Large-module battery device with double-layer structure

Abstract

The invention discloses a large-module battery device with a double-layer structure, and belongs to the technical field of new energy batteries. The invention relates to a double-layer structure large-module battery device, which comprises a box body used for accommodating a battery pack; the battery pack comprises an upper-layer battery cell mechanism and a lower-layer battery cell mechanism; and the cooling mechanism is arranged between the upper-layer battery cell mechanism and the lower-layer battery cell mechanism. The cooling mechanism is arranged between the upper-layer battery cell mechanism and the lower-layer battery cell mechanism, so that when the temperature difference is relatively large, the cooling mechanism can adjust the temperature of the battery in time and reduce the fluctuation of the temperature of the battery; heat of the battery is brought out through flowing of a working medium in the liquid cooling plate so as to achieve the effect of cooling the battery, and external temperature is brought to the battery so as to achieve the effect of heating the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and more specifically, to a large-module battery device with a double-layer structure. Background Art

[0002] The lithium batteries used in electric vehicles are sensitive to temperature changes. The optimal operating temperature of the battery is between 20 and 35 °C. Too high, too low, or too large a temperature difference will seriously affect the service life of the battery. The capacity of the lithium battery will change with the increase in temperature. Through testing, it is found that for every 1 °C increase in temperature, the capacity increases by 0.8% of the original. However, the increase in temperature will also damage the battery, and the battery cycle life and capacity will gradually decrease. According to the test, in an environment of 25 °C at room temperature, if the temperature rises by 6 to 10 °C, the battery life will be reduced by half due to the increase in the floating charge current of the battery caused by high temperature. China has a vast territory, and the temperature difference between different regions is large. However, people's demand for long-distance travel of electric vehicles is increasing. In order to increase the capacity of the vehicle's battery to meet the demand for long-distance travel, some electric vehicles often use a large-module battery powered by a double-layer structure superposition method.

[0003] Therefore, how to ensure the battery capacity and performance of the double-layer superimposed large-module battery under large temperature differences, too high or too low temperatures is an urgent problem to be solved at present. Summary of the Invention

[0004] 1. Technical Problems to be Solved by the Invention

[0005] The purpose of the present invention is to overcome the deficiency that the battery performance and capacity of the double-layer superimposed large-module battery in the prior art cannot be guaranteed under large temperature differences, too high or too low temperatures, and provide a large-module battery device with a double-layer structure.

[0006] 2. Technical Solutions

[0007] To achieve the above object, the technical solution provided by the present invention is as follows:

[0008] A large-module battery device with a double-layer structure of the present invention includes a box body for accommodating a battery pack; the battery pack includes an upper battery cell mechanism and a lower battery cell mechanism; and further includes a cooling mechanism, and the cooling mechanism is arranged between the upper battery cell mechanism and the lower battery cell mechanism. The arrangement of the cooling mechanism between the upper battery cell mechanism and the lower battery cell mechanism can enable the cooling mechanism to timely adjust the battery temperature and reduce the volatility of the battery temperature when the temperature difference is large.

[0009] As a further improvement of the present invention, the upper battery cell mechanism includes a first battery cell and a second battery cell, the lower battery cell mechanism includes a third battery cell and a fourth battery cell, and the cooling mechanism is disposed between the first battery cell and the third battery cell and between the second battery cell and the fourth battery cell. The upper battery cell mechanism and the lower battery cell mechanism are both composed of a plurality of battery cells, effectively increasing the heat dissipation of the battery.

[0010] As a further improvement of the present invention, the cooling mechanism includes a first liquid cooling plate, a second liquid cooling plate and a liquid cooling pipeline. The first liquid cooling plate is disposed between the first battery cell and the third battery cell, the second liquid cooling plate is disposed between the second battery cell and the fourth battery cell, and the first liquid cooling plate and the second liquid cooling plate are connected by a liquid cooling pipeline. The cooling mechanism is composed of liquid cooling plates. The heat of the battery is carried out by the flow of the working fluid inside the liquid cooling plate to achieve the effect of cooling the battery and the external temperature is brought to the battery to achieve the effect of heating the battery.

[0011] As a further improvement of the present invention, the liquid cooling pipeline includes a main pipe, a first branch pipe and a second branch pipe. The main pipe includes a first liquid inlet and two first liquid outlets. The first liquid inlet passes through the box body and is connected to an external pipeline. The two first liquid outlets are respectively connected to the first branch pipe and the second branch pipe. The first branch pipe is connected to the first liquid cooling plate, and the second branch pipe is connected to the second liquid cooling plate. The liquid cooling pipeline is provided with a main pipe and a plurality of branch pipes, so that the working fluid entering from the main pipe can flow evenly to the first liquid cooling plate and the second liquid cooling plate, reducing the temperature between each battery cell and increasing the overall service life of the battery.

[0012] As a further improvement of the present invention, the first branch pipe includes a second liquid inlet and two second liquid outlets. One of the two first liquid outlets is connected to the second liquid inlet, and the two second liquid outlets are connected to the liquid inlet of the first liquid cooling plate. This enables the working fluid in the first branch pipe to flow evenly to different positions of the first liquid cooling plate, effectively improving the working efficiency of the first liquid cooling plate.

[0013] As a further improvement of the present invention, the second branch pipe includes a third liquid inlet and two third liquid outlets. One of the two first liquid outlets is connected to the third liquid inlet, and the two third liquid outlets are connected to the liquid inlet of the second liquid cooling plate. This enables the working fluid in the second branch pipe to flow evenly to different positions of the second liquid cooling plate, effectively improving the working efficiency of the second liquid cooling plate.

[0014] As a further improvement of the present invention, the first liquid outlet of the main pipe on the first liquid cooling plate is arranged at the midpoint of the connection line of the two second liquid outlets of the first branch pipe; the first liquid outlet of the main pipe on the second liquid cooling plate is arranged at the midpoint of the connection line of the two third liquid outlets of the second branch pipe. This ensures that the working medium in the main pipe can be evenly distributed into the first liquid cooling plate and the second liquid cooling plate, reduces the temperature difference between each battery cell, and increases the overall service life of the battery.

[0015] As a further improvement of the present invention, the liquid cooling pipeline further includes a third branch pipe, the third branch pipe includes two fourth liquid inlets and one fourth liquid outlet, the two fourth liquid inlets are respectively arranged on the first liquid cooling plate and the second liquid cooling plate, and the fourth liquid outlet is connected to an external pipeline.

[0016] As a further improvement of the present invention, one of the two second liquid outlets of the first branch pipe and the two fourth liquid inlets is arranged on the same side of the first liquid cooling plate; the other of the two third liquid inlets of the second branch pipe and the two fourth liquid inlets is arranged on the same side of the second liquid cooling plate. Arranging them on the same side enables the working medium to have a longer loop from the inlet to the outlet in the liquid cooling plate, effectively improving the efficiency of the liquid cooling plate.

[0017] As a further improvement of the present invention, heat-conducting structural adhesives are provided between the first liquid cooling plate and the first battery cell and the third battery cell; heat-conducting structural adhesives are provided between the second liquid cooling plate and the second battery cell and the fourth battery cell. The heat-conducting structural adhesive tightly connects the liquid cooling plate and the battery cell, ensuring good mechanical performance and uniform heat conduction.

[0018] 3. Beneficial effects

[0019] Adopting the technical solution provided by the present invention, compared with the prior art, it has the following beneficial effects:

[0020] (1) The present invention is provided with a cooling mechanism between the upper battery cell mechanism and the lower battery cell mechanism, which can enable the cooling mechanism to timely adjust the battery temperature when the temperature difference is large, reducing the temperature fluctuation of the battery.

[0021] (2) The cooling mechanism of the present invention is composed of liquid cooling plates, and the heat of the battery is taken out by the flow of the working medium inside the liquid cooling plates to achieve the effect of cooling the battery, and the external temperature is brought to the battery to achieve the effect of heating the battery.

[0022] (3) The liquid cooling pipeline of the present invention is provided with a main pipe and multiple branch pipes, so that the working medium entering from the main pipe can evenly flow to the first liquid cooling plate and the second liquid cooling plate, reducing the temperature between each battery cell and increasing the overall service life of the battery. Description of the drawings

[0023] Figure 1Explosion diagram of the overall structure of a double-layer large-module battery device according to an embodiment of the present application;

[0024] Figure 2 Schematic diagram of the box structure of a double-layer large-module battery device according to an embodiment of the present application;

[0025] Figure 3 Schematic diagram of the structure of the cooling mechanism of a double-layer large-module battery device according to an embodiment of the present application;

[0026] Explanation of the reference numerals in the schematic diagram:

[0027] 100, box;

[0028] 200, battery pack; 210, upper battery cell mechanism; 211, first battery cell; 212, second battery cell; 220, lower battery cell mechanism; 221, third battery cell; 222, fourth battery cell;

[0029] 300, cooling mechanism; 310, first liquid cooling plate; 320, second liquid cooling plate; 330, liquid cooling pipeline; 331, main pipe; 331a, first liquid inlet; 331b, first liquid outlet; 332, first branch pipe; 332a, second liquid inlet; 332b, second liquid outlet; 333, second branch pipe; 333a, third liquid inlet; 333b, third liquid outlet; 334, third branch pipe; 334a, fourth liquid inlet; 334b, fourth liquid outlet;

[0030] 400, thermal conductive structural adhesive;

[0031] 500, glue blocking strip. Detailed implementation manners

[0032] To further understand the content of the present invention, the present invention will be described in detail in combination with the drawings and embodiments.

[0033] The structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented. Therefore, they do not have technical essence. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and the like cited in this specification are only for the convenience of clear narration and are not used to limit the scope that can be implemented. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope that the present invention can be implemented.

[0034] Combined with Figures 1 to 3, a double-layer structure large module battery device of this embodiment includes a box body 100 for accommodating a battery pack 200; the battery pack 200 includes an upper battery cell mechanism 210 and a lower battery cell mechanism 220; and further includes a cooling mechanism 300, and the cooling mechanism 300 is arranged between the upper battery cell mechanism 210 and the lower battery cell mechanism 220.

[0035] Specifically, the box body 100 is arranged in a rectangular structure. There is an accommodation space inside the box body 100. The battery pack 200 is placed in the accommodation space. There is a heat insulation pad between the battery pack 200 and the bottom of the box body 100, preventing the battery pack 200 from exchanging heat with the outside through the box body 100, ensuring the uniformity of the temperature of the battery pack 200 inside the box body 100, and the box body 100 can be installed on an electric vehicle. The battery pack 200 includes an upper battery cell mechanism 210 and a lower battery cell mechanism 220. There is a cooling mechanism 300 between the upper battery cell mechanism 210 and the lower battery cell mechanism 220, that is, the upper battery cell mechanism 210, the cooling mechanism 300, and the lower battery cell mechanism 220 are stacked and placed in sequence. Having the cooling mechanism 300 between the upper battery cell mechanism 210 and the lower battery cell mechanism 220 enables the cooling mechanism 300 to timely adjust the temperature of the entire large module battery when the electric vehicle has a large temperature difference, reducing the volatility of the battery temperature.

[0036] More specifically, the upper battery cell mechanism 210 includes a first battery cell 211 and a second battery cell 212, the lower battery cell mechanism 220 includes a third battery cell 221 and a fourth battery cell 222, and the cooling mechanism 300 is arranged between the first battery cell 211 and the third battery cell 221 and between the second battery cell 212 and the fourth battery cell 222. Both the upper battery cell mechanism 210 and the lower battery cell mechanism 220 are composed of multiple battery cells, and there are gaps between the battery cells, enabling the heat generated by the battery during actual operation to overflow from the gaps between the first battery cell 211 and the second battery cell 212 and between the third battery cell 221 and the fourth battery cell 222, effectively increasing the heat dissipation of the battery. Moreover, both the upper battery cell mechanism 210 and the lower battery cell mechanism 220 are composed of multiple battery cells, modularizing the large module battery pack 200 reduces the difficulty of handling the battery.

[0037] In a specific embodiment, the cooling mechanism 300 includes a first liquid cooling plate 310, a second liquid cooling plate 320, and a liquid cooling pipeline 330. The first liquid cooling plate 310 is disposed between the first battery cell 211 and the third battery cell 221, and the second liquid cooling plate 320 is disposed between the second battery cell 212 and the fourth battery cell 222. The first liquid cooling plate 310 and the second liquid cooling plate 320 are connected by the liquid cooling pipeline 330. The cooling mechanism 300 is composed of liquid cooling plates. The heat of the battery is carried out by the flow of the working fluid inside the liquid cooling plate to achieve the effect of cooling the battery, and the external temperature is brought to the battery to achieve the effect of heating the battery. The working fluid here refers to the substance flowing in the pipeline of the liquid cooling plate, generally water or other liquids capable of heat exchange, and no specific limitation is made here. By using a single-layer liquid cooling plate to regulate the temperature of the upper battery cell mechanism 210 and the lower battery cell mechanism 220 at the same time, compared with the design of one liquid cooling plate for one layer of battery modules, the number of liquid cooling plates, pipelines, and inlets and outlets is reduced, the space utilization rate inside the battery pack 200 is improved, the battery pack efficiency is enhanced, and the cost of the battery pack 200 is reduced. At the same time, the heat exchange efficiency of the liquid cooling plate is also greatly improved.

[0038] More specifically, the liquid cooling pipeline 330 includes a main pipe 331, a first branch pipe 332, and a second branch pipe 333. The main pipe 331 includes a first liquid inlet 331a and two first liquid outlets 331b. The first liquid inlet 331a passes through the box body 100 to connect to an external pipeline. The two first liquid outlets 331b are respectively connected to the first branch pipe 332 and the second branch pipe 333. The first branch pipe 332 is connected to the first liquid cooling plate 310, and the second branch pipe 333 is connected to the second liquid cooling plate 320. The liquid cooling pipeline 330 is provided with a main pipe 331 and multiple branch pipes, so that the working fluid entering from the main pipe 331 can flow evenly to the first liquid cooling plate 310 and the second liquid cooling plate 320, reducing the temperature difference between each battery cell and increasing the overall service life of the battery.

[0039] The first liquid inlet 331a passes through the side wall of the box body 100 to communicate with the external working fluid. An external liquid pump provides the power for the working fluid to flow in the pipeline. At the same time, components such as a compressor and a heat exchanger are provided outside the box body 100, which can transport the working fluid at an appropriate temperature into the liquid cooling plate through the first liquid inlet 331a. After the first liquid inlet 331a introduces the working fluid, it is divided into two parts and flows to the two first liquid outlets 331b. The two first liquid outlets 331b are respectively connected to the first branch pipe 332 and the second branch pipe 333, and then the working fluid is introduced into the first liquid cooling plate 310 and the second liquid cooling plate 320 through the first branch pipe 332 and the second branch pipe 333.

[0040] In a specific embodiment, the first branch pipe 332 includes a second liquid inlet 332a and two second liquid outlets 332b. One of the two first liquid outlets 331b is connected to the second liquid inlet 332a, and the two second liquid outlets 332b are connected to the liquid inlet of the first liquid cooling plate 310. This enables the working medium in the first branch pipe 332 to flow evenly to different positions of the first liquid cooling plate 310, effectively improving the working efficiency of the first liquid cooling plate 310. The second branch pipe 333 includes a third liquid inlet 333a and two third liquid outlets 333b. One of the two first liquid outlets 331b is connected to the third liquid inlet 333a, and the two third liquid outlets 333b are connected to the liquid inlet of the second liquid cooling plate 320. This enables the working medium in the second branch pipe 333 to flow evenly to different positions of the second liquid cooling plate 320, effectively improving the working efficiency of the second liquid cooling plate 320.

[0041] Specifically, after the second liquid inlet 332a of the first branch pipe 332 receives the working medium from the first liquid outlet 331b, it divides into two parts. The working medium is introduced into the first liquid cooling plate 310 through the two second liquid outlets 332b. By introducing the working medium into the first liquid cooling plate 310 through multiple inlets, the pipes inside the first liquid cooling plate 310 can be quickly filled with the working medium, increasing the heat exchange efficiency between the first liquid cooling plate 310, the first battery cell 211, and the third battery cell 221. Similarly, after the third liquid inlet 333a of the second branch pipe 333 receives the working medium from the first liquid outlet 331b, it divides into two parts. The working medium is introduced into the second liquid cooling plate 320 through the two third liquid outlets 333b. By introducing the working medium into the second liquid cooling plate 320 through multiple inlets, the pipes inside the second liquid cooling plate 320 can be quickly filled with the working medium, increasing the heat exchange efficiency between the second liquid cooling plate 320, the third battery cell 221, and the fourth battery cell 222.

[0042] More specifically, to ensure that after the second liquid inlet 332a of the first branch pipe 332 receives the working medium from the first liquid outlet 331b, it can be evenly divided into two parts and then the working medium is introduced into the first liquid cooling plate 310 through the two second liquid outlets 332b, the first liquid outlet 331b of the main pipe 331 on the first liquid cooling plate 310 is arranged at the midpoint of the connection line of the two second liquid outlets 332b of the first branch pipe 332. To ensure that after the third liquid inlet 333a of the second branch pipe 333 receives the working medium from the first liquid outlet 331b, it can be evenly divided into two parts and then the working medium is introduced into the second liquid cooling plate 320 through the two third liquid outlets 333b, the first liquid outlet 331b of the main pipe 331 on the second liquid cooling plate 320 is arranged at the midpoint of the connection line of the two third liquid outlets 333b of the second branch pipe 333. This effectively ensures that the working medium in the main pipe 331 can be evenly distributed into the first liquid cooling plate 310 and the second liquid cooling plate 320, reducing the temperature difference between each battery cell and increasing the overall service life of the battery.

[0043] In a specific embodiment, the liquid cooling pipeline 330 further includes a third branch pipe 334. The third branch pipe 334 includes two fourth liquid inlet ports 334a and one fourth liquid outlet port 334b. The two fourth liquid inlet ports 334a are respectively arranged on the first liquid cooling plate 310 and the second liquid cooling plate 320, and the fourth liquid outlet port 334b is connected to an external pipeline. One of the two second liquid outlet ports 332b of the first branch pipe 332 and the two fourth liquid inlet ports 334a are arranged on the same side of the first liquid cooling plate 310; the other of the two third liquid inlet ports 333a of the second branch pipe 333 and the two fourth liquid inlet ports 334a are arranged on the same side of the second liquid cooling plate 320. An "s" - shaped pipeline is provided inside the first liquid cooling plate and the second liquid cooling plate. One end of the pipeline is connected to the liquid inlet ports of the first branch pipe and the second branch pipe, and the other end of the pipeline is connected to the fourth liquid inlet port of the third branch pipe. Arranging one of the two second liquid outlet ports 332b of the first branch pipe 332 and the two fourth liquid inlet ports 334a on the same side of the first liquid cooling plate 310; and arranging the other of the two third liquid inlet ports 333a of the second branch pipe 333 and the two fourth liquid inlet ports 334a on the same side of the second liquid cooling plate 320 enables the working medium to have a longer circuit from the inlet to the outlet in the liquid cooling plate, effectively improving the cooling efficiency of the first liquid cooling plate and the second liquid cooling plate.

[0044] In a specific embodiment, a thermal conductive structural adhesive 400 is provided between the first liquid cooling plate 310 and the first battery cell 211 and the third battery cell 221; a thermal conductive structural adhesive 400 is provided between the second liquid cooling plate 320 and the second battery cell 212 and the fourth battery cell 222. The thermal conductive structural adhesive 400 tightly connects the liquid cooling plate and the battery cell, ensuring good mechanical performance and uniform heat conduction.

[0045] Specifically, a glue - blocking strip 500 is provided between the thermal conductive structural adhesives 400. While the thermal conductive structural adhesive 400 fixes the first liquid cooling plate 310 to the first battery cell 211 and the third battery cell 221, it can also exchange the heat of the first liquid cooling plate 310 with the heat of the first battery cell 211 and the third battery cell 221; while the thermal conductive structural adhesive 400 fixes the second liquid cooling plate 320 to the second battery cell 212 and the fourth battery cell 222, it can also exchange the heat of the second liquid cooling plate 320 with the heat of the second battery cell 212 and the fourth battery cell 222. The glue - blocking strip 500 arranged between the battery cell and the liquid cooling plate can realize the thickness of the glue layer. While effectively ensuring the thickness of the thermal conductive structural adhesive 400 layer, it further ensures the uniformity of the heat dissipation effect of the liquid cooling plate on the upper and lower layers of battery cells.

[0046] In a specific embodiment, flow control solenoid valves are provided at the second liquid inlet of the first branch pipe and the third liquid inlet of the second branch pipe. The flow control solenoid valve controls the opening size of the solenoid valve according to the received electrical signal, and thus controls the flow rates of the first branch pipe and the second branch pipe. Temperature acquisition devices are provided in both the first liquid cooling plate and the second liquid cooling plate. The temperature acquisition device in the first liquid cooling plate is used to acquire the actual temperature of the first liquid cooling plate, and the temperature acquisition device in the second liquid cooling plate is used to acquire the actual temperature of the second liquid cooling plate. Temperature acquisition devices are also provided on the surfaces of the first battery cell and the third battery cell. The temperature acquisition device and the temperature acquisition device in the first liquid cooling plate both send temperature signals to the control device. The control device compares the temperature difference between the temperature signals acquired by the two temperature acquisition devices with the set temperature difference, and then sends a control signal to the flow control solenoid valve in the first branch pipe according to the result to control the flow rate of the refrigerant in the first branch pipe, thereby precisely adjusting the actual temperatures of the first battery cell and the third battery cell. Similarly, the control device compares the temperature difference between the second battery cell, the fourth battery cell and the second liquid cooling plate with the set temperature difference, and then sends a control signal to the flow control solenoid valve in the second branch pipe according to the result to control the flow rate of the refrigerant in the second branch pipe, thereby precisely adjusting the actual temperatures of the second battery cell and the fourth battery cell.

[0047] In a specific embodiment, heat-insulating foam is provided at the bottom of the box body. The heat-insulating foam can balance the temperature difference between the upper battery cell mechanism and the lower battery cell mechanism. In a feasible solution, the temperature difference between the upper battery cell mechanism and the lower battery cell mechanism is detected by a set of temperature detection devices and a temperature difference signal is sent to the control device. The control device sends an electrical signal to the flow control solenoid valves provided in the first branch pipe and the second branch pipe according to the received electrical signal to control the flow rates of the refrigerant in the first branch pipe and the second branch pipe, so as to make the temperature difference between the upper battery cell mechanism and the lower battery cell mechanism as small as possible, reduce the temperature between each battery cell, and increase the overall service life of the battery.

[0048] The above schematically describes the present invention and its embodiments. The description is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and design similar structural forms and embodiments without creative efforts without departing from the spirit of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A double-layer structure large module battery device, characterized in that: include: A box (100) for accommodating a battery pack (200); A battery pack (200) comprising an upper battery cell structure (210) and a lower battery cell structure (220); It also includes a cooling mechanism (300), wherein the cooling mechanism (300) is arranged between the upper layer battery cell mechanism (210) and the lower layer battery cell mechanism (220).

2. The double-layer structure large module battery device according to claim 1, characterized in that: The upper cell structure (210) comprises a first cell (211) and a second cell (212); the lower cell structure (220) comprises a third cell (221) and a fourth cell (222); and the cooling structure (300) is arranged between the first cell (211) and the third cell (221) and between the second cell (212) and the fourth cell (222).

3. The double-layer structure large module battery device according to claim 1 or 2, characterized in that: The cooling mechanism (300) comprises a first liquid cooling plate (310), a second liquid cooling plate (320) and a liquid cooling pipeline (330); the first liquid cooling plate (310) is arranged between the first battery cell (211) and the third battery cell (221); the second liquid cooling plate (320) is arranged between the second battery cell (212) and the fourth battery cell (222); the first liquid cooling plate (310) and the second liquid cooling plate (320) are connected via the liquid cooling pipeline (330).

4. The double-layer structure large module battery device according to claim 3 is characterized in that: The liquid cooling pipeline (330) comprises a main pipe (331), a first branch pipe (332) and a second branch pipe (333); the main pipe (331) comprises a first liquid inlet (331a) and two first liquid outlets (331b); the first liquid inlet (331a) passes through the box (100) to connect to an external pipeline; the two first liquid outlets (331b) are respectively connected to the first branch pipe (332) and the second branch pipe (333); the first branch pipe (332) is connected to the first liquid cooling plate (310); and the second branch pipe (333) is connected to the second liquid cooling plate (320).

5. The double-layer structure large module battery device according to claim 4, characterized in that: The first branch pipe (332) comprises a second liquid inlet (332a) and two second liquid outlets (332b), one of the two first liquid outlets (331b) is connected to the second liquid inlet (332a), and the two second liquid outlets (332b) are connected to the liquid inlet of the first liquid cooling plate (310).

6. The double-layer structure large module battery device according to claim 4, characterized in that: The second branch pipe (333) comprises a third liquid inlet (333a) and two third liquid outlets (333b), one of the two first liquid outlets (331b) is connected to the third liquid inlet (333a), and the two third liquid outlets (333b) are connected to the liquid inlet of the second liquid cooling plate (320).

7. The double-layer structure large module battery device according to claim 5 or 6, characterized in that: The first liquid outlet (331b) of the main pipe (331) on the first liquid cooling plate (310) is arranged at the midpoint of a line connecting two second liquid outlets (332b) of the first branch pipe (332); The first liquid outlet (331b) of the main pipe (331) on the second liquid cooling plate (320) is arranged at the midpoint of a line connecting two third liquid outlets (333b) of the second branch pipe (333).

8. The double-layer structure large module battery device according to claim 7, characterized in that: The liquid cooling pipeline (330) further comprises a third branch pipe (334), the third branch pipe (334) comprises two fourth liquid inlets (334a) and a fourth liquid outlet (334b), the two fourth liquid inlets (334a) are respectively arranged on the first liquid cooling plate (310) and the second liquid cooling plate (320), and the fourth liquid outlet (334b) is connected to an external pipeline.

9. The double-layer structure large module battery device according to claim 8, characterized in that: One of the two second liquid outlets (332b) and the two fourth liquid inlets (334a) of the first branch pipe (332) is arranged on the same side of the first liquid cooling plate (310); The two third liquid inlets (333a) and the other of the two fourth liquid inlets (334a) of the second branch pipe (333) are arranged on the same side of the second liquid cooling plate (320).

10. The double-layer structure large module battery device according to claim 9 is characterized in that: A heat-conducting structural adhesive (400) is provided between the first liquid cooling plate (310) and the first battery cell (211) and the third battery cell (221); A heat-conducting structural adhesive (400) is provided between the second liquid cooling plate (320) and the second battery cell (212) and the fourth battery cell (222).

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