Sodium battery pack for pallet truck and pallet truck

Abstract

The invention relates to the technical field of electric forklifts, in particular to a sodium battery pack for a pallet truck and the pallet truck. The sodium battery pack for the pallet truck comprises a box body, and a sodium ion battery cell module, a current sensor, a battery management module and a switching device which are arranged in the box body, a charging and discharging connector is arranged on the box body; the sodium ion battery cell module, the current sensor and the switching device are connected in series to form a main loop connected to the charging and discharging connector; and the battery management module is in communication connection with the sodium ion battery cell module, the current sensor and the switching device. The low-temperature performance potential of the sodium ion battery is superior to that of a lithium ion battery, and the battery cell module, the sensing unit, the control unit and the switching device are highly integrated in the box body, so that a power supply system which is compact in structure and perfect in management is formed, and a vehicle has better safety and has more advantages in cost and low-temperature performance.

Description

Technical Field

[0001] This invention relates to the field of electric forklift technology, and in particular to a sodium battery pack for a pallet truck and the pallet truck itself. Background Technology

[0002] Electric pallet trucks, with their compact structure, lightweight design, and intuitive operation, have become highly efficient handling tools in modern logistics, warehousing, and short-distance transportation. This equipment particularly meets the upgrade needs of users of traditional manual pallet trucks, providing them with a feasible path to electrification, significantly improving operational efficiency and reducing labor intensity.

[0003] Currently, electric pallet trucks mainly use two battery technology solutions: one is lead-acid battery packs, which are mature, low-cost, and widely adaptable, but have limitations such as low energy density and relatively short cycle life; the other is lithium battery packs, which have the advantages of high energy density, long cycle life, and fast charging and discharging, and have become the preferred solution for high-end models, especially suitable for high-frequency and high-intensity operation scenarios.

[0004] However, in lightweight pallet trucks, battery capacity is typically small due to limited vehicle space. To control power consumption and cost, most models do not equip their lithium batteries with active heating, resulting in a significant performance degradation and limited applicability in low-temperature environments (such as cold storage). Lithium battery packs are not well-suited for low-temperature operations such as cold storage. Summary of the Invention

[0005] Based on this, in order to address the technical problem that lithium battery packs are not very suitable for low-temperature operation in environments such as cold storage, resulting in a significant decrease in the performance and poor applicability of pallet trucks using lithium batteries in low-temperature environments (such as cold storage), this invention provides a sodium battery pack for pallet trucks and a pallet truck.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a sodium battery pack for pallet trucks, including a housing and sodium-ion battery modules, a current sensor, a battery management module, and a switching device disposed within the housing; a charging / discharging connector is provided on the housing; the sodium-ion battery modules, the current sensor, and the switching device are connected in series to form a main circuit connected to the charging / discharging connector; the battery management module is communicatively connected to the sodium-ion battery modules, the current sensor, and the switching device.

[0008] To address the issues of limited battery compartment space in lightweight electric pallet trucks and the performance degradation of existing lithium battery solutions at low temperatures, this invention provides an integrated battery pack solution based on sodium-ion cells. Sodium-ion batteries inherently possess superior low-temperature performance potential compared to lithium-ion batteries. Furthermore, this solution highly integrates cell modules, sensing units, control units, and switching devices within the housing, forming a compact and well-managed power system. This lays the foundation for achieving stable and reliable power supply within limited space, and is particularly beneficial for improving the applicability and operational continuity of electric pallet trucks in complex working conditions, including low-temperature environments.

[0009] Compared to traditional lead-acid battery packs, the sodium battery pack of this invention is lighter and smaller, saving space in the pallet truck. This not only facilitates after-sales maintenance but also makes the vehicle structure more compact, improves operational flexibility, reduces load current, and increases vehicle efficiency. Employing a BMS management system, it fully utilizes the wide operating temperature range of -20℃ to 50℃ inherent in the sodium battery pack. Through precise temperature control management strategies, it ensures efficient operation across this entire temperature range, maintaining an energy conversion efficiency consistently above 90%. It successfully overcomes the technical challenge of significant performance degradation of traditional lithium batteries in low-temperature environments, effectively enhancing the reliability of equipment in cold climates. The sodium battery pack supports deep discharge, allowing it to be discharged to 0V and then recharged. Even in extreme discharge scenarios, it avoids the problem of lead-acid and lithium batteries failing due to prolonged undercharging, making it suitable for the long-distance sea transport conditions of electric pallet trucks. The sodium battery pack has a cycle life exceeding 3000 cycles and over 100,000 start-stop cycles, approximately twice the cycle life of lead-acid batteries, reducing long-term operating costs and providing more stable range.

[0010] As a further improvement to the above-described solution of the present invention, the switching device includes a charge / discharge MOS transistor.

[0011] As a further improvement to the above-described solution of the present invention, a pre-charge MOSFET controlled by the battery management module is also connected in parallel on the main circuit. The pre-charge MOSFET is activated during the initial charging stage to prevent high-voltage surges.

[0012] As a further improvement to the above-mentioned solution of the present invention, the sodium-ion battery cell module integrates a temperature sensor for monitoring its temperature and a voltage sensor for monitoring its terminal voltage; both the temperature sensor and the voltage sensor are communicatively connected to the battery management module. Integrating temperature and voltage sensors within the sodium-ion battery cell module enables direct, in-situ monitoring of the battery's core state parameters (temperature and voltage), allowing the battery management module to obtain more accurate and timely information about the battery cell itself. This provides crucial data support for accurately assessing the battery's state of charge (SOC), state of health (SOH), and early identification of thermal runaway risks, fundamentally enhancing the effectiveness and safety of battery management.

[0013] As a further improvement to the above-described solution of the present invention, the battery management module is configured to: when an overcurrent, overtemperature, or overvoltage fault is diagnosed based on signals collected by a current sensor, a temperature sensor, or a voltage sensor, control the switching device to turn off to disconnect the main circuit.

[0014] As a further improvement to the above-mentioned solution of the present invention, the battery management module includes an interconnected MCU main control unit and an AFE signal processing unit. The AFE signal processing unit is used to connect to a current sensor, a temperature sensor, and a voltage sensor and collect current signals, temperature signals, and voltage signals. The main control unit is used to perform state estimation and fault diagnosis based on the current signal, temperature signal, and voltage signal, and control the switching devices. This enables real-time, parallel monitoring of various typical battery faults such as overcurrent, overtemperature, and overvoltage. Once any fault is detected, a protection action can be immediately triggered to quickly disconnect the main circuit, thereby effectively preventing the fault from further escalating and protecting the sodium-ion battery cell module, electrical appliances, and the battery pack itself from damage, greatly improving the safety level of system operation.

[0015] As a further improvement to the above-described solution of the present invention, the MCU main control unit is connected to a CAN transceiver for communicating with external devices, including at least one of a vehicle controller, an instrument cluster, a charger, and a host computer. By integrating the CAN transceiver, the sodium battery pack becomes an intelligent node in the vehicle network. This allows battery status information (such as battery level and fault codes) to be uploaded to the vehicle instrument cluster or controller in real time, while also receiving instructions from the vehicle or charger (such as charging requirements and power limits), achieving deep collaboration between battery management and vehicle energy management and charging management.

[0016] As a further improvement to the above-mentioned solution of the present invention, the sodium-ion battery module is composed of multiple sodium-ion batteries, which are connected by a metal busbar and configured in series and parallel combinations to form a battery module with a nominal voltage of 24V. Compared with traditional lithium-ion batteries, sodium-ion batteries have potential advantages in terms of cost, low-temperature performance, and safety; the use of metal busbar connection has the advantages of reliable connection, low internal resistance, strong current carrying capacity, and good heat dissipation, which can improve the overall power performance and durability of the module; the 24V voltage platform can directly match the electrical system standards of most industrial vehicles, simplifying vehicle electrical design and improving versatility and ease of replacement.

[0017] As a further improvement to the above-mentioned solution of the present invention, the enclosure is made of aluminum alloy with heat dissipation fins and has an IP67 protection rating. The enclosure is made of aluminum alloy and the surface is designed with heat dissipation fins, which have both mechanical protection and heat dissipation functions. The enclosure design complies with the IP67 protection standard, which can effectively resist dust intrusion and short-term water immersion. At the same time, passive heat dissipation is achieved through structural optimization to ensure stable operation of the battery in an ambient temperature range of -20℃ to 50℃.

[0018] The present invention also provides a pallet transport vehicle, which includes a sodium battery pack for pallet transport vehicles as described above.

[0019] Compared with the prior art, the present invention has the following beneficial effects: To address the issues of limited battery compartment space in lightweight electric pallet trucks and the performance degradation of existing lithium battery solutions at low temperatures, this invention provides an integrated battery pack solution based on sodium-ion cells. Sodium-ion batteries inherently possess superior low-temperature performance potential compared to lithium-ion batteries. Furthermore, this solution highly integrates cell modules, sensing units, control units, and switching devices within the housing, forming a compact and well-managed power system. This lays the foundation for achieving stable and reliable power supply within limited space, and is particularly beneficial for improving the applicability and operational continuity of electric pallet trucks in complex working conditions, including low-temperature environments.

[0020] Compared to traditional lead-acid battery packs, the sodium battery pack of this invention is lighter and smaller, saving space in the pallet truck. This not only facilitates after-sales maintenance but also makes the vehicle structure more compact, improves operational flexibility, reduces load current, and increases vehicle efficiency. Employing a BMS management system, it fully utilizes the wide operating temperature range of -20℃ to 50℃ inherent in the sodium battery pack. Through precise temperature control management strategies, it ensures efficient operation across this entire temperature range, maintaining an energy conversion efficiency consistently above 90%. It successfully overcomes the technical challenge of significant performance degradation of traditional lithium batteries in low-temperature environments, effectively enhancing the reliability of equipment in cold climates. The sodium battery pack supports deep discharge, allowing it to be discharged to 0V and then recharged. Even in extreme discharge scenarios, it avoids the problem of lead-acid and lithium batteries failing due to prolonged undercharging, making it suitable for the long-distance sea transport conditions of electric pallet trucks. The sodium battery pack has a cycle life exceeding 3000 cycles and over 100,000 start-stop cycles, approximately twice the cycle life of lead-acid batteries, reducing long-term operating costs and providing more stable range. Attached Figure Description

[0021] Figure 1 An external view of a sodium battery pack for a pallet truck provided by the present invention; Figure 2 This invention provides a system block diagram of a sodium battery pack for a pallet transport vehicle.

[0022] Reference numerals in the attached diagram: 1. Housing; 2. Sodium-ion battery module; 3. Current sensor; 4-1. MCU main control unit; 4-2. AFE signal processing unit; 5. Charge / discharge MOSFET; 6. CAN transceiver; 7. Precharge MOSFET; 8. Charge / discharge connector. Detailed Implementation

[0023] To facilitate understanding of the present invention, a more comprehensive description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0025] Combination Figure 1 , Figure 2 This embodiment proposes a sodium battery pack for pallet trucks. Its core is to provide a power solution that combines excellent low-temperature performance, high integration and intelligent management, so as to overcome the defects of lead-acid batteries, which are bulky and have short lifespan, and lithium batteries, which have insufficient low-temperature adaptability in the background technology.

[0026] The sodium battery pack mainly consists of a housing 1 that serves as the physical load-bearing structure and provides protection, and integrated within the housing 1 are sodium-ion battery cell modules 2, current sensors 3, a battery management module (BMS), and switching devices. Charge / discharge connectors 8 are mounted on the outside of the housing 1 for connecting to an external charger or supplying power to vehicle loads. The sodium-ion battery cell modules 2, current sensors 3, and switching devices are connected in series, forming the main charge / discharge path from the cells to the external interface. The battery management module acts as the brain, communicating with all the aforementioned key components to implement comprehensive monitoring and management.

[0027] The housing 1 is made of high-strength aluminum alloy using die-casting or profile splicing processes, achieving lightweight while ensuring structural strength. Its outer surface is designed with dense heat dissipation fins to increase the heat dissipation area, utilizing airflow during vehicle operation to achieve efficient passive heat dissipation, ensuring that heat inside the battery pack can be dissipated in a timely manner and preventing heat accumulation. The sealed design of housing 1 gives it an IP67 protection rating, meaning it can completely prevent dust intrusion and withstand brief immersion (typically immersion in 1 meter of water for 30 minutes) without water ingress. This allows the battery pack to easily cope with harsh conditions commonly encountered in logistics and warehousing environments, such as dust, humidity, and even floor washing.

[0028] The sodium-ion battery module 2 is the energy core of this invention, utilizing its inherent excellent low-temperature performance and high safety characteristics. Specifically, it uses 16 square or cylindrical sodium-ion batteries with a nominal voltage of 3.0V and a nominal capacity of 12.5Ah, combined in an "8 series 2 parallel" configuration. That is, first, every two batteries are connected in parallel to form a battery cell (to improve capacity and reliability), and then eight such battery cells are connected in series to finally form a battery module with a nominal voltage of 24V and a nominal capacity of 25Ah.

[0029] The sodium-ion battery cells are electrically connected via copper or aluminum busbars through laser welding or bolt fastening. This connection method offers advantages such as low resistance, high current carrying capacity, high mechanical strength, and good heat dissipation. The module also integrates a temperature sensor 2-1 (preferably an NTC thermistor, attached to the surface of key battery cells) and a voltage sensor 2-2 (connected to the positive and negative terminals of each battery cell via sampling lines) for real-time, in-situ acquisition of temperature and voltage signals from the battery cells.

[0030] Current sensor 3 (such as a Hall current sensor or shunt) is connected in series at the total negative (or total positive) output of sodium-ion battery module 2. It continuously monitors the total current flowing through the main circuit, whether it is the charging current or the discharging current, and converts it into a voltage or digital signal that the BMS can recognize. This is the basis for achieving accurate state of charge (SOC) estimation, power limiting, and overcurrent protection.

[0031] The battery management module is the control center of the system. It is usually housed on a printed circuit board (PCB) and mainly consists of two core units: the MCU main control unit 4-1 and the AFE signal processing unit 4-2.

[0032] The AFE signal processing unit 4-2 is connected to the temperature sensor 2-1, voltage sensor 2-1 and current sensor 3 to collect data such as voltage, current and temperature in real time. The MCU main control unit 4-1 performs high-precision SOC estimation, monitors the voltage, temperature and current status of individual cells in real time and performs fault diagnosis.

[0033] The core switching device in the main circuit is the charge / discharge MOSFET 5. To further enhance the system's power-on safety, a pre-charge MOSFET 7 is also connected in parallel in the main circuit. When the battery pack is first connected to the vehicle system, the BMS will first control the pre-charge MOSFET 7 to conduct, limiting the current through the pre-charge resistor to smoothly charge the bus capacitor in the vehicle controller. Once the capacitor voltage is close to the battery voltage, the main charge / discharge MOSFET 5 will be turned on and the pre-charge MOSFET 7 will be turned off, thereby preventing the power-on surge current from impacting the MOSFET and subsequent circuits.

[0034] When the MCU main control unit 4-1 detects abnormalities such as overvoltage, overcurrent, or overtemperature in the sodium battery pack, it immediately cuts off the control terminal of the charging / discharging MOSFET 5, preventing the sodium battery pack from being charged via the charger (built-in or external charger). The power terminal of the charging / discharging MOSFET 5 also cuts off the power supply to the charging / discharging connector 8, preventing the vehicle from receiving power through the connector. The MCU main control unit 4-1 interacts with the vehicle controller, instrument panel, and charger via the CAN transceiver 6. The sodium battery pack can also be connected to a host computer via the CAN transceiver 6 to set or adjust threshold parameters such as cell voltage, current, and temperature.

[0035] During normal operation of the pallet truck, the sodium-ion battery module 2 discharges to the vehicle motor and controller through the conductive charging / discharging MOSFET 5 and charging / discharging connector 8. At this time, the current sensor 3, temperature sensor 2-1, and voltage sensor 2-2 continuously operate. The battery management module processes all data in real time, estimates the remaining battery power and displays it on the instrument panel, while closely monitoring for any abnormalities. If an abnormality occurs, a protective power-off is immediately initiated.

[0036] When charging is required, an external charger connects to the battery pack via the charging / discharging connector 8, or the battery pack is charged via the built-in charger. The BMS communicates with the charger via CAN to coordinate the charging process. Throughout its lifespan, the robust IP67 enclosure 1 provides a reliable operating environment for all internal precision components.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0038] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0039] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A sodium battery pack for a pallet truck, characterized in that, The device includes a housing (1) and a sodium-ion battery module (2), a current sensor (3), a battery management module, and a switching device disposed within the housing (1); a charging / discharging connector (8) is provided on the housing (1); the sodium-ion battery module (2), the current sensor (3), and the switching device are connected in series to form a main circuit connected to the charging / discharging connector (8); the battery management module is communicatively connected to the sodium-ion battery module (2), the current sensor (3), and the switching device.

2. The sodium battery pack for pallet trucks according to claim 1, characterized in that, The switching device includes a charge / discharge MOSFET (5).

3. The sodium battery pack for pallet trucks according to claim 1 or 2, characterized in that, The main circuit is also connected in parallel with a pre-charge MOS transistor (7) controlled by the battery management module.

4. The sodium battery pack for pallet trucks according to claim 1, characterized in that, The sodium-ion battery cell module (2) integrates a temperature sensor (2-1) for monitoring its temperature and a voltage sensor (2-2) for monitoring its terminal voltage; both the temperature sensor (2-1) and the voltage sensor (2-2) are communicatively connected to the battery management module.

5. The sodium battery pack for pallet trucks according to claim 4, characterized in that, The battery management module is configured to control the switching device to turn off the main circuit when an overcurrent, overtemperature, or overvoltage fault is diagnosed based on the signals collected by the current sensor (3), temperature sensor (2-1), or voltage sensor (2-2).

6. The sodium battery pack for pallet trucks according to claim 4, characterized in that, The battery management module includes an interconnected MCU main control unit (4-1) and an AFE signal processing unit (4-2); the AFE signal processing unit (4-2) is used to connect to the current sensor (3), temperature sensor (2-1), and voltage sensor (2-2) and collect current signals, temperature signals, and voltage signals; the main control unit (4-1) is used to perform state estimation and fault diagnosis based on the current signals, temperature signals, and voltage signals and control the switching devices.

7. The sodium battery pack for pallet trucks according to claim 6, characterized in that, The MCU main control unit (4-1) is connected to a CAN transceiver (6) for communicating with external devices, including at least one of a vehicle controller, an instrument, a charger, and a host computer.

8. The sodium battery pack for pallet trucks according to claim 1, characterized in that, The sodium-ion battery module (2) consists of multiple sodium-ion batteries. The multiple sodium-ion batteries are connected by a metal busbar and form a battery module with a nominal voltage of 24V in a series and parallel combination.

9. The sodium battery pack for pallet trucks according to claim 1, characterized in that, The enclosure (1) is made of aluminum alloy with heat dissipation fins and has an IP67 protection rating.

10. A pallet transporter, characterized in that, It includes sodium battery packs for pallet trucks as described in any one of claims 1-9.

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