Battery pack for low-speed four-wheeled vehicle
By integrating CAN communication and wireless communication modules into the battery pack of low-speed four-wheeled vehicles, the problem of the inapplicability of existing solutions is solved, achieving a balance between safety and convenience, and making it suitable for the lithium battery retrofit of small low-speed new energy four-wheeled vehicles.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LUOYANG NORTHERN EK CHOR MOTORCYCLE CO LTD
- Filing Date
- 2025-03-27
- Publication Date
- 2026-07-24
AI Technical Summary
Existing solutions are not suitable for converting lead-acid batteries to lithium batteries in small, low-speed new energy four-wheeled vehicles, as they suffer from low safety or inconvenience.
A low-speed four-wheel vehicle battery pack was designed, comprising a lithium battery pack, BMS, main relay, pre-charge relay and heating relay. It adopts a CAN communication module and a wireless communication module (such as Bluetooth), and has notches on the housing to accommodate the vehicle's wiring harness and pipelines, achieving a balance between safety and convenience.
It enables safe data communication and convenient wireless monitoring between the lithium battery pack and the vehicle, adapting to the assembly needs of small, low-speed new energy four-wheeled vehicles and improving safety and convenience.
Smart Images
Figure CN224554572U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of new energy four-wheeled vehicle technology, and specifically relates to a battery pack for low-speed four-wheeled vehicles. Background Technology
[0002] New energy vehicles, primarily low-speed electric four-wheeled vehicles, are being used more and more widely.
[0003] Currently, low-speed electric four-wheelers on the market often use lead-acid maintenance-free batteries as their power source. With the continuous maturation of lithium battery technology and the continuous reduction in lithium battery prices, the comprehensive advantages of lithium batteries over traditional lead-acid batteries are gradually becoming apparent. Specifically, low-speed four-wheelers already sold on the secondary market with lead-acid batteries will gradually be replaced with lithium batteries when the batteries reach the end of their lifespan, thereby improving the vehicle's power performance and driving range. Low-speed four-wheeler manufacturers directly replace the power battery configuration from lead-acid batteries to lithium batteries when new vehicles leave the factory.
[0004] Currently, the solution for converting lead-acid batteries to lithium batteries in the secondary market is generally to use a protection board and Bluetooth communication inside the lithium battery pack. However, this solution has a low safety factor. In addition, some new energy passenger vehicles mainly use a BMS integrated machine, relays and CAN communication inside the lithium battery pack. This solution does not have the convenience of Bluetooth communication. Neither of these solutions is suitable for small, low-speed new energy four-wheeled vehicles. Utility Model Content
[0005] To address the existing technical problems, this utility model proposes a battery pack for low-speed four-wheeled vehicles, which solves the problem that existing solutions are not suitable for converting lead-acid batteries to lithium batteries in low-speed new energy four-wheeled vehicles.
[0006] The purpose of this utility model and the technical problem it solves are achieved by the following technical solution: A low-speed four-wheeled vehicle battery pack according to this utility model includes a housing with a notch at the bottom. Inside the housing are a lithium battery pack, a BMS, a main relay, a pre-charge relay, and a heating relay. The lithium battery pack includes a cell assembly and a heating film. A main fuse and the contacts of the main relay are connected in series on the wire between the cell assembly and the positive terminal of the power output. A heating fuse and the contacts of the heating relay are connected in series on the wire between the heating film and the positive terminal of the power output. The contacts of the pre-charge relay and the pre-charge resistor are connected in series and then in parallel with the contacts of the main relay. The cell assembly and the heating film are both connected in series with a current sensor and then connected to the negative terminal of the power output. The positive and negative terminals of the power output are respectively connected to the vehicle load. One end of the coil of the main relay, the pre-charge relay, and the heating relay is connected to the BMS, and the other end is grounded. The BMS is equipped with a CAN communication interface for connecting to the vehicle load and also has a wireless communication module.
[0007] Furthermore, the housing includes a front shell and a bottom shell. The front shell is equipped with an explosion-proof valve, and the bottom shell is equipped with a communication port, a main positive interface, and a main negative interface.
[0008] Furthermore, the lithium battery pack also includes a pressure strip, an aluminum busbar, an outer vibration damping and insulation cotton, and an epoxy insulation board. The cell assembly includes several cells connected in series via an aluminum busbar. The epoxy insulation board is located at the front and rear ends of the cell assembly and between two adjacent cells. The pressure strip is located at the top of the cell assembly and extends along the length of the cell assembly. The heating film and the outer vibration damping and insulation cotton are sequentially located on the left, right, and bottom sides of the cell assembly.
[0009] Furthermore, the wireless communication module is one of the following: Bluetooth communication module, WIFI module, or mobile network module.
[0010] Furthermore, the CAN communication interface includes CAN-H, CAN-L, and CAN-shielded interfaces.
[0011] Furthermore, the front shell is provided with an upper brim, and the bottom shell is provided with a lower brim corresponding to the upper brim. A sealing strip is also provided between the upper brim and the lower brim. The front shell and the bottom shell are fixed together by the upper brim, the lower brim and the bolts.
[0012] In summary, the lithium battery pack for low-speed four-wheeled vehicles proposed in this utility model has the following advantages:
[0013] The internal BMS system of the lithium battery pack has a CAN communication module, which can communicate with relevant vehicle components (power controller, on-board charger, instrument panel, T-BOX) according to the communication protocol of low-speed four-wheeled vehicles. The internal BMS system of the lithium battery pack also has a wireless communication module, which can communicate wirelessly with external electronic devices such as mobile phones. It can conveniently and quickly monitor the operating status and fault information of the lithium battery pack. This structure integrates the wireless communication function commonly used in the protection board controller of lithium battery pack and the CAN communication function commonly used in the BMS all-in-one machine + relay control. This makes the functional structure of the lithium battery pack have both the safety of relay control of high-speed new energy passenger vehicles and the convenience of Bluetooth communication of protection board control of low-speed four-wheeled vehicles.
[0014] The bottom shell structure has a notch design to ensure the smooth passage of the vehicle's wiring harness, air conditioning pipes and brake fluid pipes, and can be adapted to the vehicle for assembly.
[0015] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this utility model more obvious and understandable, preferred embodiments are given below, and detailed descriptions are provided in conjunction with the accompanying drawings. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of a battery pack for a low-speed four-wheeled vehicle according to the present invention.
[0017] Figure 2 This is a schematic diagram of the internal structure of a battery pack for a low-speed four-wheeled vehicle according to the present invention.
[0018] Figure 3 This is an internal wiring diagram of a battery pack for a low-speed four-wheeled vehicle according to this utility model.
[0019] Figure 4 This is a schematic diagram showing the connection between a low-speed four-wheeled vehicle battery pack and the vehicle load and control devices in this utility model.
[0020] The attached diagram is described below:
[0021] 1. Front shell; 2. Bottom shell; 3. Explosion-proof valve; 4. Notch; 5. Communication port; 6. Main positive interface; 7. Main negative interface; 8. Battery cell assembly; 9. Pressure strip; 10. Heating film; 11. Aluminum busbar; 12. External vibration damping and insulation cotton; 13. Epoxy insulation board; 14. BMS; 15. Heating relay; 16. Pre-charge resistor; 17. Pre-charge relay; 18. Main relay. Detailed Implementation
[0022] The technical solution of this utility model will be further described below with reference to the accompanying drawings and preferred embodiments.
[0023] Please see Figure 1 A battery pack for a low-speed four-wheeled vehicle includes a housing consisting of a front shell 1 and a bottom shell 2. The front shell 1 has an upper brim, and the bottom shell 2 has a lower brim corresponding to the upper brim. A sealing strip is also provided between the upper brim and the lower brim. The front shell 1 and the bottom shell 2 are fixed together by the upper brim, the lower brim, and bolts, which can support the rear seat. The front shell 1 is provided with an explosion-proof valve 3, and the bottom shell 2 is provided with a communication port 5, a main positive interface 6, and a main negative interface 7. The bottom of the housing has a notch 4 extending along the width of the housing. The notch 4 is located at the bottom of the bottom shell 2, which allows the outer structure of the housing to be installed in accordance with the vehicle, and can reserve the passage position for the vehicle wiring harness, brake oil pipe and air conditioning pipe.
[0024] Please see Figure 2The housing contains a lithium battery pack, a BMS (Battery Management System) 14, a main relay 18, a pre-charge relay 17, and a heating relay 15. The lithium battery pack includes a cell assembly 8, a heating film 10, a pressure strip 9, an aluminum busbar 11, an outer vibration damping and insulation cotton 12, and an epoxy insulation board 13. The cell assembly 8 includes several cells connected in series through the aluminum busbar 11. Epoxy insulation boards 13 are provided at the front and rear ends of the cell assembly 8 and between two adjacent cells. The pressure strip 9 is located at the top of the cell assembly 8 and extends along the length of the cell assembly 8. The two ends of the pressure strip 9 are fixed to the bottom shell 2 and can be used to fix the cell assembly 8. The heating film 10 and the outer vibration damping and insulation cotton 12 are provided sequentially on the left, right, and bottom sides of the cell assembly 8.
[0025] Please see Figure 3 The contacts of the main fuse and the main relay 18 are connected in series on the wire between the battery cell assembly 8 and the positive terminal of the power output. The contacts of the heating fuse and the heating relay 15 are connected in series on the wire between the heating film 10 and the positive terminal of the power output. The contacts of the precharge relay 17 and the precharge resistor 16 are connected in series and then in parallel with the contacts of the main relay 18. The battery cell assembly 8 and the heating film 10 are connected in series with the current sensor and then connected to the negative terminal of the power output. The positive terminal of the power output and the negative terminal of the power output are connected to the main positive interface 6 and the main negative interface 7, respectively, and then connected to the vehicle load. One end of the coil of the main relay 18, the precharge relay 17 and the heating relay 15 is connected to the BMS14, and the other end is grounded. The BMS14 is equipped with a CAN communication interface for connecting to the vehicle load. The CAN communication interface includes CAN-H, CAN-L and CAN-shielded interfaces. The wires at the interface on the BMS14 are integrated and connected to the communication port 5.
[0026] The BMS14 also features a wireless communication module, which can be one of Bluetooth, WIFI, or mobile network modules. The module used in this invention is a Bluetooth communication module, which can wirelessly communicate with external electronic devices such as mobile phones, and can conveniently and quickly monitor the operating status and fault information of the lithium battery pack.
[0027] Please see Figure 4The vehicle control system includes a 12V starting power supply, ignition switch, fuse, charger, and vehicle load. The 12V starting power supply is connected to the constant 12V+ and 12V- interfaces of the BMS14. A fuse is installed on the wire between the starting power supply and the constant 12V+ interface. The ignition switch is connected to the ignition 12V+ interface of the BMS14. The CAN communication interface of the BMS14 is connected to the CAN communication interface of the vehicle load, enabling data communication with relevant vehicle components (power controller, on-board charger, instrument panel, T-BOX) according to the communication protocol of low-speed four-wheeled vehicles. The charging 12V+ interface of the BMS14 is connected to the 12V+ interface of the charger. The wire extending from the 12V- interface of the charger is connected to the wire between the 12V- interface of the BMS14 and the starting power supply. The CAN communication interface on the charger is connected to the corresponding wire extending from the CAN communication interface of the BMS14.
[0028] The discharge activation steps of this utility model are as follows:
[0029] Turn the ignition switch from LOCK to ACC or ON. At this time, the voltage signal provided by the 12V starting power supply is given to the ignition 12+ terminal of the lithium battery pack. After receiving this signal, BMS14 outputs a 12V+ voltage to the coil of the precharge relay 17, and the precharge relay 17 closes. The high voltage positive terminal of the lithium battery pack cell group 8 forms a precharge circuit through the main fuse, the contact of the precharge relay 17, the precharge resistor 16, the positive power output wire, the vehicle load, and the high voltage negative terminal of the lithium battery pack cell group 8. When BMS14 detects that the voltage between the positive and negative terminals of the power output reaches 90% of the rated voltage of the lithium battery pack cell group 8, it outputs a 12V+ voltage to the coil of the main relay 18, and the main relay 18 closes. At the same time, the 12V+ voltage to the coil of the precharge relay 17 is cut off, and the contact of the precharge relay 17 opens. The discharge activation is now complete.
[0030] The charging activation steps of this utility model are as follows:
[0031] When the charger's 220V AC input terminal is connected to an AC power supply, a 12V DC voltage signal output from the charger is sent to the charging 12+ terminal interface of the lithium battery pack. Upon receiving this signal, the BMS14 outputs a 12V+ voltage to the coil of the pre-charge relay 17, causing the pre-charge relay 17 to close. The high-voltage positive terminal of the lithium battery cell pack 8 forms a pre-charge circuit through the main fuse, the contacts of the pre-charge relay 17, the pre-charge resistor 16, the positive power output wire, the vehicle load, and the high-voltage negative terminal of the lithium battery cell pack 8. When the BMS14 detects that the voltage between the positive and negative terminals of the power output reaches 90% of the rated voltage of the lithium battery cell pack 8, it outputs a 12V+ voltage to the coil of the main relay 18, causing the main relay 18 to close. Simultaneously, the 12V+ voltage to the coil of the pre-charge relay 17 is cut off, and the contacts of the pre-charge relay 17 open, thus completing the charging activation. At this time, the BMS14 and the charger exchange information via CAN communication. The charger outputs the requested charging voltage and charging current according to the request from the BMS14 to charge the lithium battery cell pack 8.
[0032] The BMS14 has a real-time monitoring function. Throughout the entire life cycle of the lithium battery pack, the BMS14 monitors the charging and discharging status, voltage, current, temperature, balancing, insulation and other information of the lithium battery cell group 8. It compares, judges and outputs control with the set alarm and protection thresholds. Once an abnormality occurs, it immediately disconnects the connection with the external load and charging circuit to ensure that no safety accidents occur.
[0033] This invention also features a low-temperature charging heating function. The BMS14 collects the temperature signal of the internal cell group 8 of the lithium battery pack in real time. When the cell temperature is ≤0℃, after receiving the charging activation signal, the BMS14 first closes the contacts of the heating relay 15 (the pre-charge relay 17 and the main relay 18 are in the open contact state at this time). The DC voltage output by the charger is applied to both ends of the heating film 10 inside the lithium battery pack. When the heating film operates until the cell temperature is ≥5℃, the contacts of the heating relay 15 open; the pre-charge relay 17 closes, and the high-voltage positive terminal of the lithium battery cell group 8 passes through the main fuse, the contacts of the pre-charge relay 17, the pre-charge resistor 16, and the dynamic... The positive terminal of the power output, the vehicle load, and the high-voltage negative terminal of the lithium battery cell pack 8 form a pre-charge circuit. When the BMS14 detects that the voltage between the positive and negative terminals of the power output reaches 90% of the rated voltage of the lithium battery cell pack 8, it outputs a 12V+ voltage to the coil of the main relay 18, causing the main relay 18 to close. At the same time, it cuts off the 12V+ voltage to the coil of the pre-charge relay 17, causing the contacts of the pre-charge relay 17 to open. At this point, the charging activation is complete. The BMS14 and the charger exchange information via CAN communication. The charger outputs the requested charging voltage and charging current according to the request from the BMS14 to charge the lithium battery cell pack 8.
[0034] The above description is merely a preferred embodiment of this utility model. Any simple modifications, equivalent changes, and alterations made by those skilled in the art to the above embodiments based on the technical essence of this utility model without departing from the scope of the technical solution of this utility model shall still fall within the scope of the technical solution of this utility model.
Claims
1. A battery pack for low-speed four-wheeled vehicles, characterized in that: Includes a housing, with a notch (4) at the bottom of the housing, and inside the housing are a lithium battery pack, a BMS (14), a main relay (18), a precharge relay (17) and a heating relay (15). The lithium battery pack includes a cell pack (8) and a heating film (10). The contacts of the main fuse and the main relay (18) are connected in series on the wire between the battery cell assembly (8) and the positive terminal of the power output. The contacts of the heating fuse and the heating relay (15) are connected in series on the wire between the heating film (10) and the positive terminal of the power output. The contacts of the precharge relay (17) and the precharge resistor (16) are connected in series and then connected in parallel with the contacts of the main relay (18). The battery cell assembly (8) and the heating film (10) are connected in series with the current sensor and then connected to the negative terminal of the power output. The positive terminal of the power output and the negative terminal of the power output are respectively connected to the vehicle load. One end of the coil of the main relay (18), the precharge relay (17), and the heating relay (15) is connected to the BMS (14), and the other end is grounded. The BMS (14) is equipped with a CAN communication interface for connecting to the vehicle load, and the BMS (14) also has a wireless communication module.
2. The battery pack for a low-speed four-wheeled vehicle according to claim 1, characterized in that: The housing includes a front shell (1) and a bottom shell (2). The front shell (1) is equipped with an explosion-proof valve (3), and the bottom shell (2) is equipped with a communication port (5), a main positive interface (6), and a main negative interface (7).
3. The battery pack for a low-speed four-wheeled vehicle according to claim 1, characterized in that: The lithium battery pack also includes a pressure strip (9), an aluminum busbar (11), an outer vibration damping and insulation cotton (12), and an epoxy insulation board (13). The cell group (8) includes several cells, and the cells are connected in series through the aluminum busbar (11). The epoxy insulation board (13) is located at the front and rear ends of the cell group (8) and between two adjacent cells. The pressure strip (9) is located at the upper end of the cell group (8) and extends along the length of the cell group (8). The heating film (10) and the outer vibration damping and insulation cotton (12) are arranged sequentially on the left, right and bottom sides of the cell group (8).
4. A battery pack for low-speed four-wheeled vehicles according to claim 1, characterized in that: The wireless communication module is one of the following: Bluetooth communication module, WIFI module, or mobile network module.
5. A battery pack for low-speed four-wheeled vehicles according to claim 1, characterized in that: CAN communication interfaces include CAN-H, CAN-L, and CAN-shielded interfaces.
6. A battery pack for low-speed four-wheeled vehicles according to claim 2, characterized in that: The face shell (1) is provided with an upper brim, and the bottom shell (2) is provided with a lower brim corresponding to the upper brim. A sealing strip is also provided between the upper brim and the lower brim. The face shell (1) and the bottom shell (2) are fixed by the upper brim, the lower brim and the bolts.