Battery pack uniform temperature control strategy, system and device

Abstract

The invention discloses a battery pack temperature equalization control strategy, system and device. The battery pack temperature equalization control strategy comprises the following steps: acquiring battery cells meeting a temperature equalization condition; by controlling and switching communication of different branch pipelines, one end of each branch pipeline is communicated with the liquid cooling plate, and the other end of each branch pipeline is connected with the cooling water outlet or inlet, cooling water is turned to enter the water inlet and the water outlet of the liquid cooling plate, and the battery cells meeting the temperature equalization condition are subjected to temperature equalization treatment. By switching the communication states of different branch pipelines, the cooling water flow direction is dynamically adjusted, the problem that the temperature consistency of local battery cells of a battery pack is poor is solved, target battery cells can be accurately positioned, invalid cooling is avoided, the service life and performance of the batteries are effectively prolonged, energy consumption is reduced, and in addition, the battery temperature equalizing device is simple in structure, high in reliability and easy to popularize. And the temperature uniformity of the battery cells in the battery pack is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric vehicle auxiliary accessories, in particular to a battery pack uniform temperature control strategy, system and device. BACKGROUND

[0002] With the rapid development of electric vehicles, energy storage systems and other fields, lithium ion batteries have become the mainstream of electrochemical energy storage devices due to their high energy density, long cycle life and other advantages. However, the performance, life and safety of lithium ion batteries are closely related to their own temperature. During the charging and discharging process of the battery pack, significant heat will be generated, and due to the difference in the location of the battery pack internal cells and the difference in heat exchange with the outside world, the external environment at different positions of the battery pack may also differ, so it is inevitable that a temperature gradient will be generated inside the battery pack.

[0003] In a battery pack, a vehicle and an energy storage device without a module frame, a cooling liquid pipeline and a heat exchange plate are usually used to form a liquid cooling system, and the cooling liquid flows through the heat exchange plate to heat or cool the cells. However, in a large battery pack, the flow path of the cooling liquid from the inlet to the outlet is too long, resulting in a significant decrease in its heat exchange capacity along the way. This causes a large temperature difference between the cells near the inlet and outlet areas of the cooling liquid, further leading to errors in power estimation, limited charging and discharging power, and a local overheating area that may accelerate the degradation of the life and reduce the reliability of the system.

[0004] In a power battery pack liquid cooling plate and liquid cooling system, the parallel cooling flow channel is designed to shorten the single path length, trying to improve the temperature uniformity, but despite the use of parallel flow channels, the cooling liquid still has a significant temperature rise / drop during long-distance transportation, the heat exchange efficiency of the end flow channel is reduced, and the complex flow channel structure greatly increases the manufacturing process difficulty (such as high welding precision requirement, increased leakage risk), and is prone to structural failure due to vibration or corrosion during long-term operation. SUMMARY

[0005] The purpose of the present application is to provide a battery pack uniform temperature control strategy, system and device, which solves the problem of uneven temperature of the cells caused by the attenuation of the end temperature control ability due to the difference in the heat generation / heat dissipation capacity of the cells and the long flow path of the cooling liquid in the existing battery pack liquid cooling system. The present application designs a battery pack uniform temperature device and uses a uniform temperature control method to improve the temperature uniformity of the cells in the battery pack. The battery pack uniform temperature device has a simple structure, which avoids the insufficient reliability of the battery pack caused by the complex flow channel structure.

[0006] To achieve this purpose, the battery pack uniform temperature control strategy designed by the present application comprises: obtaining cells that meet the uniform temperature condition; By controlling the switching of the communication of different branch pipes connected at one end to the liquid cooling plate and at the other end to the cooling water outlet or inlet, the water inlet and outlet of the cooling water into the liquid cooling plate are adjusted, and the battery cells meeting the uniform temperature condition are subjected to uniform temperature treatment.

[0007] Further, the battery cells meeting the uniform temperature condition are obtained by the following steps: The temperature of the single battery cell in the battery pack is obtained. The temperature difference between different single battery cells is calculated according to the temperature of the single battery cell. It is judged whether the temperature difference between different single battery cells is greater than a preset temperature difference. For the battery cells with a temperature difference greater than the preset temperature difference, it is further judged whether the temperature difference is less than a preset uniform temperature capacity. For the battery cells with a temperature difference less than the uniform temperature capacity of the system, it is judged that the battery cells meet the uniform temperature condition, otherwise, it is judged that the battery cells do not meet the uniform temperature condition. The preset temperature difference includes a safety temperature difference, a durability temperature difference and a performance temperature difference, which are obtained according to the structure design of the battery pack and the simulation of the thermal management strategy. The safety temperature difference refers to that different battery cells under the temperature difference may cause safety accidents of the battery pack, the durability temperature difference refers to that different battery cells under the temperature difference may cause life attenuation of the battery pack, and the performance temperature difference refers to that different battery cells under the temperature difference may cause performance decline (such as charge and discharge power, capacity, etc.) of the battery pack. The preset uniform temperature capacity is the uniform temperature capacity of the uniform temperature system.

[0008] The application also includes a battery pack uniform temperature system, which comprises a battery cell to be uniformed and a battery pack uniform temperature device. The battery cell to be uniformed is used to obtain battery cells meeting the uniform temperature condition, and the battery pack uniform temperature device is used to control the switching of the communication of different branch pipes connected at one end to the liquid cooling plate and at the other end to the cooling water outlet or inlet, so as to adjust the water inlet and outlet of the cooling water into the liquid cooling plate, and the battery cells meeting the uniform temperature condition are subjected to uniform temperature treatment.

[0009] The application also includes a battery pack uniform temperature device, which comprises: The pipe core comprises a main pipe, at least four branch pipes arranged axially along one side of the main pipe and communicated with the main pipe, and a communication passage arranged on the other side of the main pipe and communicated with the main pipe, and the communication passage and the internal cavity of the main pipe form a first flow channel. The valve body is slidably assembled in the main pipe and sealingly matched with the inner wall of the main pipe. The inner recess structure is arranged on the side close to the branch pipe, and the inner recess structure and the inner wall of the main pipe form a second flow channel. The displacement control mechanism drives the axial movement of the valve body for switching the communication of any two branch pipes through the first flow channel or the second flow channel.

[0010] Further, the valve body extends into a first extension and a second extension at both ends, respectively, which extend out of the main pipeline and are connected to the displacement control mechanism.

[0011] Further, the pipeline core further comprises a first extension cavity and a second extension cavity at both axial ends of the main pipeline, which are spaces for the first extension and the second extension to move when the displacement control mechanism drives the valve body to move axially.

[0012] Further, it comprises an elastic reset component located in the first extension cavity and elastically connected to the first extension. a magnetic drive component located in the second extension cavity and fixedly connected to the second extension; a power supply circuit provided on the outside of the pipeline core near the magnetic drive component, for driving the magnetic drive component by controlling the current.

[0013] Further, the concave structure covers at least two branch pipelines.

[0014] Further, the branch pipeline on one side of the main pipeline comprises a first branch pipeline, a second branch pipeline, a third branch pipeline and a fourth branch pipeline.

[0015] Further, the valve body has a first position and a second position in the main pipeline. When the valve body is in the first position, the concave structure of the valve body covers the first branch pipeline and the second branch pipeline, the second flow channel formed by the concave structure and the main pipeline communicates with the first branch pipeline and the second branch pipeline, and the first flow channel communicates with the third branch pipeline and the fourth branch pipeline. When the valve body is in the second position, the concave structure of the valve body covers the second branch pipeline and the third branch pipeline, the second flow channel formed by the concave structure and the main pipeline communicates with the second branch pipeline and the third branch pipeline, and the first flow channel communicates with the first branch pipeline and the fourth branch pipeline.

[0016] The beneficial effects of the present application are: 1. In the present application, the cooling water is controlled to enter the water inlet and outlet of the liquid cooling plate, so as to realize the uniform temperature treatment of the battery cell needing uniform temperature, realize the efficient, accurate and dynamic balance of the battery pack temperature, reduce the risk of local overheating, improve the battery safety, avoid the rapid aging of the battery pack due to inconsistency, and effectively prolong the service life of the battery pack.

[0017] 2. Obtain the temperature difference between the monomer cells by calculation, set a preset temperature difference, first judge whether the current cell temperature difference is greater than the preset temperature difference, if greater than the preset temperature difference, then compare whether the cell temperature difference is less than the temperature equalization capacity, if the above comparison is satisfied, it is determined that the temperature equalization condition is satisfied, and the secondary verification mechanism is that the result of satisfying the condition has strong reliability.

[0018] 3. The present application can receive the signal of external temperature equalization by setting the temperature equalization system containing the temperature equalization device, control the temperature equalization device to switch accordingly, and realize intelligent operation.

[0019] 4. In the battery pack temperature equalization device, the pipeline core connected by the dynamic switching branch pipeline of the sliding valve body is designed, different branch combinations are covered by the sliding valve body, the cooling liquid flow path is dynamically switched, the directional temperature regulation of the battery pack branch pipeline is realized, and the partition precise temperature control is achieved; only one sliding valve body is needed to switch the branch pipeline connection, the hardware cost is reduced, and the installation space is saved.

[0020] 5. The first extension part and the second extension part at both ends of the pipeline core extend to the outside of the main pipeline, so that the displacement control mechanism for driving the valve body to move can be conveniently arranged outside the main pipeline, and the sealing property of the inside of the main pipeline is ensured.

[0021] 6. The first extension cavity and the second extension cavity are arranged, so that the first extension part and the second extension part can move in the first extension cavity and the second extension cavity, low-resistance buffer space and dynamic sealing protection are provided, displacement space is provided for the axial displacement of the valve body, and the extension cavity creates an interference-free moving channel for the extension part.

[0022] 7. In the displacement control mechanism, the power supply circuit is energized, a magnetic field is formed in the second extension cavity, the magnetic driving part moves to the position close to the side wall of the second extension cavity, and the whole valve body moves axially in the main pipeline; the elastic reset part elastically connected with the first extension part is stretched under the action, when it is needed to replace the connected branch pipeline, the power supply circuit is de-energized, the magnetic field disappears, the elastic reset part is contracted and reset after the elastic potential is released; through the cooperation of the magnetic driving part and the power supply circuit, the axial movement of the valve body in the main pipeline can be accurately controlled. The existence of the elastic reset part enables the valve body to be reliably reset after the magnetic field disappears, the displacement control mechanism has simple structure, long service life, and relatively simple maintenance operation, and the maintenance cost is reduced.

[0023] 8. The inner recess structure arranged on the side close to the branch pipeline covers at least two branch pipelines, so that at least two branch pipelines are in a connected state during the axial movement of the valve body in the main pipeline.

[0024] 9. Four branch pipes can be set, and during the axial movement of the valve body in the main pipe, the two branch pipes covered by the concave structure are communicated through the second flow channel, and the two branch pipes not covered by the concave structure are communicated through the first flow channel, forming two communication channels.

[0025] 10. The valve body is provided with two positions, and the valve body moves between the two positions by axial movement, so that the two branch pipes covered by the concave structure of the valve body also change, and the two branch pipes communicated through the communication channel on the main pipe also change, so as to realize the axial movement of the valve body and switch the communication of different branch pipes. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The flow chart of the battery pack uniform temperature control strategy in the embodiment of the application; Figure 2 The structure schematic diagram of the battery pack uniform temperature device in the embodiment of the application; Figure 3 The schematic diagram of the pipe core body in the first position in the embodiment of the application; Figure 4 The schematic diagram of the pipe core body in the second position in the embodiment of the application; Figure 5 The schematic diagram of the uniform temperature system located at the front end inside the battery pack in the embodiment of the application; Figure 6 The schematic diagram of the uniform temperature system located at the place needing local uniform temperature inside the battery pack in the embodiment of the application; Figure 7 The schematic diagram of the uniform temperature system located in the thermal management loop outside the battery pack in the embodiment of the application; Figure 8 The uniform temperature control logic flow chart in the embodiment of the application; Figure 9 The satisfaction judgment logic flow chart of the uniform temperature condition in the embodiment of the application; Among them, 1—temperature equalization system; 11—pipe core; 111—main pipe; 112—communication channel; 113—valve body; 1131—first extension portion; 1132—second extension portion; 1133—first extension cavity; 1134—second extension cavity; 114—elastic reset component; 115—magnetic drive component; 116—magnetic field; 117—concave structure; 12—power supply line; 13—installation fixing point; 14—first branch pipe; 15—second branch pipe; 16—third branch pipe; 17—second branch pipe; —Fourth branch pipeline; 2—Battery pack; 21—Battery management system; 22—Battery thermal management system; 221—Flow channel plate; 222—First flow channel interface; 223—Second flow channel interface; 224—First coolant inlet; 225—First coolant outlet; 226—Third flow channel interface; 227—Fourth flow channel interface; 228—Second coolant inlet; 229—Second coolant outlet; 23—Low-voltage connector; 2210—First vehicle thermal management pipeline; 2211—Second vehicle thermal management pipeline; DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: The present invention relates to a battery pack temperature equalization device and control method, which is used in the thermal management system of large power battery packs in fields such as new energy vehicles. It effectively equalizes the temperature of battery cells, thereby improving the overall performance of the battery pack (enhancing discharge capacity, accelerating charging speed, and extending service life), and significantly reduces the safety risks caused by excessive temperature differences, providing important guarantees for the safe and reliable operation of large-scale, high-performance battery packs.

[0028] Example 1: like Figures 1 to 9 A battery pack temperature control strategy shown includes: Obtaining battery cells that meet the uniform temperature conditions; By controlling and switching the connection of different branch pipes, one end of which is connected to the liquid cooling plate and the other end is connected to the cooling water outlet or inlet, the water inlet and outlet of the cooling water entering the liquid cooling plate are reversed, and the liquid cooling plate is used to perform temperature uniformity treatment on the battery cells that meet the temperature uniformity conditions.

[0029] Obtaining the battery cells that meet the uniform temperature condition includes obtaining the position of the battery cells. If the temperature difference of the local battery cells meets the uniform temperature condition, the local position is subjected to uniform temperature treatment. If the temperature difference of the global battery cells meets the uniform temperature condition, the global position is subjected to uniform temperature treatment.

[0030] Preferably, the battery pack contains several single cells, and each single cell can be cooled by a liquid cooling plate. The liquid cooling plate includes a pipe through which cooling water can pass. By turning the water inlet and outlet of the liquid cooling plate, the flow direction of the cooling water inside the liquid cooling plate can be turned to achieve uniform temperature.

[0031] The application realizes the switching of the water inlet and outlet of the liquid cooling plate by obtaining the battery cells meeting the uniform temperature condition, and then controlling the communication of the different branch pipes connected at one end to the outlet or inlet of the liquid cooling plate cooling water, and at one end to the outlet or inlet of the cooling water, so as to switch the flow direction of the cooling water in the liquid cooling plate, avoid the cooling effect of the cooling water in the liquid cooling plate becoming worse and worse, resulting in the temperature difference between the battery cells close to the outlet of the liquid cooling plate and the battery cells close to the water inlet of the liquid cooling plate, and realize the efficient, accurate and dynamic balance of the battery pack temperature. By switching the branch pipes to quickly reverse the inlet and outlet, the temperature distribution of the liquid cooling plate is dynamically changed, the original thermal gradient is broken, and the target area battery cells (especially the original high temperature area) can quickly obtain more effective cooling, and the temperature consistency is significantly improved. Therefore, by reducing the temperature difference of the battery cells at different positions in the battery pack, the performance of the battery pack (such as charging and discharging speed, power, capacity, etc.) can be significantly improved; further, by actively uniform temperature, the generation of local hot spots is avoided, and the safety of the battery is improved. The core function is to provide a fine and self-adjusting thermal management strategy to achieve the optimal temperature uniformity of the battery pack with the minimum energy consumption and the fastest response.

[0032] In the above technical solution, the battery cells meeting the uniform temperature condition are obtained, including the following steps: Obtaining the temperature of the single battery cell in the battery pack; Calculating the temperature difference between different single battery cells according to the temperature of the single battery cell; Judging whether the temperature difference between different single battery cells is greater than a preset temperature difference, and for the battery cells with a temperature difference greater than the preset temperature difference, continuing to judge whether the temperature difference is less than a preset uniform temperature ability, and for the battery cells with a temperature difference less than the uniform temperature ability of the system, judging that the battery cells meet the uniform temperature condition, otherwise, judging that the battery cells do not meet the uniform temperature condition; Preferably, the battery management system 21 obtains the temperature of the single battery cell in the battery pack, and calculates the temperature difference between different single battery cells according to the temperature of the single battery cell, judges whether the temperature difference between different single battery cells is greater than a preset temperature difference, and for the battery cells with a temperature difference greater than the preset temperature difference, continues to judge whether the temperature difference is less than the uniform temperature ability of the uniform temperature system, and for the battery cells with a temperature difference less than the uniform temperature ability of the uniform temperature system, judges that the battery cells meet the uniform temperature condition, and sends a uniform temperature signal to the battery pack uniform temperature system, otherwise, judges that the battery cells do not meet the uniform temperature condition; if the battery cells do not meet the uniform temperature condition, the battery management system 21 will perform a temperature difference alarm process.

[0033] The uniform temperature ability can be obtained by simulation through the battery structure / thermal management design and the position of the uniform temperature system. The uniform temperature ability represents the maximum temperature difference that can be uniformed by the uniform temperature system. If the calculated temperature difference between different single battery cells is greater than the preset temperature difference and less than the uniform temperature ability, it indicates that the system has the ability to uniform the temperature.

[0034] The preset temperature difference includes a safety temperature difference, a durability temperature difference and a performance temperature difference, which are obtained according to the structural design of the battery pack and the simulation of the thermal management strategy. The safety temperature difference refers to that different battery cells under the temperature difference may cause a safety accident of the battery pack, the durability temperature difference refers to that different battery cells under the temperature difference may cause the life attenuation of the battery pack, and the performance temperature difference refers to that different battery cells under the temperature difference may cause the performance decline (such as charge-discharge power, capacity, etc.) of the battery pack. The preset uniform temperature capability is the uniform temperature capability of the uniform temperature system.

[0035] Any one of the above safety temperature difference, durability temperature difference and performance temperature difference can be used as the preset temperature difference for comparison with the battery cell temperature difference.

[0036] The application also includes a battery pack uniform temperature system, comprising: a battery cell to be uniformed obtaining module and a battery pack uniform temperature device; The battery cell to be uniformed obtaining module can control the battery pack uniform temperature device to execute instructions in a software or hardware manner. The application adopts a software manner to control the battery pack uniform temperature device. The battery cell to be uniformed obtaining module obtains the battery cells meeting the uniform temperature condition from the battery management system 21, including the positions of the battery cells, controls the battery pack uniform temperature device to execute the power-on or power-off instructions, and performs uniform temperature treatment on the battery cells needing uniform temperature. The battery pack uniform temperature device is used to execute the control instructions of the battery pack uniform temperature device power-on or power-off sent by the battery cell to be uniformed obtaining module.

[0037] The battery cell to be uniformed obtaining module is used to obtain the battery cells meeting the uniform temperature condition. The battery pack uniform temperature device is used to control the switching of the communication of different branch pipes to change the water inlet and water outlet of the cooling water entering the liquid cooling plate, and to perform uniform temperature treatment on the battery cells meeting the uniform temperature condition by using the liquid cooling plate.

[0038] The application also includes a battery pack uniform temperature device, which comprises: The pipe core body 11 comprises a main pipe 111, at least four branch pipes in communication with the main pipe 111 and arranged axially along one side of the main pipe 111, and a communication passage 112 in communication with the main pipe 111 and arranged on the other side of the main pipe 111, the communication passage 112 and the internal cavity of the main pipe 111 form a first flow channel; The valve body 113 is slidably assembled in the internal cavity of the main pipe 111 and is in sealing cooperation with the inner wall of the main pipe 111. The valve body 113 is provided with an inner recess structure 117 on the side close to the branch pipe, and the inner recess structure 117 and the inner wall of the main pipe 111 form a second flow channel. The displacement control mechanism drives the axial movement of the valve body 113 to switch the communication of any two branch pipes through the first flow channel or the second flow channel.

[0039] In use, the inner recess structure 117 of the valve body 113 can communicate with any two branch pipes covered thereby through the second flow channel, at this time, the branch pipe not covered by the inner recess structure 117 and communicating with the main pipe 111 can communicate through the first flow channel, when it is required to switch different branch pipes to communicate, the valve body 113 is controlled to move axially in the main pipe 111 by the displacement control mechanism, the branch pipe covered by the inner recess structure 117 changes, and the branch pipe not covered by the inner recess structure 117 and communicating with the main pipe 111 changes correspondingly, so as to complete the switching of the branch pipes.

[0040] By switching the branch pipes, the flow direction of the cooling liquid in the battery pack can be changed. When the temperature of the battery cells in a certain area is too high, the branch pipes are switched to allow the cooling liquid or other heat dissipation medium to flow through the high-temperature area preferentially, absorb heat and carry away, so that the temperature of the entire battery pack tends to be uniform. In addition, the heat dissipation strategy is flexibly adjusted according to the type, working condition and temperature distribution of the battery pack. This flexibility enables the heat dissipation system to better adapt to different application scenarios, improves the versatility and adaptability of the heat dissipation system, and thus realizes more effective uniform temperature control.

[0041] In the above technical solution, the valve body 113 extends into a first extension 1131 and a second extension 1132 at both ends, respectively, and the first extension 1131 and the second extension 1132 extend out of the main pipe 111 and are connected to the displacement control mechanism.

[0042] The first extension 1131 and the second extension 1132 are narrower than the valve body 113.

[0043] The first extension 1131 and the second extension 1132 extend at both ends of the valve body 113, which facilitates the arrangement of the displacement control mechanism outside the main pipe 111 to control the valve body 113 and ensures the sealing of the inside of the main pipe 111.

[0044] In the above technical solution, the pipe core 11 further includes a first extension cavity 1133 and a second extension cavity 1134 located at both axial ends of the main pipe 111, and the first extension cavity 1133 and the second extension cavity 1134 are spaces for the first extension 1131 and the second extension 1132 to move when the displacement control mechanism drives the valve body 113 to move axially.

[0045] When the displacement control mechanism drives the valve body 113 to move axially, the first extension 1131 and the second extension 1132 can move in the first extension cavity 1133 and the second extension cavity 1134, and by providing the first extension cavity 1133 and the second extension cavity 1134, a low-resistance buffer space and dynamic sealing protection can be provided for the axial displacement of the valve body 113, and the extension cavities create a non-interference moving channel for the extensions.

[0046] The technical scheme comprises: an elastic reset component 114, which is located in the first extension cavity 1133 and is elastically connected with the first extension part 1131. A magnetic driving component 115, which is located in the second extension cavity 1134 and is fixedly connected with the second extension part 1132. A power supply circuit 12, which is arranged outside the pipe core 11 near the side of the magnetic driving component 115, is used to drive the magnetic driving component 115 by controlling the current.

[0047] Preferably, the elastic reset component 114 can be a spring. Preferably, the magnetic driving component 115 can be a magnetic driving component. The power supply circuit 12 can control whether to supply power to control whether the magnetic field 116 is generated around the magnetic driving component 115. When the magnetic field 116 is generated around the magnetic driving component 115, the magnetic driving component 115 moves towards the power supply circuit 12 and drives the second extension part 1132 to move, so that the valve body 113 moves axially in the main pipe 111, thereby realizing the switching of the branch pipes. When the magnetic driving component 115 moves towards the power supply circuit 12, the elastic reset component 114 elastically connected with the first extension part 1131 is stretched. When the magnetic field 116 disappears, the elastic potential energy of the elastic reset component 114 is released, and the elastic reset component 114 is reset to contract and move the first extension part 1131 towards the side wall of the first extension cavity 1133.

[0048] Through the cooperation of the magnetic driving component 115 and the power supply circuit 12, the accurate control of the axial movement of the valve body 113 in the main pipe 111 can be realized. The existence of the elastic reset component 114 enables the valve body 113 to be reliably reset after the magnetic field disappears. This reset mechanism can ensure that the valve body 113 can automatically return to a safe or initial state when the magnetic field disappears due to power failure or other unexpected situations, thereby enhancing the reliability of the device. Since the structures of the elastic reset component 114 and the magnetic driving component 115 are relatively simple and there is no complex mechanical transmission device, the failure points of this displacement control mechanism are less. The elastic reset component 114 and the magnetic driving component 115 have a long service life under normal use conditions and are relatively simple to maintain, thereby reducing maintenance costs.

[0049] The technical scheme comprises: the inner recess structure 117 covers at least two branch pipes.

[0050] The branch pipes covered by the inner recess structure 117 can be connected through the second flow channel, and the inner recess structure 117 covering at least two branch pipes can ensure that at least two branch pipes are in a connected state during the axial movement of the valve body 113 in the main pipe 111.

[0051] The technical scheme comprises the following steps: the one side branch pipeline of the main pipeline 111 comprises a first branch pipeline 14, a second branch pipeline 15, a third branch pipeline 16 and a fourth branch pipeline 17.

[0052] The four branch pipelines are arranged to be communicated through the second flow channel when the valve body 113 moves axially in the main pipeline 111, and the two branch pipelines not covered by the concave structure 117 are communicated through the first flow channel.

[0053] The technical scheme comprises the following steps: the valve body 113 is arranged at a first position and a second position in the main pipeline 111. When the valve body 113 is arranged at the first position, the concave structure 117 of the valve body 113 covers the first branch pipeline 14 and the second branch pipeline 15, the second flow channel formed by the concave structure 117 and the main pipeline 111 is communicated with the first branch pipeline 14 and the second branch pipeline 15, and the first flow channel is communicated with the third branch pipeline 16 and the fourth branch pipeline 17. When the valve body 113 is arranged at the second position, the concave structure 117 of the valve body covers the second branch pipeline 15 and the third branch pipeline 16, the second flow channel formed by the concave structure 117 and the main pipeline 111 is communicated with the second branch pipeline 15 and the third branch pipeline 16, and the first flow channel is communicated with the first branch pipeline 14 and the fourth branch pipeline 17.

[0054] Preferably, the pipeline core 11 is provided with a mounting fixed point 13 on the outer side, so as to facilitate the fixation of the battery pack uniform temperature device on the battery pack.

[0055] In use, the elastic reset component 114 is arranged at the first position in a free state, the magnetic driving component 115 is arranged away from the side wall of the second extension cavity 1134 in the first position, the first branch pipeline 14 is communicated with the second branch pipeline 15, and the third branch pipeline 16 is communicated with the fourth branch pipeline 17; the magnetic force action line direction of the power supply circuit 12 in the energized state is directed to the side wall of the second extension cavity 1134, so as to displace the magnetic driving component 115 to the second position close to the side wall, the elastic reset component 114 drives the valve body 113 to move to the second position in a stretched state and generates a reset force away from the side wall of the second extension cavity 1134, the valve body 113 is arranged at the second position, the second branch pipeline 15 is communicated with the third branch pipeline 16, and the first branch pipeline 14 is communicated with the fourth branch pipeline 17. The communication state of the branch pipeline is shown in Table 1.

[0056] Table 1 Embodiment 2: As Figure 5As shown, the following is a battery pack 2 with temperature equalization function, the battery pack 2 includes: temperature equalization system 1, battery management system 21, battery thermal management system 22. The temperature equalization system 1 is located at the front end inside the battery pack 2, so that the temperature equalization system is protected by the battery box, improving the reliability of the battery pack, and the whole battery pack can be temperature equalized, and the specific implementation form is as follows: The battery thermal management system 22 mainly includes a flow channel plate 221, a first flow channel interface 222, a second flow channel interface 223, a battery pack first cooling liquid inlet 224, and a battery pack first cooling liquid outlet 225. The flow channel plate 221 described herein can be an integrated flow channel plate or a split flow channel plate.

[0057] The inner side of the battery pack first cooling liquid inlet 224 is connected with the pipeline 17 of the temperature equalization system 1, and the inner side of the battery pack first cooling liquid outlet 225 is connected with the pipeline 15 of the temperature equalization system 1; the first flow channel interface 222 is connected with the pipeline 16 of the temperature equalization system 1, and the second flow channel interface 223 is connected with the pipeline 14 of the temperature equalization system 1.

[0058] The power supply line 12 of the pipeline core body 11 of the temperature equalization system 1 is connected with the low-voltage connector 23 of the battery pack 2, and respectively plays the roles of obtaining a power supply, communication, and state switching.

[0059] Implementation process: The cooling liquid passes into the first cooling liquid inlet 224, respectively passes through the fourth branch pipeline 17 and the third branch pipeline 16, then enters the water inlet at one end of the liquid cooling plate through the first flow channel interface 222, and temperature equalizes the whole battery pack, and then flows through the first branch pipeline 14 and the second branch pipeline 15 from the water outlet at the other end of the liquid cooling plate through the second flow channel interface 223, and then flows out from the first cooling liquid outlet 225; After a period of time of communication through the branch pipeline at the first position, the liquid cooling plate close to the water inlet end of the liquid cooling plate has a lower temperature and a better cooling effect because it contacts the initial cooling water, but the liquid cooling plate at the water outlet end of the liquid cooling plate has a higher temperature because the cooling water flows to the water outlet and exchanges heat along the pipeline of the liquid cooling plate, so the cooling effect of the cooling water on the water outlet is reduced at this time, and the branch pipeline needs to be switched and connected by using the temperature equalization device when the battery pack temperature equalization control strategy detects that the current battery cell temperature difference needs to be temperature equalized. After switching the connected branch pipes, the coolant enters the first coolant inlet 224 and passes through the fourth branch pipe 17 and the first branch pipe 14 respectively, and then enters the water outlet at one end of the liquid cooling plate from the second flow channel interface 223 to equalize the temperature of the battery pack as a whole. From the water inlet at the other end of the liquid cooling plate, it passes through the first flow channel interface 222, flows through the third branch pipe 16 and the second branch pipe 15 respectively, and flows out from the first coolant outlet 225; by switching the connected branch pipes through the temperature equalizing device, the water inlet and outlet of the liquid cooling plate are switched, so that the cooling water enters the liquid cooling plate from the water outlet of the liquid cooling plate and flows out of the liquid cooling plate from the water inlet. At this time, the cooling effect near the water outlet of the liquid cooling plate is better, and the cooling effect near the water inlet of the liquid cooling plate is reduced, thereby achieving the effect of balanced temperature and realizing the purpose of equalization of temperature, avoiding the loss of cooling water temperature caused by entering at a fixed end, and the part of the liquid cooling plate near the water outlet cannot be cooled, and the temperature difference of the battery cell becomes larger.

[0060] Example 3: like Figure 6 As shown below, a battery pack 2 with a temperature equalization function is shown. The battery pack 2 includes a temperature equalization system 1, a battery management system 21, and a battery thermal management system 22. The temperature equalization system 1 is located in the location where local temperature equalization is required inside the battery pack 2. The temperature equalization system 1 is protected by the battery box, which improves reliability. The temperature equalization system is located in the local area where temperature equalization is required, further enhancing the temperature equalization effect and making it more targeted. The specific implementation is as follows: When the flow channel plate 221 of the battery thermal management system 22 of the battery pack 2 is of non-integrated design, the temperature equalization system can be set at a location where local temperature equalization is required.

[0061] The second coolant inlet 228 is connected to the pipeline 17 of the temperature equalizing system 1, and the second coolant outlet 229 is connected to the pipeline 15 of the temperature equalizing system 1; the third flow channel interface 226 is connected to the pipeline 16 of the temperature equalizing system 1, and the fourth flow channel interface 227 is connected to the pipeline 14 of the temperature equalizing system 1.

[0062] The power supply line 12 of the pipe core 11 of the temperature equalization system 1 is connected to the low-voltage connector 23 of the battery pack 2, which respectively plays the role of obtaining power supply, communication and status switching.

[0063] Preferably, the location inside the battery pack 2 where local temperature uniformity is required may be the battery cell at the rear of the battery, which is far away from the coolant inlet and has poor heat dissipation conditions.

[0064] Implementation process: The coolant enters the second coolant inlet 228 and passes through the fourth branch pipe 17 and the third branch pipe 16 respectively. Then, it enters the water inlet at one end of the local liquid cooling plate from the third flow channel interface 226 to uniformly heat the entire battery pack. From the water outlet at the other end of the liquid cooling plate, it passes through the fourth flow channel interface 227, flows through the first branch pipe 14 and the second branch pipe 15, and then flows out from the second coolant outlet 229. Through the battery pack temperature control strategy, if it is detected that the current battery cell temperature difference needs to be equalized, it is necessary to use the temperature equalization device to switch the connected branch pipes; After switching the connected branch pipes, the coolant enters the second coolant inlet 228 and passes through the fourth branch pipe 17 and the first branch pipe 14 respectively, and then enters the water outlet at one end of the liquid cooling plate from the fourth flow channel interface 227 to equalize the temperature of the battery pack as a whole. After flowing through the third branch pipe 16 and the second branch pipe 15 respectively from the water inlet at the other end of the liquid cooling plate through the third flow channel interface 226, it flows out from the second coolant outlet 229; by switching the connected branch pipes through the temperature equalizing device, the water inlet and outlet of the rear liquid cooling plate are switched, so that the cooling water enters the liquid cooling plate from the water outlet of the liquid cooling plate and flows out of the liquid cooling plate from the water inlet.

[0065] Example 4: like Figure 7 As shown below, a battery pack 2 with a temperature equalization function is shown. The battery pack 2 includes a temperature equalization system 1, a battery management system 21, and a battery thermal management system 22. The temperature equalization system 1 is located in the external thermal management loop of the battery pack 2. This makes installation and modification of the temperature equalization system outside the battery pack easier, and can achieve global temperature equalization for the battery pack. The specific implementation is as follows: The outer side of the first coolant inlet 224 of the battery pack is connected to the pipeline 14 of the temperature equalizing system 1, and the outer side of the first coolant outlet 225 of the battery pack is connected to the pipeline 16 of the temperature equalizing system 1; the first vehicle thermal management pipeline 2210 is connected to the pipeline 15 of the temperature equalizing system 1, and the second vehicle thermal management pipeline 2211 is connected to the pipeline 17 of the temperature equalizing system 1.

[0066] The power supply line 12 of the pipe core 11 of the temperature equalization system 1 is connected to the low-voltage connector 23 of the battery pack 2, which respectively plays the role of obtaining power supply, communication and status switching.

[0067] Implementation process: The coolant enters the first vehicle thermal management pipeline 2210 and passes through the second branch pipeline 15 and the first branch pipeline 14 respectively. Then, it enters the water inlet at one end of the liquid cooling plate from the first coolant inlet 224 to evenly distribute the temperature of the battery pack. From the water outlet at the other end of the liquid cooling plate, it flows through the first coolant outlet 225, passes through the first branch pipeline 14 and the second branch pipeline 15 respectively, and then flows out from the second vehicle thermal management pipeline 2211. Through the battery pack temperature equalization control strategy, it is detected that the current battery temperature difference needs to be equalized, and the equalization device needs to be used to switch the connected branch pipeline; After switching the connected branch pipeline, the cooling liquid enters the first vehicle thermal management pipeline 2210, respectively passes through the second branch pipeline 15 and the third branch pipeline 16, and then enters the water outlet at one end of the liquid cooling plate from the first cooling liquid outlet 225, equalizes the whole battery pack, and then flows through the first branch pipeline 14 and the fourth branch pipeline 17 from the water inlet at the other end of the liquid cooling plate through the first cooling liquid inlet 224, and then flows out from the second vehicle thermal management pipeline 2211; through the equalization device to switch the connected branch pipeline, the water inlet and the water outlet of the rear liquid cooling plate are turned over, so that the cooling water enters the liquid cooling plate from the turned-over water outlet of the liquid cooling plate and flows out from the water inlet.

[0068] The contents not described in detail in the specification belong to the prior art known to those skilled in the art.

Claims

1. A battery pack temperature control strategy, characterized in that: include: Obtaining battery cells that meet the uniform temperature conditions; By controlling and switching the connection of different branch pipes, one end of which is connected to the liquid cooling plate and the other end is connected to the cooling water outlet or inlet, the water inlet and outlet of the cooling water entering the liquid cooling plate are reversed, and the liquid cooling plate is used to perform temperature uniformity treatment on the battery cells that meet the temperature uniformity conditions.

2. The battery pack temperature control strategy according to claim 1, characterized in that: The method of obtaining a battery cell that meets the temperature uniformity condition comprises the following steps: Get the temperature of the single cell in the battery pack; Calculate the temperature difference between different battery cells based on the temperature of the battery cell; Determine whether the temperature difference between different single battery cells is greater than the preset temperature difference. For battery cells whose temperature difference is greater than the preset temperature difference, continue to determine whether the temperature difference is less than the preset temperature averaging capability. If the temperature difference of the battery cells is less than the said temperature averaging capability, it is determined that the battery cells meet the temperature averaging conditions, otherwise, the temperature averaging conditions are not met.

3. A battery pack temperature equalization system, characterized in that: The temperature balancing system includes: a module for obtaining the battery cells to be temperature balanced and a battery pack temperature balancing device; The module for obtaining cells to be temperature-averaged is used to obtain cells that meet the temperature-averaging conditions; The battery pack temperature equalization device is used to control the switching of different branch pipe connections to adjust the water inlet and outlet of the liquid cooling plate to equalize the temperature of the battery cells that meet the temperature equalization conditions.

4. The battery pack temperature equalizing device of the battery pack temperature equalizing system according to claim 3, characterized in that: The battery pack temperature equalization device includes: A pipe core (11), the pipe core (11) comprising a main pipe (111), at least four branch pipes connected to the main pipe (111) and arranged axially along one side of the main pipe (111), and a connecting channel (112) provided on the other side of the main pipe (111) and connected to the main pipe (111), wherein the connecting channel (112) and an internal cavity of the main pipe (111) form a first flow channel; a valve body (113), the valve body (113) being slidably assembled inside the main pipe (111) and sealingly cooperating with the inner wall of the main pipe (111); a concave structure (117) being provided on a side of the valve body (113) close to the branch pipe; the concave structure (117) and the inner wall of the main pipe (111) forming a second flow channel; A displacement control mechanism drives the valve body (113) to move axially to switch any two branch pipelines to communicate through the first flow channel or the second flow channel.

5. The battery pack temperature equalizing device according to claim 4, characterized in that: include: Both ends of the valve body (113) extend into a first extension portion (1131) and a second extension portion (1132), respectively. The first extension portion (1131) and the second extension plate (1132) extend out of the main pipe (111) and are connected to a displacement control mechanism.

6. The battery pack temperature equalizing device according to claim 5, characterized in that: include: The pipe core (11) further comprises a first extension cavity (1133) and a second extension cavity (1134) located at both axial ends of the main pipe (111). The first extension cavity (1133) and the second extension cavity (1134) are spaces for the first extension portion (1131) and the second extension portion (1132) to move respectively when the displacement control mechanism drives the valve body (113) to move axially.

7. The battery pack temperature equalizing device according to claim 6, characterized in that: include: an elastic reset component (114), the elastic reset component (114) being located in the first extension cavity (1133) and elastically connected to the first extension portion (1131); a magnetic drive component (115), the magnetic drive component (115) being located in the second extension cavity (1134) and fixedly connected to the second extension portion (1132); A power supply line (12) is provided outside the pipeline core (11) on a side close to the magnetic drive component (115), and is used to drive the magnetic drive component (115) by controlling the current.

8. The battery pack temperature equalizing device according to claim 7, characterized in that: include: The concave structure (117) covers at least two branch pipes.

9. The battery pack temperature equalizing device according to claim 7, characterized in that: include: The branch pipelines on one side of the main pipeline (111) include a first branch pipeline (14), a second branch pipeline (15), a third branch pipeline (16), and a fourth branch pipeline (17).

10. The battery pack temperature equalizing device according to claim 9, characterized in that: include: The position of the valve body (113) in the main pipeline (111) includes a first position and a second position; When the valve body (113) is in the first position: the concave structure (117) of the valve body (113) covers the first branch pipe (14) and the second branch pipe (15); the second flow channel formed by the concave structure (117) and the main pipe (111) is in communication with the first branch pipe (14) and the second branch pipe (15); and the first flow channel is in communication with the third branch pipe (16) and the fourth branch pipe (17); When the valve body (113) is in the second position: the concave structure (117) of the valve body covers the second branch pipe (15) and the third branch pipe (16); the second flow channel formed by the concave structure (117) and the main pipe (111) is connected to the second branch pipe (15) and the third branch pipe (16); and the first flow channel is connected to the first branch pipe (14) and the fourth branch pipe (17).

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