Operating Condition-Based Temperature Pre-Control System and Operation Method for Lithium-Ion Batteries

Abstract

The present invention discloses a working condition-based temperature pre-control system and operation method for lithium battery thermal management. The system includes a power battery pack composed of a plurality of power batteries connected in parallel and a plurality of refrigeration units. It also includes a plate heat exchanger manifold chamber, a battery shunt chamber, a battery manifold chamber, and a plate heat exchanger shunt chamber. The inlet end and the outlet end of the refrigeration unit are respectively connected to the outlet end of the plate heat exchanger shunt chamber and the inlet end of the plate heat exchanger manifold chamber. A bypass pipe is provided between the outlet end of the plate heat exchanger shunt chamber and the inlet end of the plate heat exchanger manifold chamber, and an electronically controlled throttle valve is provided on the bypass pipe. The battery shunt chamber is used to shunt the coolant in the plate heat exchanger manifold chamber to the cooling inlets of each power battery in the power battery pack, and the battery manifold chamber is used to collect the coolant of each power battery in the power battery pack and output it to the plate heat exchanger shunt chamber. The present invention adopts an active temperature control method, which can more effectively maintain the battery temperature within a safe range and improve the reliability and stability of the battery system.

Description

Technical Field

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

[0002] With the rapid development of new energy technology, batteries, as the core power source, have been widely used in fields such as electric vehicles, energy storage systems, and electronic devices. However, during the charging and discharging process of batteries, a large amount of heat is generated, and its temperature management problem has become a key factor affecting battery performance, life, and safety.

[0003] The optimal operating temperature range of the battery is usually relatively narrow, and too high or too low temperature will have an adverse impact on its performance. High temperature may cause the internal chemical reaction of the battery to accelerate, leading to thermal runaway and even fire and explosion; low temperature will reduce the charging and discharging efficiency and capacity of the battery. Therefore, an effective battery thermal management system is crucial for maintaining battery performance, extending service life, and ensuring use safety.

[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 its heat dissipation efficiency is limited and it is difficult to meet the requirements of high-power battery packs. Phase change materials can absorb or release a large amount of latent heat, but in a high-temperature environment, there may be a problem that the phase change material completely melts and cannot continue to cool, and at the same time, the requirements for the internal heat dissipation structure of the battery are very high.

[0005] The patent document with the 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, and has a high risk of failure in the working scenarios of construction machinery with harsh environmental conditions such as vibration. Moreover, it is a passive cooling working mode, unable to adjust the cooling capacity according to the actual working conditions, and has low efficiency. Summary of the Invention

[0006] Object of the Invention: In order to overcome the deficiencies in the prior art, a working condition-based lithium battery thermal management temperature pre-control system and an operation method thereof 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 result, 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. This active temperature control method can more effectively maintain the battery temperature within a safe range compared with the traditional passive temperature control, and improve the reliability and stability of the battery system.

[0007] Technical solution: To achieve the above object, the present invention provides a working condition-based temperature pre-control system for lithium battery thermal management, which includes a power battery pack composed of a plurality of power batteries connected in parallel and a plurality of refrigeration units, and also includes a plate heat exchanger manifold chamber, a battery shunt chamber, a battery manifold chamber, and a plate heat exchanger shunt chamber. The inlet end and the outlet end of the refrigeration unit are respectively connected to the outlet end of the plate heat exchanger shunt chamber and the inlet end of the plate heat exchanger manifold chamber. A bypass pipe is provided between the outlet end of the plate heat exchanger shunt chamber and the inlet end of the plate heat exchanger manifold chamber, and an electronically controlled throttle valve is provided on the bypass pipe. The battery shunt chamber is used to shunt the coolant in the plate heat exchanger manifold chamber to the cooling inlets of each power battery in the power battery pack, and the battery manifold chamber is used to collect the coolant of each power battery in the power battery pack and output it to the plate heat exchanger shunt chamber.

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

[0009] Further, the system also includes an expansion tank. A water pump is provided between the plate heat exchanger manifold chamber and the battery shunt chamber. The expansion tank is respectively connected to the inlet pipeline of the water pump and the outlet pipeline of the battery manifold chamber, and is used for water replenishment and exhaust respectively.

[0010] Further, 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] Further, an ambient temperature sensor is provided at the air inlet of the condenser and the condenser fan.

[0012] Further, the electronically controlled throttle valve, the water pump, the condenser fan, and the compressor are all controllable frequency conversion types, and can control the rotation speed or opening degree to ensure the robustness of the thermal management system; all the compressor rotation speeds are the same, and all the condenser fan rotation speeds are the same, which ensures the convenience of control.

[0013] The present invention also provides an operation method for a working condition-based temperature pre-control system for lithium battery thermal management, including the following steps:

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

[0015] S2: Determine whether Q_req has risen. If so, turn on the electronically controlled throttle valve, increase the speeds of the water pump, condenser fan, and compressor. When Q_req, the battery inlet temperature T0, and the battery outlet temperature T1 are maintained in a stable state, proceed to step S3; 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 S3;

[0016] S3: Control the electronically controlled throttle valve in the closed state, control the speed of the water pump according to a pre-calibrated quantity, determine the system operating state based on the ambient temperature obtained by the ambient temperature sensor. When the ambient temperature < the set temperature, proceed to step S4; when the ambient temperature ≥ the set temperature, proceed to step S5;

[0017] S4: Control the speed of the condenser fan according to a calibrated quantity; control the speed of the compressor 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 speed of the compressor according to a calibrated quantity; control the speed of the condenser fan according to the sensed temperature of the battery inlet temperature sensor for closed-loop control of the battery inlet temperature T0.

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

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

[0021] 1. By considering the influencing factors of environmental conditions, the present invention divides the control strategy in detail, reducing the power consumption of the thermal management system.

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

[0023] 3. By pre-actively controlling the thermal management system, the present invention enables the battery to operate in a more stable and comfortable temperature range, preventing over-temperature and temperature fluctuations from affecting the charging and discharging of the battery, and maintaining the reliability and lifespan of the battery. Description of the Drawings

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

[0025] Figure 2 It is a flowchart of the operation of the system of the present invention. Detailed Embodiments

[0026] The present invention is further illustrated below with reference to 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, modifications of various equivalent forms of the present invention made by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0027] Example 1:

[0028] like Figure 1 As shown, this embodiment provides a lithium battery thermal management temperature pre-control system based on working conditions, including a power battery pack 2 composed of several power batteries connected in parallel, n refrigeration units, a plate exchange chamber 10, a battery shunt chamber 11, a battery shunt chamber 12, a plate exchange 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, condenser 4 and thermal expansion valve 7 are arranged in sequence 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 exchange chamber 13 branches off several branches, which are respectively connected to the coolant inlet of the plate exchanger 6, and the coolant outlet of the plate exchanger 6 is converged to the plate exchange chamber 10 through a pipeline. A bypass pipe is provided between the outlet end of the plate exchange chamber 13 and the inlet end of the plate exchange chamber 10, and an electronically controlled throttle valve 9 is provided on the bypass pipe. A water pump 1 is provided between the plate exchange chamber 10 and the battery shunt chamber 11, and the battery shunt chamber 12 is provided with a water pump 1. The shunt branch at the outlet end of the cavity 11 is 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 provided on the outlet pipeline of the water pump 1, and a battery outlet temperature sensor 15 is provided on the coolant outlet pipeline of each power battery. An ambient temperature sensor 16 is provided 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 type, which can control the speed or opening 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] Example 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 operating method of the lithium battery thermal management temperature pre-control system based on working conditions. Figure 2 , specifically including:

[0031] 1) Obtain the Q_req fluctuation based on the sensed temperature of the battery outlet temperature sensor 15. When the Q_req fluctuation is less than 5%, it is determined that the system is in a near-steady-state operating condition;

[0032] 2) Control the electronic throttle valve 9 in the closed state. Control the speed W1 of the water pump 1 according to a pre-calibrated quantity. Obtain the ambient temperature based on the ambient temperature sensor 16 and find that the ambient temperature < the set temperature of 40°C;

[0033] 3) Control the speed W2 of the condenser fan 3 according to a calibrated quantity; control the speed W3 of the compressor 5 according to the sensed temperature of the battery inlet temperature sensor 14 for closed-loop control of the battery inlet temperature T0.

[0034] In this embodiment, since the ambient temperature < the set temperature of 40°C, there is a sufficient temperature difference between the refrigerant and the air in the condenser 4. The condenser fan 3 only needs a relatively low speed to meet the heat dissipation requirements, and the fan power consumption is low. Therefore, the speed of the condenser fan 3 is calibrated, and the speed of the compressor 5 is used for closed-loop control of the battery inlet temperature T0. This control method enables the compressor power consumption to change according to the heat dissipation requirements 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 Embodiment 1 is applied as an example, and a method for operating a lithium battery thermal management temperature pre-control system based on working conditions is provided. Refer to Figure 2 , specifically including:

[0037] 1) Obtain the Q_req fluctuation based on the sensed temperature of the battery outlet temperature sensor 15. When the Q_req fluctuation is less than 5%, it is determined that the system is in a near-steady-state operating condition;

[0038] 2) Control the electronic throttle valve 9 in the closed state. Control the speed W1 of the water pump 1 according to a pre-calibrated quantity. Obtain the ambient temperature based on the ambient temperature sensor 16 and find that the ambient temperature ≥ the set temperature of 40°C;

[0039] 3) Control the speed W3 of the compressor 5 according to a calibrated quantity; control the speed W2 of the condenser fan 3 according to the sensed temperature of the battery inlet temperature sensor 14 for closed-loop control of the battery inlet temperature T0.

[0040] In this embodiment, since the ambient temperature ≥ the set temperature of 40°C, the condenser fan 3 needs to operate at a high load to meet the heat dissipation requirements of the condenser 4. Therefore, the speed W3 of the compressor 5 is looked up according to the pre-calibrated relationship with the heat dissipation quantity required by the battery, and the battery inlet temperature T0 is controlled in a closed loop through 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 Embodiment 1 is applied as an example to provide an operation method for the lithium battery thermal management temperature pre-control system based on working conditions. Refer to Figure 2 , specifically including:

[0043] 1) Obtain the Q_req fluctuation 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 nearly steady-state working condition;

[0044] 2) Determine whether Q_req is rising. If so, open the electronic control throttle valve 9 for flow control, increase the speeds of the water pump 1, the condenser fan 3, and the compressor 5. 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) Control the electronic control throttle valve 9 in the closed state, control the speed W1 of the water pump 1 according to the pre-calibrated quantity, and obtain the ambient temperature according to the ambient temperature sensor 16, and find that the ambient temperature < the set temperature of 40 °C;

[0046] 4) Control the speed W2 of the condenser fan 3 according to the calibrated quantity; control the speed W3 of the compressor 5 according to the sensed temperature of the battery inlet temperature sensor 14 for closed-loop control of the battery inlet temperature T0.

Claims

1. An operating method of a temperature pre-control system for a lithium battery thermal management based on working conditions, characterized in that, The lithium battery thermal management temperature pre-control system includes a power battery pack composed of several power batteries connected in parallel and several refrigeration units. It is characterized in that it further includes a plate heat exchanger manifold chamber, a battery shunt chamber, a battery manifold chamber and a plate heat exchanger shunt chamber. The inlet end and the outlet end of the refrigeration unit are respectively connected to the outlet end of the plate heat exchanger shunt chamber and the inlet end of the plate heat exchanger manifold chamber. A bypass pipe is provided between the outlet end of the plate heat exchanger shunt chamber and the inlet end of the plate heat exchanger manifold chamber. An electronically controlled throttle valve is provided on the bypass pipe. The battery shunt chamber is used to shunt the coolant in the plate heat exchanger manifold chamber to the cooling inlets of each power battery in the power battery pack. The battery manifold chamber is used to collect the coolant of each power battery in the power battery pack and output it to the plate heat exchanger shunt chamber; The refrigeration unit includes a condenser, a condenser fan, a compressor, a plate heat exchanger and a thermal expansion valve. The compressor, the condenser and the thermal expansion valve are sequentially arranged on the condensation pipeline of the plate heat exchanger. The condenser fan is arranged on the condenser; The system further includes an expansion tank. A water pump is provided between the plate heat exchanger manifold chamber and the battery shunt chamber. The expansion tank is respectively connected to the inlet pipeline of the water pump and the outlet pipeline of the battery manifold chamber; A battery inlet temperature sensor is provided on the outlet pipeline of the water pump. A battery outlet temperature sensor is provided on the coolant outlet pipeline of each power battery; An ambient temperature sensor is provided at the air inlet of the condenser and the condenser fan; The operation method of the lithium battery thermal management temperature pre-control system includes the following steps: S1: According to the fluctuation of Q_req, judge whether the system is close to the steady-state operation. If so, enter step S3; otherwise, enter step S2; S2: Judge whether Q_req rises. If so, open the electronically controlled throttle valve, increase the speeds of the water pump, the condenser fan and the compressor. When Q_req, the battery inlet temperature T0 and the battery outlet temperature T1 are maintained in a stable state, enter step S3; If not, when Q_req, the battery inlet temperature T0 and the battery outlet temperature T1 are maintained in a stable state, enter step S3; S3: Control the electronically controlled throttle valve in the closed state. Control the speed of the water pump according to the pre-set quantity. Determine the working state of the system according to the ambient temperature obtained by the ambient temperature sensor. When the ambient temperature < the set temperature, enter step S4; When the ambient temperature ≥ the set temperature, enter step S5; S4: Control the speed of the condenser fan according to the set quantity; Control the speed of the compressor according to the sensed temperature of the battery inlet temperature sensor for closed-loop control of the battery inlet temperature T0; S5: Control the speed of the compressor according to the set quantity; Control the speed of the condenser fan according to the sensed temperature of the battery inlet temperature sensor for closed-loop control of the battery inlet temperature T0; In step S1, if the fluctuation of Q_req is less than 5%, it is determined that the system is close to the steady-state operation; otherwise, it is determined that the system is not close to the steady-state operation.

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