Energy storage system thermal management control method

Abstract

The application provides a kind of energy storage system thermal management control method, comprising the following steps: obtaining the information of battery system;Obtain the information of liquid cooling system;Determine whether the battery system and the control system are in normal communication, if yes, adopt the first control mode: simultaneously based on the information of battery system and the information of liquid cooling system control the operation of liquid cooling system;If not, adopt the second control mode: only with the information of liquid cooling system control the operation of liquid cooling system.The application simultaneously based on the operation information of battery system, the operation information of liquid cooling system controls the operation of liquid cooling system, and the regulation efficiency is higher, and can reduce the operation time of liquid cooling system, greatly improve the system operation life.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of energy storage, in particular to an energy storage system thermal management control method capable of optimizing energy consumption. BACKGROUND

[0002] Thermal management is a very important technology for energy storage systems. The heat dissipation performance not only relates to the performance of the energy storage system, but also relates to the safety of the energy storage system in use. Liquid cooling has become a common heat dissipation method. The current energy storage system based on liquid cooling thermal management method mostly uses the algorithm of opening and closing based on the inlet and outlet water temperature. The working mode is: when the temperature of the cooling liquid reaches the threshold of heating and cooling, the corresponding operation mode is started. This method will cause the auxiliary power consumption of the liquid cooling unit to increase, and the water machine running time to increase, thereby reducing the service life of the water machine.

[0003] The inventor found that the current liquid cooling unit control method only considers the temperature of the cooling liquid, does not consider the temperature of the battery in the energy storage system, and does not consider the running state of the energy storage system. It is one of the key factors of energy consumption to adjust the heating and cooling power objectively.

[0004] Therefore, it is necessary to provide an improved energy storage system thermal management control method to solve the above technical problems. SUMMARY

[0005] The present application aims to at least solve one of the technical problems existing in the prior art, and provides an energy storage system thermal management control method.

[0006] To achieve one of the above-mentioned purposes, the present application adopts the following technical solutions:

[0007] An energy storage system thermal management control method, comprising the following steps:

[0008] Obtaining information of a battery system;

[0009] Obtaining information of a liquid cooling system;

[0010] Judging whether the battery system and the control system are in normal communication, if yes, adopting a first control mode: controlling the operation of the liquid cooling system based on the information of the battery system and the information of the liquid cooling system; if not, adopting a second control mode: controlling the operation of the liquid cooling system only based on the information of the liquid cooling system.

[0011] Further, the information of the battery system includes cell temperature, battery charge and discharge state, and the ratio of the current capacity of the cell to the rated capacity; wherein the cell temperature includes the lowest cell temperature, the average cell temperature and the highest cell temperature.

[0012] The information of the liquid cooling system includes the running state of the refrigeration unit, the running state of the heater, the running state of the circulating pump, and the temperature of the cooling liquid; wherein the temperature of the cooling liquid includes the outflow temperature T 出 of the cooling liquid flowing from the liquid cooling system to the battery system and the backflow temperature T 回 of the cooling liquid flowing back to the liquid cooling system from the battery system.

[0013] Further, if the obtained information of the battery system is abnormal, or the information of the battery system cannot be obtained for multiple times, or the information of the battery system cannot be obtained within a predetermined time, the communication between the battery system and the control system is abnormal.

[0014] Further, in the first control mode, the energy storage system thermal management control method comprises the following steps:

[0015] Obtaining the cell temperature and comparing the cell temperature with the corresponding cell temperature threshold value;

[0016] Obtaining the cooling liquid temperature and comparing the cooling liquid temperature with the current cell temperature;

[0017] When the cell temperature is greater than or equal to the corresponding cell temperature threshold value, it is determined whether the cooling liquid temperature is lower than the cell temperature by 5℃ or not, if yes, the self-circulation mode is run: the circulating pump is started; if not, the refrigeration mode is run: the refrigeration unit and the circulating pump are started at the same time; when the cell temperature is lower than the corresponding cell temperature threshold value, it is determined whether the cooling liquid temperature is higher than the cell temperature by 5℃ or not, if yes, the self-circulation mode is run: the circulating pump is started; if not, the heating mode is run: the heater and the circulating pump are started at the same time.

[0018] Further, in the refrigeration mode, the energy storage system thermal management control method comprises the following steps:

[0019] Obtaining the charging and discharging information of the battery system;

[0020] Determining whether the battery system is charging and discharging or not, if yes, the running of the liquid cooling system is controlled based on the cell temperature threshold value in the charging and discharging state; if not, the running of the liquid cooling system is controlled based on the cell temperature threshold value in the static state; wherein the cell temperature threshold value in the charging and discharging state is different from the cell temperature threshold value in the static state.

[0021] Further, the minimum cell temperature threshold value in the charging and discharging state is less than or equal to the minimum cell temperature threshold value in the static state; the average cell temperature threshold value in the charging and discharging state is less than or equal to the average cell temperature threshold value in the static state; the maximum cell temperature threshold value in the charging and discharging state is greater than or equal to the maximum cell temperature threshold value in the static state.

[0022] Further, the "controlling the running of the liquid cooling system based on the cell temperature threshold value in the charging and discharging state" comprises: when the average cell temperature is greater than or equal to T 制冷1Or the highest temperature of the battery cell ≥ T 制冷2 Turn on the refrigeration unit; when the average cell temperature is ≤ T 制冷3 Or the lowest cell temperature ≤ T 制冷4 Shut down the refrigeration unit; among which, T 制冷1 >Cell average temperature threshold>T 制冷3 T 制冷2 ≤ Maximum cell temperature threshold, T 制冷4 > Minimum temperature threshold of the battery cell.

[0023] Furthermore, "controlling the operation of the liquid cooling system based on the cell temperature threshold under static conditions" includes: when the average cell temperature ≥ T 制冷5 Or the highest temperature of the battery cell ≥ T 制冷6 Turn on the refrigeration unit when the average cell temperature is ≤ T 制冷7 Or the lowest cell temperature ≤ T 制冷8 Shut down the refrigeration unit; among which, T 制冷6 >Maximum temperature threshold of battery cell>T 制冷5 >Cell average temperature threshold>T 制冷7 > Minimum temperature threshold of battery cell ≥ T 制冷8 .

[0024] Furthermore, in heating mode, when the average cell temperature is ≤T 加热1 Or the lowest cell temperature ≤ T 加热2 Turn on the heater; when the average cell temperature is ≥T 加热3 Or the highest temperature of the battery cell is ≥T 加热4 Turn off the heater; where T 加热1 <T 加热3 <Cell average temperature threshold, T 加热2 <Minimum temperature threshold of battery cell, T 加热4 < Maximum temperature threshold of the battery cell.

[0025] Furthermore, in the self-circulation mode, when the cell temperature difference is ≥ △T1, the circulation pump is turned on; when the cell temperature difference is ≤ △T2, the circulation pump is turned off; wherein, the cell temperature difference = the highest cell temperature - the lowest cell temperature, △T1 ≥ the highest cell temperature threshold - the lowest cell temperature threshold, and △T2 ≤ the highest cell temperature threshold - the lowest cell temperature threshold.

[0026] Furthermore, when running the self-circulation mode to cool the battery cells, the refrigeration unit is simultaneously started to cool the coolant. The refrigeration power of the refrigeration unit is lower than that of the refrigeration mode.

[0027] Alternatively, when running in self-circulation mode to cool the battery cells, the refrigeration unit can be started after a delay to cool the coolant.

[0028] Further, in the second control mode, the circulating pump is started, and the refrigeration unit is started or stopped according to the outlet temperature T 出 of the cooling liquid, the return temperature T 回 of the cooling liquid, or the temperature difference between the outlet temperature and the return temperature of the cooling liquid.

[0029] Further, the energy storage system thermal management control method further comprises: obtaining a ratio of the current electric quantity and the electric capacity of the electric core, and controlling the operating state of the refrigeration unit and the heater according to the ratio.

[0030] Further, when the ratio is greater than or equal to 0.9 or the ratio is less than or equal to 0.1, it is determined whether the refrigeration unit or the heater is operating, if yes, the operation is maintained or the operation is maintained after the power is reduced, and if no, the refrigeration unit or the heater is not started or is started at a power less than a rated refrigeration power.

[0031] The energy storage system thermal management control method has the advantages that: the energy storage system thermal management control method controls the operation of the liquid cooling system based on the operation information of the battery system and the operation information of the liquid cooling system, has higher control efficiency, can reduce the operation time of the liquid cooling system, and greatly improves the system operation life. BRIEF DESCRIPTION OF DRAWINGS

[0032] Fig. 1 FIG. 1 is a topological diagram of a liquid-cooled energy storage system according to the present application;

[0033] Fig. 2 FIG. 5 is an energy storage system thermal management control method according to a preferred embodiment of the present application;

[0034] Fig. 3 FIG. 6 is an energy storage system thermal management control method according to another preferred embodiment of the present application. DETAILED DESCRIPTION

[0035] The present application will be described in detail below with reference to the specific embodiments shown in the drawings. However, these embodiments do not limit the present application, and any changes in structure, method, or function made by those of ordinary skill in the art based on these embodiments are included within the scope of protection of the present application.

[0036] In each of the drawings of the present application, the dimensions of some structures or parts are exaggerated relative to other structures or parts for ease of illustration, and therefore, only the basic structures of the subject matter of the present application are used for illustration.

[0037] Please refer to Figs. 1-3 The present application provides a liquid-cooled energy storage system and an energy storage system thermal management control method, which aims to comprehensively consider the information of the battery system and the information of the liquid cooling system for thermal management, to optimize the control method of the liquid cooling system under the premise of maintaining the temperature of the battery system, to reduce the energy consumption of the liquid cooling system, and to prolong the service life thereof.

[0038] Specifically refer to Fig. 1 As shown in the drawings, the liquid-cooled cold storage system includes a battery system, a liquid cooling system for providing cold or heat to the battery system, and a control system in communication with the battery system and the liquid cooling system.

[0039] The battery system includes a plurality of battery clusters formed by a plurality of battery packs in series. The battery pack includes a battery cell and a liquid cooling plate in communication with the liquid cooling system to cool or heat the battery cell.

[0040] The plurality of battery clusters are arranged in the up-down direction, and each battery cluster includes a plurality of battery packs arranged in an array. In a preferred embodiment, as shown in the drawings, the battery system includes 24 battery packs, and every 6 battery packs are arranged in 3 columns and 2 rows and form a battery cluster in series, and 4 battery clusters are arranged in the up-down direction; that is, the 24 battery packs are arranged in 3 columns and 8 rows. Fig. 1

[0041] The battery system also includes a battery management system (BMS) for monitoring the operating state of the battery pack, which can monitor various state indicators of the battery pack, including voltage, temperature, input / output current, power, etc. The BMS can be in communication with the control system through CAN, USB, or wireless communication protocol to send the operating state of the battery pack.

[0042] Further, two battery systems can be arranged side by side, with a common control system placed in between, which is arranged reasonably and compactly. As shown in the drawings, Fig. 1 ​As shown, the control system in the figure obtains the temperature of the 48 battery packs through the Can communication mode, and divides the corresponding relationship between the 48 packs and the 4 liquid cooling units into 4 groups of data: 1# liquid cooling unit corresponds to (pack 1-2, pack 1-3, pack 1-4, pack 2-2, pack 2-3, pack 2-4, pack 3-2, pack 3-3, pack 3-4, pack 4-2, pack 4-3, pack 4-4) a total of 12 packs. 2# liquid cooling unit corresponds to (pack 1-1, pack 1-5, pack 1-6, pack 2-1, pack 2-5, pack 2-6, pack 3-1, pack 3-5, pack 3-6, pack 4-1, pack 4-5, pack 4-6) a total of 12 packs. 3# liquid cooling unit corresponds to (pack 5-1, pack 5-2, pack 5-6, pack 6-1, pack 6-2, pack 6-6, pack 7-1, pack 7-2, pack 7-6, pack 8-1, pack 8-2, pack 8-6) a total of 12 packs; 4# liquid cooling unit corresponds to (pack 5-3, pack 5-4, pack 5-5, pack 6-3, pack 6-4, pack 6-5, pack 7-3, pack 7-4, pack 7-5, pack 8-3, pack 8-4, pack 8-5) a total of 12 packs.

[0043] The liquid cooling system includes at least two liquid cooling units for providing cold or heat to the battery system, and each battery cluster is provided with cold or heat by at least two liquid cooling units. Taking two liquid cooling units as an example, a part of the battery packs in each battery cluster are provided with cold or heat by one liquid cooling unit, and the other part of the battery packs are provided with cold or heat by the other liquid cooling unit; therefore, the heat generation of each liquid cooling unit is small, and the flow and flow resistance of the cooling liquid are small, and the temperature difference between the battery packs in the same battery cluster can be reduced, the service life of the battery packs is improved, and at the same time, the maintenance is facilitated and the maintenance cost is reduced.

[0044] The liquid cooling unit comprises cooling liquid, refrigeration unit providing cold energy to the cooling liquid, heater providing heat to the cooling liquid, circulating pump driving the cooling liquid to circulate between the liquid cooling unit and the liquid cooling plate of the battery system, liquid cooling controller. When the refrigeration unit and the circulating pump are turned on, the battery system is provided with low-temperature cooling liquid to cool the battery cells; when the heater and the circulating pump are turned on, the battery system is provided with high-temperature cooling liquid to heat the battery cells; and when only the circulating pump is turned on, the cooling liquid circulates and exchanges heat with the battery cells to provide cold energy or heat.

[0045] Specifically, as shown in Fig. 1 each battery pack in the first column and the third column in each battery cluster is cooled or heated by two liquid cooling units, and the battery packs in the second column are alternately cooled or heated from top to bottom by two liquid cooling units.

[0046] The control system comprises an information acquisition module, an information processing module and an information output module. In some application scenarios, the hardware and software control of the BMS and / or the liquid cooling controller can be integrated into the control system. For example, the BMS mainly monitors the information of the battery system, and the information acquisition module, the information processing module and the information output module of the control system and the liquid cooling controller are combined into one, to control the operation of the liquid cooling system.

[0047] The information acquisition module is in communication connection with the BMS to acquire the operation information of the battery system, and the information acquisition module is in communication connection with the liquid cooling controller to acquire the operation information of the liquid cooling system. The information processing module optimizes the operation mode of the liquid cooling system according to the information obtained by the information acquisition module, and feeds back to the liquid cooling system through the information output module or directly controls the operation of the liquid cooling system.

[0048] Based on the above system, each liquid cooling unit manages part of the battery packs, and this mode has strong reliability. Even if one liquid cooling unit is damaged, only the corresponding battery packs cannot operate, and the remaining battery packs can continue to operate. In addition, the distributed system does not need to occupy a large space, which is more conducive to the structural arrangement of the energy storage system.

[0049] Specifically, as shown in Figs. 2-3 The energy storage system thermal management control method comprises the following steps:

[0050] S1 acquiring information of the battery system;

[0051] S2 acquiring information of the liquid cooling system;

[0052] S3 judging whether the battery system and the control system are in normal communication, if yes, adopting a first control mode: controlling the operation of the liquid cooling system based on the information of the battery system and the information of the liquid cooling system; if not, adopting a second control mode: controlling the operation of the liquid cooling system only based on the information of the liquid cooling system.

[0053] It should be noted that in the control method, the battery system information corresponds to the control of the operation of the liquid cooling system, and the information of the battery system (cell temperature, etc.) is used to control the operation state of the liquid cooling unit that provides cold or heat to the corresponding battery pack.

[0054] Specifically, in step S1, the information of the battery system includes but is not limited to: cell temperature, battery charge and discharge state, ratio of current capacity to rated capacity of the cell, etc. Among them, the cell temperature includes the lowest temperature, the average temperature and the highest temperature.

[0055] In step S2, the information of the liquid cooling system includes but is not limited to: the operation state of the refrigeration unit, the operation state of the heater, the operation state of the circulating pump, the temperature of the cooling liquid. Among them, the temperature of the cooling liquid includes the outflow temperature T 出 of the cooling liquid flowing from the liquid cooling system to the battery system and the backflow temperature T 回 of the cooling liquid flowing back to the liquid cooling system from the battery system.

[0056] In step S3, if the information of the battery system is abnormal, or the information of the battery system cannot be obtained for multiple times (for example, 2-5 times), or the information of the battery system cannot be obtained within a predetermined time (for example, 60 seconds), it is considered that the communication between the battery system and the control system is abnormal, and the first control mode should be used to control the operation of the liquid cooling system.

[0057] In the first control mode, "controlling the operation of the liquid cooling system based on the information of the battery system and the information of the liquid cooling system" means: acquiring the cell temperature in real time, and comparing the cell temperature with the corresponding cell temperature threshold value; when the cell needs to be cooled, the liquid cooling system needs to provide cold to the battery system; when the cell needs to be heated, the liquid cooling system needs to provide heat to the battery system; and whether the refrigeration unit and the heater need to be started according to the temperature difference between the cooling liquid and the cell, so as to summarize the operation mode of the liquid cooling system into three modes: refrigeration mode, heating mode and self-circulation mode. It specifically includes the following steps:

[0058] Acquiring the cell temperature and comparing the cell temperature with the corresponding cell temperature threshold value, for example, comparing the lowest cell temperature with the lowest cell temperature threshold value, comparing the average cell temperature with the average cell temperature threshold value, and comparing the highest cell temperature with the highest cell temperature threshold value;

[0059] Acquiring the cooling liquid temperature and comparing the cooling liquid temperature with the current cell temperature;

[0060] When the battery cell temperature ≥ corresponding battery cell temperature threshold, the battery cell needs to be cooled, and it is continuously determined whether the cooling liquid temperature is lower than the battery cell temperature by 5℃ or not. If yes, the cooling liquid at the current temperature can provide cold to the battery system, and the self-circulation mode is run: the circulating pump is started; if not, the cooling liquid at the current temperature is insufficient to provide cold to the battery system, and the refrigeration mode is run: the refrigeration unit and the circulating pump are started at the same time to provide cold to the battery cell.

[0061] When the refrigeration mode is run, the energy storage system thermal management control method further includes the following steps:

[0062] The charge and discharge information of the battery system is obtained, which includes but is not limited to voltage and its change, current and its change, electric quantity and its change, temperature and its change, etc.

[0063] It is determined whether the battery system is being charged and discharged or not. If yes, the operation of the liquid cooling system is controlled based on the battery cell temperature threshold in the charge and discharge state; if not, the operation of the liquid cooling system is controlled based on the battery cell temperature threshold in the static state; wherein the battery cell temperature threshold in the charge and discharge state is different from the battery cell temperature threshold in the static state, and the specific reference is shown in Table 1.

[0064] Table 1

[0065]

[0066] The battery system generates heat in the charge and discharge state, so T1≤T1', to start the liquid cooling system to provide cooling as soon as possible, and avoid the phenomenon of high battery cell temperature due to the delay of the liquid cooling system to provide cooling. Of course, when the battery cell temperature is lower than T1, the heater needs to be started to provide heat to the battery system to ensure the normal work of the battery pack.

[0067] Specifically, "controlling the operation of the liquid cooling system based on the battery cell temperature threshold in the charge and discharge state" includes: when the average temperature of the battery cell ≥ T 制冷1 or the maximum temperature of the battery cell ≥ T 制冷2 , the refrigeration unit is started to start refrigeration; when the average temperature of the battery cell ≤ T 制冷3 or the minimum temperature of the battery cell ≤ T 制冷4 , the refrigeration unit is stopped to stop refrigeration. Wherein, T 制冷1 > the average temperature threshold of the battery cell > T 制冷3 , T 制冷2 ≤ the maximum temperature threshold of the battery cell, and T 制冷4 > the minimum temperature threshold of the battery cell.

[0068] In a preferred embodiment, T 制冷1 is 25℃, T 制冷2 is 35℃, and T 制冷3T 制冷4 is 15℃. In cooling mode, the temperature of the cooling liquid is 20℃, the temperature difference between the return liquid and the outlet liquid is 2℃, and the flow rate is 72L / min.

[0069] In the resting state, the battery cell does not generate a large amount of heat, and the operation of the liquid cooling system based on the battery cell temperature threshold in the resting state includes: when the average temperature of the battery cell is ≥ T 制冷5 or the maximum temperature of the battery cell is ≥ T 制冷6 , the refrigeration unit is started to start cooling; when the average temperature of the battery cell is ≤ T 制冷7 or the minimum temperature of the battery cell is ≤ T 制冷8 , the refrigeration unit is stopped to stop cooling. T 制冷6 > the maximum temperature threshold of the battery cell > T 制冷5 > the average temperature threshold of the battery cell > T 制冷7 > the minimum temperature threshold of the battery cell > T 制冷8 , preferably T 制冷5 is the median temperature of the maximum temperature threshold of the battery cell and the average temperature threshold of the battery cell, T 制冷7 is the median temperature of the minimum temperature threshold of the battery cell and the average temperature threshold of the battery cell; T 制冷6 > the maximum temperature threshold of the battery cell, preferably 1℃-2℃ higher than the maximum temperature threshold of the battery cell; T 制冷8 ≤ the minimum temperature threshold of the battery cell, preferably 1℃-2℃ lower than the minimum temperature threshold of the battery cell.

[0070] In a preferred embodiment, T 制冷5 is 30℃, T 制冷6 is 35℃, T 制冷7 is 22℃, and T 制冷8 is 15℃. In the resting mode, the temperature of the cooling liquid is 20℃, the temperature difference between the return liquid and the outlet liquid is 2℃, and the flow rate is 72L / min.

[0071] When the battery cell temperature is < the corresponding battery cell temperature threshold, the battery cell needs to be warmed up, and it is determined whether the cooling liquid temperature is higher than the battery cell temperature by 5℃ or more. If yes, the cooling liquid at the current temperature can provide heat to the battery system, and the self-circulation mode is run: the circulating pump is started; if not, the cooling liquid at the current temperature is insufficient to provide heat to the battery system, and the heating mode is run: the heater and the circulating pump are started at the same time to provide heat to the battery cell.

[0072] Specifically, in the heating mode, when the average temperature of the battery cell is ≤ T 加热1 or the minimum temperature of the battery cell is ≤ T 加热2 , the heater is started to start heating; when the average temperature of the battery cell is ≥ T 加热3 or the maximum temperature of the battery cell is ≥ T 加热4 , the heater is stopped to stop heating. Wherein, T 加热1 < T 加热3< Average temperature threshold of the battery cell, T 加热2 < Minimum temperature threshold of the battery cell, T 加热4 < Maximum temperature threshold of the battery cell.

[0073] In a preferred embodiment, T 加热1 is 18℃, T 加热2 is 15℃, T 加热3 is 22℃, T 加热4 is 35℃.

[0074] In the self-circulation mode: the coolant at the current temperature is sufficient to provide the required heat or cold to the battery system, so the circulation pump is started, and the chiller unit and the heater are in the off state, and the coolant at the current temperature provides the cold or heat to the battery system.

[0075] Specifically, when the temperature difference of the battery cell ≥ ΔΤ1, the circulation pump is started; when the temperature difference of the battery cell ≤ ΔΤ2, the circulation pump is stopped. Wherein, the temperature difference of the battery cell = the maximum temperature of the battery cell - the minimum temperature of the battery cell. ΔΤ1≥ the maximum temperature threshold of the battery cell - the minimum temperature threshold of the battery cell, which means that the maximum temperature of the battery cell exceeds the maximum temperature threshold of the battery cell, and cold needs to be provided, or the minimum temperature of the battery cell exceeds the minimum temperature threshold of the battery cell, and heat needs to be provided; ΔΤ2≤ the maximum temperature threshold of the battery cell - the minimum temperature threshold of the battery cell, which means that the temperature of the battery cell is between the maximum temperature threshold and the minimum temperature threshold, and no cold or heat needs to be provided.

[0076] In a preferred embodiment, ΔΤ1 is 8℃, and ΔΤ2 is 5℃. In the self-circulation mode, the temperature of the coolant is normal temperature, and the flow rate is 72L / min.

[0077] Further, considering that the charging and discharging process of the battery cell can release a large amount of heat; therefore, even if the self-circulation mode is run to cool the battery cell, in order to avoid the subsequent rapid increase of the temperature of the battery cell, the chiller unit can also be started to cool the coolant at the same time, and the refrigeration power of the chiller unit is lower than that in the refrigeration mode, for example, the chiller unit is run at 30%~70% of the rated refrigeration power, so that the temperature of the battery cell can be maintained within the working temperature range during the whole process.

[0078] Alternatively, when the self-circulation mode is run to cool the battery cell, the chiller unit is started to cool the coolant after a delay, and the refrigeration power of the chiller unit is not limited, which can be the rated power or reduced to a certain extent.

[0079] As described above, the self-circulation mode, the heating mode and the refrigeration mode can all enable the battery cell to be within the appropriate temperature range.

[0080] In the second control mode, the circulation pump is started, and the running state of the liquid cooling system is controlled according to the temperature of the coolant, and the running state of the liquid cooling system is controlled according to the outlet temperature T 出, the return liquid temperature T 回 , or the temperature difference between the outlet liquid temperature and the return liquid temperature, starts or stops the refrigeration unit.

[0081] Specifically, when the outlet liquid temperature T 出 is higher than the outlet liquid temperature threshold, the return liquid temperature T 回 is higher than the return liquid temperature threshold, or the temperature difference between the outlet liquid temperature and the return liquid temperature is higher than the temperature difference threshold, the refrigeration unit is started.

[0082] Further, the energy storage system thermal management control method further comprises: judging whether the battery cell temperature meets the standard, if yes, the temperature control ends and the liquid cooling system stops running; if no, a new round of control method is entered, that is, returning to the steps of obtaining the battery system information and obtaining the liquid cooling system information.

[0083] In addition, the energy storage system thermal management control method further comprises: obtaining the ratio of the current power of the battery cell to the capacity, judging the charging and discharging process according to the ratio, and controlling the running state of the refrigeration unit and the heater.

[0084] Specifically, when the ratio is greater than or equal to 0.9 or less than or equal to 0.1, it indicates that the charging and discharging is about to end and a large amount of heat will not be released, so it is further judged whether the refrigeration unit or the heater is running, if yes, the running is maintained or the power is reduced (such as reduced to 50% or below of the rated refrigeration power) and then the running is maintained; if no, the refrigeration unit or the heater is not started or is started at a power less than the rated refrigeration power (less than or equal to 50% of the rated refrigeration power); in this way, the waste of cold and heat is avoided, the energy consumption is low, and the frequent start of the refrigeration unit and the heater is avoided, prolonging the service life thereof.

[0085] In summary, the energy storage system thermal management control method of the present application controls the running of the liquid cooling system based on the running information of the battery system and the running information of the liquid cooling system, has higher regulation and control efficiency, can reduce the running time of the liquid cooling system, and greatly improves the system running life.

[0086] It should be understood that although the present specification is described in terms of embodiments, each embodiment does not necessarily contain only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand.

[0087] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present application, and are not intended to limit the protection scope of the present application, and any equivalent embodiments or changes made without departing from the spirit of the present application should be included in the protection scope of the present application.

Claims

1. A thermal management control method for an energy storage system, characterized in that, Includes the following steps: Obtain information about the battery system; Obtain information about the liquid cooling system; Determine whether the battery system and the control system are communicating normally. If yes, adopt the first control mode: control the operation of the liquid cooling system based on the information of the battery system and the information of the liquid cooling system simultaneously; if no, adopt the second control mode: control the operation of the liquid cooling system based only on the information of the liquid cooling system. The battery system information includes cell temperature, battery charge / discharge status, and the ratio of the cell's current charge to its rated capacity; wherein, the cell temperature includes the cell's minimum temperature, average temperature, and maximum temperature. The information for the liquid cooling system includes the operating status of the refrigeration unit, the operating status of the heater, the operating status of the circulating pump, and the temperature of the coolant; wherein, the temperature of the coolant includes the outlet temperature T of the coolant flowing from the liquid cooling system to the battery system. 出 The return liquid temperature T from the battery system to the liquid cooling system 回 ; In the first control mode, the thermal management control method of the energy storage system includes the following steps: acquiring the cell temperature and comparing it with the corresponding cell temperature threshold; acquiring the coolant temperature and comparing it with the current cell temperature; when the cell temperature is ≥ the corresponding cell temperature threshold, determining whether the coolant temperature is less than 5°C lower than the cell temperature; if so, operating the self-circulation mode: starting the circulation pump; if not, operating the cooling mode: simultaneously starting the refrigeration unit and the circulation pump; when the cell temperature is < the corresponding cell temperature threshold, determining whether the coolant temperature is more than 5°C higher than the cell temperature; if so, operating the self-circulation mode: starting the circulation pump; if not, operating the heating mode: simultaneously starting the heater and the circulation pump. When operating in cooling mode, the thermal management control method of the energy storage system includes the following steps: acquiring the charging and discharging information of the battery system; determining whether the battery system is charging or discharging; if so, controlling the operation of the liquid cooling system based on the cell temperature threshold of the charging and discharging state; if not, controlling the operation of the liquid cooling system based on the cell temperature threshold of the stationary state; wherein, the cell temperature threshold of the charging and discharging state is different from the cell temperature threshold of the stationary state. The lowest temperature threshold of the cell in the charging / discharging state is less than or equal to the lowest temperature threshold of the cell in the resting state; the average temperature threshold of the cell in the charging / discharging state is less than or equal to the average temperature threshold of the cell in the resting state; and the highest temperature threshold of the cell in the charging / discharging state is greater than or equal to the highest temperature threshold of the cell in the resting state.

2. The thermal management control method for an energy storage system according to claim 1, characterized in that: If the information obtained from the battery system is abnormal, or if multiple attempts are made but the information cannot be obtained, or if the information cannot be obtained within a predetermined time, then the communication between the battery system and the control system is abnormal.

3. The thermal management control method for an energy storage system according to claim 1, characterized in that: Controlling the operation of the liquid cooling system based on the cell temperature threshold of the charge / discharge state includes: when the average cell temperature ≥ T 制冷1 Or the highest temperature of the battery cell is ≥T 制冷2 Turn on the refrigeration unit; when the average cell temperature is ≤ T 制冷3 Or the lowest cell temperature ≤ T 制冷4 Shut down the refrigeration unit; among which, T 制冷1 >Cell average temperature threshold>T 制冷3 T 制冷2 ≤ Maximum cell temperature threshold, T 制冷4 >Minimum temperature threshold for battery cells; T 制冷1 At 25℃, T 制冷2 At 35℃, T 制冷3 The temperature is 22℃, T 制冷4 The temperature is 15℃.

4. The thermal management control method for an energy storage system according to claim 1, characterized in that: Controlling the operation of the liquid cooling system based on the cell temperature threshold under static conditions includes: when the average cell temperature ≥ T 制冷5 Or the highest temperature of the battery cell ≥ T 制冷6 Turn on the refrigeration unit when the average cell temperature is ≤ T 制冷7 Or the lowest cell temperature ≤ T 制冷8 Shut down the refrigeration unit; among which, T 制冷6 >Maximum temperature threshold of battery cell>T 制冷5 >Cell average temperature threshold>T 制冷7 > Minimum temperature threshold of battery cell ≥ T 制冷8 ; T 制冷5 At 30℃, T 制冷6 At 35℃, T 制冷7 The temperature is 22℃, T 制冷8 The temperature is 15℃.

5. The thermal management control method for an energy storage system according to claim 1, characterized in that: When operating in heating mode, if the average cell temperature is ≤T 加热1 Or the lowest cell temperature ≤ T 加热2 Turn on the heater; when the average cell temperature is ≥T 加热3 Or the highest temperature of the battery cell is ≥T 加热4 Turn off the heater; where T 加热1 <T 加热3 <Cell average temperature threshold, T 加热2 <Minimum temperature threshold of battery cell, T 加热4 <Maximum temperature threshold of battery cell; T 加热1 The temperature is 18℃, T 加热2 The temperature is 15℃, T 加热3 The temperature is 22℃, T 加热4 The temperature is 35℃.

6. The thermal management control method for an energy storage system according to claim 1, characterized in that: In self-circulation mode, when the cell temperature difference is ≥ △ T1, the circulation pump is turned on; when the cell temperature difference is ≤ △ T2, the circulation pump is turned off; wherein, the cell temperature difference = the highest cell temperature - the lowest cell temperature, △ T1 ≥ the highest cell temperature threshold - the lowest cell temperature threshold, △ T2 ≤ the highest cell temperature threshold - the lowest cell temperature threshold. △ T1 is 8℃, △ T2 is 5℃.

7. The thermal management control method for an energy storage system according to claim 6, characterized in that: When the self-circulation mode is used to cool the battery cells, the refrigeration unit is started at the same time to cool the coolant. The cooling power of the refrigeration unit is lower than that of the refrigeration mode. Alternatively, when running in self-circulation mode to cool the battery cells, the refrigeration unit can be started after a delay to cool the coolant.

8. The thermal management control method for an energy storage system according to claim 1, characterized in that: In the second control mode, the circulation pump is started, and the operation is based on the coolant outlet temperature T. 出 , return liquid temperature T 回 The refrigeration unit can be started or stopped based on the temperature difference between the outlet liquid temperature and the return liquid temperature.

9. The thermal management control method for an energy storage system according to claim 1, characterized in that: The thermal management control method for energy storage systems also includes: obtaining the ratio of the current charge of the battery cell to the capacitance, and controlling the operating status of the chiller and heater based on the ratio.

10. The thermal management control method for an energy storage system according to claim 9, characterized in that: When the ratio is ≥0.9 or ≤0.1, determine whether the refrigeration unit or heater is running. If yes, keep it running, or keep it running after reducing the power. If no, do not start the refrigeration unit or heater again, or start the refrigeration unit or heater with a power less than the rated refrigeration power.

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