Vanadium liquid electric pile heat management device and control method thereof

Abstract

The invention provides a vanadium liquid galvanic pile thermal management device and a control method thereof, relates to the technical field of vanadium liquid galvanic pile thermal management, and aims to more reasonably monitor the temperature of an electrolyte with non-uniform temperature. A first temperature sensor is arranged and is used for monitoring the temperature of the electrolyte at the position where a heating device of an electrolyte container is arranged; a second temperature sensor is arranged, and the second temperature sensor is used for monitoring the temperature of the electrolyte at the position with the maximum height difference from the position where the heating device is arranged in the electrolyte container; acquiring a height difference between the first temperature sensor and the second temperature sensor, and periodically acquiring monitoring values of the first temperature sensor and the second temperature sensor; determining the heating starting time according to the height difference and the monitoring value; and in the heating process, the heating closing time is determined according to the height difference and the monitoring numerical value. The invention has the advantage of realizing more reliable temperature control.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal management of vanadium liquid flow batteries, and more particularly, to a thermal management device for a vanadium liquid flow battery and a control method thereof. Background Art

[0002] A vanadium liquid flow battery is a battery in which vanadium is used as an active substance and is in a circulating liquid state.

[0003] The electrolyte of the vanadium liquid flow battery is an important part of the entire battery stack. To ensure the safety and working efficiency of the vanadium liquid flow battery, it is necessary to monitor the electrolyte so that the electrolyte is always maintained within a suitable temperature range. However, when the electrolyte is heated for temperature control and when the heating is turned off and the electrolyte temperature drops, the internal electrolyte temperature distribution is usually uneven, making it difficult to establish a reasonable and reliable temperature monitoring strategy.

[0004] Therefore, it is necessary to optimize the temperature monitoring of the vanadium liquid flow battery, more reasonably monitor the temperature of the electrolyte with uneven temperature, and achieve more reliable temperature control. Summary of the Invention

[0005] The purpose of the present invention is to provide a thermal management device for a vanadium liquid flow battery and a control method thereof, which can more reasonably monitor the temperature of the electrolyte with uneven temperature.

[0006] The present invention is achieved through the following technical solutions:

[0007] A thermal management method for a vanadium liquid flow battery, comprising the following steps:

[0008] Set a first temperature sensor for monitoring the temperature of the electrolyte at the heating device setting of the electrolyte container, and set a second temperature sensor for monitoring the temperature of the electrolyte at the location with the largest height difference from the heating device setting in the electrolyte container;

[0009] Obtain the height difference between the first temperature sensor and the second temperature sensor, and periodically obtain the monitoring values of the first temperature sensor and the second temperature sensor;

[0010] Determine the start heating time according to the height difference and the monitoring values;

[0011] During the heating process, determine the stop heating time according to the height difference and the monitoring values.

[0012] Preferably, the heating device is arranged below the electrolyte container;

[0013] The first temperature sensor is arranged at the bottom inside the electrolyte container, and the second temperature sensor is arranged at the top inside the electrolyte container.

[0014] Preferably, the method for determining the start heating time according to the height difference and the monitoring value is as follows:

[0015] Obtain the lower limit of the standard working temperature range of the electrolyte;

[0016] Set a first temperature threshold according to the rated constant temperature value;

[0017] When the temperature at the first temperature sensor is lower than the first temperature threshold, start heating.

[0018] Preferably, the method for setting the first temperature threshold according to the rated constant temperature value is as follows:

[0019]

[0020] Wherein, T th1 is the first temperature threshold, T lb is the lower limit of the standard working temperature range, ΔT is the set basic adjustment temperature difference, e is the natural constant, and H is the height difference.

[0021] Preferably, the method for obtaining the basic adjustment temperature difference ΔT is as follows:

[0022] Obtain the upper limit T ub :

[0023]

[0024] 5 ≤ N ≤ 10;

[0025] Wherein, N is a set constant.

[0026] Preferably, the method for determining the stop heating time according to the height difference and the monitoring value is as follows:

[0027] Set a second temperature threshold;

[0028] Obtain the differential heating time according to the second temperature threshold, the height difference, and the monitoring value;

[0029] After the monitoring value of the first temperature sensor reaches the second temperature threshold, stop heating after the differential heating time.

[0030] Preferably, the method for setting the second temperature threshold is as follows:

[0031] Obtain the upper and lower limits of the standard working temperature range of the electrolyte

[0032]

[0033] Wherein, Tth2 is the second temperature threshold, T lb and T ub are respectively the lower limit and the upper limit of the standard operating temperature range.

[0034] Preferably, the method for obtaining the differential heating time is as follows:

[0035] Obtain the monitored value T2 of the current second temperature sensor;

[0036] Obtain the temperature distribution gradient in the height direction of the electrolyte

[0037] Obtain the differential heating time t:

[0038]

[0039] where H is the height difference, C is the specific heat capacity of the electrolyte, m is the mass of the electrolyte, and P is the heating power.

[0040] Preferably, the method for obtaining the temperature distribution gradient is as follows:

[0041] In the historical acquisition data, obtain the monitored values of the first temperature sensor and the second temperature sensor at N time points during the heating process;

[0042] Calculate the temperature distribution gradient

[0043]

[0044] where and respectively represent the monitored values of the first temperature sensor and the second temperature sensor at the nth time point.

[0045] The present invention also provides a vanadium liquid battery stack thermal management device, which is applied to the above-mentioned vanadium liquid battery stack thermal management method, and includes:

[0046] A heating device for heating the electrolyte container;

[0047] A first temperature sensor for monitoring the temperature of the electrolyte at the heating device setting of the electrolyte container;

[0048] A second temperature sensor for monitoring the temperature of the electrolyte at the location with the largest height difference from the heating device setting in the electrolyte container;

[0049] A numerical value acquisition module for obtaining the height difference between the first temperature sensor and the second temperature sensor, and periodically obtaining the monitored values of the first temperature sensor and the second temperature sensor;

[0050] A heating time management module is configured to determine the start heating time according to the height difference and the monitored value, and during the heating process, determine the stop heating time according to the height difference and the monitored value.

[0051] The technical solution of the present invention has at least the following advantages and beneficial effects:

[0052] The present invention realizes the temperature monitoring of the electrolyte by detecting the temperatures of the heating part and the electrolyte at the farthest point from the heating part, which helps to better monitor the electrolyte temperature based on the temperature non-uniformity;

[0053] When the present invention determines whether heating is required, it takes into account the heating hysteresis of the electrolyte at the farthest point from the heating part and sets a more reasonable judgment threshold;

[0054] When the present invention determines the stop heating time, it comprehensively and quantitatively considers the temperature difference, and the heating time control is more reasonable, which helps to heat the comprehensive temperature of the electrolyte to an appropriate temperature range;

[0055] When the present invention monitors the temperatures at two points for temperature control, it also takes into account the height difference and quantifies the temperature hysteresis, which helps to accurately control the start and end times of heating, avoid overheating or underheating, and thus optimize the working performance of the vanadium liquid battery stack;

[0056] The present invention can effectively avoid overheating, improve the efficiency and cost performance of thermal management, and avoid energy waste;

[0057] The present invention is reasonably designed, the layout of each electrical component is simple, it has a high cost performance, and is convenient for popularization and implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a schematic flowchart of a vanadium liquid battery stack thermal management method provided by Embodiment 1 of the present invention;

[0059] Figure 2 It is a schematic diagram of the principle of a vanadium liquid battery stack thermal management device provided by Embodiment 2 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0061] Embodiment 1

[0062] This embodiment provides a thermal management method for a vanadium liquid flow battery stack. Refer to Figure 1 , which includes the following steps:

[0063] Set a first temperature sensor for monitoring the electrolyte temperature at the heating device setting of the electrolyte container, and set a second temperature sensor for monitoring the electrolyte temperature at the location with the largest height difference from the heating device setting in the electrolyte container;

[0064] Obtain the height difference between the first temperature sensor and the second temperature sensor, and periodically obtain the monitoring values of the first temperature sensor and the second temperature sensor;

[0065] Determine the start heating time according to the height difference and the monitoring values;

[0066] During the heating process, determine the stop heating time according to the height difference and the monitoring values.

[0067] In this embodiment, by setting the first temperature sensor and the second temperature sensor to monitor the heating device of the electrolyte container and the part with the largest temperature difference respectively, the electrolyte temperature can be ensured to be maintained within an appropriate range. Regularly obtaining the monitoring values of the temperature sensors and formulating a control strategy in combination with the height difference between the positions detected by the two sensors can make the electrolyte temperature fluctuate within the optimal working range, avoid untimely local heating, and also avoid energy waste caused by overheating, improve the efficiency of thermal management, and reduce unnecessary energy consumption. The height difference can reflect the heating delay degree between the two detection points, which helps to obtain a more accurate temperature monitoring scheme.

[0068] It should be particularly noted that the independent temperature monitoring can be carried out for the positive electrolyte and the negative electrolyte of the vanadium liquid flow battery stack according to the scheme of this embodiment.

[0069] In this embodiment, the heating device is arranged below the electrolyte container;

[0070] The first temperature sensor is arranged at the bottom inside the electrolyte container, and the second temperature sensor is arranged at the top inside the electrolyte container.

[0071] As a preferred solution, the method for determining the start heating time according to the height difference and the monitoring values is:

[0072] Obtain the lower limit of the standard working temperature range of the electrolyte;

[0073] Set a first temperature threshold according to the rated constant temperature value;

[0074] Turn on the heating when the temperature at the first temperature sensor is lower than the first temperature threshold.

[0075] Further, the method for setting the first temperature threshold according to the rated constant temperature value is:

[0076]

[0077] where T th1 is the first temperature threshold, T lb is the lower limit of the standard operating temperature range, ΔT is the set basic adjustment temperature difference, e is the natural constant, and H is the height difference.

[0078] On this basis, the method for obtaining the basic adjustment temperature difference ΔT is:

[0079] Obtain the upper limit T ub :

[0080]

[0081] 5 ≤ N ≤ 10;

[0082] where N is a set constant.

[0083] Based on the settings of this embodiment, the situation of heating delay is considered. For example, it avoids the situation where after turning on the heating, the electrolyte at the position of the second temperature sensor continues to cool down beyond the appropriate temperature range before the temperature is transmitted to that position, that is, it avoids the situation where the heating is turned on too late only considering the value of the first temperature sensor. Therefore, the setting of T th1 also sets a gain based on the size of H on the basis of T lb . The larger H is, the greater the temperature delay and the greater this gain. ΔT can be set as an empirical value.

[0084] On the other hand, the method for determining the heating-off time according to the height difference and the monitoring value is:

[0085] Set a second temperature threshold;

[0086] Obtain the differential heating time according to the second temperature threshold, the height difference, and the monitoring value;

[0087] After the monitoring value of the first temperature sensor reaches the second temperature threshold, turn off the heating after the differential heating time.

[0088] As a further preferred solution, the method for setting the second temperature threshold is:

[0089] Obtain the upper and lower limits of the standard operating temperature range of the electrolyte

[0090]

[0091] Among them, T th2 is the second temperature threshold, and T lb and T ub are the lower limit and the upper limit of the standard working temperature range respectively.

[0092] Specifically, the method for obtaining the differential heating time is as follows:

[0093] Obtain the monitored value T2 of the current second temperature sensor;

[0094] Obtain the temperature distribution gradient in the height direction of the electrolyte

[0095] Obtain the differential heating time t:

[0096]

[0097] Among them, H is the height difference, C is the specific heat capacity of the electrolyte, m is the mass of the electrolyte, and P is the heating power.

[0098] Finally, the method for obtaining the temperature distribution gradient is preferably as follows:

[0099] In the historical acquisition data, obtain the monitored values of the first temperature sensor and the second temperature sensor at N time points during the heating process;

[0100] Calculate the temperature distribution gradient

[0101]

[0102] Among them, and respectively represent the monitored values of the first temperature sensor and the second temperature sensor at the nth time point.

[0103] In this embodiment, considering the case where the heat is delayed in reaching the electrolyte at the position of the second sensor, the heating is ended as early as possible, which can not only ensure that the working temperature of the electrolyte is appropriate, but also help to save the energy consumption of heating.

[0104] The setting principle of this embodiment is:

[0105] According to the heat transfer formula and the relationship between heat and heating power, it can be known that:

[0106] P·t′=m·C·ΔT;

[0107] Wherein, t′ is the heating time, and ΔT is the temperature change after heating.

[0108] That is to say, the heating time t′ is:

[0109]

[0110] Assume that during the heating process, the temperature values from the first temperature sensor to the second temperature sensor change in a uniform gradient, and thus the corresponding gradient value can be obtained

[0111]

[0112] Wherein, TS1 and TS2 respectively represent the monitoring values of the first temperature sensor and the second temperature sensor, and it can be obtained that:

[0113]

[0114] Therefore, since the purpose is that the monitoring value of the second temperature sensor reaches T th2 :

[0115] TS2 = T th2 ;

[0116] It can be known that the value of the first temperature sensor at this time should be And at this time, the first temperature sensor just reaches T th2 , so the heating temperature difference at this point is Based on the solution of this embodiment and substituting it into the heating time t′ in the previous text, it can be known that:

[0117]

[0118] The t′ calculated here is the differential heating time t of this embodiment.

[0119] Embodiment 2

[0120] This embodiment provides a vanadium liquid flow battery thermal management device, which is applied to the above-mentioned vanadium liquid flow battery thermal management method. Refer to Figure 2 , including:

[0121] A heating device for heating the electrolyte container;

[0122] A first temperature sensor for monitoring the electrolyte temperature at the setting location of the heating device of the electrolyte container;

[0123] A second temperature sensor for monitoring the electrolyte temperature at the location with the largest height difference from the setting location of the heating device in the electrolyte container;

[0124] A numerical value acquisition module, configured to acquire the height difference between the first temperature sensor and the second temperature sensor, and periodically acquire the monitoring numerical values of the first temperature sensor and the second temperature sensor;

[0125] A heating time management module, configured to determine the start heating time according to the height difference and the monitoring numerical values, and during the heating process, determine the stop heating time according to the height difference and the monitoring numerical values.

[0126] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A thermal management method for a vanadium flow battery stack, characterized in that Including the following steps: A first temperature sensor is set, which is used to monitor the electrolyte temperature at the heating device setting of the electrolyte container, and a second temperature sensor is set, which is used to monitor the electrolyte temperature at the location with the largest height difference from the heating device setting in the electrolyte container; Obtain the height difference between the first temperature sensor and the second temperature sensor, and periodically obtain the monitoring values of the first temperature sensor and the second temperature sensor; Determine the start heating time according to the height difference and the monitoring values; During the heating process, determine the stop heating time according to the height difference and the monitoring values.

2. The method for heat management of a vanadium liquid flow battery stack according to claim 1, wherein The heating device is arranged below the electrolyte container; The first temperature sensor is arranged at the bottom inside the electrolyte container, and the second temperature sensor is arranged at the top inside the electrolyte container.

3. A method for thermal management of a vanadium flow battery stack according to claim 1, characterized in that, The method for determining the start heating time according to the height difference and the monitoring values is as follows: Obtain the lower limit of the standard working temperature range of the electrolyte; Set a first temperature threshold according to the rated constant temperature value; Start heating when the temperature at the first temperature sensor is lower than the first temperature threshold.

4. A vanadium flow battery thermal management method according to claim 3, characterized in that The method for setting the first temperature threshold according to the rated constant temperature value is as follows: Among them, T th1 is the first temperature threshold, T lb is the lower limit of the standard operating temperature range, ΔT is the set basic adjustment temperature difference, e is the natural constant, and H is the height difference.

5. A method for thermal management of a vanadium flow battery stack according to claim 4, characterized in that, The method for obtaining the basic adjustment temperature difference ΔT is as follows: Obtain the upper limit T of the standard operating temperature range of the electrolyte ub : 5≤N≤10； Where N is a set constant.

6. The vanadium flow battery stack thermal management method according to claim 1, wherein The method for determining the stop heating time according to the height difference and the monitoring values is as follows: Set a second temperature threshold; Obtain the differential heating time according to the second temperature threshold, the height difference, and the monitoring values; After the monitoring value of the first temperature sensor reaches the second temperature threshold, stop heating after the differential heating time.

7. A method for thermal management of a vanadium flow battery stack according to claim 6, characterized in that, The setting method of the second temperature threshold is as follows: Obtain the upper limit and the lower limit of the standard working temperature range of the electrolyte Among them, T th2 is the second temperature threshold, T lb and T ub are the lower limit and the upper limit of the standard operating temperature range, respectively.

8. A method for thermal management of a vanadium flow battery stack according to claim 7, characterized in that, The method for obtaining the differential heating time is as follows: Obtain the monitoring value T2 of the current second temperature sensor; Obtain the temperature distribution gradient in the height direction of the electrolyte Obtain the differential heating time t: Where H is the height difference, C is the specific heat capacity of the electrolyte, m is the mass of the electrolyte, and P is the heating power.

9. A method for thermal management of a vanadium flow battery stack according to claim 8, characterized in that, The temperature distribution gradient is obtained by the following method: In the historical acquisition data, obtain the monitoring values of the first temperature sensor and the second temperature sensor at N time points during the heating process; Calculate the temperature distribution gradient wherein, and respectively represent the monitored values of the first temperature sensor and the second temperature sensor at the nth time point.

10. A vanadium flow battery thermal management device is applied to the vanadium flow battery thermal management method according to any one of claims 1-9, and is characterized in that, Including: A heating device for heating the electrolyte container; A first temperature sensor for monitoring the electrolyte temperature at the heating device setting of the electrolyte container; A second temperature sensor for monitoring the electrolyte temperature at the location with the largest height difference from the heating device setting in the electrolyte container; A numerical value acquisition module for obtaining the height difference between the first temperature sensor and the second temperature sensor, and periodically obtaining the monitoring values of the first temperature sensor and the second temperature sensor; A heating time management module for determining the start heating time according to the height difference and the monitoring values, and during the heating process, determining the stop heating time according to the height difference and the monitoring values.

Images