Power battery pack and electric vehicle

Abstract

The application discloses a power battery pack and an electric vehicle. The power battery pack comprises a battery box, a battery module and a battery pack circuit breaking unit. The battery pack circuit breaking unit comprises a unit box, the unit box comprises a support frame, a first cavity and a second cavity distributed along a first direction in the support frame, the bottom wall of the first cavity is recessed along a second direction perpendicular to the first direction relative to the support frame, the bottom wall of the second cavity is recessed along a direction opposite to the second direction relative to the support frame, the projection of the first cavity penetrates the projection of the bottom wall of the second cavity on a plane parallel to the second direction; a charging relay, a discharging relay and a main fuse are installed in the first cavity and on the bottom wall of the first cavity; a DC / DC converter and a pre-charging resistor are installed in the second cavity and on the bottom wall of the second cavity; a pre-charging relay and a shunt are installed on the surface of the bottom wall of the second cavity away from the second cavity.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, and in particular to a power battery pack and an electric vehicle. Background Technology

[0002] With the rapid development of the new energy vehicle industry, power battery pack systems are continuously iterating towards higher integration, lighter weight, and higher safety. A power battery pack includes components such as battery modules and battery disconnect units (BDUs). The battery modules provide power, while the BDUs perform critical functions such as high-voltage circuit on / off control, overload protection, and current detection. The rationality of the structural design of each component directly affects the overall performance, space utilization, and safety of the battery pack.

[0003] Currently, battery drain circuit breakers (BDUs) are typically integrated inside the battery housing, sharing limited space with the battery module. Existing technologies generally house electrical components such as charging relays, discharging relays, main fuses, pre-charge relays, pre-charge resistors, DC / DC converters, and shunts, all concentrated within a single unit housing. In traditional BDU layout designs, various electrical components are usually simply partitioned according to electrical function or voltage level, with all components laid flat within the same planar cavity. However, the aforementioned existing BDU layout structure has the following technical drawbacks: high-voltage power devices such as charging relays, discharging relays, and main fuses are mixed with heat-generating devices such as DC / DC converters and pre-charge resistors within the same cavity, leading to heat conduction and superposition, resulting in excessively high local temperatures and affecting the long-term reliability and lifespan of each electrical component. Furthermore, the disorderly arrangement of components of different heights and with different heat generation characteristics on the same plane wastes space, increases the risk of electromagnetic interference, and complicates assembly. Summary of the Invention

[0004] The purpose of this invention is to provide a power battery pack that can optimize heat dissipation performance and space utilization, so as to solve the problems of unreasonable BDU layout structure, poor heat dissipation performance and low space utilization in the prior art. It also provides an electric vehicle that uses the power battery pack.

[0005] The first aspect of this invention discloses a power battery pack, including a battery housing, a battery module, and a battery pack circuit breaker unit. The battery module includes multiple battery cells and is disposed within the battery housing. The battery pack circuit breaker unit is connected to the battery module and is disposed within the battery housing. The battery pack circuit breaker unit includes a unit housing, a charging relay, a discharging relay, a main fuse, a DC / DC converter, a pre-charge resistor, a pre-charge relay, and a shunt. The unit housing includes a support frame, a first cavity and a second cavity disposed within the support frame and distributed along a first direction, with the bottom wall of the first cavity relative to the support frame. The first cavity is recessed along a second direction perpendicular to the first direction, and the bottom wall of the second cavity is recessed relative to the support frame in a direction opposite to the second direction. On a plane parallel to the second direction, the projection of the first cavity passes through the projection of the bottom wall of the second cavity. The charging relay, the discharging relay, and the main fuse are installed in the first cavity and on the bottom wall of the first cavity. The DC / DC converter and the pre-charge resistor are disposed in the second cavity and installed on the bottom wall of the second cavity. The pre-charge relay and the shunt are installed on the surface of the bottom wall of the second cavity away from the second cavity.

[0006] In some embodiments, the battery pack circuit breaker unit further includes a power diode and a switching relay, wherein the power diode and the switching relay are mounted in the first cavity and on the bottom wall of the first cavity.

[0007] In some embodiments, the battery pack circuit breaker unit further includes a charging heating relay and a discharging heating relay, which are mounted on the bottom wall of the second cavity away from the second cavity.

[0008] In some embodiments, the battery pack circuit breaker unit further includes a first cover fixedly connected to the unit housing and surrounding the charging relay, the discharging relay and the main fuse, and a second cover surrounding the precharge relay.

[0009] In some embodiments, a BMS mainboard located inside the battery housing is connected to the battery pack circuit breaker unit and fixed to the first housing cover and the second housing cover.

[0010] In some embodiments, the first box cover and the second box cover are provided with multiple hollow structures.

[0011] In some embodiments, the unit housing is formed by one-piece injection molding.

[0012] In some embodiments, the opposite direction of the second direction is the height direction of the battery housing, the battery housing includes two supports arranged at intervals, the battery pack circuit breaker unit is supported on the two supports and a heat dissipation channel is formed between it and the bottom wall of the battery housing.

[0013] In some embodiments, the unit housing is provided with a first mounting slot, a second mounting slot, and a third mounting slot, the shapes of which respectively match the charging relay, the discharging relay, and the pre-charge relay. The charging relay, the discharging relay, and the pre-charge relay are respectively installed in the first mounting slot, the second mounting slot, and the third mounting slot.

[0014] A second aspect of the present invention discloses an electric vehicle comprising any of the aforementioned power battery packs.

[0015] Based on the power battery pack of the present invention, by setting a first cavity and a second cavity distributed along a first direction in the unit box, and making the bottom wall of the first cavity and the bottom wall of the second cavity concave in opposite directions along a second direction, and the bottom wall of the second cavity located in the middle of the first cavity along the second direction, a unit box layout with left and right partitions and upper and lower layers is formed. At the same time, the relatively thick charging relay, discharging relay and main fuse are placed in the first cavity, while the relatively flat DC / DC converter and pre-charge resistor with relatively more heat generation are placed in the second cavity. The relatively flat pre-charge relay and shunt are placed on the other side of the bottom wall of the second cavity, so that the structural arrangement of the battery pack circuit breaker unit can be more reasonable, the height dimension of the battery pack circuit breaker unit along the second direction is more compact, the space utilization rate is high, and the overall volume of the battery pack circuit breaker unit is significantly reduced. At the same time, the device achieves spatial separation between major heat sources such as DC / DC converters and pre-charge resistors and relatively low heat-generating components such as charging relays, discharging relays, shunts, and pre-charge relays. This effectively reduces the mutual conduction and accumulation of heat, lowers the operating temperature of the components, slows down the high-temperature aging process of electrical components, and ensures the reliability of the components.

[0016] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of a portion of the structure of the battery pack circuit breaker unit of the power battery pack according to an embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of a portion of the battery pack circuit breaker unit in the illustrated embodiment from another angle. Figure 3 This is a schematic diagram of a portion of the structure of a power battery pack according to another embodiment of the present invention; Figure 4 This is a schematic diagram of a portion of the structure of a power battery pack according to another embodiment of the present invention; Figure 5 for Figure 4 A schematic diagram of a portion of the power battery pack in the illustrated embodiment from another angle; Figure 6 This is a schematic diagram of the structure of the unit housing of the battery pack circuit breaker unit according to another embodiment of the present invention; Figure 7 This is a schematic diagram of a portion of the structure of a battery pack circuit breaker unit according to another embodiment of the present invention; Figure 8 for Figure 7 A schematic diagram of a portion of the battery pack circuit breaker unit from another angle; Figure 9 This is a schematic diagram of a portion of the structure of a power battery pack according to another embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0020] In the description of this invention, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0023] like Figures 1 to 9 As shown, the power battery pack 100 in this embodiment includes a battery housing 110, a battery module 120 and a battery pack circuit breaker unit 130. The battery module 120 includes multiple battery cells and is disposed inside the battery housing 110.

[0024] The battery pack circuit breaker unit 130 is connected to the battery module 120 and is located inside the battery housing 110. The battery pack circuit breaker unit 130 is used to control the on / off state of the power supply to the battery module 120 and to protect the safety of the battery module 120. In the prior art, the battery pack circuit breaker unit 130 is typically integrated inside the power battery pack (PACK), located between the total positive / negative output terminals of the battery module and the high-voltage load of the vehicle, serving as the "main gate" for the power output of the entire power battery pack.

[0025] The battery pack circuit breaker unit 130 includes a unit housing 5, a charging relay 11, a discharging relay 12, a main fuse 15, a DC / DC converter 32, a pre-charge resistor 31, a pre-charge relay 21, and a shunt 24.

[0026] The charging relay 11 is used to close during the charging of the power battery pack, allowing external electrical energy to be connected to the battery module; the charging relay is also used to open when charging is complete. The charging relay is located in the positive charging circuit of the power battery pack and acts as a switch for the positive charging circuit. In the embodiment shown in the figure, the input terminal of the charging relay is connected to the output terminal of the main fuse, and the output terminal of the charging relay is connected to both the input terminal of the charging heating relay and the main positive charging terminal.

[0027] The discharge relay 12 is located in the main positive circuit for external discharge of the battery pack. It is a switch for the power battery pack to output power energy to the outside, used to output the electrical energy of the battery module. In the embodiment shown in the figure, the input terminal of the discharge relay is connected to the output terminal of the main fuse and the input terminal of the pre-charge relay, respectively. The output terminal of the discharge relay is connected to the anode of the power diode and the other end (i.e., the end of the pre-charge resistor).

[0028] The main fuse 15 is used to blow when the current flowing through the main circuit of the battery module exceeds a safety threshold, thereby forcibly disconnecting the output circuit of the power battery pack. The main fuse 15 is connected in series in the main positive circuit of the power battery pack. In the embodiment shown in the figure, the input terminal of the main fuse is connected to the main positive output terminal of the battery module, and the output terminal of the main fuse is connected to the input terminal of the charging relay and the input terminal of the discharging relay, respectively.

[0029] The DC / DC converter 32 is a high-voltage to low-voltage power conversion component inside the power battery pack. The DC / DC converter is used to regulate the high-voltage DC power (300V~800V) output from the power battery pack and convert it to 12V or 24V low-voltage DC power. After the power battery pack is powered on at high voltage, the DC / DC converter continuously supplies power to the vehicle's 12V battery, while simultaneously powering low-voltage components such as the power battery pack's BMS and temperature acquisition board, ensuring continuous operation of the low-voltage system during high-voltage power-on. In the embodiment shown in the figure, the high-voltage input terminal of the DC / DC converter is connected to the high-voltage DC bus of the power battery pack (i.e., the high-voltage power output from the battery module), and the low-voltage output terminal of the DC / DC converter is connected to the low-voltage power supply network, providing continuous 12V or 24V low-voltage DC power to the BMS main board, intermediate relay coils, temperature acquisition board, internal indicator lights, communication modules, and the vehicle's 12V battery.

[0030] The pre-charge resistor 31 is used to limit the current in the pre-charge circuit during the pre-charge stage by relying on its own resistance value, smoothly charging the external high-voltage capacitor at the back end and suppressing the closing inrush current. The pre-charge resistor is located in the pre-charge branch of the battery pack and is connected in series with the pre-charge relay to form the pre-charge circuit. After the pre-charge is completed, the pre-charge branch is disconnected, and the pre-charge resistor does not participate in the normal charging and discharging circuit of the power battery pack. The pre-charge resistor consumes the inrush electrical energy as heat energy, protecting the busbars, relays, and cells inside the power battery pack from damage by instantaneous large current. In the embodiment shown in the figure, one end of the pre-charge resistor is connected to the output terminal of the pre-charge relay, and the other end of the pre-charge resistor is connected to the output terminal of the discharge relay (and also connected to the input terminal of the discharge heating relay and the cathode of the power diode). The pre-charge resistor and the pre-charge relay are connected in series and then connected in parallel with the discharge relay.

[0031] The pre-charge relay 21 is used to close before the power battery pack is ready to discharge externally and before the discharge relay is closed, allowing the current to be limited by the pre-charge resistor and slowly pre-charge the capacitor inside the external motor controller. Once the difference between the total voltage of the power battery pack and the downstream load voltage has narrowed to a safe range, the pre-charge relay is disconnected, and then the discharge relay closes to connect the main discharge circuit. Through the above timing control, the pre-charge relay weakens the large arc at the moment the main relay closes, prevents the discharge relay contacts from burning and sticking, and extends the service life of the discharge relay. The pre-charge relay 21 is located in the pre-charge branch of the power battery pack, and is connected in series with the pre-charge resistor to form a pre-charge circuit.

[0032] Shunt 24 is the total current sampling element inside the power battery pack. Relying on its internal precision milliohm-level resistor, shunt 24 calculates the real-time total charging and discharging current of the entire power battery pack by collecting the voltage drop flowing through the total negative circuit, and sends the analog signal to the BMS mainboard. The current data collected by the shunt is used for power battery pack state of charge (SOC) calculation, overcurrent protection determination, and charging / discharging power limiting. Compared to Hall effect sensors, the shunt has a more compact structure, making it suitable for the limited power distribution space inside the power battery pack.

[0033] The unit housing 5 includes a support frame 50, a first cavity 51 and a second cavity 52 disposed within the support frame 50 along a first direction. The bottom wall of the first cavity 51 is recessed relative to the support frame 50 along a second direction perpendicular to the first direction, and the bottom wall of the second cavity 52 is recessed relative to the support frame 50 in a direction opposite to the second direction. Figure 3 and Figure 4 The direction m shown indicates the first direction, and the direction k indicates the second direction. In... Figure 4 In the illustrated embodiment, when the power battery pack is placed horizontally, the first direction is horizontal, and the second direction is vertically upward. For example... Figure 1 and Figure 2 , Figures 6 to 8As shown, the bottom wall of the first cavity 51, i.e., the first bottom wall 511, is recessed relative to the support frame 50 along a second direction perpendicular to the first direction. The bottom wall of the second cavity 52, i.e., the second bottom wall 521, is recessed relative to the support frame 50 in a direction opposite to the second direction. That is, the recessed directions of the first cavity and the second cavity relative to the support frame 50 are opposite. On a plane parallel to the second direction, the projection of the first cavity 51 passes through the projection of the bottom wall of the second cavity 52. ​​That is, on this plane, the two ends of the projection of the first cavity 51 along the second direction are located on both sides of the bottom wall of the second cavity 52, and in the second direction, the bottom wall of the second cavity 52 is located in the middle of the first cavity 51.

[0034] In the embodiment shown in the figure, the charging relay 11, the discharging relay 12, and the main fuse 15 are installed inside the first cavity 51 and on the bottom wall of the first cavity 51; the DC / DC converter 32 and the pre-charge resistor 31 are located inside the second cavity 52 and are installed on the bottom wall of the second cavity 52; the pre-charge relay 21 and the shunt 24 are installed on the surface of the bottom wall of the second cavity 52 away from the second cavity 52. ​​The charging relay 11, the discharging relay 12, and the main fuse 15 are relatively thick, that is, their height along the second direction is relatively high when installed, while the DC / DC converter 32, the pre-charge resistor 31, the pre-charge relay 21, and the shunt 24 are relatively flat, that is, their height along the second direction is relatively small when installed. The DC / DC converter 32, pre-charge resistor 31, pre-charge relay 21, and shunt 24 are respectively mounted on both sides of the second bottom wall 521. Their overall height along the second direction matches the height along the second direction of the charging relay 11, discharging relay 12, and main fuse 15 mounted in the first cavity, resulting in a more rational layout. Simultaneously, the second cavity is relatively isolated from the first cavity, allowing the second cavity to relatively independently concentrate the heat-generating DC / DC converter 32 and pre-charge resistor 31 together, minimizing the thermal impact on other components.

[0035] In this embodiment, the power battery pack 100 has a unit housing 5 with a first cavity 51 and a second cavity 52 distributed along a first direction. The bottom walls of the first cavity 51 and the second cavity 52 are recessed in opposite directions along a second direction, and the bottom wall of the second cavity 52 is located in the middle of the first cavity 51 along the second direction, forming a unit housing 5 layout with left and right partitions and upper and lower layers. At the same time, the relatively thick charging relay 11, discharging relay 12 and main fuse 15 are placed in the first cavity 51, while the relatively flat DC / DC converter 32 and pre-charge resistor 31 with relatively high heat generation are placed in the second cavity 52. ​​The relatively flat pre-charge relay 21 and shunt 24 are placed on the other side of the bottom wall of the second cavity 52. ​​This makes the structural arrangement of the battery pack circuit breaker unit 130 more reasonable, the height dimension of the battery pack circuit breaker unit 130 along the second direction more compact, the space utilization rate is high, and the overall volume of the battery pack circuit breaker unit 130 is significantly reduced. At the same time, it achieves physical isolation between the main heat sources such as the DC / DC converter 32 and the pre-charge resistor 31 and the relatively low heat-generating components such as the charging relay 11, the discharging relay 12, the shunt 24 and the pre-charge relay 21, thereby reducing the mutual conduction and accumulation of heat, effectively lowering the operating temperature of the components, delaying the high-temperature aging process of the electrical components, and ensuring the reliability of the components.

[0036] In some embodiments, the battery pack circuit breaker unit 130 further includes a power diode 14 and a switching relay 13, which are mounted inside the first cavity 51 and on the bottom wall of the first cavity 51. Both the power diode 14 and the switching relay 13 are high-voltage power devices, with large volumes and high mounting heights, belonging to the same category of large-volume high-voltage devices as the charging relay 11 and the discharging relay 12. Arranging them together inside the first cavity 51 allows for a concentrated arrangement of relatively thick components within the first cavity 51. The power diode 14 is connected between the output terminal of the discharging relay 12 and the input terminal of the switching relay 13, with its positive terminal connected to the output terminal of the discharging relay 12 and its negative terminal connected to the input terminal of the switching relay 13. The power diode 14 utilizes its unidirectional conduction characteristic to limit the current flow only from the discharging relay 12 side to the switching relay 13 side, preventing high-voltage current from flowing back and damaging the relay contacts and sampling chip. The input terminal of the switching relay 13 is connected to the negative terminal of the power diode 14, and the output terminal of the switching relay 13 is connected to the discharge heating relay 23. The switching relay 13 is used to switch between the fast charging input circuit and the slow charging input circuit according to the strobe signal output by the BMS motherboard, or to perform time-division switching between multiple heating circuits to achieve mutual exclusion conduction of multiple branches.

[0037] By arranging the power diode 14 and switching relay 13 together with the charging relay 11, discharging relay 12 and main fuse 15 in the first cavity 51, the large-volume high-voltage power devices are concentrated in the same area, making the height dimension of the battery pack circuit breaker unit 130 in the second direction more compact, with high space utilization, and significantly reducing the overall volume of the battery pack circuit breaker unit 130.

[0038] In some embodiments, the battery pack circuit breaker unit 130 further includes a charging heating relay 22 and a discharging heating relay 23, which are mounted on the surface of the bottom wall of the second cavity 52 away from the second cavity 52, i.e., on the back side of the bottom wall of the second cavity 52. ​​The charging heating relay 22 and the discharging heating relay 23 are used to control the on / off state of the power supply circuit for the heating film / heating sheet inside the power battery pack. The input terminal of the charging heating relay 22 is connected to the output terminal of the charging relay 11, and the output terminal of the charging heating relay 22 is connected to the input terminal of the heating fuse 25. The charging heating relay 22 is used to close in charging mode when the cell temperature is below a preset low temperature threshold to connect the heating power supply circuit, and to open when the cell temperature rises to a preset temperature threshold to stop heating.

[0039] The input terminal of the discharge heating relay 23 is connected to the other end of the pre-charge resistor 31, and the output terminal of the discharge heating relay 23 is connected to the input terminal of the charging heating relay 22 and the input terminal of the heating fuse 25. The discharge heating relay 23 is used to close in discharge driving mode when the cell temperature is below a preset low temperature threshold to draw power from the power battery pack itself to drive the internal heating components to heat up, and to open when the cell temperature rises to the preset temperature threshold. The heating fuse is connected in series in the power battery pack heating power supply line and is a dedicated one-time protection device for the heating circuit. The input terminal of the heating fuse is connected to the output terminal of the charging heating relay and the output terminal of the discharge heating relay, and the output terminal of the heating fuse 25 is connected to the heating positive terminal (i.e., the power supply positive terminal of the heating film / heating sheet inside the power battery pack). The heating fuse is used to melt itself when the heating circuit inside the battery pack is worn and short-circuited, the heating element breaks down and short-circuited, or the circuit current surges abnormally and the current flowing through it exceeds its preset breaking threshold, so as to permanently cut off the heating power supply circuit and prevent the wiring harness inside the power battery pack from overheating and catching fire and the battery cells from being baked by abnormal high temperature. It serves as the hardware fire protection for the heating branch of the thermal management of the power battery pack.

[0040] Both the charging heating relay 22 and the discharging heating relay 23 are flat devices, belonging to the same type of flat precision devices as the pre-charge relay 21 and the shunt 24. They are mounted together on the back side of the bottom wall of the second cavity 52, ensuring all flat devices are concentrated on the same side of the bottom wall, resulting in a neat and orderly layout. Simultaneously, because the charging heating relay 22 and the discharging heating relay 23 are located on the back side of the bottom wall of the second cavity 52 (i.e., the side opposite to the DC / DC converter 32 and the pre-charge resistor 31), the heat generated by the heating relays is isolated from the heat generated by the DC / DC converter 32 and the pre-charge resistor 31 through the bottom wall of the second cavity 52, preventing heat accumulation. Furthermore, the concentrated arrangement of all flat devices on the back side of the bottom wall of the second cavity 52 facilitates the unified and orderly routing of the low-voltage control wiring harness, avoiding wiring crossing the cavity.

[0041] In some embodiments, the battery pack circuit breaker unit 130 further includes a first cover 531 fixedly connected to the unit housing 5 and surrounding the charging relay 11, the discharging relay 12, and the main fuse 15, and a second cover 532 surrounding the pre-charge relay 21. The first cover 531 covers the top of the first cavity 51, is fixedly connected to the unit housing 5, and together with the first cavity, surrounds the high-voltage power devices such as the charging relay 11, the discharging relay 12, and the main fuse 15. The second cover 532 covers a portion of the back side of the bottom wall of the second cavity 52, is disposed around the pre-charge relay 21, is fixedly connected to the unit housing 5, and together with the bottom wall of the second cavity 52, surrounds the pre-charge relay 21, the heating fuse 25, the charging heating relay 22, and the discharging heating relay 23, etc.

[0042] The first cover 531 and the second cover 532 are used to isolate the components from the external environment, preventing them from being subjected to external mechanical impacts or foreign object intrusion. They also help to prevent accidental circuit contact. The first cover 531 and the second cover 532 are set around the components in different areas, rather than a single large cover covering the entire area. This allows for the individual opening of a cover as needed during later maintenance to inspect the components in a specific area without having to disassemble the entire cover, thus improving maintenance convenience.

[0043] In some embodiments, a BMS mainboard 140, which is signal-connected to the battery pack circuit breaker unit 130 and located within the battery housing 110, is also included. The BMS mainboard 140 is fixed to the first cover 531 and the second cover 532. The BMS mainboard 140 (BATTERYMANAGEMENT SYSTEM) is the core control unit of the entire electrical system inside the power battery pack. In the embodiment shown in the figure, the BMS mainboard 140 is electrically connected to various electrical components inside the battery pack circuit breaker unit 130 via plug-in terminals. In this embodiment, the BMS mainboard 140 is fixed to the first cover 531 and the second cover 532, so that the BMS mainboard 140 is located above the unit housing 5 and physically isolated from the high-voltage cavity inside the battery pack circuit breaker unit 130. When the BMS mainboard 140 malfunctions and requires repair or replacement, it can be removed simply by unplugging the connectors and loosening the mounting bolts. This eliminates the need to open the first cover 531 or the second cover 532, and avoids touching any internal high-voltage components, thus completely mitigating the risk of electric shock during maintenance. Furthermore, the BMS mainboard 140 is fixed to the cover, making full use of the space above the battery pack circuit breaker unit 130. This eliminates the need for a separate installation location for the BMS mainboard 140 within the battery housing 110, further improving the internal space utilization of the battery pack.

[0044] In some embodiments, the first cover 531 and the second cover 532 are provided with multiple perforated structures. The perforated structures are through holes or grid-like openings formed on the first cover 531 and the second cover 532. The positions of the perforated structures correspond to the positions of various components; for example, the perforated structure on the first cover 531 may be directly opposite the terminal positions of the charging relay 11, the discharging relay 12, or the main fuse 15, and the perforated structure on the second cover 532 may be directly opposite the terminal positions of the pre-charge relay 21. The perforated structures are used to dissipate heat from the inside of the first cavity 51 and the second cavity 52 to improve heat dissipation and / or serve as through holes for connecting the sampling lines and control wire harnesses of the BMS motherboard 140. By providing perforated structures on the covers, the heat dissipation requirements and wire harness routing requirements are considered while ensuring the protective function of the covers.

[0045] In some embodiments, the unit housing 5 is formed by one-piece injection molding. The unit housing 5 is made of ABS plastic or flame-retardant engineering plastic and is integrally molded using an injection mold. The first cavity 51, the second cavity 52, the support frame 50, and the bottom walls of the first cavity 51 and the second cavity 52 are all formed in one step during the injection molding process, without the need for subsequent assembly or processing. The one-piece injection molding of the unit housing 5 results in high structural strength, high dimensional accuracy, high production efficiency, and good insulation performance, which can effectively reduce the manufacturing cost of the unit housing 5 and improve mass production adaptability and product consistency.

[0046] In some embodiments, the opposite direction of the second direction is the height direction of the battery housing 110. The battery housing 110 includes two supports arranged at intervals. The battery pack circuit breaker unit 130 is supported on the two supports and a heat dissipation channel 150 is formed between it and the bottom wall of the battery housing 110. In the embodiment shown in the figure, the two supports are a first support 151 and a second support 152 located on both sides of the heat dissipation circuit breaker 150. The two supports are fixed to the bottom wall of the battery housing 110 and are arranged at intervals along the width direction of the battery housing 110. The unit housing 5 of the battery pack circuit breaker unit 130 is supported on the upper end of the two supports, so that the bottom surface of the unit housing 5 and the bottom wall of the battery housing 110 maintain a certain distance, which forms the heat dissipation channel 150. The DC / DC converter 32 and the pre-charge resistor 31 are mounted on the bottom wall of the second cavity 52. ​​The bottom wall of the second cavity 52 is recessed in the opposite direction of the second direction (i.e., downward), so that the bottom surfaces of the DC / DC converter 32 and the pre-charge resistor 31 are close to the bottom of the unit housing 5. The heat dissipation channel 150 faces the bottom area of ​​the second cavity 52, that is, directly opposite the mounting position of the DC / DC converter 32 and the pre-charge resistor 31. The heat dissipation channel 150 is used to remove heat from the bottom of the battery pack circuit breaker unit 130 by means of air convection, ensuring the heat dissipation and stable operation of high-power devices.

[0047] In some embodiments, the unit housing 5 is provided with a first mounting slot, a second mounting slot, and a third mounting slot, the shapes of which respectively match those of the charging relay 11, the discharging relay 12, and the pre-charge relay 21. The charging relay 11, the discharging relay 12, and the pre-charge relay 21 are respectively installed into the first mounting slot, the second mounting slot, and the third mounting slot. The outlines of the first mounting slot, the second mounting slot, and the third mounting slot on the unit housing 5 are substantially consistent with the outlines of the corresponding relays, and the depth of the mounting slot matches the height of the corresponding relay. During installation, the relay is directly placed into the corresponding mounting slot, and the inner wall of the mounting slot serves to limit and position the relay. Each mounting slot is used to position and limit the charging relay 11, the discharging relay 12, and the pre-charge relay 21. By setting mounting slots that match the shape of each relay, rapid alignment and precise positioning of the relay are achieved. During assembly, the operator only needs to place the relay into the corresponding mounting slot; there is no need to repeatedly calibrate the position, and the mounting slot automatically restricts the relay to the correct installation position.

[0048] In some embodiments, an electric vehicle is also disclosed, including any of the aforementioned power battery packs 100.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A power battery pack, characterized in that, The system includes a battery housing, battery modules, and a battery pack circuit breaker unit. Each battery module comprises multiple battery cells and is housed within the battery housing. The battery pack circuit breaker unit is connected to the battery modules and is also housed within the battery housing. The battery pack circuit breaker unit includes a unit housing, a charging relay, a discharging relay, a main fuse, a DC / DC converter, a pre-charge resistor, a pre-charge relay, and a shunt. The unit housing includes a support frame, a first cavity, and a second cavity disposed within the support frame along a first direction. The bottom wall of the first cavity is recessed relative to the support frame along a second direction perpendicular to the first direction. The bottom wall of the second cavity is recessed relative to the support frame along a direction opposite to the second direction. On a plane parallel to the second direction, the projection of the first cavity passes through the projection of the bottom wall of the second cavity. The charging relay, the discharging relay, and the main fuse are mounted within the first cavity and on its bottom wall. The DC / DC converter and the pre-charge resistor are disposed in the second cavity and mounted on the bottom wall of the second cavity; The precharge relay and the shunt are mounted on the bottom wall of the second cavity, away from the second cavity.

2. The power battery pack as described in claim 1, characterized in that, The battery pack circuit breaker unit also includes a power diode and a switching relay, which are installed in the first cavity and on the bottom wall of the first cavity.

3. The power battery pack as described in claim 1, characterized in that, The battery pack circuit breaker unit also includes a charging heating relay and a discharging heating relay, which are mounted on the bottom wall of the second cavity on a surface away from the second cavity.

4. The power battery pack as described in claim 1, characterized in that, The battery pack circuit breaker unit also includes a first cover fixedly connected to the unit housing and surrounding the charging relay, the discharging relay and the main fuse, and a second cover surrounding the precharge relay.

5. The power battery pack as described in claim 4, characterized in that, It also includes a BMS mainboard located inside the battery box and connected to the battery pack circuit breaker unit. The BMS mainboard is fixed on the first box cover and the second box cover.

6. The power battery pack as described in claim 4, characterized in that, The first and second box covers have multiple hollow structures.

7. The power battery pack as described in claim 1, characterized in that, The unit housing is formed by one-piece injection molding.

8. The power battery pack as described in claim 1, characterized in that, The opposite direction of the second direction is the height direction of the battery box. The battery box includes two supports arranged at intervals. The battery pack circuit breaker unit is supported on the two supports and forms a heat dissipation channel between itself and the bottom wall of the battery box.

9. The power battery pack as described in claim 1, characterized in that, The unit housing is provided with a first mounting slot, a second mounting slot, and a third mounting slot, the shapes of which respectively match the charging relay, the discharging relay, and the pre-charge relay. The charging relay, the discharging relay, and the pre-charge relay are respectively installed in the first mounting slot, the second mounting slot, and the third mounting slot.

10. An electric vehicle, characterized in that, Includes the power battery pack described in any one of claims 1-9.

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