A battery pack thermal management system and control method thereof

Abstract

The present invention provides a battery pack thermal management system composed of a first heat exchange plate (1), a second heat exchange plate (2), a battery cell (3), a semiconductor thermoelectric device (4), a power supply busbar (5), a pump (6), an expansion water tank (7), a refrigerator (8), a heater (9), a three-way valve (10), a main pipe (11), a first branch pipe (12), a second branch pipe (13), a temperature sensor array (14) and a controller (15), for improving the temperature consistency of the battery pack during operation. The present invention also provides a control method applied to the above-mentioned battery pack thermal management system: at fixed time intervals during the operation of the battery pack, the controller (15) obtains the temperature sequence T of each battery cell (3) to determine the state of the battery cell (3) corresponding to each temperature value; and one of the refrigerator (8) and the heater (9) is operated as needed to dissipate heat or heat the battery cell (3). The battery pack thermal management system provided by the present invention is simple, compact and easy to maintain; and the battery pack thermal management method has simple logic and is stable and reliable.

Description

Technical Field

[0001] The present invention relates to the field of battery energy storage, and in particular to a battery pack thermal management system and a control method thereof. Background Art

[0002] Electrochemical energy storage devices, represented by lithium-ion batteries, are widely used in various fields, including power tools, electric vehicles, and energy storage power stations. They are continuously developing towards high energy and power density, enhanced safety, and long life. To meet the energy and power requirements of various applications, multiple cells are typically connected in series and parallel to form a battery pack. A thermal management system is designed within the battery pack to maintain a reasonable operating temperature range: heating is applied if the temperature is too low, and cooling is applied if the temperature is too high. High consistency is desirable among the cells that make up the battery pack. Poor cell consistency can easily lead to a weak link, resulting in reduced battery pack performance, accelerated aging of individual cells, and ultimately premature failure of the entire pack. It can even cause thermal runaway in individual cells, leading to serious safety incidents. However, due to factors such as raw materials, manufacturing processes, and service conditions, it is impossible to ensure that every cell in a battery pack is completely identical. Therefore, technical measures are required to ensure cell consistency during operation.

[0003] The consistency of each cell in a battery pack is mainly divided into two aspects: electrical performance consistency and temperature consistency. The former mainly aims to make the capacity and internal resistance of each cell as consistent as possible. If there is a significant inconsistency, active or passive balancing circuits can be used to improve it. Specific measures include charging or discharging some cells separately and transferring the power of high-capacity cells to low-capacity cells. The latter mainly aims to minimize the temperature difference between each cell during operation. Currently known technical solutions can effectively solve the problem of inconsistent electrical performance of cells by various means such as arranging multiple circuits containing electronic switches. However, for the problem of temperature inconsistency, despite the best possible battery pack design in the early stage, it is still difficult to implement targeted temperature consistency control during battery pack operation, just as the electrical performance consistency control is required. This is because the thermal management of the battery pack mainly relies on the flow of fluid in the flow channel. If fine-grained temperature control is to be achieved at the cell level, it is necessary to arrange a separate flow channel and its control valves or motors for each cell. This will make the entire thermal management system complex, bulky, and have many failure points.

[0004] In order to meet the high performance, high safety and long life operation requirements of high energy and power density battery packs, it is urgent to draw on the ideas of current battery cell electrical performance balancing technology and develop new battery pack thermal management technology to maximize the temperature consistency of its operation process. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a battery pack thermal management system with a simple and compact structure and easy maintenance, and provides a battery pack thermal management method with simple logic, stable and reliable operation, efficient operation, and easy implementation, thereby effectively improving the temperature consistency of each battery cell during the operation of the battery pack.

[0006] According to one aspect of the present invention, a battery pack thermal management system is provided, whose technical solution is to include a battery cell array composed of a plurality of battery cell monomers, a first heat exchange plate, a second heat exchange plate and semiconductor thermoelectric devices corresponding to the battery cell monomers one by one; the semiconductor thermoelectric device includes a first heat exchange surface and a second heat exchange surface; the surface of the battery cell monomer includes a first type of surface and a second type of surface; the first type of surfaces of all battery cell monomers and the corresponding first heat exchange surfaces of the semiconductor thermoelectric devices are in contact with each other to achieve heat exchange; the second type of surfaces of all battery cell monomers and the first heat exchange plate are in contact with each other to achieve heat exchange; the second heat exchange surfaces of all semiconductor thermoelectric devices are in contact with the second heat exchange plate to achieve heat exchange.

[0007] In the above-mentioned battery pack thermal management system, heat exchange liquid flows through the first heat exchange plate and the second heat exchange plate.

[0008] The above-mentioned battery pack thermal management system supplies power to all semiconductor thermoelectric devices through a power supply bus, and the power supply bus includes a positive power supply bus and a negative positive power supply bus; the semiconductor thermoelectric device is provided with a first terminal and a second terminal, and can draw power from the power supply bus through any one of the first power supply branch and the second power supply branch; a first electronic switch pair is connected in series on the first power supply branch, and a second electronic switch pair is connected in series on the second power supply branch; wherein the first power supply branch electrically connects the first terminal to the positive power supply bus through one of the electronic switches in the first electronic switch pair, and electrically connects the second terminal to the negative positive power supply bus through the other electronic switch in the first electronic switch pair; the second power supply branch electrically connects the first terminal to the negative power supply bus through one of the electronic switches in the second electronic switch pair, and electrically connects the second terminal to the positive power supply bus through the other electronic switch in the second electronic switch pair.

[0009] The battery pack thermal management system further includes a fluid pipe network consisting of a pump, an expansion water tank, a cooler, a heater, a three-way valve, a main pipe, a first branch pipe, a second branch pipe, a first heat exchange plate, and a second heat exchange plate:

[0010] The expansion water tank is connected to the main pipe and is used to accommodate the expansion of the liquid and play a role in constant pressure and fluid replenishment;

[0011] The three-way valve includes a first passage, a second passage and a third passage;

[0012] The pump is provided with an outlet and an inlet;

[0013] The main pipe includes an outlet main pipe and an inlet main pipe;

[0014] The outlet of the pump is connected to the refrigerator, the heater and the first passage of the three-way valve in sequence through the outlet main pipe;

[0015] The second passage of the three-way valve is connected to the first heat exchange plate and the inlet main pipe in sequence through the first branch pipe;

[0016] The third passage of the three-way valve is connected to the second heat exchange plate and the inlet main pipe in sequence through the second branch pipe;

[0017] The inlet main pipe is also communicated with the inlet of the pump.

[0018] The above-mentioned battery pack thermal management system also includes a temperature sensor array and a controller, and the controller is electrically connected to the temperature sensor array, the refrigerator, the heater, the three-way valve, and all the first electronic switch pairs and the second electronic switch pairs.

[0019] In the above-mentioned battery pack thermal management system, when the first electronic switch pair is closed and the second electronic switch pair is disconnected, the first heat exchange surface of the semiconductor thermoelectric device plays a cooling role; when the first electronic switch pair is disconnected and the second electronic switch pair is closed, the first heat exchange surface of the semiconductor thermoelectric device plays a heating role.

[0020] In the above-mentioned battery pack thermal management system, the first passage (101) and the second passage (102) of the three-way valve are normally open, and the third passage is normally closed.

[0021] According to another aspect of the present invention, a control method for the above-mentioned battery pack thermal management system is provided, which operates one of the cooler and heater as needed to cool or heat the fluid in the fluid network, thereby achieving the purpose of heat dissipation or heating of the battery cells; at regular time intervals during the operation of the battery pack, the controller obtains the temperature sequence T = [T1, T2, ..., T i ,…,T n ], where n is the total number of battery cells, T i Represents the temperature value of the i-th battery cell. Calculate the average μ and standard deviation σ of each element in the sequence and control it according to the following logic:

[0022] (a) If all element values ​​in the temperature sequence T are greater than μ-Kσ and less than μ+Kσ, the first and second passages of the three-way valve are opened and the third passage is closed, and all first and second electronic switch pairs are disconnected;

[0023] (b) If there are element values ​​less than or equal to μ-Kσ in the temperature sequence T, it is determined that the battery cells corresponding to these element values ​​are in an overcooled state, and the first, second, and third passages of the three-way valve are all opened, and the first electronic switch pair of the semiconductor thermoelectric device corresponding to the battery cell in the overcooled state is opened and the second electronic switch pair is closed;

[0024] (c) If there are element values ​​greater than or equal to μ+Kσ in the temperature sequence T, it is determined that the battery cells corresponding to these element values ​​are in an overheated state, and the first, second, and third passages of the three-way valve are all opened, and the first electronic switch pair of the semiconductor thermoelectric device corresponding to the battery cell in the overheated state is closed and the second electronic switch pair is opened;

[0025] The value of the parameter K is between 2 and 5.

[0026] The present invention utilizes the Peltier effect of a semiconductor thermoelectric cooler (TEC), a phenomenon in which a direct current passes through a galvanic couple composed of two semiconductor materials, causing one end to absorb heat and the other to release heat. If the two ends of the TEC are designated as the first heat exchange surface and the second heat exchange surface, respectively, connecting the TEC in the forward direction will cause the first heat exchange surface to absorb heat, providing a cooling effect; connecting the TEC in the reverse direction will cause the first heat exchange surface to absorb heat, providing a heating effect.

[0027] In the above-mentioned battery pack thermal management system, the main circuit including the first heat exchange plate plays a conventional role in dissipating heat or heating the battery pack, and the secondary circuit including the second heat exchange plate plays a role in equalizing the temperature of the battery cells. Statistical principles are applied to determine whether there are local temperature anomalies during the operation of the battery pack. If there are temperature anomalies in individual battery cells, the secondary circuit of the second heat exchange plate is connected, and additional cooling or heating measures are taken for the battery cells with abnormal temperatures: if the temperature of an individual battery cell is too high, the semiconductor thermoelectric device in contact with it cools it and transfers its heat to the second heat exchange plate; if the temperature of an individual battery cell is too low, the semiconductor thermoelectric device in contact with it heats it and transfers the heat of the second heat exchange plate to the abnormal battery cell. The fluids in the first heat exchange plate and the second heat exchange plate eventually converge at the main pipe and are restored to the appropriate temperature through the refrigerator or heater, thus circulating the fluids.

[0028] According to the above principles, it is not difficult to find the following beneficial effects of the present invention:

[0029] 1. The battery pack thermal management system of this invention eliminates the need for additional fluid piping components and mechanical adjustment mechanisms for each battery cell, rather than requiring individual fluid piping and mechanical adjustment mechanisms. Instead, it relies on electrical components such as electronic switches, wires, and semiconductor thermoelectric devices to achieve refined thermal management and temperature equalization at the cell level. This results in a simple, compact structure and easy maintenance. Failures in the numerous temperature-equalizing components require only replacement of the electrical components, without compromising the sealing of the fluid piping network.

[0030] 2. The control method of the battery pack thermal management system of the present invention only needs to perform calculation analysis and logical judgment on the results of each temperature sampling and make control decisions in real time. Therefore, the amount of calculation is small, the logic is clear and simple, stable and reliable, easy to implement, and has the characteristics of real-time and efficient regulation; and only when there is a battery cell with abnormal temperature will the fluid circuit where the second heat exchange plate is located be turned on and the corresponding electronic switch be closed to enable the semiconductor thermoelectric device corresponding to the abnormal battery cell to work, so it has the characteristics of high efficiency and energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the battery pack thermal management system in an embodiment of the present invention. In the figure, 1 is a first heat exchange plate, 2 is a second heat exchange plate, 3 is a battery cell, 4 is a semiconductor thermoelectric device, 6 is a pump, 7 is an expansion water tank, 8 is a refrigerator, 9 is a heater, 10 is a three-way valve, 11 is a main pipe, 12 is a first branch pipe, 13 is a second branch pipe, 14 is a temperature sensor array, 31 is a first type of surface, 32 is a second type of surface, 33 is a pole of the battery cell 3, 41 is a first heat exchange surface, 42 is a second heat exchange surface, 61 is an outlet, 62 is an inlet, 101 is a first passage, 102 is a second passage, 103 is a third passage, 111 is an outlet main pipe, and 112 is an inlet main pipe.

[0032] Figure 2 3 is a schematic structural diagram of a battery cell in an embodiment of the present invention, in which 3 is a battery cell, 31 is a first type of surface, 32 is a second type of surface, and 33 is a pole of the battery cell 3.

[0033] Figure 3 This is a circuit diagram of the electrical connection between the power supply bus and the semiconductor thermoelectric device in an embodiment of the present invention. In the figure, 4 is the semiconductor thermoelectric device, 5 is the power supply bus, 43 is the first terminal, 44 is the second terminal, 45 is the first power supply branch, 46 is the second power supply branch, 47 is the first electronic switch pair, 48 is the second electronic switch pair, 51 is the positive power supply bus, and 52 is the negative positive power supply bus.

[0034] Figure 4Schematic diagram of the electrical connection between the controller and related components in an embodiment of the present invention, in which 4 is a semiconductor thermoelectric device, 8 is a cooler, 9 is a heater, 10 is a three-way valve, 13 is a second branch pipe, 14 is a temperature sensor array, 47 is a first electronic switch pair, and 48 is a second electronic switch pair.

[0035] Figure 5 Schematic diagram of the structure of a semiconductor thermoelectric device, in which 41 is the first heat exchange surface and 42 is the second heat exchange surface. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the accompanying drawings and examples.

[0037] like Figures 1 to 4 As shown, a battery pack thermal management system includes a battery cell array composed of a plurality of battery cell monomers 3, a first heat exchange plate 1, a second heat exchange plate 2 and semiconductor thermoelectric devices 4 corresponding to the battery cell monomers 3 one by one; the semiconductor thermoelectric device 4 includes a first heat exchange surface 41 and a second heat exchange surface 42; the surface of the battery cell monomer 3 includes a first type of surface 31 and a second type of surface 32; the first type of surface 31 of all battery cell monomers 3 and the corresponding first heat exchange surface 41 of the semiconductor thermoelectric device 4 are in contact with each other to achieve heat exchange; the second type of surface 32 of all battery cell monomers 3 and the first heat exchange plate 1 are in contact with each other to achieve heat exchange; the second heat exchange surfaces 42 of all semiconductor thermoelectric devices 4 are in contact with the second heat exchange plate 2 to achieve heat exchange.

[0038] In the above-mentioned battery pack thermal management system, heat exchange liquid flows through the first heat exchange plate 1 and the second heat exchange plate 2 .

[0039] The above-mentioned battery pack thermal management system supplies power to all semiconductor thermoelectric devices 4 through the power supply bus 5, and the power supply bus 5 includes a positive power supply bus 51 and a negative positive power supply bus 52; the semiconductor thermoelectric device 4 is provided with a first terminal 43 and a second terminal 44, and can be powered from the power supply bus 5 through any one of the first power supply branch 45 and the second power supply branch 46; the first power supply branch 45 is connected in series with a first electronic switch pair 47, and the second power supply branch 46 is connected in series with a second electronic switch pair 48; wherein, the first power supply The electrical branch 45 electrically connects the first terminal 43 to the positive power supply bus 51 through one of the electronic switches in the first electronic switch pair 47, and electrically connects the second terminal 44 to the negative positive power supply bus 52 through the other electronic switch in the first electronic switch pair 47; the second power supply branch 46 electrically connects the first terminal 43 to the negative power supply bus 52 through one of the electronic switches in the second electronic switch pair 48, and electrically connects the second terminal 44 to the positive power supply bus 51 through the other electronic switch in the second electronic switch pair 48.

[0040] The battery pack thermal management system further includes a fluid pipe network consisting of a pump 6, an expansion tank 7, a cooler 8, a heater 9, a three-way valve 10, a main pipe 11, a first branch pipe 12, a second branch pipe 13, a first heat exchange plate 1, and a second heat exchange plate 2:

[0041] The expansion water tank 7 is connected to the main pipe 11, and is used to accommodate the expansion of the liquid and play a role in constant pressure and fluid replenishment;

[0042] The three-way valve 10 includes a first passage 101, a second passage 102 and a third passage 103;

[0043] The pump 6 is provided with an outlet 61 and an inlet 62;

[0044] The main pipe 11 includes an outlet main pipe 111 and an inlet main pipe 112;

[0045] The outlet 61 of the pump 6 is connected to the refrigerator 8, the heater 9 and the first passage 101 of the three-way valve 10 in sequence through the outlet main pipe 111;

[0046] The second passage 102 of the three-way valve 10 is connected to the first heat exchange plate 1 and the inlet main pipe 112 in sequence through the first branch pipe 12;

[0047] The third passage 103 of the three-way valve 10 is connected to the second heat exchange plate 2 and the inlet main pipe 112 in sequence through the second branch pipe 13;

[0048] The inlet main pipe 112 is also connected to the inlet 62 of the pump 6 .

[0049] The above-mentioned battery pack thermal management system also includes a temperature sensor array 14 and a controller 15. The controller 15 is electrically connected to the temperature sensor array 14, the refrigerator 8, the heater 9, the three-way valve 10 and all the first electronic switch pairs 47 and the second electronic switch pairs 48.

[0050] In the above-mentioned battery pack thermal management system, when the first electronic switch pair 47 is closed and the second electronic switch pair 48 is disconnected, the first heat exchange surface 41 of the semiconductor thermoelectric device 4 plays a cooling role; when the first electronic switch pair 47 is disconnected and the second electronic switch pair 48 is closed, the first heat exchange surface 41 of the semiconductor thermoelectric device 4 plays a heating role.

[0051] In the above-mentioned battery pack thermal management system, the first passage 101 and the second passage 102 of the three-way valve 10 are normally open, and the third passage 103 is normally closed.

[0052] The control method applied to the above-mentioned battery pack thermal management system operates one of the cooler 8 and the heater 9 as needed to cool or heat the fluid in the fluid network, thereby achieving the purpose of heat dissipation or heating of the battery cell 3; at regular time intervals during the operation of the battery pack, the controller 15 obtains the temperature sequence T = [T1, T2, ..., T i ,…,T n ], where n is the total number of battery cells 3, T i Represents the temperature value of the i-th battery cell. Calculate the average μ and standard deviation σ of each element in the sequence and control it according to the following logic:

[0053] (a) If all element values ​​in the temperature sequence T are greater than μ-Kσ and less than μ+Kσ, the first passage 101 and the second passage 102 of the three-way valve 10 are opened and the third passage 103 is closed, and all first electronic switch pairs 47 and second electronic switch pairs 48 are disconnected;

[0054] (b) If there are element values ​​less than or equal to μ-Kσ in the temperature sequence T, the battery cells 3 corresponding to these element values ​​are determined to be in an overcooled state, and the first passage 101, the second passage 102, and the third passage 103 of the three-way valve 10 are all opened, and the first electronic switch pair 47 of the semiconductor thermoelectric device 4 corresponding to the battery cell 3 in the overcooled state is opened and the second electronic switch pair 48 is closed;

[0055] (c) If there are element values ​​greater than or equal to μ+Kσ in the temperature sequence T, the battery cells 3 corresponding to these element values ​​are determined to be in an overheated state, and the first passage 101, the second passage 102, and the third passage 103 of the three-way valve 10 are all opened, and the first electronic switch pair 47 of the semiconductor thermoelectric device 4 corresponding to the battery cell 3 in the overheated state is closed and the second electronic switch pair 48 is opened;

[0056] The value of the parameter K is between 2 and 5.

[0057] For the convenience of expression, considering that all semiconductor thermoelectric devices 4 are in parallel, Figure 3 and Figure 4 In the figure, only one semiconductor thermoelectric device 4 is drawn, and ellipsis “…” is used to represent the remaining semiconductor thermoelectric devices 4 .

[0058] Example

[0059] Please refer to Figures 1 to 4 The battery pack for a certain power tool is composed of 40 square aluminum shell lithium iron phosphate batteries connected in series. The fluid in the battery pack thermal management system pipe network is ethylene glycol solution. For the convenience of display, Figure 1As an example, only four battery cells 3 are drawn, and the remaining battery cells 3 are represented by ellipsis “…”.

[0060] The top surface of the battery cell 3 is the first heat exchange surface 31, and the bottom surface is the second heat exchange surface 32. The first heat exchange surface 31 also has a pole 33. The first heat exchange surface 31 is in indirect contact with the second heat exchange plate 2 via the semiconductor thermoelectric device 4, while the second heat exchange surface 32 is in contact with the first heat exchange plate 1. The surface of the cooler 8 is equipped with fins and a fan 81. The fan 81 forces air through the fins to cool the fluid flowing through it. The heater 9 is equipped with a heat-generating resistor 91 to heat the fluid flowing through it. In this embodiment, the parameter K is set to 2.5. All power-consuming components draw power from the battery pack after DC / DC conversion.

[0061] During a high-load operation at room temperature, the power tool controller 15 activated fan 81 to cool the fluid flowing through cooler 8. Heat-generating resistor 91 was deactivated, and heater 9 simply served as a fluid passage. Under normal conditions, the first and second passages 101 and 102 of three-way valve 10 were open, while the third passage 103 was closed. All first and second electronic switch pairs 47 and 48 were disconnected. During battery pack operation, temperature data was collected, and logical judgment and control were performed every 10 seconds. At a certain moment, the controller 15 obtains the temperature sequence of each battery cell 3 and calculates the average value μ of each element in the sequence to be 38.3°C and the standard deviation σ to be 1.2°C. Therefore, the normal temperature range of the battery cell 3 should be 35.3°C to 41.3°C. However, the temperature measurement value of the 12th battery cell at this moment is 41.5°C, which exceeds 41.3°C. Therefore, the controller 15 opens the first passage 101, the second passage 102, and the third passage 103 of the three-way valve 10, closes the first electronic switch pair 47 of the semiconductor thermoelectric device 4 corresponding to the 12th battery cell 3, and opens the second electronic switch pair 48, so that the heat of the 12th battery cell is transferred to the second heat exchange plate 2, thereby enhancing the heat dissipation and cooling of the battery cell.

[0062] After running for 2 minutes, the average value μ of each element in the temperature sequence of each battery cell 3 is 38.0°C, and the standard deviation σ is 1.1°C. Therefore, the normal temperature range of the battery cell 3 should be 35.25°C to 40.75°C. At this time, the temperatures of all battery cells 3 are within this normal temperature range. Therefore, the controller 15 opens the first passage 101 and the second passage 102 of the three-way valve 10 and closes the third passage 103, so that all first electronic switch pairs 47 and second electronic switch pairs 48 are in the disconnected state, and the operation of the battery pack thermal management system returns to normal.

[0063] The battery pack thermal management system in this embodiment of the present invention eliminates the need for additional fluid piping components and mechanical adjustment mechanisms for each battery cell. Instead, it relies on electrical components such as electronic switches, wires, and semiconductor thermoelectric devices to achieve refined thermal management and temperature equalization at the cell level. This results in a simple, compact structure and easy maintenance. Failures in the numerous temperature-equalizing components require only replacement of the electrical components, without compromising the sealing of the fluid piping network.

[0064] The control method of the battery pack thermal management system in the embodiment of the present invention only needs to perform calculation analysis and logical judgment on the results of each temperature sampling and make control decisions in real time. Therefore, the amount of calculation is small, the logic is clear and simple, stable and reliable, easy to implement, and has the characteristics of real-time and efficient regulation; and only when there is a battery cell with abnormal temperature will the fluid circuit in which the second heat exchange plate 2 is located be turned on and the corresponding electronic switch is closed to enable the semiconductor thermoelectric device corresponding to the abnormal battery cell to work, so it has the characteristics of high efficiency and energy saving.

Claims

1. A battery pack thermal management system control method, characterized in that: The battery pack thermal management system comprises a battery cell array consisting of a plurality of battery cell monomers (3), a first heat exchange plate (1), a second heat exchange plate (2), and semiconductor thermoelectric devices (4) corresponding to the battery cell monomers (3); the semiconductor thermoelectric devices (4) comprise a first heat exchange surface (41) and a second heat exchange surface (42); the surface of the battery cell monomer (3) comprises a first type of surface (31) and a second type of surface (32); the first type of surface (31) of all battery cell monomers (3) and the first heat exchange surface (41) of the corresponding semiconductor thermoelectric device (4) are in contact with each other to achieve heat exchange; the second type of surface (32) of all battery cell monomers (3) and the first heat exchange plate (1) are in contact with each other to achieve heat exchange; the second heat exchange surfaces (42) of all semiconductor thermoelectric devices (4) are in contact with the second heat exchange plate (2) to achieve heat exchange; The battery pack thermal management system further includes a fluid pipe network consisting of a pump (6), an expansion water tank (7), a refrigerator (8), a heater (9), a three-way valve (10), a main pipe (11), a first branch pipe (12), a second branch pipe (13), a first heat exchange plate (1), and a second heat exchange plate (2): The three-way valve (10) includes a first passage (101), a second passage (102) and a third passage (103); The main pipe (11) includes an outlet main pipe (111) and an inlet main pipe (112); The outlet (61) of the pump (6) is connected to the refrigerator (8), the heater (9) and the first passage (101) of the three-way valve (10) in sequence through the outlet main pipe (111); The second passage (102) of the three-way valve (10) is connected to the first heat exchange plate (1) and the inlet main pipe (112) in sequence through the first branch pipe (12); The third passage (103) of the three-way valve (10) is connected to the second heat exchange plate (2) and the inlet main pipe (112) in sequence through the second branch pipe (13); The control method comprises the following steps: operating one of the refrigerator (8) and the heater (9) as required to cool or heat the fluid in the fluid pipe network, thereby achieving the purpose of heat dissipation or heating of the battery cell (3); obtaining the temperature sequence T = [T1, T2, ..., T i ,…,T n ], where n is the total number of battery cells (3), T i Represents the temperature value of the i-th battery cell. Calculate the average μ and standard deviation σ of each element in the sequence and control it according to the following logic: (a) If all element values ​​in the temperature sequence T are greater than μ-Kσ and less than μ+Kσ, the first passage (101) and the second passage (102) of the three-way valve (10) are opened and the third passage (103) is closed, and the first electronic switch pair (47) and the second electronic switch pair (48) of all semiconductor thermoelectric devices (4) are disconnected; (b) If there are element values ​​less than or equal to μ-Kσ in the temperature sequence T, it is determined that the battery cells (3) corresponding to these element values ​​are in a supercooled state, and the first passage (101), the second passage (102) and the third passage (103) of the three-way valve (10) are all in an open state, so that the first electronic switch pair (47) of the semiconductor thermoelectric device (4) corresponding to the battery cell (3) in the supercooled state is disconnected and the second electronic switch pair (48) is closed, so that the first heat exchange surface (41) of the semiconductor thermoelectric device (4) plays a heating role; (c) If there are element values ​​greater than or equal to μ+Kσ in the temperature sequence T, it is determined that the battery cells (3) corresponding to these element values ​​are in an overheated state, and the first passage (101), the second passage (102) and the third passage (103) of the three-way valve (10) are all in an open state, so that the first electronic switch pair (47) of the semiconductor thermoelectric device (4) corresponding to the battery cell (3) in the overheated state is closed and the second electronic switch pair (48) is opened, so that the first heat exchange surface (41) of the semiconductor thermoelectric device (4) plays a cooling role; The value of parameter K is between 2 and 5.

2. The battery pack thermal management system control method according to claim 1, characterized in that: Heat exchange liquid flows through the first heat exchange plate (1) and the second heat exchange plate (2).

3. The battery pack thermal management system control method according to claim 1, characterized in that: The battery pack thermal management system supplies power to all semiconductor thermoelectric devices (4) via a power supply bus (5), wherein the power supply bus (5) includes a positive power supply bus (51) and a negative power supply bus (52); the semiconductor thermoelectric device (4) is provided with a first terminal (43) and a second terminal (44), and can obtain power from the power supply bus (5) via any one of a first power supply branch (45) and a second power supply branch (46); a first electronic switch pair (47) is connected in series to the first power supply branch (45), and a second electronic switch pair (48) is connected in series to the second power supply branch (46); wherein the first power supply branch (4 5) The first terminal (43) is electrically connected to the positive power supply bus (51) through one electronic switch in the first electronic switch pair (47), and the second terminal (44) is electrically connected to the negative positive power supply bus (52) through the other electronic switch in the first electronic switch pair (47); the second power supply branch (46) electrically connects the first terminal (43) to the negative power supply bus (52) through one electronic switch in the second electronic switch pair (48), and the second terminal (44) to the positive power supply bus (51) through the other electronic switch in the second electronic switch pair (48).

4. The battery pack thermal management system control method according to claim 1, characterized in that: In the fluid pipe network: The expansion water tank (7) is in communication with the main pipe (11), and is used to accommodate the expansion of the liquid and play a role in constant pressure and fluid replenishment; The inlet main pipe (112) is also connected to the inlet (62) of the pump (6).

5. The battery pack thermal management system control method according to claim 1, characterized in that: The battery pack thermal management system further includes a temperature sensor array (14) and a controller (15), wherein the controller (15) is electrically connected to the temperature sensor array (14), the refrigerator (8), the heater (9), the three-way valve (10), and all the first electronic switch pairs (47) and the second electronic switch pairs (48).

6. The battery pack thermal management system control method according to claim 1, characterized in that: The first passage (101) and the second passage (102) of the three-way valve (10) are normally open, and the third passage (103) is normally closed.

Images