A method for optimizing energy consumption of a liquid cooling system in a battery energy storage system

Abstract

The present invention discloses a method for optimizing the energy consumption of a liquid cooling system in a battery energy storage system, comprising: obtaining liquid cooling cycle data and battery data in the battery energy storage system; comparing the battery cell temperature with the maximum allowable temperature of the battery cell and the minimum allowable temperature of the battery cell, respectively; if the battery cell temperature is greater than or equal to the maximum allowable temperature of the battery cell, operating the compressor and fan at full load; if the battery cell temperature is less than or equal to the minimum allowable temperature of the battery cell, stopping the compressor and fan and turning on the electric heater; if the battery cell temperature is between the two, obtaining the battery status according to the charge and discharge rate, and adjusting the operating load of the compressor and fan according to the battery status so that the liquid cooling cycle data and the battery data reach a preset liquid cooling cycle temperature threshold and battery temperature threshold, respectively. This method meets the equipment control requirements under different working conditions by setting the control logic between the compressor and fan of the liquid cooling system and the external input parameters, thereby reducing the total energy consumption of the system operation.

Description

Technical Field

[0001] The present invention relates to the technical field of battery energy storage, and in particular to a method for optimizing energy consumption of a liquid cooling system in a battery energy storage system. Background Art

[0002] Currently, energy storage technology plays a pivotal role in the Energy Internet and has been widely applied in fields such as renewable energy, distributed energy, and smart grids. Electrochemical energy storage, represented by lithium iron phosphate batteries, has experienced rapid growth due to its advantages, including high energy storage density and power density, high efficiency, rapid technological advancement, and great development potential. However, due to the inherent degradation characteristics of energy storage batteries, their energy consumption decreases with use. For example, the capacity of an energy storage system has a service life of 10 years, but the battery itself has a capacity degradation of 80% after 10 years. Combined with other energy losses required to maintain the normal operation of the energy storage system, the overall energy efficiency of the energy storage system will decrease year by year.

[0003] Among the auxiliary facilities of energy storage systems, cooling equipment consumes a significant proportion of energy. As energy storage capacity increases, the system's heat generation also increases. To ensure proper battery operation, the liquid cooling system is often expanded, further wasting energy. Furthermore, extensive liquid cooling system control and management methods also result in redundant energy consumption. Currently, there are two common approaches to optimizing energy storage system energy consumption: energy consumption monitoring of the energy storage power station and energy efficiency control of the energy storage power station. Energy consumption monitoring of the energy storage power station uses a loss decomposition model for the energy storage power station's main charging and discharging circuits to calculate the losses in each link of the energy storage power station's main charging and discharging circuits. Losses in each link of the energy storage power station's auxiliary power circuits are also calculated using a loss decomposition model for the energy storage power station's auxiliary power circuits. The total energy storage power station loss and the energy storage power station loss rate are compared with corresponding standard values, and an alarm is issued if the standard values ​​are exceeded. Energy efficiency control of the energy storage power station includes a wireless receiving and transmitting module, a control module, an energy storage module, a power quality monitoring module, and multiple energy-consuming units. Energy regulation, energy consumption monitoring, data collection, statistics, and analysis are performed on each energy-consuming unit to identify potential energy savings.

[0004] However, both methods have limitations. The first method can only determine the energy consumption of the entire energy storage power station by comparing actual losses with preset standard values. The system does not have the function of automatically adjusting the losses in each link when an alarm is triggered, and is suitable for a more extensive control method. The second method has a more macro-control strategy, focusing on load analysis and power quality analysis, and rarely mentions the energy consumption control of the energy storage system itself. Summary of the Invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a method for optimizing the energy consumption of the liquid cooling system in the battery energy storage system, which further reduces the total energy consumption from the energy storage device level, thereby achieving energy saving of the energy storage device itself.

[0006] The present invention provides a method for optimizing energy consumption of a liquid cooling system in a battery energy storage system, the method comprising:

[0007] Acquire liquid cooling cycle data and battery data from the liquid cooling system and battery system in the battery energy storage system, respectively. The liquid cooling cycle data includes liquid supply temperature, liquid return temperature, and rated liquid supply temperature. The battery data includes battery cell temperature, charge and discharge rate, maximum allowable battery cell temperature, minimum allowable battery cell temperature, and rated battery cell temperature. The liquid cooling system includes a compressor, a fan, an electric heater, and a main circulation pump.

[0008] Comparing the battery core temperature with the maximum allowable battery core temperature and the minimum allowable battery core temperature respectively, and if the battery core temperature is greater than or equal to the maximum allowable battery core temperature, operating the compressor and the fan at full load;

[0009] If the battery core temperature is less than or equal to the minimum allowable temperature of the battery core, the compressor and the fan are stopped, and the electric heater is turned on;

[0010] If the battery cell temperature is between the minimum allowable temperature of the battery cell and the maximum allowable temperature of the battery cell, the battery status in the battery system is obtained according to the charge and discharge rate, and the operating load of the compressor and the fan is adjusted according to the battery status so that the liquid cooling cycle data and the battery data reach the preset liquid cooling cycle temperature threshold and battery temperature threshold respectively.

[0011] Furthermore, if the battery core temperature is greater than or equal to the maximum allowable temperature of the battery core, the step of operating the compressor and the fan at full load is:

[0012] If the battery core temperature is greater than or equal to the maximum allowable battery core temperature, the compressor and the fan are operated at full load, and the main circulation pump is kept running until the battery core temperature is equal to the rated battery core temperature.

[0013] Furthermore, if the battery core temperature is less than or equal to the minimum allowable temperature of the battery core, the step of stopping the compressor and the fan and turning on the electric heater is:

[0014] If the battery core temperature is less than or equal to the minimum allowable battery core temperature, the compressor and the fan are stopped, the main circulation pump is kept running, and the electric heater is turned on until the battery core temperature is greater than the minimum allowable battery core temperature.

[0015] Furthermore, before the step of obtaining the battery status in the battery system according to the charge and discharge rate, the method further includes:

[0016] Calculating the difference between the battery cell temperature and the rated temperature of the battery cell to obtain a battery cell temperature difference;

[0017] The battery cell temperature difference is compared with a preset first threshold and a second threshold respectively. If the battery cell temperature difference is greater than or equal to the second threshold and the battery cell temperature difference is less than or equal to the first threshold, the liquid cooling system is stopped.

[0018] Furthermore, the step of obtaining the battery status in the battery system according to the charge and discharge rate includes:

[0019] If the charge-discharge rate is zero, the battery state in the battery system is a static state;

[0020] Otherwise, the battery status in the battery system is a charging and discharging status.

[0021] Furthermore, the step of adjusting the operating loads of the compressor and the fan according to the battery status so that the liquid cooling cycle data and the battery data reach a preset liquid cooling cycle temperature threshold and a battery temperature threshold, respectively, includes:

[0022] If the battery cell temperature difference is greater than the first threshold value and the battery state is in a stationary state, the difference between the supply liquid temperature and the return liquid temperature is calculated to obtain the supply and return liquid temperature difference, the main circulation pump is kept running, and the operating loads of the compressor and the fan are adjusted so that the supply and return liquid temperature difference remains unchanged and the battery cell temperature is less than or equal to the rated battery cell temperature;

[0023] If the battery cell temperature difference is greater than the first threshold value and the battery status is in the charge and discharge state, the main circulation pump is kept running, and the operating loads of the compressor and the fan are adjusted so that the liquid supply temperature is less than or equal to the rated liquid supply temperature until the battery cell temperature is equal to the battery cell rated temperature.

[0024] Furthermore, the step of adjusting the operating load of the compressor and the fan according to the battery status so that the liquid cooling cycle data and the battery data reach a preset liquid cooling cycle temperature threshold and a battery temperature threshold, respectively, includes:

[0025] If the temperature difference of the battery cells is less than the second threshold value and the battery state is a static state, stopping the operation of the liquid cooling system;

[0026] If the temperature difference of the battery cells is less than the second threshold value and the battery state is in the charge and discharge state, the main circulation pump is kept running, and the compressor and the fan are stopped.

[0027] Furthermore, the method further comprises:

[0028] Obtaining the operating time and operating load of the liquid cooling system;

[0029] The operating energy consumption of the liquid cooling system is calculated according to the operating time and the operating load.

[0030] Furthermore, the first threshold is 0.5, and the second threshold is -0.5.

[0031] The present invention provides a method for optimizing energy consumption in a liquid cooling system within a battery energy storage system. This method controls the operating load and frequency of the compressor and fan based on the permissible state of the battery cells, the supply and return liquid temperatures, and the supply and return liquid temperature differential. This further reduces the overall energy consumption of the energy storage system at the energy storage device level, eliminates the need for additional equipment in existing battery energy storage systems, and reduces unnecessary human and material resource consumption. This is highly significant in the field of battery energy storage technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 1 is a flow chart of a method for optimizing energy consumption of a liquid cooling system in a battery energy storage system provided by an embodiment of the present invention;

[0033] Figure 2 yes Figure 1 Flow diagram of step S40;

[0034] Figure 3 yes Figure 1 Another flow chart of step S40;

[0035] Figure 4 yes Figure 1 A third flow chart of step S40;

[0036] Figure 5 yes Figure 1 A fourth flow chart of step S40;

[0037] Figure 6 This is another flow chart of a method for optimizing energy consumption of a liquid cooling system in a battery energy storage system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0039] See also Figure 1 , an embodiment of the present invention proposes a method for optimizing energy consumption of a liquid cooling system in a battery energy storage system, comprising steps S10 to S40:

[0040] Step S10, obtaining liquid cooling cycle data and battery data from the liquid cooling system and battery system in the battery energy storage system, respectively. The liquid cooling cycle data includes liquid supply temperature, liquid return temperature, and rated liquid supply temperature. The battery data includes battery cell temperature, charge and discharge rate, maximum allowable battery cell temperature, minimum allowable battery cell temperature, and rated battery cell temperature. The liquid cooling system includes a compressor, a fan, an electric heater, and a main circulation pump.

[0041] The energy consumption optimization method of this embodiment is targeted at battery energy storage systems with liquid-cooled cooling systems. Existing battery energy storage systems are generally in the form of battery energy storage cabinets, and the liquid cooling system is built into the battery energy storage cabinets. The liquid cooling system uses circulating coolant to regulate the temperature of the batteries, power conversion system (PCS), and the space inside the battery energy storage cabinet. Its operating range is within the individual battery energy storage cabinets to which it belongs.

[0042] Liquid cooling systems are generally divided into a cooling and heating circulation unit and a control and protection unit. The cooling and heating circulation unit includes the compressor, fan, main circulation pump, air conditioner, electric heater, and other equipment as well as the coolant piping. The control and protection unit consists of an electrical control unit and a parameter measurement and control unit. The electrical control unit primarily performs functions such as operation and fault protection of electrical equipment such as the compressor, fan, main circulation pump, air conditioner, and electric heater, based on the system's control requirements. The parameter measurement and control unit uses temperature and pressure transmitters to display the supply liquid temperature and pressure, return liquid temperature and return liquid pressure, and automatically adjust the supply liquid temperature. In addition to the parameter measurement provided by the liquid cooling system itself, the battery management system (BMS) in the battery energy storage cabinet can also monitor battery data, including parameters such as cell temperature and charge and discharge rate.

[0043] This embodiment sets the control logic of the liquid cooling system in an existing battery energy storage system with a liquid cooling system based on parameter measurement of the liquid cooling system and liquid cooling cycle data collected by the control unit, as well as battery data collected by the battery system, combined with internal and external parameter analysis. This allows the system to meet equipment control requirements under different operating conditions and reduce the energy consumption of the battery energy storage equipment.

[0044] In order to facilitate the detailed description of the technical solution of this embodiment below, we will mark the liquid cooling cycle data and battery data as parameters: battery cell temperature T1, charge and discharge rate C, maximum allowable battery cell temperature Tmax, minimum allowable battery cell temperature Tmin, rated battery cell temperature T1set, liquid supply temperature T2, return liquid temperature T3, and rated liquid supply temperature T2set.

[0045] Step S20 , comparing the battery cell temperature with the maximum allowable battery cell temperature and the minimum allowable battery cell temperature respectively; if the battery cell temperature is greater than or equal to the maximum allowable battery cell temperature, operating the compressor and the fan at full load.

[0046] Step S30: If the battery core temperature is less than or equal to the minimum allowable temperature of the battery core, the compressor and the fan are stopped, and the electric heater is turned on.

[0047] In this embodiment, the liquid cooling system will adjust the operating state of the liquid cooling system according to the battery cell temperature. The liquid cooling system will first compare the battery cell temperature T1 with the maximum allowable battery cell temperature Tmax and the minimum allowable battery cell temperature Tmin, respectively. If T1 ≥ Tmax, it means that the battery temperature is too high at this time. The electrical control unit of the liquid cooling system will control the compressor and the fan to run at full load while keeping the main circulation pump running, so as to achieve the purpose of quickly reducing the battery cell temperature until the battery cell temperature T1 drops to the rated battery cell temperature T1set, that is, T1 = T1set. At this time, the liquid cooling system can be controlled to stop running.

[0048] If T1 ≤ Tmin, it indicates that the battery temperature is too low. Both high and low battery temperatures can affect the operating state and lifespan of the battery energy storage system. Therefore, when the battery cell temperature is too low, the liquid cooling system must be controlled to stop the compressor and fan while maintaining the operation of the main circulation pump. The electric heater must also be turned on to rapidly heat the battery until the battery cell temperature T1 reaches the minimum allowable temperature Tmin, i.e., T1 > Tmin. At this point, the electric heater can be turned off. Clearly, this embodiment allows for flexible configuration of the liquid cooling system's operating state based on actual operating conditions, thereby reducing the overall energy consumption of the battery energy storage system. Other operating conditions may also apply, as described in detail below.

[0049] In step S40, if the battery cell temperature is between the minimum allowable temperature of the battery cell and the maximum allowable temperature of the battery cell, the battery status in the battery system is obtained according to the charge and discharge rate, and the operating load of the compressor and the fan is adjusted according to the battery status so that the liquid cooling cycle data and the battery data reach the preset liquid cooling cycle temperature threshold and battery temperature threshold, respectively.

[0050] This embodiment not only sets the working condition for the battery cell temperature outside the maximum and minimum temperature values ​​allowed, but also divides the working conditions into different conditions when the battery cell temperature is within the temperature range allowed by the battery cell, so that the liquid cooling system can better meet the requirements of different working conditions and further reduce the energy consumption of the system. The specific steps are as follows: Figure 2 As shown:

[0051] Step S401 , calculating the difference between the battery cell temperature and the rated temperature of the battery cell to obtain the battery cell temperature difference.

[0052] Step S402 : comparing the battery cell temperature difference with a preset first threshold and a second threshold respectively; if the battery cell temperature difference is greater than or equal to the second threshold and the battery cell temperature difference is less than or equal to the first threshold, stopping the liquid cooling system.

[0053] When the cell temperature is Tmin<T1<Tmax, the difference between T1 and T1set is first calculated to obtain the cell temperature difference, and the first threshold and the second threshold are pre-set. In this embodiment, the first threshold is preferably set to 0.5 and the second threshold is set to -0.5. Of course, the first threshold and the second threshold can be set to other values ​​according to actual conditions. It should be understood that this embodiment only uses preferred values ​​to facilitate the description of the solution, rather than specific limitations.

[0054] If the value of T1-T1set is within [-0.5, 0.5], it can be considered that the cell temperature T1 is maintained near the rated temperature T1set of the cell. At this time, the liquid cooling system can be stopped. If the value of T1-T1set is outside [-0.5, 0.5], the battery status needs to be judged based on the charge and discharge rate in the battery data, as follows: Figure 3 As shown:

[0055] Step S403: If the charge-discharge ratio is zero, the battery state in the battery system is a static state.

[0056] Step S404: otherwise, the battery status in the battery system is a charging and discharging status.

[0057] According to the charge and discharge rate C collected by the battery system, if C=0, then the battery state at this time is a static state; if C>0, then the battery state is a charging state; if C<0, then the battery state is a discharging state. In this embodiment, the operating conditions are preferably divided according to the charge and discharge state and the static state of the battery. Of course, according to the actual operation of the battery energy storage system, the operating conditions can also be divided according to the charging state, discharging state and static state of the battery, which will not be repeated here.

[0058] At this point, we have obtained two parameter conditions: cell temperature and battery status. Then we can divide them into four different working conditions according to these two parameters, and set different control logics for the liquid cooling system according to different working conditions, so as to further optimize the energy consumption of the liquid cooling system. The specific steps are as follows: Figure 4 and Figure 5 As shown:

[0059] Step S405: If the battery cell temperature difference is greater than the first threshold value and the battery state is in a static state, the difference between the supply liquid temperature and the return liquid temperature is calculated to obtain the supply and return liquid temperature difference, so that the main circulation pump is kept running, and the operating loads of the compressor and the fan are adjusted so that the supply and return liquid temperature difference remains unchanged and the battery cell temperature is less than or equal to the rated temperature of the battery cell.

[0060] Step S406: If the battery cell temperature difference is greater than the first threshold value and the battery state is in the charge and discharge state, the main circulation pump is kept running, and the operating loads of the compressor and the fan are adjusted to make the liquid supply temperature less than or equal to the rated liquid supply temperature until the battery cell temperature is equal to the battery cell rated temperature.

[0061] When the value of T1-T1set is greater than 0.5, that is, the battery cell temperature T1 is not maintained near the rated battery cell temperature T1set, and the actual battery cell temperature T1 is T1set+0.5<T1<Tmax. In this case, the battery status is judged. If C=0, that is, the battery status is static, then it is necessary to calculate the supply and return liquid temperature difference between the supply liquid temperature T2 and the return liquid temperature T3. Then, when the main circulation pump is running, adjust the operating load of the compressor and the fan to keep the value of T2-T3 stable and make T1≤T1set.

[0062] If C≠0, that is, the battery status is in the charge and discharge state, it is necessary to adjust the operating load of the compressor and the fan so that the liquid supply temperature T2 of the liquid cooling system is ≤ the rated liquid supply temperature T2set, until T1=T1set. At this time, the battery cell temperature is maintained near the rated temperature of the battery cell, so the liquid cooling system can be controlled to stop running.

[0063] Step S407 : If the temperature difference of the battery cells is less than the second threshold value and the battery state is a static state, the liquid cooling system is stopped.

[0064] Step S408: If the temperature difference of the battery cells is less than the second threshold value and the battery state is in the charge-discharge state, the main circulation pump is kept running, and the compressor and the fan are stopped.

[0065] When the value of T1-T1set is less than -0.5, that is, the cell temperature T1 is not maintained near the rated cell temperature T1set, and the cell temperature T1 is actually Tmin<T1<T1set-0.5, in this case, the battery status is judged. If C=0, that is, the battery status is in a static state, at this time, the temperature and status of the battery are relatively stable, so the liquid cooling system can be controlled to stop running.

[0066] If C≠0, that is, the battery status is in the charge and discharge state, at this time, the battery temperature is at a low value, and the compressor and fan do not need to run. It is only necessary to ensure that the main circulation pump is running. This ensures that the control logic of the liquid cooling system is optimized under various working conditions, reducing unnecessary energy consumption of the liquid cooling system, and thus reducing the total energy consumption of the battery energy storage system from the energy storage device level.

[0067] In addition to performing parameter analysis on the liquid cooling cycle data and battery data to meet the requirements of equipment control under different working conditions and reduce the total energy consumption of the system, this embodiment can also further process the system energy consumption data. Specifically, Figure 6 As shown:

[0068] Step S50: Obtain the operating time and operating load of the liquid cooling system.

[0069] Step S60: Calculate the operating energy consumption of the liquid cooling system according to the operating time and the operating load.

[0070] The optimization method provided in this embodiment can also collect data on the operating time of the liquid cooling system and the operating load of each part under the above-mentioned different working conditions, and calculate the operating energy consumption of the liquid cooling system under different working conditions based on the collected data. At the same time, the operating energy consumption can also be recorded and stored so that it can be analyzed in combination with the energy consumption data and operating parameters of the liquid cooling system in the future, thereby providing long-term and real data support for the future expansion of the optimization method for energy efficiency management. The specific analysis process will not be repeated here.

[0071] This embodiment provides a method for optimizing energy consumption of a liquid cooling system within a battery energy storage system. Compared to traditional methods that only determine the energy consumption of the entire energy storage station, resulting in a relatively extensive control approach and a lack of energy consumption control within the energy storage system itself, this method, without adding additional equipment, controls the operating load of the liquid cooling system's compressor and fan solely based on the operating status of the battery cells, the supply and return liquid temperatures, and the temperature difference. Parameter analysis is performed based on battery data and liquid cooling cycle data, and the control logic of the liquid cooling system is configured to meet equipment control requirements under different operating conditions. This reduces unnecessary operating energy consumption of the liquid cooling system, thereby lowering the total system operating energy consumption of the battery energy storage system at the energy storage device level.

[0072] In summary, an embodiment of the present invention proposes a method for optimizing energy consumption of a liquid cooling system in a battery energy storage system. The method obtains liquid cooling cycle data and battery data from the liquid cooling system and battery system in the battery energy storage system, respectively. The liquid cooling cycle data includes liquid supply temperature, liquid return temperature and rated liquid supply temperature. The battery data includes battery cell temperature, charge and discharge rate, maximum allowable temperature of the battery cell, minimum allowable temperature of the battery cell and rated temperature of the battery cell. The liquid cooling system includes a compressor, a fan, an electric heater and a main circulation pump; the battery cell temperature is compared with the maximum allowable temperature of the battery cell and the minimum allowable temperature of the battery cell respectively. If the battery cell temperature is If the core temperature is greater than or equal to the maximum allowable temperature of the battery cell, the compressor and the fan are operated at full load; if the battery cell temperature is less than or equal to the minimum allowable temperature of the battery cell, the compressor and the fan are stopped and the electric heater is turned on; if the battery cell temperature is between the minimum allowable temperature of the battery cell and the maximum allowable temperature of the battery cell, the battery status in the battery system is obtained according to the charge and discharge rate, and the operating load of the compressor and the fan is adjusted according to the battery status so that the liquid cooling cycle data and the battery data reach the preset liquid cooling cycle temperature threshold and battery temperature threshold respectively. This method combines the battery data and liquid cooling cycle data of the battery energy storage system for parameter analysis, sets the control logic between the compressor, fan and external input parameters of the liquid cooling system, meets the equipment control requirements under different working conditions, reduces unnecessary operating energy consumption of the liquid cooling system, and thus reduces the total system operating energy consumption of the battery energy storage system from the energy storage device level.

[0073] Each embodiment in this specification is described in a progressive manner. The same or similar parts of each embodiment can be directly referenced to each other. Each embodiment focuses on the differences from other embodiments. It should be noted that the technical features of the above embodiments can be combined in any way. To keep the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] The above-described embodiments merely represent several preferred implementations of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art could make several improvements and substitutions without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be based on the scope of protection of the claims.

Claims

1. A method for optimizing energy consumption of a liquid cooling system in a battery energy storage system, characterized in that: include: Acquire liquid cooling cycle data and battery data from the liquid cooling system and battery system in the battery energy storage system, respectively. The liquid cooling cycle data includes liquid supply temperature, liquid return temperature, and rated liquid supply temperature. The battery data includes battery cell temperature, charge and discharge rate, maximum allowable battery cell temperature, minimum allowable battery cell temperature, and rated battery cell temperature. The liquid cooling system includes a compressor, a fan, an electric heater, and a main circulation pump. Comparing the battery core temperature with the maximum allowable battery core temperature and the minimum allowable battery core temperature respectively, and if the battery core temperature is greater than or equal to the maximum allowable battery core temperature, operating the compressor and the fan at full load; If the battery core temperature is less than or equal to the minimum allowable temperature of the battery core, the compressor and the fan are stopped, and the electric heater is turned on; If the battery cell temperature is between the minimum allowable battery cell temperature and the maximum allowable battery cell temperature, obtaining a battery status in the battery system according to the charge and discharge rate, and adjusting the operating loads of the compressor and the fan according to the battery status so that the liquid cooling cycle data and the battery data reach a preset liquid cooling cycle temperature threshold and a battery temperature threshold, respectively; Before the step of obtaining the battery status in the battery system according to the charge and discharge rate, the method further includes: Calculating the difference between the battery cell temperature and the rated temperature of the battery cell to obtain a battery cell temperature difference; The battery cell temperature difference is compared with a preset first threshold and a second threshold respectively. If the battery cell temperature difference is greater than or equal to the second threshold and the battery cell temperature difference is less than or equal to the first threshold, the liquid cooling system is stopped; the first threshold is 0.5 and the second threshold is -0.

5.

2. The method for optimizing energy consumption of a liquid cooling system in a battery energy storage system according to claim 1, characterized in that: If the battery core temperature is greater than or equal to the maximum allowable temperature of the battery core, the step of operating the compressor and the fan at full load is: If the battery core temperature is greater than or equal to the maximum allowable battery core temperature, the compressor and the fan are operated at full load, and the main circulation pump is kept running until the battery core temperature is equal to the rated battery core temperature.

3. The method for optimizing energy consumption of a liquid cooling system in a battery energy storage system according to claim 1, wherein: If the battery core temperature is less than or equal to the minimum allowable temperature of the battery core, the steps of stopping the compressor and the fan and turning on the electric heater are: If the battery core temperature is less than or equal to the minimum allowable battery core temperature, the compressor and the fan are stopped, the main circulation pump is kept running, and the electric heater is turned on until the battery core temperature is greater than the minimum allowable battery core temperature.

4. The method for optimizing energy consumption of a liquid cooling system in a battery energy storage system according to claim 1, wherein: The step of obtaining the battery status in the battery system according to the charge and discharge rate includes: If the charge-discharge rate is zero, the battery state in the battery system is a static state; Otherwise, the battery status in the battery system is a charging and discharging status.

5. The method for optimizing energy consumption of a liquid cooling system in a battery energy storage system according to claim 4, characterized in that: The step of adjusting the operating loads of the compressor and the fan according to the battery status so that the liquid cooling cycle data and the battery data reach a preset liquid cooling cycle temperature threshold and a preset battery temperature threshold, respectively, includes: If the battery cell temperature difference is greater than the first threshold value and the battery state is in a stationary state, the difference between the supply liquid temperature and the return liquid temperature is calculated to obtain the supply and return liquid temperature difference, the main circulation pump is kept running, and the operating loads of the compressor and the fan are adjusted so that the supply and return liquid temperature difference remains unchanged and the battery cell temperature is less than or equal to the rated battery cell temperature; If the battery cell temperature difference is greater than the first threshold value and the battery status is in the charge and discharge state, the main circulation pump is kept running, and the operating loads of the compressor and the fan are adjusted so that the liquid supply temperature is less than or equal to the rated liquid supply temperature until the battery cell temperature is equal to the battery cell rated temperature.

6. The method for optimizing energy consumption of a liquid cooling system in a battery energy storage system according to claim 4, characterized in that: The step of adjusting the operating loads of the compressor and the fan according to the battery status so that the liquid cooling cycle data and the battery data reach a preset liquid cooling cycle temperature threshold and a preset battery temperature threshold, respectively, includes: If the temperature difference of the battery cells is less than the second threshold value and the battery state is a static state, stopping the operation of the liquid cooling system; If the temperature difference of the battery cells is less than the second threshold value and the battery state is in the charge and discharge state, the main circulation pump is kept running, and the compressor and the fan are stopped.

7. The method for optimizing energy consumption of a liquid cooling system in a battery energy storage system according to claim 1, characterized in that: The method further comprises: Obtaining the operating time and operating load of the liquid cooling system; The operating energy consumption of the liquid cooling system is calculated according to the operating time and the operating load.

Images