Split type battery system structure of vehicle

Abstract

The utility model discloses a split type battery system structure of a vehicle, a battery box is a box body structure with a side opening, a bearing slide rail extending inwards from the side opening is arranged at the bottom in the battery box, and a slide block or a roller matched with the bearing slide rail is arranged at the bottom of a battery core bag. The battery core bag is placed in the battery box in an inserting mode, the outer side face of the battery core bag is provided with a BMU communication interface and a positive and negative electrode interface, and the battery system is formed by stacking at least two battery boxes. According to the utility model, by replacing the battery core packages, the service efficiency is improved, the service life of the battery is prolonged, the cost is saved, the feasibility and safety of distributed arrangement of the battery core packages are verified, and reference significance is provided for future integrated management of multiple battery packages.

Description

Technical Field

[0001] The utility model relates to the field of new energy vehicles, and in particular to a split battery structure of a vehicle. Background Art

[0002] With the development of new energy battery technology, the energy density of batteries is getting higher and higher, the volume of batteries with the same power is getting smaller and smaller, and the charging time is getting shorter and shorter, which provides a technical basis for the split design of batteries; the modular development of new energy special vehicles also puts forward new requirements for battery design. For example, combat transport vehicles need batteries to support battery replacement functions in order to save charging time, and at the same time provide kinetic energy for emergency rescue driving for other new energy special vehicles; for example, new energy special vehicles with compact structures have limited installation space for battery packs, and need to be distributed to ensure their uniform center of mass, so that the safety performance of climbing and crossing obstacles will be more guaranteed; for example, support or marching vehicles for exercises, the use of standardized split batteries is much less difficult, and some battery packs for replacement can be stored, and the replaced batteries can also be fast-charged by the support vehicles, so the workload of support and maintenance will be much less.

[0003] The existing battery BMS, PDU and battery cells are integrated together, which is large in size. Most of them are placed on the crossbeam of the vehicle chassis and are difficult to maintain. For example, the public document with announcement number CN217956030U, publication date 2022-12-02, and patent name "Split Battery Box, Power Battery, Chassis and Vehicle" discloses that the split battery box includes a battery box body with an internal accommodating space, and a penetration channel is provided on the battery box body. The penetration channel is configured to allow the longitudinal beam of the frame to pass through the battery box body; the battery box body includes a first box body and a second box body, and the first box body and the second box body are both box-type structures with openings. The open end of the first box body is detachably connected to the open end of the second box body, and the extension direction of the penetration channel is perpendicular to the opening direction of the first box body, and passes through the open end of the first box body and / or the open end of the second box body along the opening direction of the first box body.

[0004] If the above-mentioned split battery structure encounters problems with the battery cells due to harsh working conditions, the batteries need to be disassembled and assembled, and even the entire battery pack needs to be repaired. Repacking is time-consuming and labor-intensive, and cannot meet the needs of quick replacement. If the battery pack is aged, the entire battery pack usually needs to be replaced, especially for customized battery packs, the cost and time uncertainty risks will be greater. In addition, the volume of large-capacity power batteries will also increase accordingly. If they are arranged in one place, it will affect the center of gravity of the entire vehicle. Therefore, the size of many large-capacity new energy special vehicles is limited by the volume of the battery and cannot be designed perfectly. If the battery volume is reduced blindly, the cost will be very high. If distributed battery management technology is adopted, it will be obviously much more friendly to the design size. In addition, the development of different models of vehicles has different battery capacity requirements. Vehicles with the same appearance also have different versions of endurance, and the required battery capacity and volume are also different. Since the capacity of the integrated battery pack is fixed, the corresponding development cost of developing multiple batteries will also increase.

[0005] Therefore, the disadvantages of the split battery structure are as follows:

[0006] 1. The integrated battery of new energy special vehicles is difficult to disassemble and repair, and the replacement cost is high;

[0007] 2. The battery pack of new energy special vehicles is an integrated design, which takes a long time to repair, and special areas are not yet equipped for maintenance;

[0008] 3. Large-capacity integrated batteries have high requirements for layout, which may affect the center of mass;

[0009] 4. The series models are not unified and the development cost is high;

[0010] 5. It does not support battery replacement, the charging time is long, and it cannot adapt to high-efficiency tasks. Summary of the Invention

[0011] The technical problem to be solved by the utility model is to realize a split battery system structure which is convenient for model unification, maintenance and disassembly.

[0012] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a vehicle split battery system structure, the battery box is a box structure with a side opening, the bottom of the battery box is provided with a load-bearing slide rail extending inward from the side opening, the bottom of the battery core pack is provided with a slider or roller matching the load-bearing slide rail, the battery core pack is placed in the battery box by insertion, the outer side of the battery core pack is provided with a BMU communication interface and positive and negative electrode interfaces, and the battery system is composed of at least two battery boxes stacked.

[0013] The BMU communication interface is used as a low-voltage communication wiring harness, and the positive and negative electrode interfaces are used as high-voltage wiring harnesses, adopting a standard interface form.

[0014] A load-bearing platform is provided between the upper and lower adjacent battery boxes.

[0015] A single-cell debugging interface is provided on the outer side of the battery core pack.

[0016] The battery core pack has a protruding positioning mechanism on the outer side surface, and the positioning structure fixes the battery core pack in the battery box through penetrating positioning bolts.

[0017] A handle for pulling out is provided on the outer side of the battery core pack.

[0018] Each battery cell pack is equipped with a BMU, which collects the voltage, temperature, and voltage parameters of the battery cell pack and is connected to the vehicle CAN bus through the BMU communication interface. The vehicle's BMS obtains the parameters collected by each battery cell pack BMU through the internal CAN bus.

[0019] The battery cells of the battery system are connected in parallel with each other. A BMS is provided in the PDU module of the vehicle. The PDU module is encapsulated in an independent box. The high-voltage interface and low-voltage interface of the PDU module are provided with multiple groups, which are respectively connected to the BMU communication interface and the positive and negative electrode interfaces of each battery cell through wiring harnesses.

[0020] The battery system is installed on an electric vehicle, which is a special electric vehicle.

[0021] By replacing the battery pack, this utility model improves the use efficiency, extends the battery life, saves costs, verifies the feasibility and safety of the distributed arrangement of battery packs, and has reference significance for the integrated management of multiple battery packs in the future.

[0022] The battery system structure has the functions of automatic address allocation and CAN resistor connection and disconnection, which is convenient for adding, removing and exchanging battery boxes. The standardized battery pack has strong versatility and low maintenance cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following is a brief description of the contents and marks in each figure in the utility model specification:

[0024] Figure 1 This is a schematic diagram of the vehicle split battery system structure;

[0025] Figure 2 It is the schematic diagram of the equalization circuit;

[0026] Figure 3 Schematic diagram of unbalanced bridge detection circuit

[0027] The markings in the above figure are: 1. BMU communication interface; 2. Positioning bolt; 3. Single unit debugging interface; 4. Load-bearing slide rail; 5. Positive and negative electrode interface; 6. Load-bearing platform; 7. Battery box. DETAILED DESCRIPTION

[0028] 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.

[0029] The split battery structure is generally installed on new energy special vehicles and is an important component of the modular design of the power system of new energy special vehicles. It adopts a split design that is different from the traditional integrated packaged battery, which enables the battery core pack to be replaced at any time as needed. It belongs to the technical scope of the modular development of batteries for new energy special vehicles.

[0030] Based on this, the problem that needs to be solved by the vehicle split battery system structure of the utility model is:

[0031] 1. Solve the problem of difficult maintenance and replacement of integrated batteries for new energy special vehicles;

[0032] 2. Solve the voltage equalization and management of split batteries;

[0033] 3. Verify the feasibility of distributed battery layout and reduce the difficulty of design;

[0034] 4. Extend the service life of the battery and save costs;

[0035] 5. Realize the battery replacement function to meet the needs of high efficiency and fast pace.

[0036] The key technology is the modularity, consistency and replaceability of the battery pack, which realizes the functions of replaceability and easy maintenance from the hardware perspective. In addition, the communication between BMS and multiple BMUs and the voltage equalization control are software controls that realize battery separation, ensuring the controlled stability and safety of the battery pack reassembly. Figure 1 As shown, two groups of battery packs are used as an example for explanation;

[0037] The battery box 7 is a box structure with a side opening, and is a relatively flat rectangular parallelepiped structure as a whole. The battery system is composed of at least two stacked battery boxes 7. Generally speaking, the opening sides of the battery boxes 7 are on the same side. Figure 1The battery box 7 adopts a two-layer, drawer-type design. Each battery box 7 is equipped with a battery cell pack. The size of the battery cell pack can be just embedded in the battery box 7. Each battery is equipped with an independent BMU (battery acquisition unit). The BMU circuit board is installed in the battery cell pack. As the first-level acquisition unit of the battery pack, it can collect the voltage and temperature points of each battery cell pack in real time, and report them to the battery management system (BMS) in real time through the BMS-BMUCAN bus. It has a single cell balancing function to ensure the consistency of the battery string voltage and realize the sampling and measurement of the voltage and temperature of the battery string.

[0038] The split battery wiring harness is divided into a high-voltage harness and a low-voltage communication harness. It uses standard interfaces and consistent terminal definitions to facilitate battery expansion and interchangeability. The battery packs are connected in parallel and connected to the vehicle. The entire battery system consists of the battery box 7, PDU, BMS, BMU, wiring harness, and split battery packs.

[0039] The battery pack is inserted into the battery box 7. The outer side of the battery pack is equipped with a BMU communication interface 1 and positive and negative electrode interfaces 5. The BMU communication interface 1 serves as a low-voltage communication wiring harness, while the positive and negative electrode interfaces 5 serve as high-voltage wiring harnesses, adopting standard interface formats. The vehicle's PDU module is equipped with a BMS. The BMS control board is installed in the PDU box. As the battery's second-level protection and management unit, the BMS control board obtains voltage and temperature data from the battery pack's two battery collection units (BMUs) via the internal CAN bus. If the voltages are inconsistent, it sends balancing instructions to the BMUs, which complete the cell balancing operation, providing graded warnings and comprehensive safety protection for the battery pack's charging and discharging. In addition, the battery pack also has a single-cell debugging interface 3 on its outer side, which can be used to debug the battery pack's performance.

[0040] The battery pack adopts a unified design standard. The packed battery pack is placed in the two-layer battery box 7 through the drawer load-bearing track. The battery pack is taken out and placed through the handle of the battery pack and positioned with the fixing screws; then it is connected to the high-voltage interface of the PDU through the high-voltage interface, and then the communication line is connected to the BMS interface of the PDU.

[0041] The bottom of the battery box 7 is provided with a load-bearing slide 4 extending inward from the side opening. The load-bearing slide 4 is preferably provided with two. The bottom of the battery cell pack is provided with a slider or roller matching the load-bearing slide 4. The battery cell pack is pulled out by sliding, and the handle on the outer side of the battery cell pack can make the replacement of the battery cell pack more convenient. If a load-bearing platform 6 is provided between the upper and lower adjacent battery boxes 7, the battery cell pack is of large mass, and the load-bearing platform 6 can prevent the battery box 7 from being deformed. The outer side of the battery cell pack has a protruding positioning mechanism, and the positioning mechanism is located at the bottom and has a vertical mounting hole. The positioning structure fixes the battery cell pack in the battery box 7 through a penetrating positioning bolt 2 to ensure that the installed battery cell pack will not be displaced. The battery system is installed on electric vehicles, and is particularly suitable for special electric vehicles, such as electric forklifts. The entire battery system is installed at the bottom of the forklift to facilitate the insertion of batteries.

[0042] When the task only requires one set of battery packs, the connection and disconnection of the CAN matching resistor can be achieved through the upper computer software settings. When the first set of batteries is installed, the BMU circuit located in the battery box 7, as the first-level acquisition unit of the battery pack, collects the voltage and temperature points of each battery box 7 in real time, and reports it to the battery management system (BMS) in real time through the BMS-BMUCAN bus in the external communication cable. At the same time, it has the single cell balancing function to ensure the consistency of the battery string voltage and realize the sampling and measurement of the voltage and temperature of the battery string.

[0043] When the task requires two sets of battery packs, the first thing to be solved is the communication problem. In order to facilitate the free interchange of battery boxes 7, the BMU address automatic allocation function is realized by receiving the address allocation instruction on the BMS-BMUCAN bus and combining it with the address line signal; if the BMU program needs to be updated after the battery box 7 is assembled, the upper computer can upgrade the program of all BMU microcontrollers through the internal CAN bus.

[0044] Balanced circuit design:

[0045] The internal equalization circuit is as follows Figure 2 As shown, CELL1 is connected to the positive electrode of the first string, CELL0 is connected to the negative electrode of the first string, VC1 is the balancing control pin of the front-end chip. When balancing is turned on, VC1 outputs a level relative to CELL0 to turn on the transistor. The voltage range for cell balancing is 3.3~3.65V. After the transistor is turned on, the balancing resistor is connected between CELL1 and CELL0 to perform passive (energy-consuming) balancing on the first string of batteries.

[0046] During charging, if the voltage of a single cell in a string is too high to meet the balancing conditions (voltage greater than 3.5V, voltage difference greater than 40mV), the BMS sends a balancing instruction to the BMU to perform single-string battery balancing. The purpose is to slow down the charging speed of the high-voltage battery, make the voltage of each string consistent (voltage difference less than 20mV), and finally fully charge the battery pack.

[0047] External balancing circuit design: If the voltages of two batteries are inconsistent when they are replaced, the BMS will adjust the control parameters in real time based on the detected voltage value and the external load or charging status input by the VCU, and use the principles of time-sharing control to achieve voltage balancing by controlling the switching of switch components.

[0048] The principle of insulation resistance measurement is as follows Figure 3 : The insulation resistance between the positive and negative electrodes of the battery pack and the casing is measured separately using the unbalanced bridge detection method.

[0049] The unbalanced bridge detection method uses two equal-valued resistors to ground inside the high-voltage acquisition unit through electronic switches K1 and K2 in a certain opening and closing sequence. The unbalanced bridge detection principle is shown below. Figure 3 .

[0050] The split battery system structure of the utility model is a battery system structure that can meet the modular development and rapid battery replacement of new energy special vehicles, as well as the needs of future distributed battery integration systems. It adopts a configuration in which the battery box 7 is fixed and the battery core pack is replaceable. The pull-out structure is more convenient for maintenance and replacement. The BMS and multiple BMUs are matched and the addresses are automatically allocated and the connection and disconnection of the CAN resistors are controlled by software. The battery separation and combination can be controlled by software, and the voltage equalization control ensures the safety and controllability of the battery.

[0051] 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. A vehicle split battery system structure, characterized by: The battery box is a box structure with a side opening. The bottom of the battery box is provided with a load-bearing slide rail extending inward from the side opening. The bottom of the battery core pack is provided with a slider or roller matching the load-bearing slide rail. The battery core pack is placed in the battery box by insertion. The outer side of the battery core pack is provided with a BMU communication interface and positive and negative electrode interfaces. The battery system is composed of at least two stacked battery boxes.

2. The vehicle split battery system structure according to claim 1, characterized in that: The BMU communication interface is used as a low-voltage communication wiring harness, and the positive and negative electrode interfaces are used as high-voltage wiring harnesses, adopting a standard interface form.

3. The vehicle split battery system structure according to claim 1 or 2, characterized in that: A load-bearing platform is provided between the upper and lower adjacent battery boxes.

4. The vehicle split battery system structure according to claim 3, characterized in that: A single-cell debugging interface is provided on the outer side of the battery core pack.

5. The vehicle split battery system structure according to claim 4, characterized in that: The battery core pack is provided with a protruding positioning mechanism on the outer side surface, and the positioning mechanism fixes the battery core pack in the battery box via penetrating positioning bolts.

6. The vehicle split battery system structure according to claim 5, characterized in that: A handle for pulling out is provided on the outer side of the battery core pack.

7. The vehicle split battery system structure according to claim 1 or 6, characterized in that: Each battery cell pack is equipped with a BMU, which collects the voltage, temperature, and voltage parameters of the battery cell pack and is connected to the vehicle CAN bus through the BMU communication interface. The vehicle's BMS obtains the parameters collected by each battery cell pack BMU through the internal CAN bus.

8. The vehicle split battery system structure according to claim 7, characterized in that: The battery cells of the battery system are connected in parallel with each other. A BMS is provided in the PDU module of the vehicle. The PDU module is encapsulated in an independent box. The high-voltage interface and low-voltage interface of the PDU module are provided with multiple groups, which are respectively connected to the BMU communication interface and the positive and negative electrode interfaces of each battery cell through wiring harnesses.

9. The vehicle split battery system structure according to claim 1 or 8, characterized in that: The battery system is installed on an electric vehicle, which is a special electric vehicle.

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