High-low voltage integrated power battery system for pure electric vehicle

Abstract

A high-low voltage integrated power battery system for a pure electric vehicle belongs to the related technical field of power batteries, and comprises a high-voltage unit, a low-voltage unit integrated with the high-voltage unit, a battery power distribution unit and a signal acquisition unit, the signal acquisition unit is in signal connection with the whole vehicle VCU; and the high-voltage unit is connected with the low-voltage unit through the battery power distribution unit and the DC / DC converter so as to form a low-voltage charging line loop for charging the low-voltage unit under the working conditions of driving, parking or charging. The low-voltage unit and the high-voltage unit are integrated, an independent arrangement structure of a low-voltage storage battery of the whole vehicle is omitted, only the signal acquisition unit is reserved in the power battery system, the integration degree of the whole vehicle system is improved, and the system cost is reduced. After the high-voltage unit and the low-voltage unit are integrated, a high-low-voltage integrated circuit is further designed, and the functions of external quick charging, quick discharging, alternating-current charging, high-voltage-to-low-voltage charging, socket-to-low-voltage charging and low-voltage external discharging can be achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of power batteries, and more specifically, to a high-low voltage integrated power battery system for pure electric vehicles. Background Art

[0002] Lead-acid batteries have a relatively high operating temperature range and can operate normally within the temperature range of -20°C to 50°C. At the same time, they also have good adaptability to humidity and high-altitude environments, and have the advantages of low cost, mature technology, and perfect recycling system. Therefore, as automotive low-voltage batteries, they are widely used in the automotive field. Especially in conditions such as start-stop, coasting, and energy recovery, the auxiliary role of lead-acid batteries is indispensable. Although lead-acid batteries have many advantages, they still have some defects, such as low energy density and high self-discharge rate, which can cause the battery to discharge easily during long-term parking of the vehicle. In addition, lead-acid batteries are relatively large in size, which will additionally occupy the interior space of the vehicle and affect the vehicle's cruising range.

[0003] Lead is one of the main raw materials of lead-acid batteries. As a heavy metal element, it poses a potential threat to the environment and human health. During the manufacturing, use, and recycling of lead-acid batteries, if not properly handled, it will cause environmental pollution.

[0004] With the progress of technology and the development of new energy vehicles, more and more automobile manufacturers are beginning to search for more efficient, environmentally friendly, and reliable battery technologies to replace traditional lead-acid batteries. Lithium-ion batteries, due to their advantages such as high energy density, long cycle life, and good environmental friendliness, can replace lead-acid batteries as automotive batteries. They can not only reduce the space occupied by the vehicle, but also provide long-term power supply for in-vehicle intelligent systems and remote communication modules due to their low self-discharge rate. Summary of the Utility Model

[0005] (1) Technical Problem

[0006] In summary, how to provide a lithium-ion battery system integrated with a low-voltage power supply and a high-voltage power supply system has become an urgent problem for those skilled in the art.

[0007] (2) Technical Solution

[0008] To achieve the above object, the utility model provides the following technical solution:

[0009] The utility model provides a high-low voltage integrated power battery system for pure electric vehicles. In the utility model, the high-low voltage integrated power battery system for pure electric vehicles includes: a high-voltage unit, a low-voltage unit integrated with the high-voltage unit, a battery power distribution unit, and a signal acquisition unit;

[0010] The signal acquisition unit is used to collect in real time the state parameters of each battery cell in the battery packs of the high-voltage unit and the low-voltage unit, and the state parameters include voltage, current, and temperature.

[0011] The signal acquisition unit is signal-connected to the vehicle VCU, and the vehicle VCU is connected to the battery distribution unit.

[0012] Among them, the high-voltage unit is connected to the low-voltage unit through the battery distribution unit to form a low-voltage charging line loop for charging the low-voltage unit under driving, parking, or charging conditions.

[0013] Preferably, in the high-low voltage integrated power battery system for pure electric vehicles provided by the present invention, the battery distribution unit includes a BDU high-voltage fuse connected to the high-voltage unit, a fast discharge interface and a fast charge interface connected to the BDU high-voltage fuse, a low-voltage charging interface, and a BDU low-voltage fuse connected to the low-voltage charging interface; it also includes a charging fuse connected to a charging interface. The high-voltage unit, the BDU high-voltage fuse, the fast discharge interface, the charging fuse, the DC / DC converter, the low-voltage charging interface, the BDU low-voltage fuse, and the low-voltage unit are sequentially connected to form the low-voltage charging line loop.

[0014] Preferably, in the high-low voltage integrated power battery system for pure electric vehicles provided by the present invention, the battery distribution unit includes a low-voltage discharge interface; it also includes a solenoid valve. The low-voltage unit, the BDU low-voltage fuse, the low-voltage discharge interface, and the solenoid valve are connected to form a low-voltage line loop.

[0015] Preferably, in the high-low voltage integrated power battery system for pure electric vehicles provided by the present invention, a socket is connected to the solenoid valve for external connection of a low-voltage power supply; and / or the solenoid valve is a normally open solenoid valve.

[0016] Preferably, in the high-low voltage integrated power battery system for pure electric vehicles provided by the present invention, it also includes a charging component and a DC / AC converter. The charging component, the DC / AC converter, the fast charge interface, the BDU high-voltage fuse, and the high-voltage unit are connected to form an AC slow charge line loop. During the charging of the high-voltage unit through the AC slow charge line loop, the high-voltage unit can also charge the low-voltage unit through the low-voltage charging line loop.

[0017] Preferably, in the high-voltage and low-voltage integrated power battery system for pure electric vehicles provided by the present utility model, the high-voltage unit leads out a high-voltage line loop through the battery power distribution unit. The high-voltage line loop is respectively connected to a drive motor, a PTC, and an air conditioner through multiple branches, and a safety fuse is provided on each branch; and / or the lifespan and endurance duration of the low-voltage unit are greater than those of the high-voltage unit.

[0018] Preferably, in the high-voltage and low-voltage integrated power battery system for pure electric vehicles provided by the present utility model, it further includes a housing assembly. The housing assembly includes a lower box body and an upper cover. The upper cover is arranged on the lower box body to form a sealed installation space with the lower box body. The high-voltage unit, the low-voltage unit, the battery power distribution unit, and the signal acquisition unit are integrated in the installation space.

[0019] Preferably, in the high-voltage and low-voltage integrated power battery system for pure electric vehicles provided by the present utility model, a sealing ring is provided between the upper cover and the lower box body; and / or an energy-absorbing collapsible beam and longitudinal and transverse beams are arranged in the lower box body.

[0020] Preferably, in the high-voltage and low-voltage integrated power battery system for pure electric vehicles provided by the present utility model, the vehicle VCU estimates the battery power, determines the thermal management strategy, and determines the high-voltage and low-voltage power balance strategy according to the state parameters collected by the signal acquisition unit.

[0021] Preferably, in the high-voltage and low-voltage integrated power battery system for pure electric vehicles provided by the present utility model, a liquid cooling plate is arranged at the bottom of the lower box body, and a bottom guard plate is covered outside the liquid cooling plate.

[0022] (III) Beneficial effects

[0023] The present utility model provides a high-voltage and low-voltage integrated power battery system for pure electric vehicles. In the present utility model, the high-voltage and low-voltage integrated power battery system for pure electric vehicles includes: a high-voltage unit, a low-voltage unit integrated with the high-voltage unit, and a battery power distribution unit; wherein, the high-voltage unit is connected to the low-voltage unit through the battery power distribution unit and a DC / DC converter to form a low-voltage charging line loop for charging the low-voltage unit under driving, parking, or charging conditions.

[0024] Through the above structural design, the present utility model integrates the low-voltage unit and the high-voltage unit, cancels the separate structure of the vehicle low-voltage battery, improves the vehicle system integration degree, and reduces the system cost. After integrating the high-voltage unit and the low-voltage unit, the present utility model also designs a high-voltage and low-voltage integrated circuit, which can realize functions such as external fast charging, fast discharging, AC charging, high-voltage charging of low-voltage, socket charging of low-voltage, and low-voltage external discharging.

[0025] In addition, in the low-voltage external discharge circuit of the present utility model, a normally-closed solenoid valve is added. When the low-voltage unit is working normally, the solenoid valve is turned on, and the low-voltage unit supplies power to the vehicle accessories. If the low-voltage unit fails, the solenoid valve is closed, and the vehicle can externally connect a 12V power supply through a socket to supply power to the vehicle accessories and turn on the high-voltage unit.

[0026] The present utility model also provides a signal acquisition unit, that is, the slave control PCB board of the original BMS is retained, which is used to collect the state parameters of each battery unit in the battery pack in real time. The state parameters include voltage, current, and temperature. The signal acquisition unit is signal-connected to the vehicle VCU. The vehicle VCU estimates the power, determines the thermal management strategy, and determines the high- and low-voltage power balance strategy according to the state parameters collected by the signal acquisition unit. The utility model integrates the BMS of the power battery system into the vehicle controller, that is, integrates the operation function of the main control PCB board of the original BMS onto the vehicle controller, and only the signal acquisition unit is retained in the power battery system, improving the integration degree of the vehicle system and reducing the system cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The schematic diagrams in the specification that form a part of this application are used to provide a further understanding of the present utility model. The schematic embodiments and descriptions thereof of the present utility model are used to explain the present utility model and do not constitute an improper limitation to the present utility model. Among them:

[0028] Figure 1 is a schematic structural diagram of a high- and low-voltage integrated power battery system for a pure electric vehicle in an embodiment of the present utility model;

[0029] Figure 2 is a schematic structural diagram of a high-voltage unit in an embodiment of the present utility model;

[0030] Figure 3 is a circuit diagram of a high- and low-voltage integrated power battery system for a pure electric vehicle in an embodiment of the present utility model;

[0031] Figure 4 is a block schematic diagram of the signal connection between the signal acquisition unit and the vehicle VCU in an embodiment of the present utility model;

[0032] Figure 5 is a circuit schematic diagram of the BDU in an embodiment of the present utility model.

[0033] In Figure 3In the figure: The high-voltage circuit loop is composed of components connected by single solid lines, and the high-voltage unit supplies power to the high-voltage electrical equipment of the electric vehicle; the low-voltage charging circuit loop is composed of components connected by double solid lines, and the high-voltage unit can supply power to the low-voltage unit, or the charging component can supply power to the low-voltage unit; the low-voltage circuit loop is composed of components connected by triple solid lines, and the low-voltage unit or an external 12V low-voltage power supply supplies power to the low-voltage electrical equipment of the electric vehicle; the AC slow-charging circuit loop is composed of components connected by quadruple solid lines, and the charging component supplies power to the high-voltage unit.

[0034] In Figure 4 the BMS only has the acquisition function, that is, the signal acquisition unit in the present invention.

[0035] In Figure 1 and Figure 2 the corresponding relationship between the component names and the reference numerals is as follows:

[0036] Upper cover 1, high-voltage unit 2, thermal conductive structural adhesive 3, sealing ring 4, lower box body 5, liquid cooling plate 6, bottom guard plate 7, signal acquisition unit 8, fast-charging plug 9, mounting point 10, fast-discharging plug 11, low-voltage plug-in 12, BDU 13, low-voltage unit 14, high-voltage and hazardous chemicals label 15, Busbar 16, single cell 17, PC end plate 18; main positive relay 19, main negative relay 20, pre-charge relay 21, fast-charging positive relay 22, shunt 23, fuse 24, fast-charging negative relay 25. Detailed implementation manners

[0037] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present invention rather than a limitation of the present invention. In fact, those skilled in the art will clearly understand that modifications and variations can be made to the present invention without departing from the scope or spirit of the present invention. For example, features shown or described as part of one embodiment can be used in another embodiment to yield yet another embodiment. Therefore, it is desirable that the present invention includes such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0038] In the description of the present utility model, the orientation or positional relationship indicated by terms such as "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model rather than requiring the present utility model to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. The terms "connected" and "coupled" used in the present utility model should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0039] Please refer to Figures 1 to 5 , in which, Figure 1 is a schematic structural diagram of a high-voltage and low-voltage integrated power battery system for a pure electric vehicle in an embodiment of the present utility model; Figure 2 is a schematic structural diagram of a high-voltage unit in an embodiment of the present utility model; Figure 3 is a circuit diagram of a high-voltage and low-voltage integrated power battery system for a pure electric vehicle in an embodiment of the present utility model; Figure 4 is a block schematic diagram of the signal connection between the signal acquisition unit and the vehicle VCU in an embodiment of the present utility model; Figure 5 is a simplified circuit diagram of the BDU in an embodiment of the present utility model.

[0040] The object of the present utility model is to solve the disadvantages of the existing vehicle low-voltage battery, such as short service life, high self-discharge rate, and large volume. To solve the above problems, the present utility model provides a high-voltage and low-voltage integrated power battery system for a pure electric vehicle. For a complete pure electric vehicle, it can generally be divided into a power battery system and a vehicle electrical system. The power battery system further includes a high-voltage unit and a low-voltage unit, and the vehicle electrical system includes high-voltage electrical equipment and low-voltage electrical equipment. The present utility model integrates the vehicle low-voltage battery (i.e., the low-voltage unit 14, which provides electrical energy of 12V voltage) with the high-voltage power battery system (i.e., the high-voltage unit 2, which provides electrical energy of hundreds of volts voltage), and at the same time integrates the BMS (battery management system) of the power battery system onto the vehicle controller, thereby improving the component integration degree of the vehicle system and reducing the component cost of the vehicle.

[0041] The description of the integration of BMS of the present utility model into the vehicle is as follows:

[0042] In the prior art, the original BMS (battery management system) hardware structure mainly includes a main control PCB board (one AFE operation chip) and several slave control PCB boards (several AFE sampling chips), which have operation and monitoring functions. In the present utility model, for the operation functions it has, such as fault diagnosis, relay control, safety protection function, SOX calculation, charge and discharge control, etc., they are integrated into the vehicle VCU (vehicle controller). For the monitoring functions it has, such as high-voltage detection, current detection, relay drive circuit, AFE single-cell sampling circuit, CAN communication circuit, etc., they are retained. That is: the operation function of the BMS main control PCB board is integrated into the vehicle VCU, and only the slave control board is retained to implement the sampling function.

[0043] The high-voltage and low-voltage integrated power battery system for pure electric vehicles provided by the present utility model has the following structure, including a lower box body, a bottom guard plate, a liquid cooling plate, a sealing ring, an upper cover, a high-voltage unit, a low-voltage unit, a BDU (battery distribution unit), a signal acquisition unit, high-voltage charge and discharge connectors (fast discharge interface and fast charge interface), a low-voltage charging connector (low-voltage charging interface), a low-voltage discharge connector (low-voltage discharge interface), a signal communication connector, etc.

[0044] The manufacturing material of the lower box body is selected as sheet metal or aluminum profile, and it is processed by stamping and bending or extrusion and other processes. It plays a role in supporting and protecting the liquid cooling plate, the high-voltage unit, and the low-voltage unit, and is connected to the vehicle through several mounting points. Energy-absorbing crushable beams are provided on both sides of the lower box body to protect the internal high-voltage unit and low-voltage unit when the power battery system is collided.

[0045] The bottom guard plate is formed by stamping and bending sheet metal, and the surface is sprayed with stone impact-resistant coating (1 mm thick PVC coating) to protect the liquid cooling plate of the power battery system. It is fixed below the lower box body through fastening bolts, and there is a sealing ring between it and the liquid cooling plate to avoid hard contact.

[0046] The liquid cooling plate is formed by aluminum profile through extrusion / stamping brazing / high-frequency welding and other processes, and different-shaped cooling channels are built in to regulate the temperature of the power battery system.

[0047] The sealing ring (set between the upper cover and the lower box body, and between the bottom guard plate and the liquid cooling plate) is a porous, low-density, compressible elastomer, with good waterproof sealing, flame retardancy, and stability, and is single-sided adhesive, pasted on the upper surface of the lower box body.

[0048] The upper cover is made of materials such as sheet metal, PCM, SMC, etc., and is made by different processes (depending on the selected materials, the processing processes are different). It is fixed on the lower box body through bolts, and forms a sealed structure with the sealing ring and the lower box body.

[0049] The high-voltage unit is composed of several lithium battery cells (single cell 17) combined in series and parallel. This unit includes several lithium battery cells (single cell 17), a PC end plate, insulating foam, a CCS (integrated busbar), and other components. The lithium battery cells are composed of a material system with high energy density, high cycle life, and high rate. Their size, shape, and capacity are determined according to the requirements of the vehicle system, and the operating temperature range is generally -40°C to 60°C. The PC end plate is composed of polycarbonate (PC) and glass fiber (GF), and has the characteristics of high strength, impact resistance, high voltage resistance, high temperature resistance, and low density. It is integrally formed by an injection molding process, which has the advantages of high production efficiency, low cost, high dimensional accuracy, and large-scale production, and can meet the production requirements of various complex shapes and structural parts. The insulating foam is made of raw materials such as silicone rubber raw rubber, fillers, vulcanization accelerators, and foaming agents. After being uniformly mixed, it is made into a porous, low-density, compressible polymer elastomer material under high pressure and high temperature, with good compressibility, good heat insulation, and high thermal stability. The CCS is composed of a blister film, an FPC (flexible printed circuit board), connectors, aluminum palladium sheets, etc. While realizing the series and parallel connection between lithium battery cells, it can also collect information such as the voltage, current, and temperature of each lithium battery cell.

[0050] The low-voltage unit is composed of several lithium battery cells, a PC end plate, a collection harness, and other components. The lithium battery cells that make up the low-voltage unit are composed of a material system with ultra-high cycle life, ultra-low self-discharge rate, and ultra-high capacity retention rate at low temperatures. Its rated voltage is 12V, and it can supply power normally at -40°C to maintain the normal operation of the vehicle controller. The collection harness is composed of multiple wire harnesses and is used to collect information such as the voltage, current, and temperature of the lithium battery cells.

[0051] The BDU (battery distribution unit) is composed of a main positive relay 19, a main negative relay 20, a pre-charge relay 21, a fast charge relay (the fast charge relay includes a fast charge positive relay 22 and a fast charge negative relay 25), a shunt 23, a fuse 24, and other components. Three electrical units, such as the main positive relay 19, the main negative relay 20, and the fuse 24, are responsible for connecting the high-voltage unit circuit to ensure that the high-voltage unit forms a complete closed circuit. The fast charge relay mainly detects abnormalities (such as overcurrent, overvoltage, short circuit, etc.) in the circuit during the fast charge process. The fast charge relay will immediately disconnect the circuit to cut off the fault source, thereby protecting the battery pack and the entire high-voltage circuit from damage. The shunt 23 uses the Hall effect principle to measure the charge and discharge current of each battery in the battery pack in real time and accurately. The battery management system can more accurately evaluate the battery state and formulate a more reasonable power distribution and charging strategy.

[0052] The signal acquisition unit is composed of components such as connectors and PCB boards. The connectors and PCB boards collect the state parameters of each battery cell in the battery pack in real time, including voltage, current, temperature, etc., and then transmit the signals to the vehicle VCU through CAN communication. The VCU performs precise power estimation, thermal management strategy determination, high and low voltage power balance control, etc.

[0053] Through the above structural design, the advantages of the present utility model at least include:

[0054] 1. The present utility model integrates the vehicle low-voltage battery and the high-voltage power battery into one, and integrates the BMS of the power battery system into the vehicle controller, eliminating the space occupied by the low-voltage battery in the vehicle. At the same time, integrating the BMS of the power battery system into the vehicle controller, only the signal acquisition unit is retained in the power battery system, which can improve the utilization rate of the vehicle's space volume, increase the integration degree of vehicle parts, and reduce the cost of vehicle parts.

[0055] 2. The present utility model designs a low-voltage unit with long endurance and long life in the power battery system, replacing the vulnerable low-voltage battery in the prior art and reducing the after-sales operation cost of the vehicle. The original vehicle low-voltage battery was arranged in the engine hood compartment of the vehicle for easy maintenance and replacement, and was in an environment above 40°C for a long time in summer, which aggravated the calendar life attenuation of the lithium battery. However, the low-voltage unit in the present utility model is in the power battery system, and the designed calendar life and cycle life of the low-voltage unit are higher than those of the high-voltage unit. Therefore, the low-voltage unit can be used as a vehicle lifetime warranty part to replace the vehicle low-voltage battery as a vulnerable part.

[0056] 3. The present utility model designs a high and low voltage integrated circuit, including a high-voltage circuit loop, a low-voltage circuit loop, a low-voltage charging circuit loop, an AC slow charging circuit loop, etc., which can realize functions such as external fast charging, fast discharging, AC charging, charging of the low-voltage unit by the high-voltage unit (when the low-voltage unit needs to be charged, the vehicle VCU controls the high-voltage unit to charge the low-voltage unit), charging of the low-voltage unit by the socket, and discharging of the low-voltage unit to the outside.

[0057] 4. In the low-voltage external discharge circuit of the present utility model, a normally closed solenoid valve is added. When the low-voltage unit is working normally, the solenoid valve is turned on, and the low-voltage unit supplies power to the vehicle accessories. If the low-voltage unit fails, the solenoid valve is closed, and the vehicle can externally connect a 12V power supply through a socket to supply power to the vehicle accessories, solving the problem that pure electric vehicles cannot be charged due to the discharge of the low-voltage battery after being parked for a long time. The normally closed solenoid valve is turned on when energized, thus realizing low-voltage power supply from the low-voltage discharge interface to the rest of the vehicle accessories. When the low-voltage unit is powered off, the low-voltage unit stops supplying power. At this time, external power supply can be used, and the normally closed solenoid valve is turned on to realize low-voltage power supply from the socket to the rest of the vehicle accessories. After the low-voltage power supply of the vehicle's low-voltage unit is cut off, power supply can still be continued through the charging socket. Specifically, the rest of the vehicle accessories include electronic components such as in-vehicle computers, in-vehicle sensors, in-vehicle cameras, and vehicle lights.

[0058] Specifically, the present utility model provides a high- and low-voltage integrated power battery system for a pure electric vehicle. As Figure 1 shown, the high- and low-voltage integrated power battery system for a pure electric vehicle provided by the present utility model includes components such as an upper cover 1, a high-voltage unit 2, a thermally conductive structural adhesive 3, a sealing ring 4, a lower box body 5, a liquid cooling plate 6, a bottom guard plate 7, a signal acquisition unit 8, a fast charging plug 9, a mounting point 10, a fast discharging plug 11, a low-voltage plug-in 12, a BDU 13, a low-voltage unit 14, a high-voltage and hazardous chemicals label 15, etc. The high-voltage unit 2 includes a Busbar 16, a single cell 17, and a PC end plate 18.

[0059] The upper cover 1 is integrally formed by PCM high-temperature molding, with a wall thickness of 1.2 mm. The material properties are as follows: tensile strength 507 Mpa, elongation at break 2.09%. 57 hexagon flange bolts are arranged along the perimeter of the upper cover 1. The upper cover 1 is arranged on the upper side of the lower box body 5 (the upper side of the lower box body 5 is an open structure). A sealing ring 4 is provided between the upper cover 1 and the lower box body 5. The upper cover 1, the sealing ring 4, and the lower box body 5 form a sealed structure.

[0060] The high-voltage unit 2 is composed of a number of lithium battery monomers (single cells 17) combined in series and parallel, including a number of Busbars (busbars) 16, a number of single cells 17, and a PC end plate 18. The specific structure is as Figure 2 shown. The Busbar 16 is formed by stamping Al1060 (1060 aluminum plate), with a wall thickness of 1.5 mm. The Busbar 16 is designed according to the arrangement of the single cells 17 and the circuit design. By designing different forms of Busbar 16, series and parallel connections between a number of single cells 17 are realized. The manufacturing material of the Busbar 16 is 1060 aluminum plate, which can minimize the use of copper bars. Since the cost of copper bars is relatively high and the cost of aluminum bars is relatively low, replacing copper bars with aluminum bars for the Busbar 16 can reduce costs.

[0061] The material system of the single cell 17 is LFP. Its peak charge-discharge power meets the requirements of 6C / 10C, and the continuous charging electric power meets the requirements of 4C / 5C. The cycle life and calendar life meet 8 years and 800,000 kilometers. The detailed parameters are shown in Table 1.

[0062] Table 1 shows the specification parameters of the high-voltage unit 2

[0063]

[0064] The PC end plate 18 is made of a mixture of polycarbonate (PC) and 30% glass fiber (GF), with a wall thickness of 3 mm. It is formed by injection molding process. It is stacked together with the insulating sheet, heat insulation pad, and single cell 17, and a pre-tightening force of 300 kgf is applied during assembly.

[0065] The thermal conductive structural adhesive 3 is formed by mixing component A - polyol and component B - isocyanate in proportion, with a thickness of 0.8 mm. The material properties are as follows: thermal conductivity > 1.2 W / m*K, shear strength > 10 Mpa, tensile strength > 10 Mpa. It is used to bond the single cell 17 and the liquid cooling plate 6. The single cell 17 is arranged inside the lower box body 5 and is connected to the inner side surface of the bottom plate of the lower box body 5 through the thermal conductive structural adhesive 3. The liquid cooling plate 6 is arranged outside the lower box body 5 and is connected to the inner side surface of the bottom plate of the lower box body 5 through the thermal conductive structural adhesive 3.

[0066] The sealing ring 4 is a porous, low-density, compressible elastomer. Before compression, its wall thickness is 5 mm and width is 25 mm. It is positioned on the upper surface of the lower box body 5 through adhesive. When the upper cover 1 is installed on the lower box body 5, pressure can be applied to the sealing ring 4, and the sealing connection with the lower box body 5 is achieved through the sealing ring 4.

[0067] The lower box body 5 is made by extrusion and welding of Al-T6061 (6061 aluminum alloy), with a wall thickness of 2.5 mm. The cross-sectional shape is in the shape of a "rice" character. The material properties are as follows: yield strength 250 Mpa, tensile strength 270 Mpa, elongation at break 16.5%. A total of 13 mounting points are set on the outer periphery of the lower box body 1, which are divided into 3 main load-bearing points and 10 auxiliary load-bearing points. Absorbing energy and collapsing beams with a width of 70 mm are set on both sides of the lower box body 1, and 10 hexagonal flange bolts are arranged at the inner bottom for fixing 10 transverse and longitudinal beams arranged inside.

[0068] The liquid cooling plate 6 is formed by stamping and brazing of Al-T3003 (3003 aluminum alloy). The wall thickness of the upper plate is 1.2 mm, and the wall thickness of the lower plate is 1.0 mm. The material properties are as follows: yield strength 121 Mpa, tensile strength 163 Mpa, elongation at break 11%. A plurality of cooling channels (in the shape of an L) are built inside the liquid cooling plate 6, and 77 FDS bolts are arranged around the liquid cooling plate 6 for fixing between the lower box body 5 and the bottom guard plate 7.

[0069] The bottom guard plate 7 is integrally formed by stamping and bending HC420 / LA (high-strength steel for cold forming), with a wall thickness of 0.8 mm. The material properties are as follows: yield strength 420 Mpa, tensile strength 470 Mpa, and elongation at break 17%. A 1-mm-thick PVC coating is sprayed on the surface of the bottom guard plate 7, and 78 rivet nuts are arranged around it and fixed on the lower box body 5. A liquid cooling plate 6 is provided on the outer bottom surface of the lower box body 5, and the bottom guard plate 7 is designed according to the liquid cooling plate 6 to be able to cover the liquid cooling plate 6 and meet the design standard for installation on the lower box body 5.

[0070] The signal acquisition unit is composed of components such as plugs and PCB boards. Among them, the functions of the PCB board are: to realize functions such as high-voltage detection, current detection, relay drive circuit, AFE single-cell sampling circuit, and CAN communication circuit; the functions of the plug are: to connect to the whole vehicle and realize signal transmission. The plug and the PCB board collect the state parameters of each battery cell in the battery pack in real time, including voltage, current, temperature, etc., and then transmit the signals to the vehicle VCU (vehicle controller) through CAN communication. The VCU performs accurate power estimation, thermal management strategy determination, high- and low-voltage power balance strategy determination, etc.

[0071] The BDU 13 is composed of components such as the main positive relay 19, the main negative relay 20, the pre-charge relay 21, the fast-charge relay, the Hall current sensor, and the fuse 24, and together with the high-voltage unit 2, the fast-charge plug 9, the fast-discharge plug 11, the low-voltage plug 12, and the low-voltage unit 14, they form a high- and low-voltage circuit, as Figure 3 shown.

[0072] The utility model has a high-voltage circuit loop and a low-voltage circuit loop. The high-voltage circuit loop (such as the single solid-line circuit shown in Figure 3 ) includes the high-voltage unit 2, the fuse 24 (including the BDU high-voltage fuse 24 and multiple other fuses 24), the fast-charge plug 9, the fast-discharge plug 11, etc., and is connected to the drive motor, fast / slow charge (charging components), PTC (positive temperature coefficient thermistor electric heater, which is a heat source in electric vehicles), the air-conditioning system, etc. at the vehicle end to realize the charging and discharging function of the power battery system for the whole vehicle. The low-voltage circuit loop includes the low-voltage unit 14, the fuse 24 (including the BDU low-voltage fuse 24), the low-voltage plug 12 (specifically referring to the low-voltage discharge interface here), the solenoid valve, vehicle accessories, etc., to realize the function of the power battery system to drive vehicle accessories.

[0073] A normally closed solenoid valve is added to the low-voltage circuit loop. When the low-voltage unit 14 is working normally, the solenoid valve is turned on, and the low-voltage unit 14 supplies power to the vehicle accessories. If the low-voltage unit 14 fails or has a power feed under-voltage, the solenoid valve closes, and the vehicle can externally connect a 12V power supply through a socket to supply power to the vehicle accessories, solving the problem that the pure electric vehicle cannot be charged due to the power feed of the low-voltage battery after being parked for a long time.

[0074] The utility model is also provided with a low-voltage charging line circuit, which is composed of a high-voltage unit 2, a BDU high-voltage fuse, a quick-release plug 11, a DC / DC converter, a low-voltage plug 12 (low-voltage charging interface), a low-voltage unit 14, a fast / slow charge (charging component), a socket, etc., and can achieve two functions: one is that in the driving / parking condition, the high-voltage unit 2 can charge the low-voltage unit 14 through the DC / DC converter to ensure that the SOC of the low-voltage unit 14 is not lower than 60%; the other is that in the charging condition, the charging socket can charge the low-voltage unit 14 through the DC / DC converter to ensure that the SOC of the low-voltage unit 14 is not lower than 60%.

[0075] The utility model also has an AC slow-charging line circuit, which includes a high-voltage unit 2, a fuse 24 (charging fuse and BDU high-voltage fuse), a quick-release plug 11, a DC / AC converter, a fast / slow charge (charging component), a socket, etc., and can charge the high-voltage unit 2 through the DC / AC converter, and the high-voltage unit 2 then charges the low-voltage unit 14 through the DC / DC converter.

[0076] The above DC / AC converter is used to convert 220V alternating current into 400V direct current, which is an existing configuration of the whole vehicle. The DC / DC converter is used to convert 400V direct current into 24V direct current, which is an existing configuration of the whole vehicle.

[0077] Compared with the high-voltage unit 2, the difference of the low-voltage unit 14 is mainly that the single-cell battery 17 is composed of a material system with ultra-high cycle life, ultra-low self-discharge rate, and ultra-high low-temperature capacity retention rate (see the cycle life & calendar life in the table), and does not require high-rate charge and discharge. The working window is 60%-98% SOC, and its cycle life meets the service life of ten years and the calendar life meets the service life of fifteen years. The detailed parameters are shown in Table 2.

[0078] Table 2 is the specification parameters of the low-voltage unit 14

[0079]

[0080] The differences between the high-voltage unit and the low-voltage unit in terms of structure and materials are as follows:

[0081] 1. Compared with the low-voltage unit, the high-voltage unit has a larger over-current capacity and a larger connection area at the connection between the cell terminal post and the cell package;

[0082] 2. In terms of the positive and negative electrode materials, the high-voltage unit selects a negative electrode material with higher rate performance, and the low-voltage unit selects a positive electrode material with higher tap density;

[0083] 3. In terms of the electrolyte, the high-voltage unit selects an electrolyte with better kinetic performance, and the low-voltage unit selects an electrolyte with better storage performance.

[0084] As can be seen from the above technical content, the innovation of the present utility model lies in:

[0085] 1. The present utility model integrates the vehicle low-voltage battery (low-voltage unit) and the high-voltage power battery (high-voltage unit) into one, cancels the structure of separately arranging the vehicle low-voltage battery in the prior art, improves the integration degree of the vehicle system, and reduces the system cost.

[0086] 2. The present utility model integrates the BMS of the power battery system into the vehicle controller, and only the signal acquisition unit is retained in the power battery system, which improves the integration degree of the vehicle system and reduces the system cost.

[0087] 3. The present utility model designs a low-voltage battery (low-voltage unit) with long endurance and long life, replaces the original vehicle low-voltage battery as a vulnerable part, and reduces the after-sales operation cost of the vehicle.

[0088] 4. The present utility model designs a high-low voltage integrated circuit, which can realize functions such as external fast charging, fast discharging, AC charging, high-voltage to low-voltage charging, socket to low-voltage charging, and low-voltage external discharging.

[0089] 5. In the low-voltage external discharging circuit of the present utility model, a normally open solenoid valve is added. When the low-voltage unit works normally, the solenoid valve is turned on, and the low-voltage unit supplies power to the vehicle accessories; if the low-voltage unit fails, the solenoid valve is closed, and the vehicle can externally connect a 12V power supply through the socket to supply power to the vehicle accessories and connect the high-voltage unit.

[0090] The above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. For those skilled in the art, various changes and modifications can be made to the present utility model. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A high and low voltage integrated power battery system for a pure electric vehicle, characterized in that including: it includes a vehicle VCU, a high voltage unit, a low voltage unit integrated with the high voltage unit, a battery distribution unit, and a signal acquisition unit; the signal acquisition unit is used to collect in real time the state parameters of each battery unit in the battery packs of the high voltage unit and the low voltage unit, and the state parameters include voltage, current, and temperature; the signal acquisition unit is signal-connected to the vehicle VCU, and the vehicle VCU is connected to the battery distribution unit; wherein, the high voltage unit is connected to the low voltage unit through the battery distribution unit to form a low voltage charging line loop for charging the low voltage unit under driving, parking or charging conditions.

2. The high and low voltage integrated power battery system for a pure electric vehicle according to claim 1, characterized in that the battery distribution unit includes a BDU high voltage fuse connected to the high voltage unit, a fast discharge interface and a fast charge interface connected to the BDU high voltage fuse, a low voltage charging interface, and a BDU low voltage fuse connected to the low voltage charging interface; it further includes a DC / DC converter and a charging fuse connected to a charging interface; the high voltage unit, the BDU high voltage fuse, the fast discharge interface, the charging fuse, the DC / DC converter, the low voltage charging interface, the BDU low voltage fuse, and the low voltage unit are connected in sequence to form the low voltage charging line loop.

3. The high and low voltage integrated power battery system for a pure electric vehicle according to claim 2, characterized in that the battery distribution unit includes a low voltage discharge interface; it further includes a solenoid valve; the low voltage unit, the BDU low voltage fuse, the low voltage discharge interface, and the solenoid valve are connected to form a low voltage line loop.

4. The high and low voltage integrated power battery system for a pure electric vehicle according to claim 3, characterized in that a socket is connected to the solenoid valve for externally connecting a low voltage power supply; and / or the solenoid valve is a normally open solenoid valve.

5. The high and low voltage integrated power battery system for a pure electric vehicle according to claim 2, characterized in that it further includes a charging component and a DC / AC converter; the charging component, the DC / AC converter, the fast charge interface, the BDU high voltage fuse, and the high voltage unit are connected to form an AC slow charge line loop; during the charging of the high voltage unit through the AC slow charge line loop, the high voltage unit can also charge the low voltage unit through the low voltage charging line loop.

6. The high and low voltage integrated power battery system for a pure electric vehicle according to claim 1, characterized in that the high voltage unit leads out a high voltage line loop through the battery distribution unit, and the high voltage line loop is respectively connected to a drive motor, a PTC, and an air conditioner through multiple branches, and a safety fuse is provided on each branch; and / or the lifespan and endurance duration of the low voltage unit are greater than those of the high voltage unit.

7. The high and low voltage integrated power battery system for a pure electric vehicle according to claim 1, characterized in that It further includes a housing assembly, and the housing assembly includes a lower box body and an upper cover. The upper cover is disposed on the lower box body to form a sealed installation space with the lower box body, and the high-voltage unit, the low-voltage unit, the battery power distribution unit, and the signal acquisition unit are integrated in the installation space.

8. The high- and low-voltage integrated power battery system for a pure electric vehicle according to claim 7, wherein a sealing ring is provided between the upper cover and the lower box body; and / or an energy-absorbing collapsible beam and transverse and longitudinal beams are provided in the lower box body.

9. The high- and low-voltage integrated power battery system for a pure electric vehicle according to claim 7, wherein the vehicle VCU estimates the battery power, determines the thermal management strategy, and determines the high- and low-voltage power balance strategy according to the state parameters collected by the signal acquisition unit.

10. The high- and low-voltage integrated power battery system for a pure electric vehicle according to claim 9, wherein a liquid cooling plate is provided at the bottom of the lower box body, and a bottom guard plate is covered outside the liquid cooling plate.

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