Bidirectional liquid cooling pipeline flow distribution system for energy storage product

Abstract

The utility model discloses a bidirectional liquid cooling pipeline flow distribution system for an energy storage product, which comprises a plurality of battery plug-in boxes for storing energy, a liquid cooling unit for providing cooling liquid and a liquid supply and return pipeline for the circulation of the cooling liquid, and the plurality of battery plug-in boxes are connected with the liquid cooling unit through the liquid supply and return pipeline. The liquid supply and return pipeline is provided with a reversing device for changing the flow direction of the cooling liquid in the liquid supply and return pipeline and a shunting device for uniformly distributing the cooling liquid to the plurality of battery subracks. The bidirectional liquid cooling pipeline flow distribution system synchronously realizes bidirectional switching of the liquid cooling system and uniform flow distribution of each liquid supply branch of the liquid cooling system, and effectively solves the problems of temperature difference in the battery plug-in boxes and temperature difference between the battery plug-in boxes, so that the temperature distribution consistency of the whole energy storage system is better controlled, the thermal management effect is improved, and the service life of the energy storage system is prolonged. And the performance, the service life and the guarantee safety of energy storage products are improved.

Description

Technical Field

[0001] This utility model belongs to the field of electrochemical energy storage, and in particular relates to a liquid cooling pipeline system. Background Technology

[0002] In the energy storage field, traditional air-cooling technology once dominated low-power scenarios due to its advantages such as simple structure and low cost. However, as energy storage systems develop towards higher power density and larger capacity, air-cooling technology has gradually revealed its bottlenecks, including low heat dissipation efficiency and inability to achieve precise battery temperature control. Liquid cooling technology has emerged to meet the dual requirements of high power density and low energy consumption. Liquid cooling systems achieve precise battery temperature control through liquid convection, ensuring uniform cooling, which is crucial for battery performance stability and lifespan. Furthermore, liquid cooling technology does not require complex air duct designs, has a smaller footprint, lower failure rate, and is more environmentally friendly. Therefore, with the continuous advancement of energy storage technology and increasingly stringent requirements for efficiency, safety, and environmental protection, liquid cooling technology is gradually replacing air cooling technology as the new favorite in the energy storage field.

[0003] Currently, in energy storage liquid cooling technology, the liquid cooling system of an integrated outdoor energy storage unit mainly includes a liquid cooling unit, liquid cooling pipelines, and multiple battery compartments. The working principle of the liquid cooling system is as follows: low-temperature coolant flows from the chiller unit, enters the liquid cooling plate at the bottom of the battery compartment, exchanges heat with the battery pack inside, becomes high-temperature coolant, flows out of the battery compartment, and finally flows back to the liquid cooling unit for cooling. Currently, integrated outdoor energy storage units on the market typically include 5-8 battery compartments. For a single battery compartment, the maximum temperature difference between cells can usually be controlled within 3℃; for the entire battery cluster, it is usually controlled within 5-7℃. Although the above temperature control range represents a good level, the impact of uneven temperature between cells on the cells is significant. First, temperature differences lead to different SOCs (State of Charge) of the cells, which can easily cause large capacity losses in a series circuit. Second, cells with higher temperatures age faster, generate more heat, and are more prone to high temperatures, creating a vicious cycle that affects the lifespan of the entire energy storage system and may even lead to serious safety accidents. Therefore, higher requirements are still needed for the temperature uniformity between battery cells, and better solutions for controlling the maximum temperature difference are needed.

[0004] Analysis revealed that the temperature difference mainly exists in two aspects: the temperature difference within the battery compartment and the temperature difference between battery compartments. For the temperature difference within the battery compartment, current liquid cooling systems primarily use a unidirectional flow method for heat exchange. This means the coolant flows from the liquid cooling unit, enters the liquid cooling plate of the battery compartment through the supply pipe, and then returns to the liquid cooling unit through the return pipe. This unidirectional flow system design is simple and easy to operate. However, during the charging and discharging process of the battery compartment, due to the thermal characteristics of the battery, a large amount of heat is generated inside the battery pack, causing the battery temperature to rise. If the flow direction of the coolant remains unchanged, uneven temperature distribution between the cells is inevitable. Regarding the temperature difference between battery compartments, the height difference between the highest and lowest compartment inlets is between 1-2 meters. The more battery compartments there are, the higher the flow imbalance rate and the greater the temperature difference between battery compartments. To address the common problem of uneven flow distribution between battery compartments, the most common solutions are as follows: The first method is to adjust the specifications of the tees on the liquid cooling pipes through hydraulic calculations and testing, mainly adjusting the size of the branch connection ports. However, this method has limited balancing effect, mainly because the tee is a standard component, inevitably leading to results exceeding expectations after adjustment. The second method is to adjust the diameter of the supply / return / fluid branch pipes corresponding to certain battery boxes, but this method suffers from the same limitations as the first. The final method is to change the fluid supply / return method from a reverse-flow to a same-flow system. This method is better than the first two, although it complicates the piping system, it can overcome the problem of uneven flow distribution caused by different flow resistances in each branch to the greatest extent. However, this method still has limitations. In actual engineering, manufacturing deviations of pipe fittings, differences in connections between fittings, and gravity factors can all affect flow distribution. Therefore, effectively addressing the temperature difference within and between battery boxes and synchronously controlling it is key to effectively improving the temperature uniformity of the battery cells. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the deficiencies and defects mentioned in the background art above, and to provide a bidirectional liquid cooling pipeline flow distribution system for energy storage products that can effectively solve the temperature difference problem inside the battery compartment and between battery compartments, synchronously control the entire energy storage system, and keep the temperature distribution of the entire energy storage system consistent.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this utility model is as follows:

[0007] A bidirectional liquid-cooled pipeline flow distribution system for energy storage products includes multiple battery cells for energy storage, a liquid-cooled unit for supplying coolant, and supply and return pipelines for coolant circulation. The multiple battery cells are connected to the liquid-cooled unit via the supply and return pipelines. The supply and return pipelines are equipped with a reversing device for changing the flow direction of the coolant and a distribution device for evenly distributing the coolant to the multiple battery cells. The liquid-cooled unit is a high-efficiency, energy-saving refrigeration device, a conventional product, mainly composed of a control system, a refrigeration system, a heat dissipation system, and a liquid-cooled circulation system. The liquid-cooled circulation system interfaces include a supply port, a return port, and an injection port, whose functions are respectively to deliver low-temperature coolant, recover high-temperature coolant, and inject or replenish coolant.

[0008] In the aforementioned bidirectional liquid cooling pipeline flow distribution system, preferably, the supply and return liquid pipelines include a first main pipe and a second main pipe. The liquid cooling unit is connected to the battery compartments via the first and second main pipes. The end of the first main pipe furthest from the liquid cooling unit has multiple first branch pipes, each connected to one of the battery compartments. The end of the second main pipe furthest from the liquid cooling unit has multiple second branch pipes, each connected to one of the battery compartments. This pipeline configuration achieves a relatively balanced flow distribution, ensuring that each battery compartment receives an appropriate coolant flow, thereby improving cooling efficiency and the consistency of battery performance.

[0009] In the above-mentioned bidirectional liquid-cooled pipeline flow distribution system, preferably, the number of battery boxes is an even number, the number of first branch pipes is half the number of battery boxes, and the end of the first branch pipe away from the first main pipe is provided with a first upper branch pipe and a first lower branch pipe, which are respectively connected to two battery boxes arranged vertically adjacent to each other.

[0010] In the above-mentioned bidirectional liquid cooling pipeline flow distribution system, preferably, the number of battery boxes is an odd number, and the number of the first branch pipes is equal to the number of battery boxes, and they are set in a one-to-one correspondence.

[0011] This utility model is designed for energy storage systems composed of different numbers of battery boxes. It distinguishes between odd and even numbers in the supply and return liquid pipelines. When there are a large number of battery boxes, this design can ensure the uniformity of flow distribution in each branch pipe, while simplifying the supply and return liquid pipeline setup and reducing the complexity of the pipeline layout.

[0012] In the aforementioned bidirectional liquid-cooled pipeline flow distribution system, preferably, the first main pipe and the second main pipe are connected to the liquid-cooled unit and the battery compartment via the reversing device.

[0013] In the aforementioned bidirectional liquid-cooled pipeline flow distribution system, preferably, the switching device is a two-position four-way reversing solenoid valve. This two-position four-way reversing solenoid valve has two outlets and two inlets. The first main pipe connects to one outlet and one inlet, and the second main pipe connects to the other outlet and the other inlet. The two-position four-way reversing solenoid valve is a fluid control element, a conventional product, which achieves precise switching between coolant supply and return channels through electromagnetic control, enabling bidirectional supply and return of coolant to the liquid-cooled plate end.

[0014] In the aforementioned bidirectional liquid cooling pipeline flow distribution system, preferably, the flow distribution device is located on the first main pipe or the second main pipe. This arrangement allows the liquid cooling system to achieve uniform flow distribution through each battery compartment during operation through the regulation of the flow distribution device.

[0015] In the aforementioned bidirectional liquid-cooled pipeline flow distribution system, preferably, the flow distribution device is a smart flow meter manifold. The smart flow meter manifold includes a main manifold pipe and visual flow meters and flow regulating valves spaced apart on the main manifold pipe. Each visual flow meter and flow regulating valve corresponds to one of the first or second branch pipes. The smart flow meter manifold is a fluid control element, a conventional product, which controls the stroke of the valve core within the pipe diameter to change the flow resistance entering each branch pipe, thereby achieving a uniform distribution of the liquid supply flow to each branch pipe. The smart flow meter manifold can be manually adjusted and visually adjusted, allowing for convenient and intuitive viewing of the flow rate in each branch pipe and rapid adjustment. Of course, the smart flow meter manifold can also be interlocked with the battery management system.

[0016] In the aforementioned bidirectional liquid-cooled pipeline flow distribution system, preferably, the battery compartment includes multiple lithium batteries and a liquid-cooled plate for contacting the bottom surfaces of the multiple lithium batteries via thermally conductive adhesive. The liquid-cooled plate has evenly distributed internal flow channels that communicate with the first and second branch pipes. The contact between the liquid-cooled plate and the bottom surfaces of the lithium batteries via the thermally conductive adhesive effectively conducts the heat generated by the batteries to the liquid-cooled plate, which is then carried away by the flow of coolant, achieving a highly efficient heat dissipation effect. The evenly distributed internal flow channels on the liquid-cooled plate help to distribute the coolant evenly, making the temperature of the battery compartment more uniform, avoiding localized overheating, and improving battery performance and lifespan.

[0017] In the aforementioned bidirectional liquid-cooled pipeline flow distribution system, preferably, the commutation device is connected to a battery management system. The battery management system is a conventional product, and the commutation device is controlled by connecting to the battery management system. The commutation device, through the battery management system, can achieve bidirectional switching to provide uniform liquid cooling flow. The cooperation between the battery management system and the commutation device is a mature existing technology. The battery management system can be a highly integrated controller; for example, it can input a temperature signal and output high and low electrical frequencies, and the commutation device adjusts the flow direction based on these frequencies. Of course, in this invention, the shunt device can also be connected to the battery management system.

[0018] Compared with the prior art, the advantages of this utility model are:

[0019] This invention, through the design and coordination of the reversing device and the diversion device, achieves reversibility of the supply and return of liquid during the static process of cyclic charging and discharging, and achieves uniform flow distribution during the operation of the liquid cooling system. It simultaneously realizes bidirectional switching of the liquid cooling system and uniform flow distribution of each liquid supply branch of the liquid cooling system, effectively solving the problems of temperature difference inside the battery compartment and temperature difference between battery compartments. This allows for better control of the temperature distribution consistency of the entire energy storage system, improves thermal management, and enhances the performance, lifespan, and safety of energy storage products. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a topology diagram of the bidirectional liquid cooling pipeline flow distribution system for odd-numbered battery packs in Example 1;

[0022] Figure 2 This is a schematic diagram illustrating the working principle of the bidirectional liquid cooling pipeline flow distribution system for odd-numbered battery boxes in Example 1, showing the forward flow of coolant.

[0023] Figure 3 This is a schematic diagram illustrating the working principle of the bidirectional liquid cooling pipeline flow distribution system for odd-numbered battery boxes in Example 1, showing the reverse flow of coolant.

[0024] Figure 4 A schematic diagram illustrating the temperature difference between battery cells during the cyclic charging and discharging process of the battery pack, showing the unidirectional flow of coolant.

[0025] Figure 5 This is a topology diagram of the even-numbered battery pack bidirectional liquid cooling pipeline flow distribution system in Example 2;

[0026] Figure 6 This is a schematic diagram illustrating the working principle of the even-numbered battery pack bidirectional liquid cooling pipeline flow distribution system in Example 2, showing the forward flow of coolant.

[0027] Figure 7 This is a schematic diagram illustrating the working principle of the coolant reverse flow in the bidirectional liquid cooling pipeline flow distribution system for even-numbered battery boxes in Example 2.

[0028] Legend

[0029] 1. Battery compartment; 2. Supply and return liquid pipelines; 3. Liquid cooling unit; 4. Two-position four-way reversing solenoid valve; 5. Intelligent flow meter manifold; 6. Battery management system; 21. First main pipe; 22. Second main pipe; 23. First branch pipe; 24. Second branch pipe; 25. First upper branch pipe; 26. First lower branch pipe; 41. First cavity; 42. Second cavity; 43. Third cavity; 44. Fourth cavity; 45. Fifth cavity; 46. Solenoid valve. Detailed Implementation

[0030] To facilitate understanding of this utility model, it will be described more comprehensively and in detail below with reference to the accompanying drawings and preferred embodiments. However, the scope of protection of this utility model is not limited to the following specific embodiments.

[0031] It should be noted that when a component is described as being "fixed to, attached to, connected to or connected to" another component, it can be directly fixed to, attached to, connected to or connected to the other component, or it can be indirectly fixed to, attached to, connected to or connected to the other component through other intermediate connectors.

[0032] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of protection of this invention.

[0033] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0034] Example 1:

[0035] like Figures 1 to 3As shown, the bidirectional liquid-cooled pipeline flow distribution system for energy storage products in this embodiment includes multiple battery cells 1 for energy storage, a liquid cooling unit 3 for supplying coolant, and supply and return pipelines 2 for coolant flow. The multiple battery cells 1 are connected to the liquid cooling unit 3 via the supply and return pipelines 2. The supply and return pipelines 2 are equipped with a reversing device for changing the flow direction of the coolant in the pipelines 2, and a distribution device for evenly distributing the coolant to the multiple battery cells 1. In this embodiment, the coolant is a refrigerant, which can be a 50% (by volume) ethylene glycol solution.

[0036] In this embodiment, the supply and return liquid pipeline 2 includes a first main pipe 21 and a second main pipe 22. The liquid cooling unit 3 is connected to the battery box 1 through the first main pipe 21 and the second main pipe 22. The end of the first main pipe 21 away from the liquid cooling unit 3 is provided with a plurality of first branch pipes 23, which are respectively connected to a plurality of battery boxes 1. The end of the second main pipe 22 away from the liquid cooling unit 3 is provided with a plurality of second branch pipes 24, which are respectively connected to a plurality of battery boxes 1.

[0037] In this embodiment, the number of battery boxes 1 is an odd number (e.g., 5), and the number of first branch pipes 23 is equal to the number of battery boxes 1, and they are set in a one-to-one correspondence.

[0038] In this embodiment, the first main pipe 21 and the second main pipe 22 are connected to the liquid cooling unit 3 and the battery box 1 through a reversing device.

[0039] In this embodiment, the reversing device is a two-position four-way reversing solenoid valve 4. The two-position four-way reversing solenoid valve 4 has two outlets and two inlets. The first main pipe 21 is connected to one of the outlets and one of the inlets, and the second main pipe 22 is connected to the other outlet and the other inlet.

[0040] In this embodiment, the two-position four-way reversing solenoid valve 4 includes five chambers connected by through holes. The chambers include a first cavity 41, a second cavity 42, a third cavity 43, a fourth cavity 44, and a fifth cavity 45. A solenoid valve 46 is slidably disposed in the chamber to close the through holes at different positions, thereby changing the flow direction of the coolant.

[0041] In this embodiment, the diversion device is located on the first main pipe 21. The diversion device is a smart flow meter manifold 5, which includes a manifold main pipe and visual flow meters and flow regulating valves spaced apart on the manifold main pipe. The visual flow meters and flow regulating valves are configured one-to-one with the first branch pipes 23. In other embodiments, the diversion device can be located on the second main pipe 22, and the visual flow meters and flow regulating valves of the diversion device are configured one-to-one with the second branch pipes 24.

[0042] In this embodiment, the battery housing 1 includes multiple square lithium batteries and a liquid cooling plate for contacting the bottom surfaces of the multiple square lithium batteries via thermally conductive adhesive. The liquid cooling plate has internal flow channels evenly distributed and connected to the first branch pipe 23 and the second branch pipe 24. In other embodiments, cylindrical lithium batteries, etc., may be used.

[0043] In this embodiment, the commutation device is connected to a battery management system 6. In a more preferred embodiment, the shunt device may also be connected to the battery management system 6.

[0044] In this embodiment, the specific steps are as follows: the coolant flows out from the liquid cooling unit 3, flows along the first main pipe 21 through the two-position four-way reversing solenoid valve 4, and if it does not reverse, as... Figure 2 As shown, at this time, solenoid valve 46 is not activated. The second cavity 42, third cavity 43, fourth cavity 44, and fifth cavity 45 are connected. The coolant flows in the forward direction, exiting from the liquid cooling unit 3, flowing into the second cavity 42, and then exiting from the third cavity 43 to the intelligent flow meter manifold 5. After the manifold performs its water distribution function, the coolant flows along the first branch pipe 23 into the liquid cooling plate at the bottom of the battery compartment 1, absorbing the heat generated by the battery cells. The coolant, with its increased temperature after absorbing heat, flows sequentially through the second branch pipe 24 and the second main pipe 22, flowing into the fourth cavity 44 of the two-position four-way reversing solenoid valve 4, and finally flowing back to the liquid cooling unit 3 through the fifth cavity 45 for cooling, completing one cooling cycle. If reversal is required, such as... Figure 3 As shown, the solenoid valve 46 is pushed, connecting the first cavity 41, the second cavity 42, and the fifth cavity 45, and connecting the third cavity 43 and the fourth cavity 44. The coolant flows in reverse, flowing out of the liquid cooling unit 3, into the second cavity 42, through the first cavity 41, out of the fifth cavity 45, through the second main pipe 22 and the second branch pipe 24 into the liquid cooling plate at the bottom of the battery compartment 1, and then through the first branch pipe 23 into the intelligent flow meter manifold 5. At this time, the intelligent flow meter manifold 5 performs the function of collecting water and also plays the role of flow distribution. Finally, it flows back to the liquid cooling unit 3 through the first main pipe 21 for cooling and temperature reduction, completing one cooling cycle.

[0045] like Figure 4As shown, the cyclic charging and discharging process of the battery pack includes a charging phase, a resting phase, a discharging phase, a second resting phase, and repeating the above steps as needed. For existing liquid-cooled energy storage systems, the coolant flow direction remains constant throughout the entire process. Before the cycle begins, all cells in the battery pack have the same temperature, with a temperature difference of 0, i.e., Δt0 = 0℃. As the initial charging (or discharging) proceeds, the coolant flow causes different cell temperatures within the battery pack; that is, the cells near the inlet have a lower overall temperature, while the cells near the outlet have a slightly higher temperature (Tmax represents the maximum cell temperature, and Tmin represents the minimum cell temperature). According to actual test results, during the entire initial charging (or discharging) process, the maximum temperature difference between cells first increases and then decreases, eventually reaching a relatively low temperature difference level of Δt1. However, during the resting phase after the initial charging (or discharging) ends, the temperature difference may widen again due to the unchanged coolant flow direction. The resting time is typically 10-30 minutes. At the end of the resting period, the maximum temperature difference is usually greater than at any point during the initial charging (or discharging) process, i.e., Δt2 > MAX(Tmax-Tmin during initial charging) > Δt1. This temperature difference is inherited by the subsequent discharging (or charging) process and continues to increase, i.e., Δt3 > Δt2. After several cycles, an equilibrium state is reached with a relatively high maximum temperature difference, close to Δt3. Therefore, to avoid frequent operation of the two-position four-way reversing solenoid valve 4 during the charging or discharging phase of the battery compartment 1, affecting cooling efficiency, the reversing action is only performed after each charging or discharging phase. The timing and duration of the reversing action are determined based on the maximum temperature difference of each battery compartment 1, the rate of temperature drop after the end of the phase, and the set duration of the resting period, so that Δ2 and Δ4 approach 0℃.

[0046] Example 2:

[0047] like Figure 5 As shown, the bidirectional liquid-cooled pipeline flow distribution system for energy storage products in this embodiment is basically the same as that in Embodiment 1, except that: the number of battery boxes 1 is an even number (e.g., 8), the number of first branch pipes 23 is half the number of battery boxes 1, and the end of the first branch pipe 23 away from the first main pipe 21 is provided with a first upper branch pipe 25 and a first lower branch pipe 26, which are respectively connected to two adjacent battery boxes 1 arranged vertically. This arrangement ensures uniform flow distribution in each branch pipe when the number of battery boxes is large, while simplifying the setting of the supply and return liquid pipelines 2, facilitating flow distribution, and reducing the complexity of the pipeline layout.

[0048] In this embodiment, the specific steps may be as follows: Figure 6As shown, if the flow is not reversed, the coolant flows in the forward direction, exiting from the liquid-cooled unit 3, flowing into the second cavity 42, and then from the third cavity 43 to the intelligent flow meter manifold 5. After the manifold performs its water-dividing function, the coolant flows along the first branch pipe 23 into the first upper branch pipe 25 and the first lower branch pipe 26, then into the liquid-cooled plate at the bottom of the battery compartment 1, flowing sequentially through the second branch pipe 24 and the second main pipe 22, into the fourth cavity 44 of the two-position four-way reversing solenoid valve 4, and finally flows back to the liquid-cooled unit 3 through the fifth cavity 45 for cooling, completing one cooling cycle. If reversal is required, as... Figure 7 As shown, the solenoid valve 46 is pushed, connecting the first cavity 41, the second cavity 42, and the fifth cavity 45, and connecting the third cavity 43 and the fourth cavity 44. The coolant flows in reverse, flowing out of the liquid cooling unit 3, into the second cavity 42, through the first cavity 41, out of the fifth cavity 45, through the second main pipe 22 and the second branch pipe 24, and sequentially into the liquid cooling plate at the bottom of the battery compartment 1, the first upper branch pipe 25 and the first lower branch pipe 26, the first branch pipe 23, and then into the intelligent flow meter manifold 5. Finally, it flows back to the liquid cooling unit 3 through the first main pipe 21 for cooling and temperature reduction, completing one cooling cycle.

[0049] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A bidirectional liquid-cooled pipeline flow distribution system for energy storage products, comprising a plurality of battery boxes (1) for energy storage, a liquid-cooled unit (3) for supplying coolant, and a supply and return pipeline (2) for coolant flow, wherein the plurality of battery boxes (1) are connected to the liquid-cooled unit (3) via the supply and return pipeline (2), characterized in that, The supply and return fluid pipeline (2) is provided with a reversing device for changing the flow direction of the coolant in the supply and return fluid pipeline (2), and a diversion device for evenly distributing the coolant to the multiple battery boxes (1).

2. The bidirectional liquid-cooled pipeline flow distribution system according to claim 1, characterized in that, The supply and return liquid pipeline (2) includes a first main pipe (21) and a second main pipe (22). The liquid cooling unit (3) is connected to the battery box (1) through the first main pipe (21) and the second main pipe (22). The first main pipe (21) is provided with a plurality of first branch pipes (23) at the end away from the liquid cooling unit (3), which are respectively connected to a plurality of battery boxes (1). The second main pipe (22) is provided with a plurality of second branch pipes (24) at the end away from the liquid cooling unit (3), which are respectively connected to a plurality of battery boxes (1).

3. The bidirectional liquid-cooled pipeline flow distribution system according to claim 2, characterized in that, The number of battery boxes (1) is an even number, and the number of first branch pipes (23) is half the number of battery boxes (1). The first branch pipe (23) is provided with a first upper branch pipe (25) and a first lower branch pipe (26) at the end away from the first main pipe (21), which are respectively connected to two battery boxes (1) arranged adjacent to each other.

4. The bidirectional liquid-cooled pipeline flow distribution system according to claim 2, characterized in that, The number of battery boxes (1) is odd, and the number of first branch pipes (23) is equal to the number of battery boxes (1), and they are set in a one-to-one correspondence.

5. The bidirectional liquid-cooled pipeline flow distribution system according to claim 2, characterized in that, The first main pipe (21) and the second main pipe (22) are connected to the liquid cooling unit (3) and the battery box (1) through the reversing device.

6. The bidirectional liquid-cooled pipeline flow distribution system according to claim 5, characterized in that, The reversing device is a two-position four-way reversing solenoid valve (4). The two-position four-way reversing solenoid valve (4) has two outlets and two inlets. The first main pipe (21) is connected to one of the outlets and one of the inlets, and the second main pipe (22) is connected to the other outlet and the other inlet.

7. The bidirectional liquid-cooled pipeline flow distribution system according to claim 2, characterized in that, The diversion device is located on the first main pipe (21) or the second main pipe (22).

8. The bidirectional liquid-cooled pipeline flow distribution system according to claim 7, characterized in that, The diversion device is a smart flow meter manifold (5). The smart flow meter manifold (5) includes a main manifold pipe and a visible flow meter and a flow regulating valve spaced apart on the main manifold pipe. The visible flow meter and the flow regulating valve are arranged in a one-to-one correspondence with the first branch pipe (23) or the second branch pipe (24).

9. The bidirectional liquid-cooled pipeline flow distribution system according to claim 2, characterized in that, The battery box (1) includes a plurality of lithium batteries and a liquid cooling plate for contacting the bottom surface of the plurality of lithium batteries with thermally conductive adhesive. The liquid cooling plate is uniformly provided with internal flow channels that are connected to the first branch pipe (23) and the second branch pipe (24).

10. The bidirectional liquid-cooled pipeline flow distribution system according to any one of claims 1-9, characterized in that, The commutation device is connected to a battery management system (6).

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