A temperature logic control method for battery cells of air-cooled chiller

Abstract

The present invention provides a logic control method for the temperature of the battery cells of an air-cooled chiller, which relates to the technical field of temperature control of an energy storage battery cell group. The control method includes the following steps: The chiller obtains the maximum temperature value T of the battery cells through communication with the host computer max , the minimum temperature value T min , the average temperature value T avg , the average temperature heating start point T 加热 , the average temperature dead band T avg回差 , the temperature difference value T 温差 , the temperature difference dead band T 回差 , and the average temperature limit value T0, the minimum temperature limit value T1, the maximum temperature limit value T2, and the temperature difference limit value T3. Based on the comparison of the above parameters, the operating state of the chiller is judged. The method can effectively reduce the air-conditioning energy consumption, achieve the maximum energy saving of the energy storage system, and improve the service life of the chiller.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage battery cell group temperature control, and in particular to a method for logic control of battery cell temperature of an air-cooled chiller. Background Art

[0002] Energy storage cells generate a lot of heat during the charging and discharging process, and air-cooled chillers are required to control the temperature of the cells under various working conditions to keep the cell temperature within a reasonable range and to exert efficient charging and discharging characteristics during the life cycle. In the existing technology for controlling the temperature of the cell, the return liquid temperature control mode is often used to control the temperature of the cell. In the return liquid temperature control mode, the water pump needs to be turned on all day to meet the temperature control requirements of the cell. After the cell is charged and discharged, the water pump still needs to self-circulate to ensure the uniform temperature requirements of the cells in each cell cluster. This control method has the defects of not being able to effectively match the cell load requirements and the high energy consumption of the temperature control system. Summary of the invention

[0003] The purpose of the present invention is to solve the defects of the prior art and provide a temperature logic control method for a battery cell of an air-cooled chiller, which can solve the problem of high energy consumption in the control method of the chiller in the prior art.

[0004] In order to achieve the above purpose and other purposes, the present invention is implemented by including the following technical solutions: The present invention provides a temperature logic control method for the battery core of an air-cooled chiller, the control method comprising the following steps: obtaining the temperature parameters of the battery core, the temperature parameters including the maximum temperature value T max , minimum temperature value T min , average temperature value T avg , temperature difference T 温差 、Temperature difference T 回差 , average temperature limit T0, maximum temperature limit T2, minimum temperature limit T1, average temperature hysteresis T avg回差 , temperature difference limit T3, average temperature heating start point T 加热 ;

[0005] Determine whether the temperature parameter satisfies T avg ≥T0 or satisfies T max ≥T2, if the judgment result is yes, then enter the cooling mode and judge whether the temperature parameter meets T avg ≤T0-T avg回差 Or satisfy T min ≤T1, if the judgment result is yes, then exit the cooling mode;

[0006] Determine whether the temperature parameter satisfies T avg ≤T 加热 Or satisfy T min≤T1, if the judgment result is yes, then enter the heating mode and judge whether the temperature parameter meets T avg ≥T0-T avg回差 Or satisfy T max ≥T2, if the judgment result is yes, then exit the heating mode;

[0007] Determine whether the temperature parameters simultaneously meet T 加热 ≤T avg ≤T0 and T min ≥T1 and T max ≤T2 and T 温差 ≥T3, if the judgment result is yes, then enter the self-circulation mode to determine whether the temperature parameters meet T 加热 ≤T avg ≤T0 and T min ≥T1 and T max ≤T2 and T 温差 ≤T3-T 回差 , if the judgment result is yes, then exit the self-loop mode.

[0008] Compared with the prior art, the present invention relates to a temperature logic control method for a battery cell of an air-cooled chiller. The logic is simple and not prone to misjudgment. By introducing the battery cell-related temperature as a control variable, the battery cell temperature control method has the advantages of more precise temperature control and lower air conditioning energy consumption compared to the return liquid temperature control method of a traditional air conditioner. The air conditioning energy consumption accounts for the largest proportion of the energy consumption of an energy storage cabinet. The present control method can effectively reduce the air conditioning energy consumption and achieve energy saving in the energy storage system.

[0009] The battery cell temperature control mode adopted in this application refines the control mode and requirements to achieve precise control. The daily working time of the water pump can be reduced by 5h to 8h, which increases the life of the water pump. When the water machine is on standby, the impact corrosion rate of the system pipelines (including the pipeline system, cold water plate, etc.) can be reduced, which is beneficial to increasing the life of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Shown is a logic principle diagram in an embodiment of the control method of the present invention. DETAILED DESCRIPTION

[0011] See also Figure 1 The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0012] The present invention discloses a temperature logic control method for a battery cell of an air-cooled chiller. In one embodiment, the control method comprises the following steps:

[0013] —S0: The upper computer CMU of the chiller sends the real-time operating status temperature parameters of the battery cell to the chiller control system. The temperature parameters include the maximum temperature value T max , minimum temperature value T min , average temperature value T avg , temperature difference T 温差 、Temperature difference T 回差 , average temperature limit T0, maximum temperature limit T2, minimum temperature limit T1, average temperature hysteresis T avg回差 , temperature difference limit T3, average temperature heating start point T 加热 ;

[0014] —S1: The chiller control system self-checks to determine whether the communication with the host computer is normal;

[0015] —S2: When the chiller control system self-checks and determines that there is an abnormality in the communication with the host computer, the chiller control system switches to the return liquid temperature control mode, and automatically operates according to the return liquid temperature detected by the chiller control system to determine the cell load demand and perform duty in abnormal situations:

[0016] - S3: When the chiller control system self-checks and determines that the communication with the host computer is normal in S1, the chiller control system makes the following judgments based on the battery cell operating status temperature parameters received from the host computer:

[0017] Average temperature value T avg ≥Average temperature limit T0 or maximum temperature value T max ≥ Maximum temperature limit T2, one of the two conditions is met, the chiller enters the cooling mode, the refrigeration system power components start, and the battery cells are cooled;

[0018] —S4: Determine whether the temperature obtained in S3 meets the following characteristics:

[0019] Average temperature value T avg ≤Average temperature limit T0-Average temperature difference T avg回差 Or minimum temperature value T min ≤minimum temperature limit T1, if the judgment result is yes, the chiller is controlled to exit the cooling mode.

[0020] —S5: Determine whether the temperature obtained in S3 meets the following characteristics: average temperature value T avg ≤Average temperature heating start point T 加热 Or minimum temperature value T min≤ minimum temperature limit T1. If it is met, the chiller enters the heating mode, the power components of the heating system start, and the heating of the battery cells is turned on.

[0021] —S6: Determine whether the temperature obtained in S5 meets the following characteristics: average temperature value T avg ≥Average temperature limit T0-Average temperature difference T avg回差 Or meet the maximum temperature value T max ≥ Maximum temperature limit T2, if met, exit heating mode.

[0022] —S7: Determine whether the temperature obtained in S3 satisfies the following characteristics at the same time: Average temperature heating start point T 加热 ≤Average temperature value T avg ≤ average temperature limit T0 and minimum temperature value T min ≥ minimum temperature limit T1 and maximum temperature value T max ≤ maximum temperature limit T2 and temperature difference T 温差 ≥Temperature difference limit T3. If it is met, the chiller enters the self-circulation mode. In the self-circulation mode, the water pump of the water system power component of the chiller is started separately to drive the coolant to circulate in the battery cell cooling circuit to ensure the uniform temperature of the battery cell.

[0023] —S8: Determine whether the temperature obtained in S7 satisfies the following characteristics at the same time: Average temperature heating start point T 加热 ≤Average temperature value T avg ≤ average temperature limit T0 and minimum temperature value T min ≥ minimum temperature limit T1 and maximum temperature value T max ≤ maximum temperature limit T2 and temperature difference T 温差 ≤Temperature difference limit T3-Temperature difference hysteresis T 回差 , if satisfied, the chiller exits the self-circulation mode.

[0024] like Figure 1 As shown, in step S0, the battery cell is an energy storage battery cell group, and the energy storage battery cell group can be composed of multiple lithium-ion battery cells connected in series and parallel, that is, the battery cell is a component of the energy storage battery cell group. The air-cooled chiller of the present invention can directly use the air condenser on the unit to discharge heat into the air. Air-cooled machines will be used in areas where there is a shortage of water or it is inconvenient to use water. The air-cooled chiller adopts a fin-type condenser, and directly uses a fan to force air flow to take away the heat of the refrigerant. No other auxiliary equipment is required. The air-cooled chiller can be used in the temperature control of the energy storage battery cell.

[0025] The temperature parameters include a maximum temperature value T max , minimum temperature value T min , average temperature value T avg , temperature difference T温差 、Temperature difference T 回差 , average temperature limit T0, maximum temperature limit T2, minimum temperature limit T1, average temperature hysteresis T avg回差 , temperature difference limit T3, average temperature heating start point T 加热 , where the maximum temperature value T max That is, the maximum and minimum temperature values ​​T measured by the temperature probe on the battery cell min That is, the minimum temperature measured by the temperature probe on the battery cell, the average temperature value T avg That is, the average temperature measured by the temperature probes on the battery cells, the temperature difference T 温差 That is, the difference between the maximum temperature value and the minimum temperature value measured by the temperature probe placed on the battery cell.

[0026] The average temperature limit T0 is a specific parameter value of a cell set by logic, the maximum temperature limit T2 is a maximum temperature parameter value set by logic, the minimum temperature limit T1 is a minimum temperature parameter value set by logic, and the temperature difference hysteresis T 回差 And the average temperature difference T avg回差 That is, in order to avoid frequent start and stop of the chiller, the logic exit parameter value is set, and the average temperature heating start point T 加热 That is, the heating mode battery cell average temperature start parameter value set by logic, and the temperature difference limit T3 is the battery cell temperature difference parameter value set by logic.

[0027] In step S1, the chiller control system determines whether the communication with the host computer is normal, and the chiller control system communicates with the host computer through the 485 communication protocol.

[0028] In step S2, if the chiller control system determines that there is an abnormality in the communication with the host computer, the chiller control system enters the liquid return temperature control mode. The liquid return temperature control mode may include setting the cooling and heating set points locally, obtaining the coolant return temperature T of the coolant flowing back to the chiller after the battery cell circulation. 回液 and compare it with the local cooling and heating set points.

[0029] Furthermore, the return liquid temperature T 回液 It can be the temperature of the coolant at the inlet pipe of the superheat management system. The coolant can be a mixture of water and ethylene glycol solution.

[0030] In steps S3 to S8, the chiller control system obtains the maximum temperature value T of the battery cell. max , minimum temperature value T min , average temperature value T avg , temperature difference T 温差Further, the above parameters can be obtained by arranging points on the battery cell for detection, and sent to the chiller through the energy storage control system. Further, the point arrangement includes using calibrated thermocouple points, and the point arrangement can be evenly arranged on the upper, middle and lower parts of the front, back, left and right surfaces of the battery cell. The average temperature heating start point T 加热 , average temperature difference T avg回差 、Temperature difference T 回差 , and the average temperature limit T0, the minimum temperature limit T1, the maximum temperature limit T2, and the temperature difference limit T3 are preset by the chiller control system. For example, the above variables can be opened to the communication protocol table of the host computer, and the host computer can set the values ​​of the above variables according to its needs.

[0031] The battery cell heating mode or cooling mode of the present invention can be set based on the principle of keeping the temperature inside the battery cell group at about 20°C in order to prevent the heat from rising during the charging and discharging process of the battery cell group and causing thermal runaway. In some embodiments, 10°C < the average temperature heating start point T 加热 <Average temperature limit T0 <25°C, 10°C <minimum temperature limit T1 <average temperature limit T0 <maximum temperature limit T2 <35°C. The average temperature hysteresis T avg回差 、Temperature difference T 回差 The temperature range of can be 3~5 ℃, and the temperature range of the temperature difference limit value T3 is 8~10 ℃.

[0032] like Figure 1 As shown, in steps S3, S4, S5, S6, S7, and S8, in some embodiments, in order to prevent thermal runaway caused by heat rise during the charging and discharging of the battery pack, when a logical conflict occurs between the heating mode and the cooling mode, the cooling mode is followed. In addition, there is no order of priority in the logical judgment of S3, S5, and S7 of the present invention.

[0033] The present invention takes the cooling and heating temperatures of the battery cells as the targets of the water temperatures of the energy storage system, and takes into account the possibility of uneven heating and cooling of the liquid circulation. The maximum and minimum temperatures are detected and compared with the positive and negative deviations of the target values, so as to determine which mode the water chiller should enter to respond to the different states of cooling, heating, self-circulation and standby of the energy storage battery cell system.

[0034] Furthermore, the cooling mode of the chiller of the present invention specifically includes: when the battery pack is charged and discharged, the temperature values ​​of different positions of the battery cells in the battery pack are collected, and the maximum value, minimum value, average value and the average temperature return difference T of the control parameter are compared and calculated. avg回差 , as well as the average temperature limit T0, the minimum temperature limit T1, and the maximum temperature limit T2 are used to compare and determine whether the chiller enters the cooling mode. This cooling mode is used to cool the energy storage battery pack.

[0035] The heating mode of the chiller of the present invention specifically includes: when the battery pack is charged and discharged, the temperature values ​​of different positions of the battery cells in the battery pack are collected, and the maximum value, minimum value, average value and control parameter average temperature are compared and calculated to obtain the heating start point T 加热 , average temperature difference T avg回差 , average temperature limit T0, minimum temperature limit T1, and maximum temperature limit T2 are used to compare and determine whether the chiller enters the heating mode. This heating mode is used to heat the energy storage battery pack.

[0036] The self-circulation state of the chiller of the present invention specifically includes: collecting the temperature values ​​of different positions of the battery cells in the battery cell group, comparing and calculating the maximum value, minimum value and average value. The difference between the maximum temperature and the minimum temperature is greater than or equal to the temperature difference limit value T3 and does not meet the cooling condition and does not meet the heating condition to enter the self-circulation mode, and when the battery cell temperature difference T 温差 Less than or equal to the temperature difference limit T3-temperature difference hysteresis T 回差 The chiller exits the self-circulation mode. The self-circulation mode is used to circulate the cooling liquid in the energy storage battery pack to help the overall temperature of the battery pack to be uniform.

[0037] like Figure 1 As shown, the standby state of the chiller of the present invention specifically includes entering this state when the unit has no cooling, heating, or self-circulation requirements.

[0038] In some embodiments, when the cooling and heating states conflict, cooling is performed first, and when the heating and self-circulation modes conflict, heating is performed first. The present invention adopts such a control mode to improve the safety of the control system. The preferred principle is that the consequences of thermal runaway caused by excessive temperature are more serious than condensation, and the condensation caused by excessively low temperature is more serious than uneven temperature inside the battery cell.

[0039] In the traditional return liquid temperature control mode, the water pump needs to be turned on all day to meet the temperature control requirements of the battery cell. After the battery cell is charged and discharged, the water pump still needs to circulate to ensure the uniform temperature requirements in the battery cell cluster. After the battery cell temperature control is adopted, when the battery cell does not need cooling, heating, and self-circulation temperature control requirements, the water machine remains in standby mode to minimize the energy consumption of the temperature control system.

[0040] Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value. The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology can modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for controlling the temperature logic of a battery cell of an air-cooled chiller, characterized in that: The control method comprises the following steps: Get the temperature parameters of the battery cell, the temperature parameters include the maximum temperature value T max , minimum temperature value T min , average temperature value T avg , temperature difference T 温差 、Temperature difference T 回差 , average temperature limit T0, maximum temperature limit T2, minimum temperature limit T1, average temperature hysteresis T avg回差 , temperature difference limit T3, average temperature heating start point T 加热 ; Determine whether the temperature parameter satisfies T avg ≥T0 or satisfies T max ≥T2, if the judgment result is yes, then enter the cooling mode and judge whether the temperature parameter meets T avg ≤T0-T avg回差 Or satisfy T min ≤T1, if the judgment result is yes, then exit the cooling mode; Determine whether the temperature parameter satisfies T avg ≤T 加热 Or satisfy T min ≤T1, if the judgment result is yes, then enter the heating mode and judge whether the temperature parameter meets T avg ≥T0-T avg回差 Or satisfy T max ≥T2, if the judgment result is yes, then exit the heating mode; Determine whether the temperature parameters simultaneously meet T 加热 ≤T avg ≤T0 and T min ≥T1 and T max ≤T2 and T 温差 ≥T3, if the judgment result is yes, then enter the self-circulation mode to determine whether the temperature parameters meet T 加热 ≤T avg ≤T0 and T min ≥T1 and T max ≤T2 and T 温差 ≤T3-T 回差 , if the judgment result is yes, then exit the self-circulation mode; The control method includes: when the cooling mode conflicts with the heating mode, executing the cooling mode; when the heating mode conflicts with the self-circulation mode, executing the heating mode.

2. The control method according to claim 1, characterized in that: The control method includes the control system of the chiller determining whether communication with a host computer is normal.

3. The control method according to claim 2, characterized in that: The control method includes entering a liquid return temperature control mode when the chiller control system communicates abnormally with the host computer.

4. The control method according to claim 1, characterized in that: The maximum temperature value T max , the minimum temperature value T min , the temperature difference T 温差 And the average temperature value T avg The method is obtained by arranging detection points on the battery cell.

5. The control method according to claim 1, characterized in that: The average temperature heating start point T 加热 , average temperature difference T avg回差 、Temperature difference T 回差 , as well as the average temperature limit T0, the minimum temperature limit T1, the maximum temperature limit T2, and the temperature difference limit T3 are preset by the control system of the chiller and opened to the communication protocol table of the host computer.

6. The control method according to claim 1, characterized in that: The average temperature heating start point and the average temperature limit satisfy: 10°C < T 加热 <T0<25℃; the average temperature limit, the minimum temperature limit and the maximum temperature limit satisfy: 10℃<T1<T0<T2<35℃.

7. The control method according to claim 1, characterized in that: The average temperature difference T avg回差 And the temperature difference T 回差 The temperature range is 3-5°C, and the temperature range of the temperature difference limit T3 is 8-10°C.

8. The control method according to claim 1, characterized in that: When the temperature parameter judgment result does not satisfy the cooling mode, the heating mode and the self-circulation mode, the standby mode is entered.

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