Electric forklift applying sodium battery

Abstract

The utility model discloses an electric forklift applying a sodium battery, which comprises an electric forklift body, the electric forklift body is provided with a sodium battery system for providing electric energy for the electric forklift body, the sodium battery system is provided with two independent sodium ion battery packs, each sodium ion battery pack is provided with an independent BMS (Battery Management System) unit, the two BMS units communicate with the fire extinguisher unit through signal lines, one sodium ion battery pack is connected with a low-voltage loop and supplies power to the low-voltage loop, and the other sodium ion battery pack is connected with a high-voltage loop and supplies power to the high-voltage loop. According to the forklift, the safety is remarkably improved, the performance in a low-temperature environment is improved, the use working condition is improved, the service life of a battery is prolonged, higher environmental adaptability is achieved, and economic benefits are improved.

Description

Technical Field

[0001] The utility model relates to the field of electric forklifts, in particular to the technical field of forklifts using sodium batteries as power sources. Background Art

[0002] As new energy vehicle sales continue to surge, lithium salt prices remain high. Sodium-ion batteries, a new battery technology, continue to gain popularity, driving a diverse range of battery technology development paths to supplement and enrich the new energy battery market. 2023 marked the first year for sodium-ion batteries, with a number of domestic companies entering mass production and related packs gradually being adopted by OEMs.

[0003] In the industrial vehicle sector, sodium-ion batteries have viable applications. First, sodium is abundant and widely distributed in the Earth's crust, hundreds of times more abundant than lithium. This gives sodium batteries a cost advantage in raw material procurement, facilitating large-scale production and application. Second, sodium batteries have an energy density of 160Wh / kg, significantly higher than lead-acid batteries. They also offer comparable performance compared to conventional lithium batteries at low discharge currents, which are around 200Wh / kg.

[0004] In small-tonnage forklifts, since the lifting objects are concentrated below 2 tons, when using an 80V voltage platform, the operating current is less than 100A when fully loaded on a flat road, and about 150A when fully loaded forklifts. This operating condition is within the application range for sodium-ion battery packs.

[0005] For example, the public document with application number 202320333191.8 and patent name "A hybrid energy system of fuel cell and sodium ion battery and industrial vehicle" discloses a hybrid energy system of fuel cell and sodium ion battery and industrial vehicle, wherein the hybrid energy system includes a fuel cell, a sodium ion battery, a fuel cell management module and a sodium ion battery management module; the fuel cell and the sodium ion battery are respectively connected to the vehicle's motor controller through power lines; the fuel cell management module is respectively connected to the fuel cell and the motor controller through a low-voltage signal line; the sodium ion battery management module is respectively connected to the sodium ion battery and the motor controller through a low-voltage signal line.

[0006] Similar problems exist in existing sodium-ion battery-powered forklifts:

[0007] 1. While the use of hydrogen fuel cells in industrial vehicles offers certain energy supply advantages, the complex hydrogen pipeline interfaces and elbows pose significant safety risks in actual use. Hydrogen system failures may occur due to complex road conditions or accidents, making accidental hydrogen leaks unavoidable throughout the vehicle's lifecycle. There is also a significant risk of accidental electrical ignition. If hydrogen leaks from a vehicle, the relatively enclosed battery compartment with poor ventilation and heat dissipation could combine with the 1200°C high temperature generated by thermal runaway of the sodium-ion battery, potentially causing combustion and explosion.

[0008] 2. In the prior art, hydrogen fuel cells are used as power generation units. When the sodium-ion battery is low on energy, it is charged via a DC-DC converter. In practical applications, the power of DC-DC converters is limited. DC converters are generally suitable for converting high voltage to low voltage to avoid electric shock hazards to people caused by voltages above DC60V. Even a 1kW 353V to 12V converter in the industry only has a current of 3A on the high-voltage side. If it is an 80V to 12V DC converter, according to the formula I = P / U, because the conventional charging current must reach more than 100A, according to calculations, the prior art fuel cell using DC is insufficient to achieve meaningful charging of the sodium battery.

[0009] In general, the sodium-ion batteries used in existing vehicles (including forklifts) are difficult to "self-rescue" in the event of an accident, which can easily cause the accident to escalate. In addition, it is difficult to ensure the reliability of battery monitoring and management when power is supplied, which poses a safety hazard. Summary of the Invention

[0010] The technical problem to be solved by the utility model is to realize a sodium battery electric forklift with a reasonable layout and conducive to improving the working safety of the battery.

[0011] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an electric forklift using a sodium battery, comprising an electric forklift body, the electric forklift body being provided with a sodium battery system for providing electrical energy to the electric forklift, the sodium battery system being provided with a sodium ion battery pack and a BMS unit for independently supplying power to a low-voltage circuit, and a sodium ion battery pack and a BMS unit for independently supplying power to a high-voltage circuit.

[0012] The sodium battery system is provided with two groups of sodium ion battery packs and a BMS unit connected in parallel. The low-voltage circuit includes but is not limited to a lighting circuit, a horn circuit, an identity recognition circuit and an electric fan circuit. The high-voltage circuit includes but is not limited to a power supply circuit for the electric forklift body travel power motor and a power supply circuit for the forklift frame power motor.

[0013] The sodium battery system for electric energy is provided with a battery compartment, a compartment door is provided on the side of the battery compartment, and the two sodium ion battery packs are two independent detachable batteries.

[0014] The battery compartment is separated by a partition into two independent storage spaces, upper and lower, which are used to store two independent sodium ion battery packs respectively.

[0015] The partition is provided with a fireproof base material layer, and each storage space is provided with a sprinkler head, and the sprinkler head is connected to the fire extinguisher unit through a fire extinguishing pipe provided with a solenoid valve.

[0016] The fire extinguisher unit is fixed on the top of the battery compartment.

[0017] The fire extinguisher unit is connected to and controls the switching status of the two solenoid valves.

[0018] The fire extinguisher unit is fixed to the top of the battery compartment by fasteners, and a temperature signal connector for connecting two BMS units to obtain temperature signals is provided on the outside of the fire extinguisher unit.

[0019] The sodium battery system is fixed in the vehicle body below the driver's cabin seat of the electric forklift.

[0020] The utility model has the following advantages:

[0021] Battery Management System (BMS) optimization: An independent battery management system monitors the battery status of each independent functional unit in real time to improve the stability and reliability of battery operation;

[0022] Fire extinguishing system configuration in the battery compartment: An efficient fire extinguishing system is integrated into the battery compartment, which can automatically activate when abnormally high temperatures are detected, quickly suppressing the fire source and reducing potential safety risks;

[0023] Distributed battery drive design: The vehicle's power supply circuit is organized and the battery is designed in a distributed manner to independently power different functional units, improving the system's flexibility and reliability.

[0024] Environmental adaptability: Through the rational layout of the battery in the forklift, the stability and adaptability of the battery in different environments are improved, ensuring that the forklift can maintain optimal performance under various working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The following is a brief description of the contents and marks in each figure in the utility model specification:

[0026] Figure 1 This is a schematic diagram of the structure of an electric forklift using sodium batteries;

[0027] Figure 2 This is a block diagram of the working principle of the sodium battery system;

[0028] Figure 3 Schematic diagram of the sodium battery system structure;

[0029] The marks in the above figure are: 1. Fire extinguisher unit; 2. Sodium-ion battery pack; 3. Battery compartment; 4. Partition; 5. Fire extinguishing pipe; 6. Solenoid valve; 7. Sprinkler head; 8. Temperature signal connector; 9. Battery pack signal connector; 10. Sodium battery system. DETAILED DESCRIPTION

[0030] Below, with reference to the accompanying drawings, through the description of the embodiments, the specific implementation methods of the present invention, such as the shape, structure, relative positions and connection relationships of the various components involved, the functions and working principles of the various parts, the manufacturing process and operating methods, etc., are further explained in detail to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0031] The core technology of sodium battery forklifts lies in their sodium-ion batteries. Compared to traditional lead-acid and lithium-ion batteries, sodium-ion batteries offer advantages such as a stable raw material supply, high cost-effectiveness, and strong environmental friendliness. Furthermore, sodium-ion batteries offer superior high-current discharge and fast-charging capabilities, enabling faster charge rates than current lithium-ion batteries. They can be fully charged from 0% in just 15 minutes, providing strong support for the high-intensity and continuous operation of forklifts. Furthermore, sodium batteries exhibit improved aging safety. During use, lithium batteries develop lithium metal dendrites on their electrodes. Over time, these can pierce the SEI separator, causing internal short circuits and potentially fires and explosions. Therefore, the safety of lithium batteries gradually deteriorates with repeated charging and discharging, and the safety of older batteries deteriorates. The hard carbon anode material in sodium batteries, unlike the layered graphite structure of lithium batteries, is less susceptible to sodium metal precipitation. Even if trace amounts of sodium metal do precipitate, they are flat, rather than the sharp, pointed forms of lithium dendrites.

[0032] Sodium batteries (SIBs) offer the advantages of high rate performance and excellent low-temperature charge and discharge performance. Discharge at temperatures below -10°C is almost identical to that at room temperature, and capacity retention is above 90% at -20°C. Sodium batteries can achieve an energy density of 140 watt-hours per kilogram, which, while lower than lithium iron phosphate batteries, is significantly higher than lead-acid batteries.

[0033] Applications:

[0034] Industrial Logistics and Handling: Sodium battery forklifts, with their superior performance and cost advantages, especially their exceptional charging speed, have broad application prospects in the industrial logistics and handling sector. For cost-sensitive businesses, the 15-minute recharge rate eliminates the need for additional investment in battery swapping stations, compared to the industry's standard battery swapping stations. For high-volume production enterprises, the 1-2 hour recharge time for lithium batteries can be significantly reduced, helping to improve logistics efficiency and reduce operating costs.

[0035] Cold chain logistics: Due to the good low-temperature performance of sodium batteries, sodium battery forklifts also have unique application advantages in the field of cold chain logistics. They can work normally in low-temperature environments, ensuring the smooth operation of cold chain logistics.

[0036] Operations in high-altitude and cold regions: For high-altitude and cold regions, the high and low temperature performance of sodium battery forklifts enables them to adapt to extreme weather conditions and meet the needs of local industrial production and logistics handling.

[0037] Development Trends

[0038] With the continuous development of new energy technologies and the continued growth of market demand, the technological fields and application scope of sodium battery forklifts will continue to expand. In the future, we can expect to see the application of more innovative technologies and the emergence of more diverse application scenarios. At the same time, as the industrial chain continues to improve and costs continue to decrease, sodium battery forklifts are expected to be promoted and applied in a wider range of fields.

[0039] In summary, the utility model patent application designs a forklift that uses a sodium battery pack to meet operational needs.

[0040] The structure of electric forklift using sodium battery is as follows Figure 1 As shown, the sodium battery system 10 is fixed under the seat in the forklift cab and mainly consists of a battery compartment 3 and a fire extinguisher unit 1. The battery compartment 3 contains a sodium-ion battery pack 2 and a BMS unit, and the fire extinguisher unit 1 is fixed to the top of the battery compartment 3. The sodium-ion battery pack 2 in the battery compartment 3 is divided into two independent groups: one for low-voltage power supply and the other for high-voltage power supply for the entire vehicle. The low-voltage circuit units of the vehicle, such as the lighting circuit, horn circuit, identification circuit, electric fan circuit, etc., which are powered by DC12V or DC24V, are powered by one independent battery group, while circuits greater than DC60V, such as the motor, are powered by another independent battery group.

[0041] By equipping a forklift with two battery packs of appropriately matched capacities, the low-voltage circuit unit can be handheld for battery replacement. This avoids the traditional issue of single-battery power supply, where depletion of the battery renders the entire vehicle's low-voltage circuit unit inoperable in emergency situations. This issue can prevent personnel from operating in situations where a forklift-provided lighting is required for repairs. This design also offers the advantage of being able to remove the battery packs individually and, due to their small capacity, enabling extremely rapid charging.

[0042] Compared to lithium batteries, which operate in temperatures ranging from -20°C to 60°C, sodium-ion batteries can withstand temperatures ranging from -40°C to 80°C. This significantly enhances the adaptability of sodium-ion forklifts in high-temperature environments such as metallurgical plants and steel mills. The fire extinguishing system further ensures vehicle safety. When overheating occurs, the fire extinguishing system promptly activates the spray nozzles, reducing the severity of the accident or even preventing it from occurring.

[0043] The detailed mechanical layout of the battery compartment 3 is as follows Figure 3 As shown, the fire extinguisher unit 1 is located on the top layer and is fixed to the battery compartment 3 plate by fasteners. Two temperature signal connectors 8 are arranged outside the fire extinguisher unit 1, wherein the temperature signal connector 8 is connected to the battery pack signal connector 9 of the sodium ion battery pack 2 of the low-voltage circuit.

[0044] The low-voltage sodium-ion battery pack 2 is equipped with an independent BMS unit, which transmits the excessive temperature signal to the fire extinguisher unit 1 through the bus. Similarly, another temperature signal connector 8 is connected to the battery pack signal connector 9 of the sodium-ion battery pack 2 of the high-voltage circuit. The high-voltage sodium-ion battery pack 2 is also equipped with an independent BMS unit, which transmits the excessive temperature signal to the fire extinguisher unit 1 through the bus. Both sodium-ion battery packs 2 are equipped with temperature sensors, which transmit the signal to the corresponding BMS unit, and then connect and transmit it to the fire extinguisher unit 1 via a signal line. In addition to common thermal management functions, the BMS unit also has a built-in DC converter, which can output according to the voltage level of the adapted low-voltage unit.

[0045] A fire extinguishing pipe 5 is led out from the lower part of the fire extinguisher unit 1. When a fire extinguishing situation occurs, the relevant fire extinguishing medium flows in the pipe. A sprinkler head 7 is provided at the end of the fire extinguishing pipe 5. When a fire occurs, the fire extinguisher unit 1 sends a fire extinguishing start signal, and the solenoid valve 6 and the solenoid valve 6 must be switched from the normally closed state to the open state, so that the fire extinguishing medium can flow through the pipe to the corresponding sprinkler head 7 for fire extinguishing. The function of the sprinkler head 7 is to extinguish the fire in the space corresponding to the low-voltage battery unit. When a fire extinguishing situation occurs, the fire extinguishing medium is sprayed out by the sprinkler head 7 to eliminate the fire. The solenoid valve 6 is provided between the sprinkler head 7 and the fire extinguishing pipe 5. In the absence of a fire, the solenoid valve 6 is in the normally closed state. When the fire extinguisher unit 1 is started, the solenoid valve 6 opens to extinguish the fire.

[0046] The battery unit can be set up differently according to the operating conditions and discharge current levels of forklifts of different tonnages, such as 1.5-ton and 2-ton forklifts. During the forklift design process, the rated power of low-voltage electrical components such as lamps is determined. When considering the margin factor K, it is usually set within the range of 1.4-1.8 times the power of the full calculated electrical components to ensure the use of the entire component.

[0047] Traditionally, forklifts have relied on a single battery as the vehicle's power source. When the battery is low, both high- and low-voltage components cease to function, causing inconvenience during maintenance. This is especially true at night, when additional lighting is required. Furthermore, in poorly lit areas, it can be difficult for outsiders to detect the forklift's presence, creating safety risks during maintenance.

[0048] The low-voltage battery unit ensures independent operation of the lighting fixture, ensuring safety during maintenance. The sodium-ion battery pack 2 is fixed to the mounting partition 4. The low-voltage unit has a low discharge current, typically tens of amperes, so the design is small in capacity and weight, allowing it to be carried by an adult male. This design allows for quick portable replacement in areas where logistics and charging are not available.

[0049] The partition 4 is preferably double-layered, and a fire-resistant substrate can be filled between the double-layer partitions 4. This provides an isolated area for the fire to spread if it is not extinguished, preventing it from rapidly spreading. The sprinkler heads 7 and 7 have sufficient time to extinguish the fire. The fire-resistant substrate was selected primarily to consider that the temperature of a lithium battery explosion can reach 2000°C. In this embodiment, a substrate that meets this requirement was selected for filling.

[0050] The high-voltage battery unit is located at the bottom of the battery compartment 3 and consists of a sodium-ion battery pack 2 and a BMS unit. The battery unit supplies power to high-voltage components such as the lifting motor, drive motor, and electronic control. The capacity of the sodium-ion battery pack 2 is larger than that of the lithium-ion battery pack 2, and the two are matched according to the operating conditions of different models of electric forklifts. Similarly, the sprinkler head 7 and the solenoid valve 6 extinguish the fire in this area, and the solenoid valve 6 is in a normally closed state when it does not receive a fire extinguishing signal. The temperature connector is connected to the temperature signal connector 8 of the fire extinguisher unit 1 to monitor the temperature. By designing different temperature connectors, early fire hazards can be perceived in a targeted manner. During the use of the forklift, the heat of the hydraulic pipeline and the heat of the electrical components are different around the forklift battery. Two sets of temperature sensors can be used to perform independent fire extinguishing actions in a layered manner.

[0051] Similarly, the deployment of distributed battery units simplifies troubleshooting power circuits, eliminating the need to troubleshoot both the power and lighting circuits simultaneously. When a low-voltage or high-voltage circuit experiences a power failure, repairs can be quickly performed based on the specific circuit type.

[0052] By configuring different battery cells, the current sodium-ion battery packs, with a generally lower energy density of 160Wh / kg compared to lithium batteries and a lower discharge current, can be improved for forklift applications. Discharge current under operating conditions is divided into high-voltage and low-voltage cell currents, enabling the system to meet the operating current requirements of forklifts under 2 tons.

[0053] The forklift structure has the following technical effects:

[0054] 1. Significantly improved safety: The use of a pure sodium-ion battery system and an automatic fire extinguishing system significantly improves the safety of industrial vehicles during use;

[0055] 2. Improved performance in low-temperature environments: Optimized electric heating film technology ensures the discharge performance of sodium-ion batteries in extremely low-temperature environments, improving vehicle starting efficiency;

[0056] 3. Improved operating conditions: By calibrating the discharge cut-off voltage of the sodium-ion battery pack 2, it can meet the 8-hour operating requirement under forklift operating conditions. In addition, due to the distributed battery configuration of the relevant power supply units, it has a larger discharge capacity for low-voltage components, ensuring the needs of vehicle emergency lighting;

[0057] 4. Higher environmental adaptability: Forklifts equipped with sodium-ion battery packs 2 can adapt to a wider range of working environments, including high temperature, high humidity and extreme temperature conditions, improving the reliability and applicability of the forklift. Sodium battery forklifts have significant advantages over lithium-ion forklifts in terms of operating capacity and thermal stability control;

[0058] 5. Improved economic benefits: Through cost control and supply chain optimization, the overall cost of ownership of sodium battery forklifts is reduced, allowing companies to enjoy high-performance electric forklifts at a lower cost, thereby improving market competitiveness.

[0059] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. An electric forklift using a sodium battery, comprising an electric forklift body, wherein the electric forklift body is provided with a sodium battery system for providing power to the electric forklift, characterized in that: The sodium battery system is provided with a sodium ion battery pack and a BMS unit that independently supply power to a low-voltage circuit, and a sodium ion battery pack and a BMS unit that independently supply power to a high-voltage circuit.

2. The electric forklift using a sodium battery according to claim 1, characterized in that: The sodium battery system is provided with two groups of sodium ion battery packs and a BMS unit connected in parallel. The low-voltage circuit includes but is not limited to a lighting circuit, a horn circuit, an identity recognition circuit and an electric fan circuit. The high-voltage circuit includes but is not limited to a power supply circuit for the electric forklift body travel power motor and a power supply circuit for the forklift frame power motor.

3. The electric forklift using a sodium battery according to claim 2, characterized in that: The sodium battery system for electric energy is provided with a battery compartment, a compartment door is provided on the side of the battery compartment, and the two sodium ion battery packs are two independent detachable batteries.

4. The electric forklift using a sodium battery according to claim 3, characterized in that: The battery compartment is separated by a partition into two independent storage spaces, upper and lower, which are used to store two independent sodium ion battery packs respectively.

5. The electric forklift using a sodium battery according to claim 4, characterized in that: The partition is provided with a fireproof base material layer, and each storage space is provided with a sprinkler head, and the sprinkler head is connected to the fire extinguisher unit through a fire extinguishing pipe provided with a solenoid valve.

6. The electric forklift using a sodium battery according to claim 5, characterized in that: The fire extinguisher unit is fixed on the top of the battery compartment.

7. The electric forklift using a sodium battery according to claim 6, characterized in that: The fire extinguisher unit is connected to and controls the switching status of the two solenoid valves.

8. The electric forklift using a sodium battery according to claim 7, characterized in that: The fire extinguisher unit is fixed to the top of the battery compartment by fasteners, and a temperature signal connector for connecting two BMS units to obtain temperature signals is provided on the outside of the fire extinguisher unit.

9. The electric forklift using a sodium battery according to claim 1 or 8, characterized in that: The sodium battery system is fixed in the vehicle body below the driver's cabin seat of the electric forklift.

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