Lithium battery thermal management temperature pre-control system based on working conditions and operation method

Abstract

The invention discloses a lithium battery thermal management temperature pre-control system based on working conditions and an operation method.The system comprises a power battery pack formed by connecting a plurality of power batteries in parallel and a plurality of refrigerating units and further comprises a plate exchange confluence cavity, a battery shunt cavity, a battery confluence cavity and a plate exchange shunt cavity; the inlet end and the outlet end of the refrigerating unit are connected with the outlet end of the plate exchange flow dividing cavity and the inlet end of the plate exchange flow converging cavity respectively, a bypass pipe is arranged between the outlet end of the plate exchange flow dividing cavity and the inlet end of the plate exchange flow converging cavity, and an electric control throttling valve is arranged on the bypass pipe. The battery shunting cavity is used for shunting the cooling liquid in the plate exchange confluence cavity to a cooling inlet of each power battery in the power battery pack, and the battery confluence cavity is used for confluence of the cooling liquid of each power battery in the power battery pack and outputting the confluence to the plate exchange shunting cavity. According to the invention, an active temperature control mode is adopted, so that the battery temperature can be more effectively maintained in a safe range, and the reliability and stability of a battery system are improved.

Description

Technical Field

[0001] The present invention belongs to the field of new energy, relates to lithium battery temperature management technology, and specifically relates to a lithium battery thermal management temperature pre-control system based on working conditions and an operation method. Background Art

[0002] With the rapid development of new energy technologies, batteries have been widely used as core power sources in electric vehicles, energy storage systems, electronic equipment, etc. However, batteries generate a lot of heat during the charging and discharging process, and their temperature management issues have become a key factor affecting battery performance, life and safety.

[0003] The optimal operating temperature range of batteries is usually narrow, and temperatures that are too high or too low will have an adverse effect on their performance. High temperatures may accelerate chemical reactions inside the battery, causing thermal runaway or even fire and explosion; low temperatures will reduce the battery's charging and discharging efficiency and capacity. Therefore, an effective battery thermal management system is crucial to maintaining battery performance, extending service life, and ensuring safety in use.

[0004] Existing battery thermal management technologies include air cooling, liquid cooling, phase change material cooling, etc. The air cooling system has a simple structure and low cost, but the heat dissipation efficiency is limited and it is difficult to meet the needs of high-power battery packs. Phase change materials can absorb or release a large amount of latent heat, but in a high temperature environment, the phase change material may be completely melted and cannot be cooled further. At the same time, the heat dissipation structure in the battery is very demanding.

[0005] Patent document with publication number CN218160482U discloses an anode circulation pump assembly and a fuel cell system for a fuel cell system, which adopts a liquid cooling method, but it is an immersion type. This cooling method has a complex system, high cost and low reliability. It has a high risk of failure in engineering machinery working scenarios with harsh environmental conditions such as vibration. Moreover, it is a passive cooling working mode, and the cooling amount cannot be adjusted according to the actual working conditions, and the efficiency is low. Summary of the invention

[0006] Purpose of the invention: In order to overcome the deficiencies in the prior art, a lithium battery thermal management temperature pre-control system and operation method based on working conditions are provided. By predicting the temperature change trend of the battery in advance and adjusting the working mode of the thermal management system in advance according to the prediction results, effective intervention can be carried out before the battery temperature reaches the critical value, thereby avoiding the occurrence of dangerous situations such as thermal runaway. Compared with traditional passive temperature control, this active temperature control method can more effectively maintain the battery temperature within a safe range and improve the reliability and stability of the battery system.

[0007] Technical solution: To achieve the above-mentioned purpose, the present invention provides a lithium battery thermal management temperature pre-control system based on working conditions, including a power battery pack composed of a plurality of power batteries connected in parallel and a plurality of refrigeration units, and also including a plate exchange confluence chamber, a battery shunt chamber, a battery confluence chamber and a plate exchange shunt chamber. The inlet end and the outlet end of the refrigeration unit are respectively connected to the outlet end of the plate exchange shunt chamber and the inlet end of the plate exchange confluence chamber, a bypass pipe is arranged between the outlet end of the plate exchange shunt chamber and the inlet end of the plate exchange confluence chamber, an electrically controlled throttle valve is arranged on the bypass pipe, the battery shunt chamber is used to shunt the coolant in the plate exchange confluence chamber to the cooling inlet of each power battery in the power battery pack, and the battery confluence chamber is used to converge the coolant of each power battery in the power battery pack and output it to the plate exchange shunt chamber.

[0008] Furthermore, the refrigeration unit includes a condenser, a condenser fan, a compressor, a plate exchanger and a thermal expansion valve. The compressor, condenser and thermal expansion valve are sequentially arranged on the condensation pipeline of the plate exchanger, and the condenser fan is arranged on the condenser.

[0009] Furthermore, the system also includes an expansion water tank, a water pump is arranged between the plate converter confluence cavity and the battery diversion cavity, and the expansion water tank is respectively connected to the inlet pipeline of the water pump and the outlet pipeline of the battery confluence cavity, and is used for water replenishment and exhaust respectively.

[0010] Furthermore, a battery inlet temperature sensor is provided on the outlet pipeline of the water pump, and a battery outlet temperature sensor is provided on the coolant outlet pipeline of each power battery.

[0011] Furthermore, an ambient temperature sensor is provided at the air inlet of the condenser and the condenser fan.

[0012] Furthermore, the electronically controlled throttle valve, water pump, condenser fan and compressor are all controllable variable frequency types, and the rotation speed or opening degree can be controlled to ensure the robustness of the thermal management system; all compressors have the same rotation speed, and all condenser fans have the same rotation speed, ensuring the convenience of control.

[0013] The present invention also provides an operating method of a lithium battery thermal management temperature pre-control system based on working conditions, comprising the following steps:

[0014] S1: According to the fluctuation of Q_req, determine whether the system is close to steady-state operation. If so, proceed to step S3, otherwise proceed to step S2;

[0015] S2: Determine whether Q_req increases. If yes, open the electronically controlled throttle valve to increase the speed of the water pump, condenser fan and compressor. When Q_req, battery inlet temperature T0 and battery outlet temperature T1 are maintained in a stable state, proceed to step S3. If not, when Q_req, battery inlet temperature T0 and battery outlet temperature T1 are maintained in a stable state, proceed to step S3.

[0016] S3: The electronically controlled throttle valve is controlled in a closed state, the water pump speed is controlled according to a pre-calibrated amount, and the system working state is determined according to the ambient temperature obtained by the ambient temperature sensor. When the ambient temperature is less than the set temperature, the process proceeds to step S4; when the ambient temperature is greater than or equal to the set temperature, the process proceeds to step S5;

[0017] S4: Control the condenser fan speed according to the calibration value; control the compressor speed according to the sensed temperature of the battery inlet temperature sensor, for closed-loop control of the battery inlet temperature T0;

[0018] S5: Control the compressor speed according to the calibration value; control the condenser fan speed according to the sensed temperature of the battery inlet temperature sensor, so as to control the battery inlet temperature T0 in a closed loop.

[0019] Furthermore, if the Q_req fluctuation in step S1 is less than 5%, it is determined that the system is close to steady-state operation; otherwise, it is determined that the system is not close to steady-state operation.

[0020] Beneficial effects: Compared with the prior art, the present invention adopts an active pre-intervention temperature control method, which has the following advantages:

[0021] 1. The present invention reduces the power consumption of the thermal management system by taking into account the influencing factors of environmental conditions and dividing the control strategy in detail.

[0022] 2. The present invention improves the robustness and real-time performance of the thermal management system and the reliability and life of the battery through the pre-intervention of transient control.

[0023] 3. The present invention actively controls the thermal management system in advance to make the battery work in a more stable and comfortable temperature range, prevent overheating and temperature fluctuations from affecting battery charging and discharging, and maintain battery reliability and life. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structural connection of the system of the present invention;

[0025] Figure 2 The figure is a flow chart of the operation of the system of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0027] Embodiment 1:

[0028] like Figure 1 As shown, the present embodiment provides a lithium battery thermal management temperature pre-control system based on working conditions, including a power battery pack 2 composed of a plurality of power batteries connected in parallel, n refrigeration units, a plate exchanger flow chamber 10, a battery shunt chamber 11, a battery shunt chamber 12, a plate exchanger flow chamber 13, and an expansion water tank 8. The refrigeration unit includes a condenser 4, a condenser fan 3, a compressor 5, a plate exchanger 6, and a thermal expansion valve 7. The compressor 5, the condenser 4, and the thermal expansion valve 7 are sequentially arranged on the condensation pipeline of the plate exchanger 6. The condenser fan 3 is arranged on the condenser 4. The outlet end of the plate exchanger flow chamber 13 shunts a plurality of branches, which are respectively connected to the coolant inlet of the plate exchanger 6. The coolant outlet of the plate exchanger 6 is converged to the plate exchanger flow chamber 10 through a pipeline. A bypass pipe is arranged between the outlet end of the plate exchanger flow chamber 13 and the inlet end of the plate exchanger flow chamber 10. An electrically controlled throttle valve 9 is arranged on the bypass pipe. A water pump 1 is arranged between the plate exchanger flow chamber 10 and the battery shunt chamber 11. The shunt branches at the outlet end of the cavity 11 are respectively connected to the coolant inlet of each power battery in the power battery pack 2, and the coolant outlet of each power battery in the power battery pack 2 is connected to the inlet of the battery confluence cavity 12 through a pipeline, and the outlet of the battery confluence cavity 12 is connected to the inlet of the plate exchange shunt cavity 13 through a pipeline. The expansion water tank 8 is respectively connected to the inlet pipeline of the water pump 1 and the outlet pipeline of the battery confluence cavity 12. A battery inlet temperature sensor 14 is arranged on the outlet pipeline of the water pump 1, and a battery outlet temperature sensor 15 is arranged on the coolant outlet pipeline of each power battery. An ambient temperature sensor 16 is arranged at the air inlet of the condenser 4 and the condenser fan 3. The electronically controlled throttle valve 9, the water pump 1, the condenser fan 3, and the compressor 5 are all controllable variable frequency types, and the speed or opening can be controlled to ensure the robustness of the thermal management system; all compressors 5 have the same speed, and all condenser 4 fans have the same speed, which ensures the convenience of control.

[0029] Embodiment 2:

[0030] In this embodiment, the lithium battery thermal management temperature pre-control system provided in Example 1 is used as an example to provide an operation method of the lithium battery thermal management temperature pre-control system based on working conditions. Figure 2 , specifically including:

[0031] 1) The Q_req fluctuation is obtained according to the sensed temperature of the battery outlet temperature sensor 15. If the Q_req fluctuation is less than 5%, it is determined that the system is in a near-steady-state working state;

[0032] 2) The electronically controlled throttle valve 9 is controlled in a closed state, the speed W1 of the water pump 1 is controlled according to a pre-calibrated amount, and the ambient temperature is obtained by the ambient temperature sensor 16, and it is found that the ambient temperature is less than the set temperature of 40°C;

[0033] 3) The speed W2 of the condenser fan 3 is controlled according to the calibration value; the speed W3 of the compressor 5 is controlled according to the sensed temperature of the battery inlet temperature sensor 14, so as to control the battery inlet temperature T0 in a closed loop.

[0034] In this embodiment, the ambient temperature is less than the set temperature of 40°C, and there is a sufficient temperature difference between the refrigerant and the air in the condenser 4. The condenser fan 3 can meet the heat dissipation demand as long as it has a relatively low speed, and the fan power consumption is relatively low. Therefore, the speed of the condenser fan 3 is calibrated, and the speed of the compressor 5 is closed-loop controlled to control the battery inlet temperature T0. This control method allows the compressor power consumption to change as needed with the heat dissipation demand of the heat dissipation system, thereby reducing the overall power consumption of the thermal management system.

[0035] Embodiment 3:

[0036] In this embodiment, the lithium battery thermal management temperature pre-control system provided in Example 1 is used as an example to provide an operation method of the lithium battery thermal management temperature pre-control system based on working conditions. Figure 2 , specifically including:

[0037] 1) The Q_req fluctuation is obtained according to the sensed temperature of the battery outlet temperature sensor 15. If the Q_req fluctuation is less than 5%, it is determined that the system is in a near-steady-state working state;

[0038] 2) The electronically controlled throttle valve 9 is controlled in a closed state, the speed W1 of the water pump 1 is controlled according to a pre-calibrated amount, and the ambient temperature is obtained by the ambient temperature sensor 16, and it is found that the ambient temperature is ≥ the set temperature of 40°C;

[0039] 3) The speed W3 of the compressor 5 is controlled according to the calibration value; the speed W2 of the condenser fan 3 is controlled according to the sensed temperature of the battery inlet temperature sensor 14, so as to control the battery inlet temperature T0 in a closed loop.

[0040] In this embodiment, the ambient temperature is ≥ the set temperature of 40°C, and the condenser fan 3 needs to run at a high load to meet the heat dissipation demand of the condenser 4. Therefore, the speed W3 of the compressor 5 is looked up in a table according to the relationship between the pre-calibrated and the required heat dissipation of the battery, and the battery inlet temperature T0 is closed-loop controlled by the speed W2 of the condenser fan 3.

[0041] Embodiment 4:

[0042] In this embodiment, the lithium battery thermal management temperature pre-control system provided in Example 1 is used as an example to provide an operation method of the lithium battery thermal management temperature pre-control system based on working conditions. Figure 2 , specifically including:

[0043] 1) The Q_req fluctuation is obtained according to the sensed temperature of the battery outlet temperature sensor 15. If the Q_req fluctuation is greater than 5%, it is determined that the system is not in a near-steady-state working state;

[0044] 2) Determine whether Q_req increases. If yes, open the electronically controlled throttle valve 9 to control the flow rate, increase the speed of the water pump 1, the condenser fan 3 and the compressor 5, and when Q_req, the battery inlet temperature T0 and the battery outlet temperature T1 are maintained in a stable state, proceed to step 3); if not, when Q_req, the battery inlet temperature T0 and the battery outlet temperature T1 are maintained in a stable state, proceed to step 3);

[0045] 3) The electronically controlled throttle valve 9 is controlled in a closed state, the speed W1 of the water pump 1 is controlled according to a pre-calibrated amount, and the ambient temperature is obtained by the ambient temperature sensor 16, and it is found that the ambient temperature is less than the set temperature of 40°C;

[0046] 4) The speed W2 of the condenser fan 3 is controlled according to the calibration value; the speed W3 of the compressor 5 is controlled according to the sensed temperature of the battery inlet temperature sensor 14, so as to control the battery inlet temperature T0 in a closed loop.

Claims

1. A lithium battery thermal management temperature pre-control system based on working conditions, comprising a power battery pack composed of a plurality of power batteries connected in parallel and a plurality of refrigeration units, characterized in that: It also includes a plate exchange confluence chamber, a battery shunt chamber, a battery confluence chamber and a plate exchange shunt chamber. The inlet and outlet ends of the refrigeration unit are respectively connected to the outlet end of the plate exchange shunt chamber and the inlet end of the plate exchange confluence chamber. A bypass pipe is arranged between the outlet end of the plate exchange shunt chamber and the inlet end of the plate exchange confluence chamber. An electric-controlled throttle valve is arranged on the bypass pipe. The battery shunt chamber is used to shunt the coolant in the plate exchange confluence chamber to the cooling inlet of each power battery in the power battery pack. The battery confluence chamber is used to converge the coolant of each power battery in the power battery pack and output it to the plate exchange shunt chamber.

2. A lithium battery thermal management temperature pre-control system based on working conditions according to claim 1, characterized in that: The refrigeration unit comprises a condenser, a condenser fan, a compressor, a plate exchanger and a thermal expansion valve. The compressor, the condenser and the thermal expansion valve are arranged in sequence on the condensation pipeline of the plate exchanger, and the condenser fan is arranged on the condenser.

3. A lithium battery thermal management temperature pre-control system based on working conditions according to claim 2, characterized in that: It also includes an expansion water tank. A water pump is arranged between the plate exchanger confluence cavity and the battery diversion cavity. The expansion water tank is respectively connected to the inlet pipeline of the water pump and the outlet pipeline of the battery confluence cavity.

4. A lithium battery thermal management temperature pre-control system based on working conditions according to claim 3, characterized in that: A battery inlet temperature sensor is provided on the outlet pipeline of the water pump, and a battery outlet temperature sensor is provided on the coolant outlet pipeline of each power battery.

5. A lithium battery thermal management temperature pre-control system based on working conditions according to claim 4, characterized in that: Ambient temperature sensors are provided at the air inlets of the condenser and the condenser fan.

6. The lithium battery thermal management temperature pre-control system based on working conditions according to claim 3, characterized in that: The electronically controlled throttle valve, water pump, condenser fan and compressor are all controllable variable frequency type; all compressors have the same rotation speed, and all condenser fans have the same rotation speed.

7. The method for operating a lithium battery thermal management temperature pre-control system based on working conditions according to claim 5, characterized in that: The steps include: S1: According to the fluctuation of Q_req, determine whether the system is close to steady-state operation. If so, proceed to step S3, otherwise proceed to step S2; S2: Determine whether Q_req increases. If yes, open the electronically controlled throttle valve to increase the speed of the water pump, condenser fan and compressor. When Q_req, battery inlet temperature T0 and battery outlet temperature T1 are maintained in a stable state, proceed to step S3. If not, when Q_req, battery inlet temperature T0 and battery outlet temperature T1 are maintained in a stable state, proceed to step S3. S3: The electronically controlled throttle valve is controlled in a closed state, the water pump speed is controlled according to a pre-calibrated amount, and the system working state is determined according to the ambient temperature obtained by the ambient temperature sensor. When the ambient temperature is less than the set temperature, the process proceeds to step S4; when the ambient temperature is greater than or equal to the set temperature, the process proceeds to step S5; S4: Control the condenser fan speed according to the calibration value; control the compressor speed according to the sensed temperature of the battery inlet temperature sensor, for closed-loop control of the battery inlet temperature T0; S5: Control the compressor speed according to the calibration value; control the condenser fan speed according to the sensed temperature of the battery inlet temperature sensor, so as to control the battery inlet temperature T0 in a closed loop.

8. The method for operating a lithium battery thermal management temperature pre-control system based on working conditions according to claim 7, characterized in that: In step S1 , if the Q_req fluctuation is less than 5%, it is determined that the system is close to steady-state operation; otherwise, it is determined that the system is not close to steady-state operation.

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