtain the corrected DC resistance of the battery pack.

31. An energy management system, characterized in that, comprising a memory and a processor, where the memory is used to store instructions, and the processor is used to read the instructions and execute the DC resistance detection method according to any one of claims 1 to 8 based on the instructions.

32. A battery management system, characterized in that, comprising a memory and a processor, where the memory is used to store instructions, and the processor is used to read the instructions and execute the DC resistance detection method according to any one of claims 9 to 15 based on the instructions.

33. A energy storage system, characterized in that, comprising: a plurality of battery packs connected in parallel, the energy management system according to claim 31, the battery management system according to claim 32, and a power control system connected between the plurality of battery packs and the power grid.

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