Spraying immersion energy storage system and temperature control method

Abstract

The invention relates to the technical field of battery temperature control, and discloses a spraying immersion energy storage system and a temperature control method. Comprising a battery plug-in box, a grading pipeline, an electric control valve, a liquid cooling unit and an EMS temperature control management module, the grading pipeline is connected with the interior of the battery plug-in box, the grading pipeline is provided with a plurality of nozzles in the battery plug-in box, and cooling liquid is contained in the grading pipeline; the EMS temperature control management module collects the temperature of a battery cell in the battery plug-in box, adjusts the opening degree of the electric adjusting valve according to the temperature of the battery cell to control the flow of cooling liquid entering the battery plug-in box, and adjusts the frequency of a compressor of the liquid cooling unit according to the temperature of the battery cell to control the temperature of the cooling liquid in the circulation pipeline. The double adjusting loops solve the problem that an existing fully-immersed battery temperature control system cannot effectively reduce the temperature of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of battery temperature control, and in particular to a spray immersion energy storage system and a temperature control method. Background Art

[0002] With the development of the lithium-ion energy storage industry, the single-cell capacity of energy storage cells is increasing. This increase in energy density leads to an increasing risk of thermal runaway. Effective thermal management is a key factor in maintaining the continuous and safe operation of energy storage cabinets. Keeping the temperature of the battery cells within the optimal range not only allows the cells to maintain optimal charging and discharging conditions, but also improves the cycle life of the battery cells, maximizing the economic benefits of the energy storage system over its entire life cycle. As the core component of the energy storage system, batteries rapidly release large amounts of heat when thermal runaway occurs, causing large-scale thermal runaway of the battery pack, resulting in fire or explosion accidents. Therefore, good thermal management of energy storage systems, especially battery systems, is crucial to controlling and resolving the risks brought about by thermal runaway.

[0003] The existing fully immersed battery temperature control system fills the battery box with insulating coolant, which also has the problem of high temperature at the top and low temperature at the bottom. The density of the coolant decreases after heating and flows to the upper layer. The heating efficiency of the battery modules in the battery plug-in box is also different, and the heat exchange between them and the coolant is inconsistent, which further aggravates the temperature stratification of the battery cells. The material cost of insulating coolant is also very high for large-scale application. Summary of the Invention

[0004] The present invention provides a spray immersion energy storage system and a temperature control method to solve the problem that the existing fully immersed battery temperature control system cannot effectively reduce the battery temperature.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions: In a first aspect, the present invention provides a spray immersion energy storage system, comprising a battery box, a grading pipeline, an electric regulating valve, and an EMS temperature control management module. The grading pipeline is inserted into the battery box, and the grading pipeline is provided with multiple nozzles inside the battery box. Coolant is provided inside the grading pipeline. The EMS temperature control management module collects the temperature of the battery cells inside the battery box and adjusts the opening of the electric regulating valve according to the battery cell temperature to control the flow of coolant entering the battery box.

[0006] Furthermore, it also includes a liquid cooling unit, which includes a coolant storage tank, a circulation pump, an evaporator, a compressor, a condenser and a heater; The bottom of the battery plug-in box is connected to the grading pipeline to form a cooling liquid circulation passage for the battery plug-in box, the grading pipeline, the liquid cooling unit, the grading pipeline and the battery plug-in box.

[0007] Furthermore, the EMS temperature control management module collects the battery cell temperature inside the battery box and the working status of the energy storage system and adjusts and controls the operating frequency of the compressor according to the battery cell temperature and the working status of the energy storage system.

[0008] Furthermore, the EMS temperature control management module adopts a first PID control to realize the opening of the electric regulating valve, and the EMS temperature control management module adopts a second PID control to realize the operating frequency adjustment of the compressor.

[0009] In a second aspect, the present invention further provides a temperature control method for a spray immersion energy storage system, which is applied to the above-mentioned spray immersion energy storage system. The temperature control method for the spray immersion energy storage system comprises the following steps: Step 1: collecting the cell temperature of the battery cell inside the battery box, and controlling the opening of the electric regulating valve based on the cell temperature and a preset first temperature threshold in combination with a first PID control; Step 2: Based on the operating status of the energy storage system, the battery cell temperature, and the preset second and third temperature thresholds, the operating frequency of the compressor is adjusted in combination with the second PID control to further control the coolant temperature, thereby completing the temperature control of the battery cells and coolant of the energy storage system.

[0010] Furthermore, the battery core temperature includes the maximum battery core temperature, the average temperature of the cabinet battery core, the average temperature of the plug-in box, the average temperature difference of the cabinet, and the average temperature difference of the plug-in box. The average temperature difference of the cabinet is the difference between the average temperature of the cabinet battery core and the preset target temperature, and the average temperature difference of the plug-in box is the difference between the average temperature of the plug-in box and the preset target temperature. The controlling of the opening of the electric regulating valve based on the battery cell temperature and a preset first temperature threshold in combination with the first PID control includes: when the maximum temperature of the battery cell is greater than or equal to the first temperature threshold, fully opening the corresponding electric regulating valve and sending a prohibition power-on command to the energy storage system; if the temperature does not exceed the first temperature threshold, adjusting the corresponding electric regulating valve in combination with the average temperature difference of the plug-in box and the first PID control, and executing step 2.

[0011] Furthermore, the step of further controlling the coolant temperature by adjusting the operating frequency of the compressor based on the energy storage system operating state, the battery cell temperature, and the preset second and third temperature thresholds in combination with the second PID control includes: If the energy storage system is in a standby state, determining whether the average temperature difference of the cabinets is less than a second temperature threshold; if so, controlling the compressor to be in a standby state; if greater than or equal to the second temperature threshold, setting a limit value for the operating frequency of the compressor, and adjusting the operating frequency of the compressor in combination with a second PID control; If the energy storage system is in a charging or discharging state, determining whether the cabinet average temperature difference is less than a third temperature threshold, and if so, adjusting the maximum operating frequency of the compressor to a limit value; If the temperature is greater than or equal to the third temperature threshold, the operating frequency of the compressor is not limited, and the operating frequency of the compressor is adjusted in combination with the second PID control.

[0012] Furthermore, if the first temperature threshold is not exceeded, the first PID control is combined to adjust the corresponding electric regulating valve, including: if the maximum temperature of the battery cell does not exceed the first temperature threshold, further determining whether the average temperature difference of the plug-in box is less than a fourth temperature threshold, and if it is less than the fourth temperature threshold, closing the electric regulating valve; If the temperature is greater than or equal to the fourth temperature threshold, the electric regulating valve is adjusted in combination with the first PID control.

[0013] Furthermore, all battery boxes in the energy storage system are individually combined with the first PID control to adjust the corresponding electric regulating valves.

[0014] Beneficial effects: The present invention provides a spray immersion energy storage system and temperature control method. By installing an electric regulating valve at the water inlet of the battery plug box, the flow rate of the coolant entering the battery cell is controlled. After the flow rate stabilizes, the temperature of the battery cell approaches the set value and reaches the optimal operating temperature of the battery cell. The spraying method allows most of the battery cell surface to dissipate heat through the coolant, significantly improving the heat exchange effect; PID control improves temperature control stability. By using total coolant temperature as the primary control and battery compartment cell temperature as the secondary control, the secondary control is responsible for quickly responding to system transients, eliminating transient errors and reducing overshoot. The primary control is responsible for stabilizing the system's long-term behavior, enabling the system to quickly return to the setpoint and withstand load changes, using the primary PID control. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the piping structure of a spray immersion energy storage system according to Example 1 of the present invention; Figure 2 This is a schematic diagram of a first PID control flow chart of a temperature control method for a spray immersion energy storage system according to Example 1 of the present invention; Figure 3 This is a schematic diagram of a second PID control flow chart of a temperature control method for a spray immersion energy storage system according to Example 1 of the present invention; Figure 4 This is a schematic diagram of the battery cell temperature adjustment process of the first PID control according to Example 2 of the present invention; Figure 5 This is a schematic diagram of the coolant temperature adjustment process of the second PID control in Example 2 of the present invention.

[0016] In the picture: 1. Battery plug-in box; 2. Grading pipeline; 3. Electric regulating valve; 4. EMS temperature management module; 21. Nozzle; 5. Liquid cooling unit; 51. Coolant storage tank; 52. Circulation pump; 53. Evaporator; 54. Compressor; 55. Condenser; 56. Heater. DETAILED DESCRIPTION

[0017] The following is a clear and complete description of the technical solutions of the present invention. It should be understood that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0018] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "a" do not indicate a quantity limitation, but rather indicate the existence of at least one. Words such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship also changes accordingly.

[0019] Example 1 See Figure 1 The present application provides a spray immersion energy storage system, including a battery box 1, a grading pipeline 2, an electric regulating valve 3, and an EMS temperature control management module 4. The grading pipeline 2 is inserted into the battery box 1, and the grading pipeline 2 is provided with multiple nozzles 21 inside the battery box 1. Cooling liquid is provided inside the grading pipeline 2. The EMS temperature control management module 4 collects the temperature of the battery cells inside the battery box 1 and adjusts the opening of the electric regulating valve 3 according to the battery cell temperature to control the flow of coolant entering the battery box 1. The liquid cooling unit 5 includes a cooling liquid storage tank 51, a circulating pump 52, an evaporator 53, a compressor 54, a condenser 55 and a heater 56; The bottom of the battery plug box 1 is connected to the grading pipeline 2, forming a coolant circulation path of the battery plug box 1, the grading pipeline 2, the liquid cooling unit 5, the grading pipeline 2, and the battery plug box 1; The EMS temperature control management module 4 collects the battery cell temperature and the working status of the energy storage system inside the battery plug box 1 and adjusts the operating frequency of the compressor 54 according to the battery cell temperature and the working status of the energy storage system; In this embodiment, a manual switch valve is also provided at the water outlet of the battery box 1; The EMS temperature control management module 4 uses the first PID control to realize the opening of the electric regulating valve 3, and the EMS temperature control management module 4 uses the second PID control to realize the operating frequency adjustment of the compressor 54; See Figure 2-3 , the embodiment of the present application also provides a temperature control method for a spray immersion energy storage system, comprising the following steps: Step 1: collecting the cell temperature of the battery cell inside the battery box 1, and controlling the opening of the electric regulating valve 3 based on the cell temperature and a preset first temperature threshold in combination with a first PID control; The cell temperature includes the maximum cell temperature, the average temperature of the cabinet cells, the average temperature of the plug-in box, the average temperature difference of the cabinet, and the average temperature difference of the plug-in box. The average temperature difference of the cabinet is the difference between the average temperature of the cabinet cells and the preset target temperature, and the average temperature difference of the plug-in box is the difference between the average temperature of the plug-in box and the preset target temperature. Controlling the opening of the electric regulating valve 3 based on the battery cell temperature and a preset first temperature threshold in combination with the first PID control includes: when the maximum temperature of the battery cell is greater than or equal to the first temperature threshold, fully opening the corresponding electric regulating valve 3 and sending a prohibition start-up command to the energy storage system; if the temperature does not exceed the first temperature threshold, adjusting the corresponding electric regulating valve 3 in combination with the first PID control and executing step 2; The expression of the first PID control is: ; in, Indicates the output of the electric regulating valve opening to control the flow rate. Indicates the error in the flow control by the electric regulating valve opening. represents the proportional gain, represents the integration time, Indicates the derivative time.

[0020] Step 2: Based on the energy storage system operating state, the battery cell temperature, and the preset second and third temperature thresholds, the operating frequency of the compressor 54 is adjusted in combination with the second PID control to further control the coolant temperature, thereby completing the temperature control of the battery cells and coolant of the energy storage system; If the energy storage system is in standby mode, determine whether the average cabinet temperature difference is less than a second temperature threshold. If so, control the compressor 54 to be in standby mode. If so, set a limit value for the operating frequency of the compressor 54 and adjust the operating frequency of the compressor 54 in combination with the second PID control. The expression of the second PID control is: ; in, Indicates the output of the compressor frequency to control the coolant temperature. Indicates the error of the compressor frequency in controlling the coolant temperature. represents the proportional gain, represents the integration time, Indicates the derivative time.

[0021] If the energy storage system is in a charging or discharging state, determining whether the average temperature difference of the cabinets is less than a third temperature threshold, and if so, adjusting the maximum operating frequency of the compressor 54 to a limit value; If the temperature is greater than or equal to the third temperature threshold, the operating frequency of the compressor 54 is not limited, and the operating frequency of the compressor 54 is adjusted in combination with the second PID control.

[0022] All battery boxes 1 in the energy storage system are individually combined with the first PID control to adjust the corresponding electric regulating valves 3.

[0023] Example 2 The spray immersion energy storage method provided by the present invention is used to control the battery temperature of the spray immersion energy storage system, as follows.

[0024] See Figure 4 The battery plug box 1 is currently operating at an ambient temperature of 25°C, the first temperature threshold is set to 65°C, the second temperature threshold is set to 5°C, the third temperature threshold is set to 0°C, the fourth temperature threshold is set to 2°C, and the preset target temperature is set to 23°C.

[0025] The cell temperature at this time is collected, and it is found that the maximum cell temperature is 38°C. The average temperature of the plug-in box is 35°C, so the average temperature difference of the plug-in box is 35-23=12°C.

[0026] At this time, the maximum cell temperature of 38°C is lower than the set first temperature threshold of 65°C, so there is no need to fully open the electric control valve. Since the average temperature difference of the plug-in box is 12°C at this time, which is higher than the set fourth temperature threshold of 2°C, the corresponding electric control valve is adjusted in combination with the first PID control. ; in, Indicates the output of the electric regulating valve opening to control the flow rate. Indicates the error in the flow control by the electric regulating valve opening. represents the proportional gain, represents the integration time, represents the differential time; In this embodiment, the parameters of the first PID control are set as follows: ; ; ; Then the flow control corresponding to the output of the first PID control is: Proportional term: ; Integral item: ; Differential term: ; but In this embodiment, the adjustment range of the electric control valve 3 is: 0% (0 L / min) to 100% (10 L / min), that is, the electric control valve 3 is fully opened at this time. At this time, the coolant flow rate is 10 L / min. According to the heat exchange principle, the battery cell temperature drops at a rate of 1°C / min, and this process lasts for 8 minutes.

[0027] After 8 minutes of control, the average temperature of the substation is measured again and is 25°C. The average temperature difference of the substation is 2°C, which means there is an error. According to the heat exchange principle, the average temperature of the substation should be 27°C. The average temperature difference of the substation is 4°C. The corresponding error temperature between the target substation average temperature and the actual substation average temperature is 2°C. The error temperature is included in the calculation of the integral term, and the first PID control is performed again: Proportional term: ; Integral item: ; Differential term: ; correspond , then the opening of the electric regulating valve 3 is adjusted so that the coolant flow rate is 2.8 L / min at this time to suppress overshoot. This process lasts for 8 minutes; Finally, another measurement shows that the average temperature of the plug-in box is 23.2°C. The temperature error is 0.2°C, and there is an ambient thermal disturbance of ±0.3°C. The first PID control is performed again: Proportional term: ; Integral item: ; Differential term: ; correspond , then the opening of the electric regulating valve 3 is adjusted accordingly so that the coolant flow rate at this time is 0.04 L / min; During the temperature regulation process of the above three battery cells, the response speed of the cooling stage was from 35°C to 25°C within 480 seconds, with no overshoot below 22.8°C throughout the process. The temperature fluctuation was 23±0.5°C, which complies with the ISO 6469-3 standard. The final steady-state flow rate was less than 0.5 L / min, reducing the power consumption of the liquid cooling unit circulation pump.

[0028] See Figure 5 While executing the first PID control of the three battery core temperatures, the second PID control is also performed on the coolant temperature. In this embodiment, the operating frequency of the compressor 54 and the condenser 55 are both continuously adjustable from 0 to 100%. The expression of the second PID control is: ; in, Indicates the output of the compressor frequency to control the coolant temperature. Indicates the error of the compressor frequency in controlling the coolant temperature. represents the proportional gain, represents the integration time, Indicates the derivative time.

[0029] The corresponding parameters of the second PID control are as follows: ; ; .

[0030] Within 0 to 30 seconds of starting control, the average temperature of the cabinet battery cells is collected to be 35°C, initialization control is executed, and the preset temperature curve is loaded. At this time, the target temperature decreases at a rate of 0.2°C / S, and the frequency of compressor 54 is directly increased to 85% by feedforward control (to overcome system inertia), and the second PID control is started.

[0031] After 30 seconds, the main cooling phase begins. When the temperature enters the 30-24°C range, an anti-saturation integral algorithm is used to limit the integral term increase to ≤3% / s, and the frequency of the compressor 54 is dynamically adjusted. when When the frequency is kept ≥70%; when When the frequency is adjusted linearly according to the PID output (45-70%), the temperature change rate prediction is introduced: if , add 5% frequency compensation, and this process lasts for three minutes.

[0032] After three minutes, the overshoot suppression phase begins and the temperature approaches the set value of 24-23.5°C. At this point, dual threshold control is enabled: When the average temperature of the cabinet battery cells is greater than or equal to 23.3 degrees Celsius and less than or equal to 23.7 degrees Celsius, it switches to low gain mode (Kp is reduced by 40%); when When the differential term operation is frozen, the frequency fluctuation range of compressor 54 is narrowed to 32-38% (standard deviation ), this process lasts for 1 minute.

[0033] Four minutes after the start of regulation, the system entered a steady state, using sliding window filtering (window width 5s) to eliminate sensor noise, and automatically calibrating PID parameters every 30 seconds. The frequency of compressor 54 stabilized at 35.2±1.8%, and energy consumption was reduced to 28% of the initial stage.

[0034] Control effect: The average rate in the cooling stage is 0.18℃ / s, there is no temperature overshoot, the steady-state control accuracy is 23±0.27℃, the computing energy consumption is reduced by 42%, and the temperature fluctuation is reduced by 58%.

[0035] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A spray immersion energy storage system, characterized in that: The invention comprises a battery plug box (1), a grading pipeline (2), an electric regulating valve (3) and an EMS temperature control management module (4), wherein the grading pipeline (2) is inserted into the battery plug box (1), and the grading pipeline (2) is provided with a plurality of nozzles (21) in the battery plug box (1), and a cooling liquid is provided in the grading pipeline (2), and the EMS temperature control management module (4) collects the temperature of the battery core inside the battery plug box (1) and adjusts the opening of the electric regulating valve (3) according to the temperature of the battery core to control the flow of the cooling liquid entering the battery plug box (1).

2. The spray immersion energy storage system according to claim 1, characterized in that: It also includes a liquid cooling unit (5), wherein the liquid cooling unit (5) includes a cooling liquid storage tank (51), a circulating pump (52), an evaporator (53), a compressor (54), a condenser (55), and a heater (56); The bottom of the battery plug box (1) is connected to the grading pipeline (2), forming a cooling liquid circulation path for the battery plug box (1), the grading pipeline (2), the liquid cooling unit (5), the grading pipeline (2), and the battery plug box (1).

3. The spray immersion energy storage system according to claim 2, characterized in that: The EMS temperature control management module (4) collects the battery core temperature and the working state of the energy storage system inside the battery plug box (1) and adjusts and controls the working frequency of the compressor (54) according to the battery core temperature and the working state of the energy storage system.

4. The spray immersion energy storage system according to claim 3, characterized in that: The EMS temperature control management module (4) uses a first PID control to realize the opening of the electric regulating valve (3), and the EMS temperature control management module (4) uses a second PID control to realize the operating frequency adjustment of the compressor (54).

5. A temperature control method for a spray immersion energy storage system, characterized in that: Applied to the spray immersion energy storage system according to claim 4 above, the temperature control method of the spray immersion energy storage system comprises the following steps: Step 1: collecting the cell temperature of the battery cell inside the battery box (1), and controlling the opening of the electric regulating valve (3) based on the cell temperature and a preset first temperature threshold value in combination with a first PID control; Step 2: Based on the operating state of the energy storage system, the battery cell temperature and the preset second temperature threshold, the third temperature threshold and the second PID control, the operating frequency of the compressor (54) is adjusted to further control the coolant temperature, thereby completing the temperature control of the battery cell and the coolant of the energy storage system.

6. The temperature control method of the spray immersion energy storage system according to claim 5, characterized in that: The battery core temperature includes the maximum battery core temperature, the average temperature of the cabinet battery core, the average temperature of the plug-in box, the average temperature difference of the cabinet and the average temperature difference of the plug-in box. The average temperature difference of the cabinet is the difference between the average temperature of the cabinet battery core and the preset target temperature. The average temperature difference of the plug-in box is the difference between the average temperature of the plug-in box and the preset target temperature. The control of the opening of the electric regulating valve (3) based on the battery cell temperature and a preset first temperature threshold in combination with the first PID control comprises: when the maximum temperature of the battery cell is greater than or equal to the first temperature threshold, fully opening the corresponding electric regulating valve (3) and sending a power-on prohibition command to the energy storage system; if the first temperature threshold is not exceeded, adjusting the corresponding electric regulating valve (3) in combination with the average temperature difference of the plug-in box and the first PID control, and executing step 2.

7. The temperature control method of the spray immersion energy storage system according to claim 6, characterized in that: The method of further controlling the coolant temperature by adjusting the operating frequency of the compressor (54) based on the operating state of the energy storage system, the battery core temperature, and the preset second temperature threshold and third temperature threshold in combination with the second PID control comprises: If the energy storage system is in a standby state, determining whether the cabinet average temperature difference is less than a second temperature threshold, if it is less than the second temperature threshold, controlling the compressor (54) to be in a standby state, and if it is greater than or equal to the second temperature threshold, setting a limit value for the operating frequency of the compressor (54), and adjusting the operating frequency of the compressor (54) in combination with a second PID control; If the energy storage system is in a charging or discharging state, determining whether the cabinet average temperature difference is less than a third temperature threshold, and if so, adjusting the maximum operating frequency of the compressor (54) to a limit value; If the temperature is greater than or equal to the third temperature threshold, the operating frequency of the compressor (54) is not limited, and the operating frequency of the compressor (54) is adjusted in combination with the second PID control.

8. The temperature control method of the spray immersion energy storage system according to claim 6, characterized in that: If the first temperature threshold is not exceeded, the corresponding electric regulating valve (3) is adjusted in combination with the first PID control, including: if the maximum temperature of the battery cell does not exceed the first temperature threshold, further determining whether the average temperature difference of the plug-in box is less than a fourth temperature threshold, and if it is less than the fourth temperature threshold, closing the electric regulating valve (3); If the temperature is greater than or equal to a fourth temperature threshold, the electric regulating valve (3) is regulated in combination with the first PID control.

9. The temperature control method of the spray immersion energy storage system according to any one of claims 5 to 8, characterized in that: All battery plug-in boxes (1) in the energy storage system are individually combined with the first PID control to adjust the corresponding electric regulating valve (3).

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