Lithium ion power battery system of electric forklift

Abstract

The invention discloses a lithium ion power battery system of an electric forklift. The lithium ion power battery system comprises a battery box body, a radiator, a water pump, a water storage tank, a connecting water pipe and a battery management system, a lithium ion battery monomer, a cooling aluminum plate, an aluminum plate connecting pipe and a heat-conducting flame-retardant filler are arranged in the battery box body. A cooling water path is arranged in the cooling aluminum plate, and water spraying holes are formed in the aluminum plate connecting pipe. The water injection nozzle is provided with a high-temperature fuse piece. A discharge port is formed in the bottom surface of the battery box body. When thermal runaway occurs in the single lithium ion battery, high-temperature gas and liquid generated by the single lithium ion battery are discharged downwards from the discharge port, meanwhile, the high-temperature fuse piece on the aluminum plate connecting pipe near the single lithium ion battery with thermal failure is molten, and cooling water is sprayed out from the water spraying holes and finally flows out from the discharge port of the battery box body. The cooling water has a cooling effect, and the heat-conducting flame-retardant filler has a flame-retardant effect, so that the harm caused by thermal failure of the lithium ion battery is inhibited, and the safety of the lithium ion power battery system and the electric forklift is improved.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology for electric forklifts, specifically referring to a lithium-ion power battery system for electric forklifts. Background Technology

[0002] Electric forklifts are widely used in warehousing and logistics, factory workshops, airports, and train stations due to their advantages such as low noise, zero emissions, and high energy efficiency. Lithium-ion batteries, with their high power density, high charge / discharge rate, and long cycle life, are gradually replacing lead-acid batteries and becoming the mainstream power source for electric forklifts.

[0003] However, due to factors such as the inherent properties of the materials, manufacturing defects, and the operating environment, lithium-ion batteries are susceptible to thermal runaway. Thermal runaway can lead to serious safety accidents, threatening the safety of operators and equipment, and causing severe property damage.

[0004] Currently, research on thermal runaway in lithium-ion batteries mainly focuses on prevention and early warning, while technical solutions for effectively controlling the situation and mitigating the damage after thermal runaway occurs are relatively scarce.

[0005] Therefore, based on the current state of lithium-ion battery technology development and the working characteristics of lithium-ion batteries, it is very important to adopt a scientific and reasonable technical solution for electric forklift lithium-ion power battery systems to suppress the hazards caused by lithium-ion battery thermal failure to a large extent and improve the safety of lithium-ion power battery systems and electric forklifts. Summary of the Invention

[0006] This application provides a lithium-ion power battery system for electric forklifts to address the safety issues of lithium-ion power battery systems and electric forklifts caused by thermal runaway of lithium-ion batteries in existing technologies. To this end, this application employs methods such as filling the space between each lithium-ion battery cell and the cooling aluminum plate with a thermally conductive and flame-retardant filler, installing water spray holes in the aluminum plate connecting pipes between the cooling aluminum plates and sealing the water spray holes with high-temperature fusible links, and providing a discharge port at the bottom of the battery housing away from directly below the forklift seat. These methods suppress the adverse effects of lithium-ion battery thermal failure and improve the safety of the lithium-ion power battery system and the electric forklift.

[0007] This application provides a lithium-ion power battery system for electric forklifts, including a battery housing, a radiator, a water pump, a water tank, connecting water pipes, and a battery management system.

[0008] The battery box contains lithium-ion battery cells. The pressure relief valve of each lithium-ion battery cell faces the bottom of the battery box. There is a gap between the lithium-ion battery cell and the inner surface of the battery box wall. Cooling aluminum plates are arranged between the lithium-ion battery cells. Thermally conductive and flame-retardant filler is filled between the cooling aluminum plates and the lithium-ion battery cells. Water channels are provided inside the cooling aluminum plates. Aluminum plate connecting pipes are provided between the cooling aluminum plates.

[0009] The battery compartment has an exhaust port located at the bottom, away from directly below the forklift seat.

[0010] The radiator, the water pump, the connecting water pipe, the aluminum plate connecting pipe inside the battery box, and the cooling aluminum plate constitute a cooling water passage.

[0011] Furthermore, the aluminum plate connecting pipe is provided with water spray holes, which are sealed with high-temperature fused plates.

[0012] Furthermore, the thermally conductive and flame-retardant filler is a mixture of paraffin wax, aluminum powder, and flame retardant, with the composition ratio of paraffin wax, aluminum powder, and flame retardant being 8:1.5:0.5.

[0013] This application discloses a lithium-ion power battery system for electric forklifts, including a battery housing, a radiator, a water pump, a water tank, connecting water pipes, and a battery management system. The battery housing contains lithium-ion battery cells, a cooling aluminum plate, an aluminum plate connecting pipe, and a thermally conductive and flame-retardant filler. The cooling aluminum plate has cooling water channels, and the aluminum plate connecting pipe has water spray holes. High-temperature fusible links are provided at the water spray holes. A discharge port is provided on the bottom surface of the battery housing. When a lithium-ion battery cell experiences thermal runaway, the high-temperature gas and liquid generated by the lithium-ion battery cell are discharged downwards from the discharge port. Simultaneously, the high-temperature fusible link on the aluminum plate connecting pipe near the thermally failed lithium-ion battery cell melts, and cooling water is sprayed out from the water spray holes and ultimately flows out from the battery housing discharge port. Using this lithium-ion power battery system, the cooling water cools the thermally runaway lithium-ion battery cell and the high-temperature gas and liquid at the discharge port, and the thermally conductive and flame-retardant filler has a flame-retardant effect, thereby suppressing the hazards caused by lithium-ion battery thermal failure and improving the safety of the lithium-ion power battery system and the electric forklift.

[0014] The advantages of this application, employing the aforementioned structure and technical features, are as follows: When a lithium-ion battery cell is operating normally, the heat it generates is conducted to the cooling aluminum plate through the thermally conductive and flame-retardant filler, and then dissipated by the cooling water in the cooling aluminum plate's water channels. Simultaneously, the paraffin wax in the thermally conductive and flame-retardant filler can absorb some heat during phase transitions, thus ensuring the lithium-ion battery cell remains at a reasonable ambient temperature. When thermal runaway occurs in the lithium-ion battery, the generated high-temperature gas and liquid are sprayed towards the bottom of the battery casing through the battery's pressure relief valve and released outside the battery casing through the exhaust port at the bottom of the casing. Since the exhaust port is far from directly beneath the forklift seat, the safety of the forklift operator is largely guaranteed. Furthermore, the aluminum powder and flame retardant in the thermally conductive and flame-retardant filler surrounding the lithium-ion battery cell have flame-retardant properties, inhibiting the spread or propagation of thermal runaway. Meanwhile, the high-temperature fusible link of the aluminum plate connecting pipe near the thermally controlled lithium-ion battery melts, causing cooling water to spray out from the spray nozzle to cool the thermally runaway lithium-ion battery cells and the generated high-temperature gas and liquid. The cooling water sprayed from the nozzle flows from the gap between the lithium-ion battery cells and the inner surface of the battery box wall to the discharge port, thereby cooling the discharge port and the high-pressure gas and liquid discharged from it, further suppressing the hazards caused by thermal runaway, and thus improving the safety of the lithium-ion power battery system and the electric forklift.

[0015] Additional aspects and advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0016] The above and / or additional aspects and advantages of this application will become apparent and readily understood through a more detailed description of the embodiments in conjunction with the accompanying drawings, and constitute a part of the specification. These drawings, used together with the embodiments of this application, serve to explain the application and do not constitute a limitation thereof. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. Wherein:

[0017] Figure 1 This is a schematic diagram of the composition of an electric forklift lithium-ion power battery system according to an embodiment of this application;

[0018] Figure 2 This is a schematic diagram of the external shape of a lithium-ion battery cell according to an embodiment of this application;

[0019] Figure 3 This is a top view of the motherboard according to an embodiment of this application;

[0020] Figure 4 This is a schematic diagram of the cooling aluminum plate structure provided according to an embodiment of this application;

[0021] Figure 5This is a schematic diagram of the aluminum plate connecting pipe structure provided according to an embodiment of this application;

[0022] Figure 6 This is a top view of the battery box arrangement provided according to an embodiment of this application. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application more apparent, embodiments of this application will be described in detail below with reference to the accompanying drawings, examples of which are shown in the drawings. It should be understood that the embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0024] An electric forklift lithium-ion power battery system includes a battery housing, a radiator, a water pump, a water tank, connecting water pipes, and a battery management system. The battery housing contains lithium-ion battery cells, with the pressure relief valves of the lithium-ion battery cells facing the bottom of the battery housing. There is a gap between the lithium-ion battery cells and the inner surface of the battery housing wall. Cooling aluminum plates are arranged between the lithium-ion battery cells, and thermally conductive and flame-retardant filler is filled between the cooling aluminum plates and the lithium-ion battery cells. The cooling aluminum plates have water channels, and aluminum plate connecting pipes are provided between the cooling aluminum plates.

[0025] The bottom of the battery box is provided with an exhaust port away from directly below the forklift seat.

[0026] The radiator, the water pump, the connecting water pipe, the aluminum plate connecting pipe inside the battery box, and the cooling aluminum plate constitute a cooling water passage.

[0027] The aluminum plate connecting pipe is equipped with water spray holes, which are sealed with high-temperature fused plates.

[0028] The thermally conductive and flame-retardant filler is a mixture of paraffin wax, aluminum powder, and flame retardant, with a composition ratio of 8:1.5:0.5.

[0029] Example

[0030] Specifically, Figure 1 This is a schematic diagram of the composition of the lithium-ion power battery system 10 for electric forklifts provided according to an embodiment of this application.

[0031] like Figure 1 As shown, the electric forklift lithium-ion power battery system 10 includes a battery box 100, a radiator 200, a water pump 300, a water storage tank 400, a first connecting water pipe 500, a second connecting water pipe 600, a third connecting water pipe 700, and a battery management system 800.

[0032] Specifically, the battery box 100 is connected to the radiator 200 via the first connecting water pipe 500, the radiator 200, the water pump 300, and the water storage tank 400 are connected via the second connecting water pipe 600, and the water pump 300 is connected to the battery box 100 via the third connecting water pipe 700.

[0033] The battery housing 100 has a housing wall 101 made of a relatively thick metal plate that can withstand the mechanical impact of high-pressure gas and liquid generated by the thermal runaway of the lithium-ion battery. Preferably, the housing wall 101 is made of a steel plate with a thickness greater than 8 mm.

[0034] Preferably, the battery management system 800 is installed on the outer side of the enclosure wall 100.

[0035] The battery housing 100 has an exhaust port 108 at its bottom, which is located directly below the forklift seat away from the battery housing.

[0036] The battery housing 100 contains electrically connected lithium-ion battery cells, specifically including lithium-ion battery cells 102.

[0037] Among them, cooling aluminum plates are arranged between the lithium-ion battery cells, specifically including cooling aluminum plate 104.

[0038] Furthermore, Figure 2 This is a schematic diagram of the external shape of a lithium-ion battery cell according to an embodiment of this application.

[0039] Figure 3 This is a top view of the motherboard 107 provided according to an embodiment of this application.

[0040] like Figure 1 and Figure 2 As shown, the positive terminal 1021, negative terminal 1022, and pressure relief valve 1023 of the lithium-ion battery cell are located on the end face 1024. When the lithium-ion battery cell is installed in the battery case 100, the positive terminal 1021 is installed on the positive terminal seat 1072 of the busbar 107, and the negative terminal 1022 is installed on the negative terminal seat 1073 of the busbar 107.

[0041] Among them, the busbar plate 107 is located above the bottom of the box wall 101 and has a gap with the box wall.

[0042] Preferably, such as Figure 3 The busbar 107 is made of epoxy resin board 1071, and has a positive electrode seat and a negative electrode seat on it. The lithium-ion battery cells are connected in series or in parallel through copper busbars, including a positive electrode seat 1072, a negative electrode seat 1073 and a copper busbar 1074.

[0043] Preferably, the busbar plate 107 is provided with a through hole at the position of the pressure relief valve 1023, including a through hole 1075, and the area of ​​the through hole is not less than the maximum cross-sectional area of ​​the pressure relief valve 1023.

[0044] like Figure 1 As shown, cooling aluminum plates are arranged between lithium-ion battery cells, specifically including cooling aluminum plate 103.

[0045] Furthermore, Figure 4 This is a schematic diagram of the cooling aluminum plate structure provided according to an embodiment of this application;

[0046] like Figure 3 As shown, the cooling aluminum plate has a cooling water channel 1041, and the two ends of the cooling water channel 1041 are respectively provided with a water inlet 1042 and a water outlet 1043.

[0047] The inlet hole 1042 and the outlet hole 1043 are used to connect the aluminum plate connecting pipe between the cooling aluminum plates and to connect with the first connecting water pipe 500 and the third connecting water pipe 700.

[0048] like Figure 1 As shown, a thermally conductive and flame-retardant filler is filled between the cooling aluminum plate and the lithium-ion battery cell. Specifically, this includes filling a thermally conductive and flame-retardant filler 103 between the lithium-ion battery 102 and the cooling aluminum plate 104.

[0049] Specifically, the thermally conductive and flame-retardant filler is a mixture of paraffin wax, aluminum powder, and flame retardant, with a volume composition ratio of 8:1.5:0.5.

[0050] Preferably, the flame retardant of the thermally conductive and flame-retardant filler is ammonium polyphosphate.

[0051] like Figure 1 As shown, adjacent cooling aluminum plates are connected together by aluminum plate connecting pipes, specifically including aluminum plate connecting pipe 105.

[0052] Furthermore, Figure 5 This is a schematic diagram of an aluminum plate connecting pipe structure provided according to an embodiment of this application.

[0053] like Figure 5 As shown, the aluminum plate connecting pipe is equipped with water spray holes 1051, and a high-temperature fusion strip 1052 covers the water spray holes 1051. When the ambient temperature is not higher than the melting temperature of the high-temperature fusion strip, the high-temperature fusion strip 1052 seals the water spray holes 1051; when the ambient temperature is higher than the melting temperature of the high-temperature fusion strip, the high-temperature fusion strip 1052 melts, and cooling water is sprayed out from the water spray holes 1051.

[0054] Preferably, the melting temperature of the high-temperature molten sheet is 105°C.

[0055] Specifically, Figure 6This is a top view of the battery box arrangement provided according to an embodiment of this application.

[0056] like Figure 6 As shown, in the electric forklift lithium-ion battery system according to the embodiments of this application, if the number of lithium-ion battery cells in the battery box is n, then the number of cooling aluminum plates is n+1, and the number of thermally conductive and flame-retardant fillers is 2n.

[0057] According to the electric forklift lithium-ion battery system of this application embodiment, when a lithium-ion battery cell is working normally, the heat it generates is conducted to the cooling aluminum plate through the thermally conductive and flame-retardant filler, and the heat is dissipated by the cooling water in the cooling aluminum plate's water channel. Simultaneously, the paraffin in the thermally conductive and flame-retardant filler can absorb some heat during phase change, thereby ensuring that the lithium-ion battery cell is at a reasonable ambient temperature. When thermal runaway occurs in the lithium-ion battery, the generated high-temperature gas and liquid are sprayed towards the bottom of the battery housing through the battery's pressure relief valve and released outside the battery housing through the exhaust port at the bottom of the battery housing. Since the exhaust port is far from directly below the forklift seat, the safety of the forklift operator can be largely guaranteed. At the same time, the aluminum powder and flame retardant in the thermally conductive and flame-retardant filler around the thermally runaway lithium-ion battery cell have a flame-retardant effect, inhibiting the spread or propagation of thermal runaway. Meanwhile, the high-temperature fusible link of the aluminum plate connecting pipe near the thermally controlled lithium-ion battery melts, causing cooling water to spray out from the spray nozzle to cool the thermally runaway lithium-ion battery cells and the generated high-temperature gas and liquid. The cooling water sprayed from the nozzle flows from the gap between the lithium-ion battery cells and the inner surface of the battery box wall to the discharge port, thereby cooling the discharge port and the high-pressure gas and liquid discharged from it, further suppressing the hazards caused by thermal runaway, and thus improving the safety of the lithium-ion power battery system and the electric forklift.

[0058] In the description of this specification, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," "third," etc., may explicitly or implicitly include at least one of that feature.

[0059] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

[0060] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A lithium-ion power battery system for electric forklifts, characterized in that: The lithium-ion power battery system of the electric forklift includes a battery box (100), a radiator (200), a water pump (300), a water tank (400), a first connecting water pipe (500), a second connecting water pipe (600), a third connecting water pipe (700), and a battery management system (800). The battery box (100) is connected to the radiator (200) via a first connecting water pipe (500); The radiator (200) is connected to the water pump (300) via a second connecting water pipe (600); The water storage tank (400) is connected to the water pump (300) via a second connecting water pipe (600); The water pump (300) is connected to the battery box (100) via a third connecting water pipe (700); The battery management system (800) is installed on the outer side of the battery housing (100).

2. The lithium-ion power battery system for electric forklifts according to claim 1, characterized in that: The battery housing (100) is composed of a metal plate for the housing wall (101).

3. The lithium-ion power battery system for electric forklifts according to claim 2, characterized in that: The box wall (101) is made of steel plate with a thickness greater than 8mm.

4. The lithium-ion power battery system for electric forklifts according to claim 1, characterized in that: The bottom of the battery box (100) is provided with a discharge port (108), which is located directly below the forklift seat away from the battery box.

5. The lithium-ion power battery system for electric forklifts according to claim 1, characterized in that: The battery housing (100) contains a plurality of electrically connected lithium-ion battery cells (102); Cooling aluminum plates (104) are arranged between adjacent lithium-ion battery cells (102); The battery box (100) has a busbar (107) above the bottom, and there is a gap between the busbar (107) and the box wall (101).

6. The lithium-ion power battery system for an electric forklift according to claim 6, characterized in that: The busbar (107) is made of epoxy resin board (1071). The epoxy resin board (1071) has a positive electrode seat (1072), a negative electrode seat (1073) and a copper busbar (1074). The copper busbar (1074) enables the lithium-ion battery cells to form a series or parallel electrical connection. The positive electrode post (1021), negative electrode post (1022), and pressure relief valve (1023) of the lithium-ion battery cell (102) are located on the end face (1024); When the lithium-ion battery cell (102) is installed in the battery case (100), the positive terminal (1021) is installed on the positive terminal seat (1072) of the busbar (107), and the negative terminal (1022) is installed on the negative terminal seat (1073) of the busbar (107). The busbar plate (107) is provided with a through hole (1075) at the position of the pressure relief valve (1023), and the area of ​​the through hole is not less than the maximum cross-sectional area of ​​the pressure relief valve (1023).

7. The lithium-ion power battery system for an electric forklift according to claim 5, characterized in that: The cooling aluminum plate (104) has a cooling water channel (1041) inside, and the cooling water channel (1041) is provided with an inlet hole (1042) and an outlet hole (1043) at both ends; The inlet hole (1042) and outlet hole (1043) are used to connect the aluminum plate connecting pipe between the cooling aluminum plates and to connect with the first connecting water pipe (500) and the third connecting water pipe (700).

8. The lithium-ion power battery system for electric forklifts according to claim 1, characterized in that: A thermally conductive and flame-retardant filler (103) is filled between the cooling aluminum plate (104) and the lithium-ion battery cell. The thermally conductive and flame-retardant filler is a mixture of paraffin wax, aluminum powder, and flame retardant, with a volume composition ratio of 8:1.5:0.

5. The flame retardant for the thermally conductive and flame-retardant filler is ammonium polyphosphate.

9. The lithium-ion power battery system for an electric forklift according to claim 8, characterized in that: The internal water channels of adjacent cooling aluminum plates are connected together by aluminum plate connecting pipes (105); The aluminum plate connecting pipe is equipped with water spray holes (1051), and the water spray holes (1051) are covered with high-temperature fused plates (1052). When the ambient temperature is not higher than the melting temperature of the high-temperature fused plates, the high-temperature fused plates (1052) seal the water spray holes (1051); when the ambient temperature is higher than the melting temperature of the high-temperature fused plates, the high-temperature fused plates (1052) melt, and cooling water is sprayed out from the water spray holes (1051).

10. The lithium-ion power battery system for an electric forklift according to claim 1, characterized in that: If the number of lithium-ion battery cells inside the battery box is n, then the number of cooling aluminum plates is n+1, and the number of thermally conductive and flame-retardant fillers is 2n.

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