A lithium battery pack thermal management system and control method

Abstract

The present application relates to the technical field of battery thermal management, and particularly relates to a lithium battery pack thermal management system and a control method. The lithium battery pack thermal management system comprises a cooling air pipe fixed to a battery box, a bottom guard plate installed on the battery box, a cooling plate installed in the battery box, a cooling channel arranged in the cooling plate, a first inflow part, a second inflow part and a third inflow part arranged in the cooling channel, the cooling plate being provided with lithium batteries, and an upper cover plate fixed to the battery box. An electric control ball valve is installed on the cooling plate. The first inflow part, the second inflow part and the third inflow part are arranged to control the flow direction of the cooling liquid, so that the cooling liquid preferentially enters the area for temperature reduction in the battery box, the cooling liquid preferentially contacts the area with a higher temperature, the cooling liquid carrying the heat of the area with a higher temperature continues to flow, and the temperature of each part in the battery box is reduced, thereby reducing the influence of uneven temperature distribution on the work of the lithium battery pack.

Description

Technical Field

[0001] This invention relates to the field of battery thermal management technology, and in particular to a lithium battery pack thermal management system and control method. Background Technology

[0002] With the rapid development of electric vehicles and energy storage devices, lithium battery packs are widely used due to their high energy density and long cycle life. However, lithium batteries generate a lot of heat during operation due to internal resistance and chemical reactions. If the heat cannot be dissipated in time, it will lead to problems such as overheating inside the battery pack, performance degradation, or even thermal runaway. Therefore, an efficient and precise thermal management system is crucial to ensuring the safety and stability of lithium battery packs. At present, thermal management of lithium battery packs mainly relies on cooling methods such as air cooling, liquid cooling, and phase change materials. Among them, liquid cooling systems are widely used due to their high heat dissipation efficiency.

[0003] However, traditional liquid cooling systems often use fixed flow channel designs for their cooling plates, resulting in a single flow direction for the coolant. Due to varying heat dissipation conditions, the temperature distribution across different parts of a lithium battery pack can be uneven. If the hottest areas of the lithium battery pack are far from where the coolant enters, the coolant cannot directly cool these localized hot areas after entering the cooling plate. Furthermore, the coolant is affected by the temperature of other areas during its flow. This leads to a decrease in the cooling effect of the coolant when it reaches the hottest areas of the lithium battery pack, resulting in delayed heat dissipation in the hottest areas and exacerbating the uneven temperature distribution across the lithium battery. Summary of the Invention

[0004] In order to overcome the shortcomings mentioned in the background art, the present invention provides a lithium battery pack thermal management system and control method.

[0005] The technical implementation of the present invention is as follows: a lithium battery pack thermal management system, including a cooling duct fixed to the battery box and communicating with its interior, and a bottom protective plate installed on the lower side of the battery box. The cooling duct is connected to an external air supply system. A cooling plate is installed inside the battery box. A cooling channel is provided inside the cooling plate. The cooling channel is provided with a first inlet, a second inlet, and a third inlet. A plurality of lithium batteries located inside the battery box are arranged on the upper side of the cooling plate. A top cover plate is fixed to the upper side of the battery box.

[0006] The cooling plate and the upper cover are both equipped with an electrically controlled ball valve. The electrically controlled ball valve is connected to an inlet pipe, which is connected to an external cooling circulation system. The electrically controlled ball valve is used to supply coolant to one of the first inlet, the second inlet, and the third inlet to control the direction of coolant flow within the cooling channel of the cooling plate.

[0007] More preferably, the upper side of the cooling plate is provided with the same number of venting slots as the lithium batteries, and the venting slots are located below the adjacent lithium batteries.

[0008] More preferably, the cooling plate is fixedly connected to three first pipes, which are respectively connected to the first inlet, the second inlet and the third inlet, and the first pipes are equipped with temperature sensors.

[0009] More preferably, all the first pipes are rotatably connected to a rotating plate, and the valve stem of the electrically controlled ball valve is fixedly connected to the rotating plate to make the rotating plate rotate. The rotating plate is provided with three flow holes, which are used to communicate with one of the first inlet, the second inlet, and the third inlet. The battery box is fixedly connected to a second pipe rotatably connected to the rotating plate. The second pipe is provided with three connecting ports, and the flow holes are used to communicate with one of the connecting ports on the second pipe. The second pipe is connected to an external cooling circulation system.

[0010] More preferably, both the first pipe and the second pipe are provided with a shielding part, with one shielding part on the first pipe and three shielding parts on the second pipe, the shielding parts being used to shield the flow hole.

[0011] More preferably, the cooling plate is provided with several groups of linearly distributed branch channels, which are connected to the cooling channels in the cooling plate, and each group of branch channels contains several of them.

[0012] More preferably, the cooling plate is slidably connected with linearly distributed sliding plates of the same number as the number of branch channel groups. The sliding plates are used to block several adjacent branch channels in the same group. The sliding plates are provided with holes for connecting several adjacent branch channels in the same group. The cooling plate is slidably connected with trigger blocks of the same number as the branch channels. The trigger blocks are fixedly connected to adjacent sliding plates. The cooling plate is also slidably connected with sliding blocks of the same number as the trigger blocks. The trigger blocks are used to push adjacent sliding blocks to move. The sliding blocks are used to insert into the cooling channels of the cooling plate to adjust the flow area of ​​the cooling channels in the cooling plate. An elastic block is fixedly connected between the sliding block and the cooling plate.

[0013] More preferably, a trigger frame is provided in a sealed sliding connection between the battery box, the cooling plate and the upper cover plate, the sliding plate is fixedly connected to the trigger frame, and an elastic element is fixedly connected between the trigger frame and the adjacent battery box.

[0014] More preferably, the width of the trigger block is smaller than the diameter of the cooling channel on the cooling plate, so that the sliding block can move a distance smaller than the diameter of the cooling channel on the cooling plate.

[0015] A control method for a lithium battery pack thermal management system, based on the aforementioned lithium battery pack thermal management system, includes the following specific steps:

[0016] Step 1: The external cooling circulation system and the electronically controlled ball valve are opened. The external cooling circulation system supplies coolant to the inlet pipe. By controlling the rotation of the electronically controlled ball valve, the coolant enters one of the first inlet, the second inlet, and the third inlet. Then the coolant enters the cooling channel of the cooling plate. The coolant flows first into the area with a higher temperature.

[0017] Step 2: During the rotation of the electric ball valve, the valve stem of the electric ball valve drives the rotating plate to rotate, which blocks one of the first pipes and aligns the other two first pipes with the adjacent flow holes. Then, the coolant in the cooling plate flows back to the external cooling circulation system through the first pipe, the flow hole and the second pipe to achieve the circulation and cooling of the coolant.

[0018] Step 3: After the temperature distribution is uniform throughout the battery box, turn on the external air supply system. The airflow generated by the external air supply system blows the trigger frame to move. The trigger frame triggers the sliding block to move through the trigger block. The elastic block is compressed and the sliding block is inserted into the cooling channel of the cooling plate. The flow area of ​​the cooling channel on the cooling plate is reduced. Part of the coolant flows along the cooling channel of the cooling plate, and the other part of the coolant flows into the branch channel, increasing the range through which the coolant circulates.

[0019] Step 4: When the temperature distribution is uneven in different parts of the battery box, turn off the external air supply system. The elastic block rebounds and drives the sliding block to reset, so that the sliding block is no longer inserted into the cooling channel of the cooling plate, and the range through which the coolant flows during circulation is greatly reduced.

[0020] Step 5: When it is necessary to stop using the system, turn off the external air supply system, the external cooling circulation system, and the electrically controlled ball valve.

[0021] Compared with the prior art, the present invention has the following advantages: 1. The present invention controls the flow direction of the coolant by setting a first inlet, a second inlet and a third inlet, so as to control the area where the coolant is preferentially cooled after entering the battery box, so that the coolant preferentially contacts the area with a higher temperature, and the coolant carries the heat of the area with a higher temperature to continue to flow, thereby cooling all parts of the battery box, thereby reducing the impact of uneven temperature distribution on the operation of the lithium battery pack.

[0022] 2. By controlling the range of coolant flow within the cooling plate, when the local temperature of the battery box is too high, the range of coolant circulation within the cooling plate is reduced, thereby increasing the coolant circulation speed and rapidly cooling the localized high temperature. When the temperature distribution within the battery box is uniform, the range of coolant circulation within the cooling plate is increased to uniformly cool the battery box, thus ensuring the uniformity of temperature distribution within the battery box and ensuring the working efficiency of the lithium battery. Attached Figure Description

[0023] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0024] Figure 2 This is a three-dimensional structural cross-sectional view of the battery box and the top cover of the present invention;

[0025] Figure 3 This is an exploded three-dimensional view of the battery box, cooling plate, and top cover of the present invention.

[0026] Figure 4 This is a three-dimensional structural diagram of the electrically controlled ball valve of the present invention;

[0027] Figure 5 This is a three-dimensional structural cross-sectional view of the cooling plate of the present invention;

[0028] Figure 6 This is a three-dimensional structural schematic diagram of the ventilation groove of the present invention;

[0029] Figure 7 This is an exploded three-dimensional view of the first pipe, the rotating plate, and the second pipe of the present invention.

[0030] Figure 8 This is a three-dimensional structural diagram of the trigger frame of the present invention;

[0031] Figure 9 This is a three-dimensional structural diagram of the trigger block and sliding block of the present invention;

[0032] Figure 10 This is a schematic diagram of the system of the present invention.

[0033] The reference numerals in the attached drawings are as follows: 1. Battery box; 101. Cooling duct; 2. Bottom cover plate; 3. Cooling plate; 301. First inlet; 302. Second inlet; 303. Third inlet; 304. Ventilation slot; 4. Lithium battery; 5. Top cover plate; 6. Electronically controlled ball valve; 601. Liquid inlet pipe; 7. First pipe; 701. Temperature sensor; 8. Rotating plate; 801. Flow hole; 9. Second pipe; 10. Shielding part; 11. Branch channel; 12. Sliding plate; 13. Trigger block; 14. Sliding block; 15. Elastic block; 16. Trigger frame. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] This embodiment discloses a lithium battery pack thermal management system for regulating the temperature of various parts of the lithium battery pack.

[0037] like Figures 1-6 and Figure 10As shown, the battery pack includes a cooling duct 101 fixed to and communicating with the battery box 1, and a bottom protective plate 2 installed on the lower side of the battery box 1. The bottom protective plate 2 is used to resist direct impact of road obstacles on the battery pack, reducing the risk of damage to the battery box 1 due to physical impact. A battery management system (BMS) is installed inside the battery box 1. An external air supply system is connected to the cooling duct 101. The external air supply system is an existing structure and is not shown in the figure. The external air supply system is electrically connected to the battery management system. A cooling plate 3 is installed inside the battery box 1. The cooling plate 3 adopts an existing assembly method and is composed of upper and lower halves spliced ​​together. Multiple locations inside the battery box 1 are equipped with devices that are electrically connected to the battery management system. A connected temperature monitoring module is used to monitor the temperature at various locations within the battery box 1. This temperature monitoring module is an existing structure and is not shown in the diagram. A serpentine cooling channel is provided within the cooling plate 3, with a first inlet 301, a second inlet 302, and a third inlet 303. Several lithium batteries 4 located within the battery box 1 are mounted on the upper side of the cooling plate 3. All lithium batteries 4 are electrically connected to the battery management system via connectors. A top cover 5 is fixedly attached to the upper side of the battery box 1. An electrically controlled ball valve 6 is installed on both the cooling plate 3 and the top cover 5. The electrically controlled ball valve 6 is an existing structure, consisting of a motor and a ball valve with an opening on the right side. The electrically controlled ball valve 6 is electrically connected to the battery management system. The first inlet... Part 301 is located on the left side of the electronically controlled ball valve 6, the second inlet part 302 is located in front of the electronically controlled ball valve 6, and the third inlet part 303 is located on the right side of the electronically controlled ball valve 6. A liquid inlet pipe 601 is connected to the lower side of the electronically controlled ball valve 6. The liquid inlet pipe 601 is used to supply coolant to the right opening of the ball valve on the electronically controlled ball valve 6. The liquid inlet pipe 601 is connected to an external cooling circulation system, which is electrically connected to the battery management system. The electronically controlled ball valve 6 is used to supply coolant to one of the first inlet part 301, the second inlet part 302, and the third inlet part 303 to control the direction of coolant flow within the cooling channel of the cooling plate 3. When the temperature at the rear of the battery box 1 is too high, the electronically controlled ball valve 6... The right opening of the upper ball valve is rotated to align with the first inlet 301, allowing coolant to enter the cooling channel of the cooling plate 3 from the first inlet 301, prioritizing cooling the rear part of the battery box 1. When the temperature in the middle part of the battery box 1 is too high, the right opening of the upper ball valve of the electronically controlled ball valve 6 is rotated to align with the second inlet 302, allowing coolant to enter the cooling channel of the cooling plate 3 from the second inlet 302, prioritizing cooling the middle part of the battery box 1. When the temperature in the front part of the battery box 1 is too high, the right opening of the upper ball valve of the electronically controlled ball valve 6 is rotated to align with the third inlet 303, allowing coolant to enter the cooling channel of the cooling plate 3 from the third inlet 303, prioritizing cooling the front part of the battery box 1.

[0038] like Figure 6As shown, the upper side of the cooling plate 3 is provided with the same number of ventilation slots 304 as the lithium battery 4. The ventilation slots 304 are located below the adjacent lithium battery 4, so that the hot air between the lithium battery 4 and the cooling plate 3 can be discharged through the ventilation slots 304, thereby reducing the probability of the cooling plate 3 being deformed by the high temperature and high pressure generated by the lithium battery 4.

[0039] like Figure 6 and Figure 7 As shown, the cooling plate 3 is fixedly connected to three first pipes 7, which are respectively connected to the first inlet 301, the second inlet 302 and the third inlet 303. A temperature sensor 701 is installed on the first pipe 7 and is electrically connected to the battery management system. During the circulation of coolant, the temperature sensor 701 monitors the temperature of the coolant in the adjacent first pipes 7, thereby monitoring the temperature of the coolant entering the cooling plate 3 and the temperature after exiting the cooling plate 3, so as to monitor the overall temperature inside the battery box 1 in real time.

[0040] like Figure 4 , Figure 6 and Figure 7 As shown, all the first pipes 7 are rotatably connected to a rotating plate 8. The valve stem of the electrically controlled ball valve 6 is fixedly connected to the rotating plate 8. The valve stem of the electrically controlled ball valve 6 is used to drive the rotating plate 8 to rotate. The rotating plate 8 is provided with three flow holes 801, which are used to communicate with one of the first inlet 301, the second inlet 302, and the third inlet 303. The battery box 1 is fixedly connected to a second pipe 9 that is rotatably connected to the rotating plate 8, such as... Figure 4 As shown, the fixed position of the second pipe 9 is located at the rear of the battery box 1. The second pipe 9 is provided with three connecting ports. The flow hole 801 is used to connect with one of the connecting ports on the second pipe 9. The second pipe 9 is connected to the external cooling circulation system. Taking the right opening of the ball valve on the electronically controlled ball valve 6 rotated to align with the third inlet 303 as an example, at this time, the three flow holes 801 are located at the front, left and rear of the rotating plate 8, respectively. The first pipe 7 on the right side is blocked by the rotating plate 8. The flow direction of the coolant is as follows: the third inlet 303, the cooling channel of the cooling plate 3, the first inlet 301 and the second inlet 302, the first pipe 7 on the left side and the first pipe 7 on the front side, and the second pipe 9.

[0041] like Figure 7 As shown, both the first pipe 7 and the second pipe 9 are provided with a shielding part 10. The first pipe 7 has one shielding part 10, and the second pipe 9 has three shielding parts 10. The shielding part 10 is used to shield the flow hole 801. The area of ​​the shielding part 10 is more than twice that of the flow hole 801. When the flow hole 801 is about to connect with a first pipe 7, the flow hole 801 is temporarily shielded by the shielding part 10 to prevent the coolant in the first pipe 7 from leaking through the flow hole 801.

[0042] The specific working principle of the lithium battery thermal management system in this embodiment is as follows:

[0043] When the operator needs to use this device for thermal management of the lithium battery pack, the vehicle starts running, and the battery management system controls the temperature monitoring module to turn on. If the temperature distribution is uneven at different locations of the lithium battery 4 due to differences in heat dissipation conditions, taking the case where the temperature monitoring module detects that the rear temperature inside the battery box 1 is higher than normal, the battery management system controls the external cooling circulation system and the electronically controlled ball valve 6 to open. The external cooling circulation system supplies coolant to the right opening of the ball valve on the electronically controlled ball valve 6 through the inlet pipe 601. The electronically controlled ball valve 6 then rotates the right opening of its ball valve to the position of the first... The inlet 301 is aligned so that the coolant enters the cooling channel of the cooling plate 3 from the first inlet 301, prioritizing the cooling of the rear part of the battery box 1. By setting the first inlet 301, the second inlet 302 and the third inlet 303, the flow direction of the coolant is controlled to control the area where the coolant is prioritized for cooling after entering the battery box 1. This allows the coolant to contact the higher temperature area first, and the coolant carries the heat from the higher temperature area to continue flowing, cooling all parts of the battery box 1, thereby reducing the impact of uneven temperature distribution on the operation of the lithium battery pack.

[0044] During the process of the right opening of the ball valve on the electric ball valve 6 rotating to align with the first inlet 301, the valve stem of the electric ball valve 6 drives the rotating plate 8 to rotate. When the right opening of the ball valve on the electric ball valve 6 rotates to align with the first inlet 301, the battery management system closes the electric ball valve 6. At this time, the three flow holes 801 are located on the front, right and rear sides of the rotating plate 8, respectively, so that the first pipe 7 on the left side is blocked by the rotating plate 8, and the first pipe 7 on the front side and the first pipe 7 on the right side are connected to the adjacent flow holes 801 respectively.

[0045] After the coolant circulates into the cooling channel of the cooling plate 3 (taking the coolant entering the cooling channel of the cooling plate 3 from the first inlet 301 as an example), the coolant is discharged into the first pipe 7 on the front and right sides through the second inlet 302 and the third inlet 303. Then the coolant flows into the second pipe 9 through the front flow hole 801 and the right flow hole 801. Finally, the coolant flows back into the external cooling circulation system through the second pipe 9.

[0046] When the operator needs to stop using this device, the battery management system shuts down the temperature monitoring module, the external cooling circulation system, and the electronically controlled ball valve 6.

[0047] Example 2

[0048] This embodiment discloses a lithium battery pack thermal management system, which is a further improvement on Embodiment 1.

[0049] like Figure 5 , Figure 8 and Figure 9 As shown, the cooling plate 3 is provided with several groups of branch channels 11 arranged in a straight line from front to back. The branch channels 11 are connected to the cooling channels in the cooling plate 3. Each group of branch channels 11 contains several of them. The branch channels 11 in the same group are arranged in a straight line along the left and right direction to increase the area of ​​coolant circulation in the cooling plate 3.

[0050] like Figure 8 and Figure 9 As shown, sliding plates 12, arranged in a straight line and numbered the same as the number of branch channels 11, are slidably connected inside the cooling plate 3. The sliding plates 12 are used to block several adjacent branch channels 11 within the same group. The sliding plates 12 have holes for connecting several adjacent branch channels 11 within the same group. Trigger blocks 13, the same number as the branch channels 11, are slidably connected inside the cooling plate 3. A first inclined surface is provided on the left side of each trigger block 13. The trigger blocks 13 are fixedly connected to adjacent sliding plates 12. Sliding blocks 14, the same number as the trigger blocks 13, are slidably connected inside the cooling plate 3. A second inclined surface is provided on the front right side of each sliding block 14. When the sliding plate 12 moves the trigger block 13 to the left, the first inclined surface of the trigger block 13 presses against the second inclined surface of the adjacent sliding block 14, causing the sliding block 14 to move backward and insert into the cooling channel of the cooling plate 3 to adjust the flow area of ​​the cooling channel in the cooling plate 3. At the same time, the hole of the sliding plate 12 moves to the left to align with the adjacent branch channel 11. An elastic block 15 is fixed between the sliding block 14 and the cooling plate 3. The elastic block 15 is made of elastic rubber. The width of the trigger block 13 is smaller than the diameter of the cooling channel on the cooling plate 3, so that the distance that the sliding block 14 can move is smaller than the diameter of the cooling channel on the cooling plate 3.

[0051] like Figure 3 and Figure 9 As shown, a trigger frame 16 is slidably connected between the battery box 1, the cooling plate 3, and the upper cover plate 5. There is a gap between the left side of the trigger frame 16 and the left side of the battery box 1. The sliding plate 12 is fixedly connected to the trigger frame 16. An elastic element, which is a tension spring, is fixedly connected between the trigger frame 16 and the adjacent battery box 1. When the external air supply system is turned on, the airflow in the cooling air duct 101 blows the left side of the trigger frame 16, causing the trigger frame 16 to move to the left. The elastic element between the trigger frame 16 and the adjacent battery box 1 is stretched.

[0052] The working process of this embodiment follows that of Embodiment 1, and is described in detail as follows:

[0053] When the temperature monitoring module detects that the temperature distribution is uniform throughout the battery box 1, the battery management system controls the external air supply system to start. When the external air supply system is started, the airflow in the cooling duct 101 blows the trigger frame 16 to the left, stretching the elastic element of the trigger frame 16. The trigger frame 16 drives all the sliding plates 12 to move to the left, and the holes of the sliding plates 12 move to the left until they are aligned with the adjacent branch channels 11. The sliding plates 12 also drive all the trigger blocks 13 on them to move to the left. The trigger blocks 13 squeeze the adjacent sliding blocks 14 to move backward, and the elastic blocks 15 are compressed. The sliding blocks 14 are inserted into the cooling channels of the cooling plate 3, which reduces the flow area of ​​the cooling channels on the cooling plate 3. Part of the coolant flows along the cooling channels of the cooling plate 3, and the other part of the coolant flows into the holes of the sliding plates 12 and the branch channels 11, increasing the range through which the coolant circulates.

[0054] When the temperature monitoring module detects uneven temperature distribution within the battery box 1, the battery management system shuts down the external air supply system. The elastic element of the trigger frame 16 contracts and resets, causing the trigger frame 16 to move to the right and reset. The trigger frame 16 then moves all the sliding plates 12 to the right and resets. Each sliding plate 12 moves all the trigger blocks 13 on it to the right and resets. The elastic block 15 rebounds and resets, causing the sliding block 14 to reset. The sliding block 14 is no longer inserted into the cooling channel of the cooling plate 3, and the reset of the sliding plate 12 disconnects its holes from the branch channel 11. The coolant no longer enters the branch channel 11, which greatly reduces the range through which the coolant circulates. By controlling the range through which the coolant circulates in the cooling plate 3, when the local temperature of the battery box 1 is too high, the range of coolant circulation in the cooling plate 3 is reduced, thereby increasing the speed of coolant circulation and quickly cooling the local high temperature. When the temperature distribution in the battery box 1 is uniform, the range of coolant circulation in the cooling plate 3 is increased to uniformly cool the battery box 1, thereby ensuring the uniformity of temperature distribution in the battery box 1 and ensuring the working efficiency of the lithium battery 4.

[0055] When the operator needs to stop using this device, the battery management system shuts down the temperature monitoring module, the external cooling circulation system, and the external air supply system.

[0056] Example 3

[0057] like Figures 1-10 As shown, a control method for a lithium battery pack thermal management system, based on the aforementioned lithium battery pack thermal management system, includes the following specific steps:

[0058] Step 1: The external cooling circulation system and the electronically controlled ball valve 6 are turned on. The external cooling circulation system supplies coolant to the inlet pipe 601. By controlling the rotation of the electronically controlled ball valve 6, the coolant enters one of the first inlet 301, the second inlet 302 and the third inlet 303. Then the coolant enters the cooling channel of the cooling plate 3. The coolant flows into the area with higher temperature first.

[0059] Step 2: During the rotation of the electric ball valve 6, the valve stem of the electric ball valve 6 drives the rotating plate 8 to rotate, so that one of the first pipes 7 is blocked, and the other two first pipes 7 are aligned with the adjacent flow holes 801 respectively. Then the coolant in the cooling plate 3 flows back to the external cooling circulation system through the first pipe 7, the flow hole 801 and the second pipe 9 to achieve the circulation and cooling of the coolant.

[0060] Step 3: After the temperature distribution is uniform throughout the battery box 1, turn on the external air supply system. The airflow generated by the external air supply system blows the trigger frame 16 to move. The trigger frame 16 triggers the sliding block 14 to move through the trigger block 13. The elastic block 15 is compressed and the sliding block 14 is inserted into the cooling channel of the cooling plate 3. The flow area of ​​the cooling channel on the cooling plate 3 is reduced. Part of the coolant flows along the cooling channel of the cooling plate 3, and another part of the coolant flows into the branch channel 11, increasing the range through which the coolant circulates.

[0061] Step 4: When the temperature distribution in the battery box 1 becomes uneven, the external air supply system is turned off. The elastic block 15 rebounds and drives the sliding block 14 to reset, so that the sliding block 14 is no longer inserted into the cooling channel of the cooling plate 3, and the range through which the coolant flows during circulation is greatly reduced.

[0062] Step 5: When it is necessary to stop using the system, turn off the external air supply system, the external cooling circulation system, and the electrically controlled ball valve 6.

[0063] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A lithium battery pack thermal management system, comprising a cooling duct (101) fixed to and communicating with the battery box (1), and a bottom protective plate (2) installed on the lower side of the battery box (1), wherein the cooling duct (101) is connected to an external air supply system, and a cooling plate (3) is installed inside the battery box (1), wherein the cooling plate (3) is provided with a cooling channel, characterized in that, The cooling channel is provided with a first inlet (301), a second inlet (302) and a third inlet (303). Several lithium batteries (4) located in the battery box (1) are provided on the upper side of the cooling plate (3). A top cover plate (5) is fixedly connected to the upper side of the battery box (1). The cooling plate (3) and the upper cover plate (5) are jointly equipped with an electrically controlled ball valve (6). The electrically controlled ball valve (6) is connected to an inlet pipe (601). The inlet pipe (601) is connected to an external cooling circulation system. The electrically controlled ball valve (6) is used to supply coolant to one of the first inlet (301), the second inlet (302) and the third inlet (303) to control the direction of coolant flow in the cooling channel of the cooling plate (3). The cooling plate (3) is fixedly connected to three first pipes (7), which are respectively connected to the first inlet (301), the second inlet (302) and the third inlet (303). The first pipes (7) are equipped with temperature sensors (701). All the first pipes (7) are rotatably connected to a rotating plate (8). The valve stem of the electrically controlled ball valve (6) is fixedly connected to the rotating plate (8) to make the rotating plate (8) rotate. The rotating plate (8) is provided with three flow holes (801). The flow holes (801) are used to communicate with one of the first inlet (301), the second inlet (302) and the third inlet (303). The battery box (1) is fixedly connected to a second pipe (9) rotatably connected to the rotating plate (8). The second pipe (9) is provided with three connecting ports. The flow holes (801) are used to communicate with one of the connecting ports on the second pipe (9). The second pipe (9) is connected to an external cooling circulation system.

2. A lithium battery pack thermal management system according to claim 1, characterized in that, The upper side of the cooling plate (3) is provided with the same number of ventilation slots (304) as the lithium battery (4), and the ventilation slots (304) are located below the adjacent lithium battery (4).

3. A lithium battery pack thermal management system according to claim 2, characterized in that, Both the first pipe (7) and the second pipe (9) are provided with a shielding part (10). The first pipe (7) has one shielding part (10), and the second pipe (9) has three shielding parts (10). The shielding part (10) is used to shield the flow hole (801).

4. A lithium battery pack thermal management system according to claim 3, characterized in that, The cooling plate (3) is provided with several groups of branch channels (11) arranged in a straight line. The branch channels (11) are connected to the cooling channels in the cooling plate (3). Each group of branch channels (11) contains several of them.

5. A lithium battery pack thermal management system according to claim 4, characterized in that, The cooling plate (3) is slidably connected with linearly distributed sliding plates (12) of the same number as the number of branches (11). The sliding plates (12) are used to block several branches (11) in adjacent groups. The sliding plates (12) are provided with holes. The holes of the sliding plates (12) are used to connect several branches (11) in adjacent groups. The cooling plate (3) is slidably connected with trigger blocks (13) of the same number as the branches (11). The trigger blocks (13) are fixed to the adjacent sliding plates (12). The cooling plate (3) is slidably connected with sliding blocks (14) of the same number as the trigger blocks (13). The trigger blocks (13) are used to squeeze the adjacent sliding blocks (14) to move. The sliding blocks (14) are used to insert into the cooling channel of the cooling plate (3) to adjust the flow area of ​​the cooling channel in the cooling plate (3). An elastic block (15) is fixed between the sliding block (14) and the cooling plate (3).

6. A lithium battery pack thermal management system according to claim 5, characterized in that, A trigger frame (16) is provided for the sealed sliding connection between the battery box (1), the cooling plate (3) and the upper cover plate (5). The sliding plate (12) is fixedly connected to the trigger frame (16), and an elastic element is fixedly connected between the trigger frame (16) and the adjacent battery box (1).

7. A lithium battery pack thermal management system according to claim 6, characterized in that, The width of the trigger block (13) is smaller than the diameter of the cooling channel on the cooling plate (3) so that the sliding block (14) can move a distance smaller than the diameter of the cooling channel on the cooling plate (3).

8. A control method for a lithium battery pack thermal management system, using the lithium battery pack thermal management system described in claim 7, comprising the following specific steps: Step 1: The external cooling circulation system and the electric ball valve (6) are turned on. The external cooling circulation system supplies coolant to the inlet pipe (601). By controlling the rotation of the electric ball valve (6), the coolant enters one of the first inlet (301), the second inlet (302) and the third inlet (303). Then the coolant enters the cooling channel of the cooling plate (3). The coolant flows into the area with higher temperature first. Step 2: During the rotation of the electric ball valve (6), the valve stem of the electric ball valve (6) drives the rotating plate (8) to rotate, so that one of the first pipes (7) is blocked, and the other two first pipes (7) are aligned with the adjacent flow holes (801) respectively. Then the coolant in the cooling plate (3) flows back to the external cooling circulation system through the first pipe (7), the flow hole (801) and the second pipe (9) to achieve the circulation and cooling of the coolant. Step 3: After the temperature distribution in the battery box (1) is uniform, turn on the external air supply system. The airflow generated by the external air supply system blows the trigger frame (16) to move. The trigger frame (16) triggers the sliding block (14) to move through the trigger block (13). The elastic block (15) is compressed and the sliding block (14) is inserted into the cooling channel of the cooling plate (3). The flow area of ​​the cooling channel on the cooling plate (3) is reduced. A part of the coolant flows along the cooling channel of the cooling plate (3), and another part of the coolant flows into the branch channel (11), increasing the range through which the coolant circulates. Step 4: When the temperature distribution in the battery box (1) is uneven, the external air supply system is turned off. The elastic block (15) rebounds and drives the sliding block (14) to reset, so that the sliding block (14) is no longer inserted into the cooling channel of the cooling plate (3), and the range through which the coolant circulates is greatly reduced. Step 5: When it is necessary to stop using the system, turn off the external air supply system, the external cooling circulation system and the electric ball valve (6).

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