Lithium iron phosphate battery module

Abstract

The invention relates to the technical field of new energy batteries, in particular to a lithium iron phosphate battery module which comprises a bottom plate, an outer shell, an inner shell and a plurality of battery monomers, the outer shell, the inner shell and the plurality of battery monomers are all arranged on the upper surface of the bottom plate, the inner shell is arranged in the outer shell, the plurality of battery monomers are all arranged in the inner shell, and the inner shell is arranged in the bottom plate. The electric kettle further comprises a water cooling mechanism, a stirring mechanism and a heat guiding mechanism, and the inner shell is filled with a phase change material. Through fixed connection of a connecting rod and a plurality of water cooling pipes, in the running process of a new energy automobile, the plurality of water cooling pipes can synchronously move up and down by utilizing inertia, so that stirring of a phase change material in a molten state is realized, heat adsorbed in the phase change material in the molten state can be uniformly distributed, and the heat absorption efficiency of the phase change material in the molten state is improved. And the cooling effect is improved in the flowing process of the cooling liquid in the water cooling pipe.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy batteries, and in particular to a lithium iron phosphate battery module. Background Art

[0002] Lithium iron phosphate battery is a lithium-ion battery that uses lithium iron phosphate as the positive electrode material and carbon as the negative electrode material. Lithium iron phosphate batteries are widely used to power new energy vehicles. During the charging process, some lithium ions in the lithium iron phosphate are released, transferred to the negative electrode through the electrolyte, and embedded in the negative electrode carbon material; at the same time, electrons are released from the positive electrode and reach the negative electrode from the external circuit to maintain the balance of the chemical reaction. During the discharge process, lithium ions are released from the negative electrode and reach the positive electrode through the electrolyte. At the same time, the negative electrode releases electrons and reaches the positive electrode from the external circuit to provide energy to the outside world.

[0003] During the charging and discharging process of the battery, a large amount of heat is generated due to the electrochemical reaction. The temperature causes changes in electrochemical performance. High temperature promotes the growth of the solid electrolyte interface film, increases the anode resistance, and the active substances inside the battery are constantly decaying, which leads to an increase in the internal resistance of the battery and accelerates the degradation of the battery. At the same time, there are also problems such as internal short circuits and thermal runaway, which affect the performance and life of the battery. In response to the above problems, there are good solutions in the prior art. For example, in patent CN110165332B, a large amount of heat generated is transferred to the heat conductive sheet in contact with the side of the battery cell, and then transferred to the composite phase change material in the cooling box. When the temperature exceeds the melting point of the composite phase change material, the phase change material begins to change phase, and absorbs a large amount of latent heat by changing from solid to molten state, thereby effectively slowing down the temperature rise of the battery pack and preventing it from overheating. However, the following problems still exist: when the vehicle needs to frequently control the accelerator pedal when driving on a bumpy road, the battery module will generate more heat in a short period of time, and the thermal conductivity of the phase change material in the molten state is small. When the battery module continues to heat up, the temperature absorbed by the phase change material filled in the inner cavity during the phase change process cannot be transferred through the cooling channel in time, thereby affecting the normal cooling of the battery module and further affecting the service life of the battery module.

[0004] Therefore, in order to solve the problem that when the temperature of the battery module continues to rise, the temperature absorbed by the phase change material filled in the inner cavity during the phase change process cannot be transferred through the cooling channel in time, a lithium iron phosphate battery module is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a lithium iron phosphate battery module, which solves the problem that when the battery module continues to heat up, the temperature absorbed by the phase change material filled in the inner cavity during the phase change process cannot be transferred through the cooling channel in time. Through the fixed connection of the connecting rod and multiple water-cooling pipes, inertia can be used to achieve the synchronous up and down movement of multiple water-cooling pipes during the driving of the new energy vehicle, thereby achieving the stirring of the phase change material in the molten state, so that the heat adsorbed inside the phase change material in the molten state can be evenly distributed, and the cooling effect is improved during the flow of the coolant inside the water-cooling pipe.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A lithium iron phosphate battery module, comprising a bottom plate, an outer shell, an inner shell and a plurality of battery cells, wherein the outer shell, the inner shell and the plurality of battery cells are all arranged on the upper surface of the bottom plate, the inner shell is arranged inside the outer shell, and the plurality of battery cells are all arranged inside the inner shell, and further comprising a water cooling mechanism, a stirring mechanism and a heat guiding mechanism, the interior of the inner shell is filled with a phase change material, and each of the battery cells is immersed in the phase change material, the water cooling mechanism comprises a water cooling pipe, a plurality of the water cooling pipes are arranged, the water cooling pipes are arranged in a serpentine shape and penetrate between the plurality of battery cells, the water cooling pipes penetrate in the phase change material filled in the inner shell, the water cooling mechanism further comprises a water pump, a first U-shaped plate, a second U-shaped plate, a water pumping pipe, a water delivery pipe, a rubber water inlet pipe and a rubber water outlet pipe, the water pump, the first U-shaped plate and the second U The first U-shaped plate and the second U-shaped plate are both hollow and filled with coolant. The two ends of the water pump are respectively connected to the first U-shaped plate and the input end of the water pump, and the two ends of the water delivery pipe are respectively connected to the second U-shaped plate and the output end of the water pump. One end of the water-cooling pipe is connected to the second U-shaped plate through a rubber water inlet pipe, and the other end of the water-cooling pipe is connected to the first U-shaped plate through a rubber water outlet pipe. The stirring mechanism is arranged inside the inner shell. When the phase change material is heated and is in a molten state and the bottom plate is bumped up and down, the stirring mechanism drives multiple water-cooling pipes to move up and down synchronously. The heat guiding mechanism is arranged on the outside of the inner shell and penetrates into the inside of the inner shell. When the phase change material is heated and is in a molten state, the heat inside the inner shell is guided to the outside of the inner shell through the heat guiding mechanism.

[0008] It can be seen that there are many ways to cool the battery module to ensure the service life of the battery module, including natural convection cooling, phase change material cooling, pure water cooling, phase change material coupled water cooling and other different cooling methods. Considering the actual cooling effect, the phase change material coupled water cooling method has the best cooling effect. However, compared with this solution, the above solution has a fixed position of the water cooling pipe. After absorbing heat, the phase change material has a low thermal conductivity coefficient and cannot be cooled in time by water cooling, resulting in the temperature absorbed by the phase change material covering the outside of multiple battery cells, thereby affecting the cooling effect of the battery module.

[0009] Preferably, the stirring mechanism includes a connecting rod, annular plate 1, a bellows, annular plate 2 and a spring, the connecting rod is fixedly sleeved with the water cooling pipe, a through hole is opened at the top of the inner shell, the connecting rod is passed through the inside of the through hole, the annular plate 1, the bellows and the annular plate 2 are all sleeved with the connecting rod, the spring is arranged between the annular plate 1 and the annular plate 2, the spring is sleeved with the bellows, the annular plate 1 is fixedly connected to the top inner wall of the inner shell, the annular plate 1 and the annular plate 2 are arranged at both ends of the bellows, and a heat pipe is arranged inside the connecting rod.

[0010] It can be seen that there are many ways to stir the phase change material filled in the inner shell in a molten state. The most common way is to stir it through a motor and a stirring blade. Considering the actual size and energy consumption of the battery module, this solution is adopted. When the new energy vehicle is driving on a bumpy road, the connecting rod and multiple water cooling pipes will move in the vertical direction due to inertia, and continue to move under the elastic force of the spring and the buoyancy of the molten phase change material, realizing automatic stirring of the molten phase change material, reducing the volume of the battery module while reducing energy consumption.

[0011] Preferably, the through hole is arranged in a conical shape, and the diameter of the upper end of the through hole is smaller than that of the lower end.

[0012] By adopting the above scheme, the aperture of the through hole is larger at the bottom and smaller at the top. When the annular plate 2 moves upward, it can squeeze the fluid gathered inside the bellows. Under the gathering effect of the upper end aperture, the flow rate of the fluid can be accelerated, thereby achieving cooling treatment of the upper end of the heat pipe.

[0013] Preferably, the distance between two adjacent battery cells is equal to the minimum distance between the side wall of each battery cell and the inner wall of the shell, and the distance between the top of the battery cell and the top inner wall of the inner shell is greater than the distance between two adjacent battery cells.

[0014] It can be seen that the temperature difference between different battery cells inside the battery module will have a significant impact on the performance, life and safety of the battery cells. By adopting the above solution, the thickness of the phase change material filled in the inner shell covering the outside of each battery cell can be the same, avoiding the situation where the temperature difference around different battery cells becomes large when the phase change material changes from a solid state to a molten state, thereby ensuring the service life of the battery module.

[0015] Preferably, two adjacent water-cooling tubes are staggered, the vertical cross-sections of the top and bottom of each water-cooling tube are triangular, and the buoyancy of each water-cooling tube in the phase change material in a molten state is equal to its own weight.

[0016] It can be seen that there is resistance inside the phase change material in a molten state. The connecting rod and multiple water-cooling tubes will reduce the movement speed and amplitude due to the resistance during the up and down movement. By setting the vertical cross-sections of the top and bottom of each water-cooling tube to a triangle, the resistance encountered during the up and down movement of each water-cooling tube can be reduced, and multiple water-cooling tubes can achieve rapid stirring of the phase change material in a molten state, so that the temperature distribution inside the phase change material in a molten state is more uniform, thereby accelerating the cooling rate during the flow of coolant inside the water-cooling tube.

[0017] Preferably, the plurality of water cooling tubes are arranged in sequence and at equal intervals, and when the phase change material is in a molten state, the distance between the top of the battery cell and the uppermost water cooling tube is equal to the distance between the bottom of the battery cell and the lowermost water cooling tube.

[0018] It can be seen that the cooling range of each water-cooling tube is limited. By arranging multiple water-cooling tubes in sequence at equal intervals, the cooling range of each water-cooling tube can be expanded in the process of continuous movement of the multiple water-cooling tubes up and down, thereby achieving comprehensive cooling of the surrounding side of each battery cell, thereby ensuring the cooling effect.

[0019] Preferably, the heat guiding mechanism includes a top plate and a main rod, the top plate is sleeved on the top of the inner shell, the main rod is fixedly arranged between the bottom plate and the top plate, the first U-shaped plate and the second U-shaped plate are both arranged on the upper surface of the bottom plate, the upper surfaces of the first U-shaped plate and the second U-shaped plate are both connected to the lower end of the main rod, the rod wall of the main rod is provided with a plurality of sub-rods, each of the sub-rods penetrates into the interior of the inner shell, the sub-rods located in the upper half of the main rod axis are all copper rods, and are provided with penetration grooves inside, and the notch of each of the penetration grooves is located inside the inner shell.

[0020] It can be seen that after the heat of multiple battery cells is generated, the heat will gather upwards, and when the new energy vehicle is driving on a smooth road, the frequent start and stop caused by traffic jams will cause the molten phase change material to shake continuously inside the inner shell along the direction of the vehicle. Under the action of the main rod and multiple auxiliary rods, the top plate and the inner shell and the top plate are fixedly connected, so that the stability of the inner shell can be increased when the molten phase change material shakes, and part of the heat absorbed by the molten phase change material can be guided to the outside of the inner shell, so that the temperature of multiple battery cells can be further reduced.

[0021] Preferably, a liquid reservoir is provided inside the top plate, and the inside of the liquid reservoir is filled with coolant, and the connecting rods are provided in multiple groups, and a floating block located inside the liquid reservoir is provided at the upper end of each group of connecting rods, and each floating block is arranged in an inverted trapezoidal shape, and the liquid level of the coolant inside the liquid reservoir is a, and when the bottom plate is stationary and the phase change material inside the inner shell is in a molten state, the distance between the top of the floating block and the top inner wall of the liquid reservoir is b, and the distance between the liquid level of the coolant inside the liquid reservoir and the bottom surface of the floating block is c, wherein c <a<b。

[0022] It can be seen that vehicles are traveling on smooth roads in most cases, but traffic jams are inevitable. When in traffic jams, the accelerator pedal needs to be frequently controlled. At this time, the battery module will heat up rapidly and cause the phase change material to be in a molten state. The coolant in the reservoir will sway along the direction of vehicle travel under the action of inertia. Under the action of the floating block and the coolant in the reservoir, the inertia of the coolant can be used to drive the floating block to move in the vertical direction, thereby driving the connecting rod to drive multiple water-cooling tubes to move in the vertical direction, achieving stirring of the phase change material in the molten state, thereby improving the cooling effect.

[0023] Preferably, the spring is arranged above the phase change material, and the compression length of the spring is d, where d <b。

[0024] By adopting the above solution, the phase change material is prevented from melting and submerging the spring to affect the normal stretching and contraction of the spring, ensuring that the inertia generated by the new energy vehicle during the bumpy process can drive multiple water-cooling tubes to move up and down synchronously through the connecting rod, while also ensuring that the floating block has space to move up and down inside the liquid storage tank, avoiding the floating block from colliding with the top of the liquid storage tank.

[0025] Preferably, a cavity one is opened inside the connecting rod, and two groups of openings are opened on the side walls of the cavity one, and the two groups of openings are respectively arranged on both sides of the annular plate two, and the opening on the upper side extends to the outside of the inner shell, and the axis of the heat pipe is perpendicular to the plane where the bottom plate is located, the upper end of the heat pipe is located inside the liquid storage tank, and the lower end of the heat pipe is the evaporation end and is located inside the inner shell.

[0026] By adopting the above scheme, the upper end of the heat pipe is arranged inside the liquid storage tank, so that the condensation end of the heat pipe can directly contact the coolant inside the liquid storage tank, thereby accelerating the condensation speed of the condensation end of the heat pipe, that is, accelerating the cooling speed of the heat pipe, and quickly cooling the heat accumulated in the upper half of multiple battery cells.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. In the existing battery module, the position of the water cooling tube is fixed. When the battery module heats up and the phase change material changes from a solid state to a molten state, the water cooling tube cannot evenly cool the heat in the phase change material. This problem will cause the heat absorbed by the phase change material to accumulate, and then cause the heat inside the battery module to be unable to be dissipated in time. In order to improve this defect, a stirring component and multiple independent water cooling tubes are set up. When the frequent control of the vehicle's accelerator pedal causes the battery module to heat up quickly in a short period of time, causing the phase change material to change from a solid state to a molten state, multiple water cooling tubes are driven to continuously stir the phase change material in the molten state, expanding the water cooling range while achieving uniform distribution of heat in the molten phase change material, effectively improving the cooling effect. Since the rubber water inlet pipe and rubber water outlet pipe at both ends of each water cooling pipe are independently set, each water cooling pipe can be cooled independently, further improving the cooling effect.

[0029] 2. By setting the connecting rod and spring, when the new energy vehicle is driving on a bumpy road, the battery module generates more heat in a short time and melts the phase change material due to frequent control of the accelerator pedal, the inertia generated by the bump of the car can drive the connecting rod to move. During the movement of the connecting rod, multiple water-cooling tubes can be driven to overcome the resistance of the phase change material, thereby driving the multiple water-cooling tubes to move synchronously in the vertical direction. Under the elastic force of the spring, the connecting rod and multiple water-cooling tubes can be continuously shaken in the vertical direction, which expands the distribution range of the water-cooling tubes inside the inner shell and realizes the stirring of the phase change material in the molten state, so that the heat absorbed by the phase change material during the melting process can be effectively transferred by the coolant in the water-cooling tube during the flow process, thereby realizing effective cooling of the battery module, avoiding the situation where the phase change material absorbs heat and wraps around the surface of the battery module, and effectively ensuring the service life of the battery module.

[0030] 3. By setting the coolant in the liquid storage tank and the floating blocks at the upper end of each group of connecting rods, when the new energy vehicle is traveling on a smooth road but the road is congested, the battery module generates more heat and melts the phase change material in a short time due to frequent control of the accelerator pedal. The coolant in the liquid storage tank will shake along the direction of travel of the new energy vehicle due to inertia. During the shaking of the coolant in the liquid storage tank, it can drive multiple floating blocks to move back and forth in the vertical direction through the elastic force of the spring, which also expands the distribution range of the water cooling tube inside the inner shell, and realizes the stirring of the phase change material in the molten state, further ensuring the service life of the battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the present invention;

[0032] Figure 2 It is a partial cross-sectional structural schematic diagram of the present invention;

[0033] Figure 3 It is a schematic diagram of the connection structure of the bottom plate, the water cooling mechanism and a plurality of battery cells of the present invention;

[0034] Figure 4 For the present invention Figure 2 An enlarged view of a local portion A in FIG.

[0035] Figure 5 It is a schematic diagram of the connection structure between multiple water cooling tubes and multiple battery cells of the present invention;

[0036] Figure 6 It is a schematic diagram of a partial cross-sectional connection structure of a bottom plate, a heat guiding mechanism and a plurality of battery cells of the present invention;

[0037] Figure 7 For the present invention Figure 6 An enlarged view of a local portion B in FIG.

[0038] Figure 8 It is a schematic diagram of a partial cross-sectional connection structure of a connecting rod and a heat pipe of the present invention.

[0039] In the figure:

[0040] 1. Bottom plate;

[0041] 2. Shell;

[0042] 3. Inner shell; 31. Through hole;

[0043] 4. Battery cells;

[0044] 5. Water cooling mechanism; 51. Water cooling pipe; 52. Water pump; 53. First U-shaped plate; 54. Second U-shaped plate; 55. Water pump; 56. Water supply pipe; 57. Rubber water inlet pipe; 58. Rubber water outlet pipe;

[0045] 6. stirring mechanism; 61. connecting rod; 611. cavity 1; 6111. opening; 62. annular plate 1; 63. bellows; 64. annular plate 2; 65. spring; 66. heat pipe;

[0046] 7. heat guiding mechanism; 71. top plate; 711. liquid storage tank; 72. main rod; 73. auxiliary rod; 731. infiltration tank;

[0047] 8. Floating block. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] See also Figures 1 to 8 The present invention provides a lithium iron phosphate battery module, and the technical solution is as follows:

[0050] For details, please refer to Figure 1 , Figure 2 and Figure 3 , a lithium iron phosphate battery module, comprising a bottom plate 1, an outer shell 2, an inner shell 3 and a plurality of battery cells 4, the outer shell 2, the inner shell 3 and the plurality of battery cells 4 are all arranged on the upper surface of the bottom plate 1, the inner shell 3 is arranged inside the outer shell 2, and the plurality of battery cells 4 are all arranged inside the inner shell 3, and also comprises a water cooling mechanism 5, a stirring mechanism 6 and a heat guiding mechanism 7, the interior of the inner shell 3 is filled with a phase change material, each of the battery cells 4 is immersed in the phase change material, the water cooling mechanism 5 comprises a water cooling pipe 51, a plurality of the water cooling pipes 51 are arranged, the water cooling pipes 51 are serpentinely arranged and penetrated between the plurality of battery cells 4, the water cooling pipes 51 are penetrated in the phase change material filled in the inner shell 3, the phase change material can use calcium chloride hexahydrate, since the optimal operating temperature range of the lithium iron phosphate battery module is 0-35 degrees Celsius, and the phase change temperature of calcium chloride hexahydrate is 26-28 degrees Celsius. Therefore, before the battery module temperature exceeds the optimal operating temperature range, calcium chloride hexahydrate has already transformed from a solid state to a molten state. In a low temperature environment, solid calcium chloride hexahydrate can have a heat preservation effect, so that the battery module always works within the optimal temperature range, effectively ensuring the discharge efficiency of the battery module.

[0051] As an embodiment of the present invention, refer to Figure 2 and Figure 3The water cooling mechanism 5 also includes a water pump 52, a first U-shaped plate 53, a second U-shaped plate 54, a water pumping pipe 55, a water supply pipe 56, a rubber water inlet pipe 57 and a rubber water outlet pipe 58. The water pump 52, the first U-shaped plate 53 and the second U-shaped plate 54 are all arranged on the upper surface of the bottom plate 1. The first U-shaped plate 53 and the second U-shaped plate 54 are both hollow and filled with coolant. The two ends of the water pumping pipe 55 are respectively connected to the first U-shaped plate 53 and the input end of the water pump 52, the two ends of the water supply pipe 56 are respectively connected to the second U-shaped plate 54 and the output end of the water pump 52, one end of the water cooling pipe 51 is connected to the second U-shaped plate 54 through the rubber water inlet pipe 57, and the water cooling pipe The other end of 51 is connected to the first U-shaped plate 53 through a rubber water outlet pipe 58. When the water pump 52 is working, the coolant filled in the first U-shaped plate 53 can be transported to the inside of the second U-shaped plate 54 through the water suction pipe 55 and the water supply pipe 56. As the amount of coolant in the second U-shaped plate 54 increases, it can be transported to different water-cooling pipes 51 through different rubber water inlet pipes 57. When the coolant flows in the water-cooling pipe 51, it can absorb and guide the heat generated by the battery cell 4, and finally flow back to the inside of the first U-shaped plate 53 through different rubber water outlet pipes 58. Since the water-cooling pipe 51 is set in the phase change material, the heat adsorbed in the phase change material can be cooled.

[0052] As an embodiment of the present invention, refer to Figure 2 , Figure 3 and Figure 4 The stirring mechanism 6 is arranged inside the inner shell 3, and the stirring mechanism 6 includes a connecting rod 61, an annular plate 1 62, a bellows 63, an annular plate 2 64 and a spring 65. The connecting rod 61 is fixedly sleeved with the water cooling tube 51. A through hole 31 is opened at the top of the inner shell 3. The connecting rod 61 is penetrated into the through hole 31. The annular plate 1 62, the bellows 63 and the annular plate 2 64 are all sleeved with the connecting rod 61. The spring 65 is arranged between the annular plate 1 62 and the annular plate 2 64. The spring 65 is sleeved with the bellows 63. The annular plate 1 62 is fixedly connected to the inner wall of the top of the inner shell 3. The annular plate 1 62 and the annular plate 2 64 are arranged at both ends of the bellows 63. A heat pipe 66 is arranged inside the connecting rod 61.

[0053] When the vehicle is traveling on a bumpy road, the battery module will heat up quickly in a short time due to the need to frequently control the ignition switch. After the phase change material absorbs heat and changes from a solid state to a molten state, the inertia generated by the vehicle bump will drive the connecting rod 61 to drive multiple water cooling tubes 51 to shake synchronously in the molten phase change material, and under the action of the spring 65, the elastic force of the spring 65 can achieve the synchronous shaking of the connecting rod 61 and the multiple water cooling tubes 51, so as to achieve the effect of stirring the multiple water cooling tubes 51 in the molten phase change material. With the stirring of the multiple water cooling tubes 51, the heat in the molten phase change material can be evenly dispersed, and in the process of the coolant flowing inside the water cooling tube 51, the heat in the molten phase change material can be absorbed, which expands the cooling range of the water cooling tube 51 while ensuring the cooling effect on the battery module. The heat pipe 66 provided can achieve auxiliary cooling, further ensuring the cooling effect.

[0054] As an embodiment of the present invention, refer to Figure 4 The through hole 31 is arranged in a conical shape, and the aperture of the upper end of the through hole 31 is smaller than that of the lower end. The through hole 31 opened can ensure the normal installation and movement of the connecting rod 61 in the vertical direction. With the use of the bellows 63, the phase change material inside the inner shell 3 can be prevented from flowing to the outside of the inner shell 3 due to shaking when it is in a molten state. At the same time, when the annular plate 64 moves upward, the fluid gathered in the bellows 63 can be squeezed. Under the gathering effect of the upper end aperture, the flow rate of the fluid can be accelerated, thereby realizing the cooling treatment of the upper end of the heat pipe 66.

[0055] As an embodiment of the present invention, refer to Figure 5 , the distance between two adjacent battery cells 4 is equal to the minimum distance between the side wall of each battery cell 4 and the inner wall of the shell, and the distance between the top of the battery cell 4 and the top inner wall of the inner shell 3 is greater than the distance between two adjacent battery cells 4. Under this setting condition, the thickness of the phase change material filled in the inner shell 3 covering the outside of each battery cell 4 is the same, avoiding the situation where the temperature difference around different battery cells 4 becomes larger when the phase change material changes from a solid state to a molten state, thereby ensuring the service life of the battery module. The two adjacent water-cooling tubes 51 are staggered, and the vertical cross-sections of the top and bottom of each water-cooling tube 51 are triangular. The buoyancy of each water-cooling tube 51 in the phase change material in the molten state is equal to its own gravity. Since the cooling range of each water-cooling tube 51 is limited, by arranging multiple water-cooling tubes 51 in sequence at equal intervals, the cooling range of each water-cooling tube 51 can be expanded in the process of continuous up and down movement of the multiple water-cooling tubes 51, thereby achieving comprehensive cooling of the surrounding side of each battery cell 4, thereby ensuring the cooling effect.

[0056] As an embodiment of the present invention, refer to Figure 6 and Figure 7 The heat guiding mechanism 7 is arranged on the outside of the inner shell 3 and penetrates into the interior of the inner shell 3. The heat guiding mechanism 7 includes a top plate 71 and a main rod 72. The top plate 71 is sleeved on the top of the inner shell 3. The main rod 72 is fixedly arranged between the bottom plate 1 and the top plate 71. The first U-shaped plate 53 and the second U-shaped plate 54 are both arranged on the upper surface of the bottom plate 1. The upper surfaces of the first U-shaped plate 53 and the second U-shaped plate 54 are both connected to the lower end of the main rod 72. The rod wall of the main rod 72 is provided with a plurality of sub-rods 73, each of which penetrates into the interior of the inner shell 3. The sub-rods 73 located at the upper half of the axis of the main rod 72 are all copper rods, and are provided with penetration grooves 731 inside. The notch of each penetration groove 731 is located inside the inner shell 3.

[0057] When the vehicle starts and stops frequently due to traffic jams, the phase change material in the molten state will continue to shake along the direction of the vehicle's travel. The inertia generated by the shaking will affect the stability of the inner shell 3. Under the action of the main rod 72 and multiple auxiliary rods 73, the stability of the inner shell 3 can be effectively guaranteed. Under the action of the copper rod, the heat accumulated on the upper part of the inner shell 3 can be guided to the outside of the inner shell 3, and the airflow entering the outer shell 2 is used for cooling, which further ensures the cooling effect on the battery module.

[0058] As an embodiment of the present invention, refer to Figure 6 and Figure 7 A liquid reservoir 711 is provided inside the top plate 71, and the liquid reservoir 711 is filled with coolant. A plurality of connecting rods 61 are provided, and a floating block 8 located inside the liquid reservoir 711 is provided at the upper end of each connecting rod 61. Each floating block 8 is arranged in an inverted trapezoidal shape. The liquid level of the coolant inside the liquid reservoir 711 is a. When the bottom plate 1 is stationary and the phase change material inside the inner shell 3 is in a molten state, the distance between the top of the floating block 8 and the top inner wall of the liquid reservoir 711 is b. The distance between the liquid level of the coolant inside the liquid reservoir 711 and the bottom surface of the floating block 8 is c, wherein c <a<b。

[0059] When the phase change material is in a molten state and the coolant in the liquid storage tank 711 shakes due to inertia, the float 8 will float up and down under the action of the coolant. When floating, the float 8 can drive multiple water-cooling tubes 51 to shake synchronously inside the inner shell 3 through the corresponding connecting rod 61, further stirring the molten phase change material. By setting the distance, it can be ensured that the float 8 is always in a floating state, that is, when the coolant in the liquid storage tank 711 shakes, it can immediately drive the float 8 to shake, and then can immediately stir the molten phase change material.

[0060] As an embodiment of the present invention, refer to Figure 4 and Figure 8 The spring 65 is disposed above the phase change material, and the compression length of the spring 65 is d, where d < b, which avoids the phase change material submerging the spring 65 after melting and affecting the normal stretching and contraction of the spring 65, ensuring that the inertia generated during the bumpy process of the new energy vehicle can drive the plurality of water-cooled tubes 51 to move up and down synchronously through the connecting rod 61, and also ensuring the up and down movement space of the floating block 8 inside the liquid storage tank 711, and avoiding the floating block 8 colliding with the top of the liquid storage tank 711.

[0061] As an embodiment of the present invention, referring to Figure 8 A cavity one 611 is opened inside the connecting rod 61, and two groups of openings 6111 are opened on the side wall of the cavity one 611. The two groups of openings 6111 are respectively disposed on both sides of the annular plate two 64. The upper opening 6111 extends to the outside of the inner shell 3. The axis of the heat pipe 66 is perpendicular to the plane where the bottom plate 1 is located. The upper end of the heat pipe 66 is located inside the liquid storage tank 711, and the lower end of the heat pipe 66 is the evaporation end and is located inside the inner shell 3.

[0062] Since the evaporation end of the heat pipe 66 is located inside the inner shell 3, and the heat generated during the operation of the battery module will gather upward and thus contact the evaporation end of the heat pipe 66, enabling the heat pipe 66 to guide the heat inside the inner shell 3 from the evaporation end to the condensation end for cooling, realizing further temperature reduction treatment for the battery module.

[0063] Working principle: In a low-temperature environment, the phase change material is solid and wraps around the plurality of battery cells 4, which can achieve heat preservation for the plurality of battery cells 4 and avoid the situation of reducing the discharge efficiency of the battery module due to low temperature; when the temperature of the battery module exceeds the phase change temperature of the phase change material, the phase change material changes from a solid state to a molten state, and during the transformation process, it can absorb the heat generated by the battery module and cooperate with water cooling for temperature reduction treatment to prevent the battery module from overheating; when frequently controlling the accelerator pedal of the vehicle causes the battery module to heat up rapidly within a short time and exceed the optimal working temperature range, it can stir the molten phase change material, make the heat inside the phase change material evenly distributed, and accelerate the dissipation as the coolant in the water-cooled tube 51 continuously flows, thereby ensuring the normal operation of the battery module.

[0064] Specifically:

[0065] When the vehicle is traveling on a bumpy road, the battery module heats up quickly in a short period of time due to frequent control of the accelerator pedal, and when the temperature exceeds the phase change temperature of the phase change material, the phase change material changes to a molten state, and the connecting rod 61 moves back and forth up and down in coordination with the corresponding spring 65 under the action of inertia. Since the connecting rod 61 is fixedly sleeved with the water cooling tube 51, it can drive multiple water cooling tubes 51 to move back and forth synchronously in the vertical direction during the movement, thereby stirring the molten phase change material, so that the heat in the phase change material is evenly distributed, and the coolant in each water cooling tube 51 can expand the cooling range due to the movement of the water cooling tube 51 during the flow process, thereby achieving effective cooling treatment around each battery cell 4 and ensuring the service life of the battery module;

[0066] When the vehicle is traveling on a smooth road, the battery module is frequently heated up in a short period of time due to frequent control of the accelerator pedal due to traffic jams, and when the temperature exceeds the phase change temperature of the phase change material, the phase change material changes to a molten state, and the coolant in the liquid storage tank 711 will continue to shake along the driving direction of the vehicle under the action of inertia. During the shaking of the coolant, the multiple floating blocks 8 in the liquid storage tank 711 will be driven to shake up and down. Since the bottom of each floating block 8 is connected to multiple connecting rods 61, it can drive multiple water cooling tubes 51 to stir the molten phase change material, which can also achieve effective cooling of the battery module, thereby ensuring the service life of the battery module;

[0067] When the ambient temperature is high and the phase change material becomes molten, since the auxiliary rods 73 located at the upper half of the axis of the main rod 72 are copper rods and have penetration grooves 731 opened inside, part of the molten phase change material will penetrate into the penetration grooves 731. Since the copper rods have good thermal conductivity, the heat gathered above the inner shell 3 after the battery module is heated up will be guided to the outside of the inner shell 3 through the copper rods, thereby achieving further cooling of the battery module.

[0068] When the ambient temperature gradually decreases, causing the phase change material to change from a molten state to a solid state, there is no need to cool the battery module. The connecting rod 61 and the water cooling tube 51 will be fixed in the phase change material, avoiding frequent shaking of the connecting rod 61 and the water cooling tube 51 during vehicle bumps.

[0069] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A lithium iron phosphate battery module, comprising a base plate (1), an outer shell (2), an inner shell (3) and a plurality of battery cells (4), characterized in that: The battery cell (4) further comprises a water cooling mechanism (5), a stirring mechanism (6) and a heat guiding mechanism (7); the interior of the inner shell (3) is filled with a phase change material, and each of the battery cells (4) is immersed in the phase change material; the water cooling mechanism (5) comprises a water cooling pipe (51); a plurality of the water cooling pipes (51) are arranged in a serpentine shape and penetrate between the plurality of battery cells (4); the water cooling pipes (51) penetrate the phase change material filled in the inner shell (3); The stirring mechanism (6) is arranged inside the inner shell (3), and when the phase change material is heated and in a molten state and the bottom plate (1) is shaken up and down, the stirring mechanism (6) drives the multiple water cooling tubes (51) to move up and down synchronously, and the heat guiding mechanism (7) is arranged outside the inner shell (3) and penetrates into the inner shell (3), and when the phase change material is heated and in a molten state, the heat inside the inner shell (3) is guided to the outside of the inner shell (3) through the heat guiding mechanism (7).

2. A lithium iron phosphate battery module according to claim 1, characterized in that: The stirring mechanism (6) comprises a connecting rod (61), an annular plate 1 (62), a bellows (63), annular plate 2 (64) and a spring (65); the connecting rod (61) is fixedly sleeved with the water cooling tube (51); a through hole (31) is provided at the top of the inner shell (3); the connecting rod (61) is inserted into the inside of the through hole (31); the annular plate 1 (62), the bellows (63) and the annular plate 2 (64) are all sleeved with the connecting rod (61); the spring (65) is arranged between the annular plate 1 (62) and the annular plate 2 (64); the spring (65) is sleeved with the bellows (63); the annular plate 1 (62) is fixedly connected to the inner wall of the top of the inner shell (3); the annular plate 1 (62) and the annular plate 2 (64) are arranged at both ends of the bellows (63); and a heat pipe (66) is arranged inside the connecting rod (61).

3. A lithium iron phosphate battery module according to claim 2, characterized in that: The through hole (31) is arranged in a conical shape, and the diameter of the upper end of the through hole (31) is smaller than that of the lower end.

4. A lithium iron phosphate battery module according to claim 2, characterized in that: The distance between two adjacent battery cells (4) is equal to the minimum distance between the side wall of each battery cell (4) and the inner wall of the shell, and the distance between the top of the battery cell (4) and the top inner wall of the inner shell (3) is greater than the distance between two adjacent battery cells (4).

5. A lithium iron phosphate battery module according to claim 2, characterized in that: Two adjacent water cooling tubes (51) are staggered, the vertical cross-sections of the top and bottom of each water cooling tube (51) are triangular, and the buoyancy of each water cooling tube (51) in the phase change material in a molten state is equal to its own weight.

6. A lithium iron phosphate battery module according to claim 5, characterized in that: The plurality of water cooling tubes (51) are arranged in sequence at equal intervals, and when the phase change material is in a molten state, the distance between the top of the battery cell (4) and the topmost water cooling tube (51) is equal to the distance between the bottom of the battery cell (4) and the bottommost water cooling tube (51).

7. A lithium iron phosphate battery module according to claim 4, characterized in that: The heat guiding mechanism (7) comprises a top plate (71) and a main rod (72), wherein the top plate (71) is sleeved on the top of the inner shell (3), and the main rod (72) is fixedly arranged between the bottom plate (1) and the top plate (71). A plurality of auxiliary rods (73) are arranged on the rod wall of the main rod (72), and each of the auxiliary rods (73) penetrates into the interior of the inner shell (3). The auxiliary rods (73) located at the upper half of the axis of the main rod (72) are all copper rods and are provided with penetration grooves (731) inside, and the notch of each of the penetration grooves (731) is located inside the inner shell (3).

8. A lithium iron phosphate battery module according to claim 7, characterized in that: A liquid storage tank (711) is provided inside the top plate (71), and the liquid storage tank (711) is filled with cooling liquid. The connecting rods (61) are provided in a plurality of groups, and a floating block (8) located inside the liquid storage tank (711) is provided at the upper end of each group of connecting rods (61). Each floating block (8) is arranged in an inverted trapezoidal shape. The liquid level of the cooling liquid inside the liquid storage tank (711) is a. When the bottom plate (1) is stationary and the phase change material inside the inner shell (3) is in a molten state, the distance between the top of the floating block (8) and the inner wall of the top of the liquid storage tank (711) is b. The distance between the liquid level of the cooling liquid inside the liquid storage tank (711) and the bottom surface of the floating block (8) is c, wherein c is <a<b。 9. A lithium iron phosphate battery module according to claim 8, characterized in that: The spring (65) is arranged above the phase change material, and the compression length of the spring (65) is d, wherein d <b。 10. A lithium iron phosphate battery module according to claim 9, characterized in that: A cavity one (611) is provided inside the connecting rod (61), and two groups of openings (6111) are provided on the side wall of the cavity one (611). The two groups of openings (6111) are respectively arranged on both sides of the annular plate two (64), and the opening (6111) on the upper side extends to the outside of the inner shell (3). The axis of the heat pipe (66) is perpendicular to the plane where the bottom plate (1) is located. The upper end of the heat pipe (66) is located inside the liquid storage tank (711), and the lower end of the heat pipe (66) is an evaporation end and is located inside the inner shell (3).

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