Battery pack

Abstract

The battery pack comprises a box body, a battery pack and a battery pack circuit breaking unit, and the box body is internally provided with a battery bin and an electrical bin which are formed by separation of a separation beam; the battery pack is arranged in the battery compartment, and the battery pack circuit breaking unit is arranged in the electrical compartment; the battery pack circuit breaking unit comprises a shell, a circuit board and electronic elements connected with the circuit board, the circuit board is arranged in the shell, the electronic elements are arranged on two side board surfaces of the circuit board, a main positive relay and a main negative relay are arranged on the lower board surface of the circuit board at intervals, and a heating relay and a pre-charging relay are arranged on the upper board surface of the circuit board. By applying the scheme, the board area of the circuit board of the battery pack circuit breaking unit can be reduced, the space occupied by the battery pack circuit breaking unit in the battery pack can be saved, the size of an electrical cabin can be effectively reduced, and more accommodating space in a battery pack box body can be distributed to one side of the battery cabin; and a good technical guarantee is provided for integrally improving the energy density of the battery.

Description

[0001] This application is a divisional application of the Chinese patent application filed with the China Patent Office on October 14, 2024, with application number 202411428316.0 and invention name “A Battery Pack”. The entire contents of the Chinese patent application are incorporated into this application by reference. Technical Field

[0002] The present invention relates to the technical field of battery pack disconnecting units, and in particular to a battery pack. Background Art

[0003] The battery disconnect unit (BDU) is an important component of new energy vehicles, used to provide charge and discharge control, circuit overload protection, etc. for the high-voltage system. Among them, various relays are important components in the battery disconnect unit, providing support for the normal operation of the battery disconnect unit.

[0004] In the related art, the electrical components in the BDU are usually arranged on the same side of the circuit board, making the overall structure more compact and the outline more regular. Limited by the configuration of the BDU, the electrical compartment of the battery pack needs to provide corresponding assembly space, which directly affects the battery energy density. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a battery pack, which can effectively reduce the space occupied by the BDU in the battery pack and improve the battery energy density through solution optimization.

[0006] The present invention provides a battery pack, which includes a box body, a battery group and a battery pack circuit breaker unit, wherein the box body includes a bottom plate and a box body frame, wherein the box body frame is fixed to the bottom plate to enclose a storage space of the box body; a partition beam is arranged in the box body, and the partition beam divides the storage space into a battery compartment and an electrical compartment; the battery group is arranged in the battery compartment, and the battery pack circuit breaker unit is arranged in the electrical compartment; the battery pack circuit breaker unit includes a shell, a circuit board and electronic components connected to the circuit board, the circuit board is arranged in the shell body, and the electronic components are arranged on both side surfaces of the circuit board, and the electronic components include a main positive relay, a main negative relay, a heating relay and a pre-charging relay, the main positive relay and the main negative relay are arranged at intervals on the lower surface of the circuit board, and the heating relay and the pre-charging relay are arranged on the upper surface of the circuit board.

[0007] Compared with the prior art, the present invention proposes a battery pack implementation scheme in a different way. Specifically, the electronic components are arranged on both side panels of the circuit board of the battery pack circuit breaker unit. Compared with the prior art, the present scheme has electronic components arranged on both side panels of the circuit board, which can reduce the board area of ​​the circuit board and save the space occupied by the battery pack circuit breaker unit in the battery pack. The application of this scheme can effectively reduce the size of the electrical compartment, and can allocate more of the accommodation space in the battery pack box to one side of the battery compartment. As a result, the volume of the battery pack can be increased accordingly, providing a good technical guarantee for improving the overall battery energy density.

[0008] In addition, electronic components can be flexibly arranged on the upper and lower sides of the circuit board. On the one hand, this reduces the influence of electrical components on each other due to their own heat generation, which is beneficial to the heat dissipation of electronic components; on the other hand, it is also beneficial to reduce electromagnetic interference between electronic components and ensure the effective transmission of control signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A schematic diagram of a box assembly relationship of a battery pack according to an embodiment of the present application;

[0010] Figure 2 for Figure 1 An exploded view of the assembly of the battery pack disconnect unit shown in FIG.

[0011] Figure 3 is a schematic diagram of a battery pack disconnecting unit described in an embodiment of the present invention;

[0012] Figure 4 for Figure 3 A schematic diagram of the layout of one side of the circuit board of the battery pack disconnect unit shown in FIG.

[0013] Figure 5 for Figure 3 A schematic diagram of the layout of the other side of the circuit board of the battery pack disconnect unit shown in FIG.

[0014] Figure 6 A schematic diagram of a layout above the circuit board described in an embodiment of the present invention;

[0015] Figure 7 A schematic diagram of a layout below the circuit board described in an embodiment of the present invention;

[0016] Figure 8 Schematic diagram of the assembly relationship between the circuit board and the BMS mainboard in an embodiment of the present invention.

[0017] In the figure: battery pack circuit breaker unit 10, housing 1, first housing 11, second housing 12, avoidance recess 13, circuit board 2, heating fuse 31, heating relay 32, pre-charge relay 33, main positive relay 34, main negative relay 35, main fuse 36, pre-charge resistor 37, BMS mainboard 4, copper bus 5, high-voltage sampling connector 6, low-voltage communication connector 7;

[0018] Box body 20 , bottom plate 21 , box body frame 22 , partition beam 23 , reinforcement beam 24 . DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0020] As the demand for driving range continues to increase, controlling the volume of battery packs and effectively improving battery energy density have become the focus of research and development in the industry. Usually, the battery pack box includes a battery compartment and an electrical compartment. Figure 1 and Figure 2 ,in, Figure 1 This is a schematic diagram of a box assembly relationship of a battery pack described in an embodiment of the present application. Figure 2 for Figure 1 The exploded view of the battery pack disconnect unit is shown in the figure. Figure 1 and Figure 2 The battery compartment shown in the figure does not show the functional components such as the battery pack.

[0021] The battery pack includes a box body 20, a battery pack (not shown in the figure) and a battery pack disconnecting unit 10. The box body 20 includes a bottom plate 21 and a box body frame 22, and the box body frame 22 is fixedly connected to the bottom plate 21 to enclose a receiving space of the box body 20 to assemble internal components such as the battery pack and the battery pack disconnecting unit 10.

[0022] like Figure 1 and Figure 2 As shown, a partition beam 23 is provided in the box body 20, and the partition beam 23 divides the accommodation space into a battery compartment A and an electrical compartment B. The battery pack is arranged in the battery compartment A, and the battery pack disconnecting unit 10 is arranged in the electrical compartment B.

[0023] See also Figure 3 , Figure 4 and Figure 5 ,in, Figure 3 is a schematic diagram of a battery pack disconnecting unit described in an embodiment of the present invention, Figure 4 for Figure 3 The schematic diagram of the layout of the circuit board of the battery pack disconnect unit is shown in FIG. Figure 5 for Figure 3The schematic diagram of the board layout on the other side of the circuit board of the battery pack disconnect unit is shown in FIG.

[0024] like Figure 3 As shown, the battery pack disconnecting unit 10 includes a housing 1 and a circuit board disposed in the housing 1, as well as electrical components including but not limited to various relays. The housing 1 shown in the figure includes a first housing 11 and a second housing 12 connected to each other, which are assembled to form a housing 1 for accommodating various components.

[0025] In this embodiment, electrical components are arranged on both sides of the circuit board 2. In other words, electrical components connected to the circuit board 2 are distributed above and below the circuit board 2. For the convenience of description, the first housing 11 shown in the figure is defined as the housing part located at the bottom, and the second housing 12 is defined as the housing part located at the top.

[0026] like Figure 4 As shown in FIG. 1 , the figure shows a schematic diagram of the layout of electrical components on the circuit board 2. The circuit board 2 is provided with electrical components such as a heating fuse 31, a heating relay 32 and a pre-charge relay 33. Figure 5 As shown in the figure, the schematic diagram of the layout of electrical components under the circuit board 2 is shown. The lower surface of the circuit board 2 is provided with a main positive relay 34 and a main negative relay 35, both of which are electrically connected to the output end of the battery pack (not shown in the figure). The lower surface of the circuit board 2 is also provided with electrical components such as a main fuse 36 and a pre-charging resistor 37.

[0027] Among them, the main positive relay 34 is the main relay on the positive side of the high-voltage system, and the main negative relay 35 is the main relay on the negative side of the high-voltage system. The pre-charging relay 33 is applied to the pre-charging circuit as a switch of the pre-charging circuit to realize the on-off and overcurrent of the pre-charging circuit, that is, before the main relay works, the pre-charging circuit is turned on for self-test. The heating relay 32 is applied to the heating circuit as a switch of the heating circuit to realize the on-off and overcurrent of the heating circuit. As a non-manually operated mechanical switch electrical appliance, the above-mentioned relay has only one rest position and can connect, carry and disconnect the current under normal circuit conditions (including overload operating conditions).

[0028] Among them, the pre-charging resistor 37 is a power resistor. When the whole vehicle executes the high-voltage power instruction, the pre-charging circuit is first closed to charge the X capacitor at the electric drive end. At this time, the pre-charging resistor 37 acts as a current limiting resistor to prevent the circuit from being impacted by a large current at the moment of power-on, thereby causing damage to the electrical components, lines and batteries in the circuit.

[0029] Among them, when the heating circuit has an abnormal short circuit, the internal fuse of the heating fuse 31 will melt quickly in a short time due to instantaneous heat accumulation, thereby disconnecting the heating circuit and protecting other electrical components, circuits and batteries in the circuit from damage. In a specific implementation, when the current exceeds the specified value for a long enough time, the current is disconnected by melting one or several proportional specially designed fuses, thereby disconnecting the device connected to the circuit. The specific method can be determined according to the overall design requirements of the product, and is not limited in the embodiments of the present application.

[0030] In this way, based on the double-sided board layout of the circuit board 2, the board area of ​​the circuit board can be reduced, saving the space occupied by the battery pack circuit breaker unit 10 in the battery pack. Compared with the implementation method of arranging electrical components on a single side of the board, under the same electrical performance configuration, this solution can effectively reduce the size of the electrical compartment B, and more storage space in the box 20 can be allocated to the battery compartment A side.

[0031] In a specific implementation, the projection area of ​​the electrical compartment B on the bottom plate 21 of the box body 20 may be 5% to 20% of the area of ​​the bottom plate 21; for example, but not limited to, the projection area of ​​the electrical compartment B on the bottom plate 21 of the box body 20 may be 6%, 12% or 18% of the area of ​​the bottom plate 21. Thus, the volume of the battery pack may be increased accordingly, and the overall battery energy density may be improved.

[0032] In addition, electronic components are flexibly arranged on the upper and lower surfaces of the circuit board 2, which, on the one hand, reduces the influence of electrical components on each other due to their own heat generation, which is beneficial to the heat dissipation of electronic components; on the other hand, it is also beneficial to reduce electromagnetic interference between electronic components and ensure the effective transmission of control signals.

[0033] In order to improve reliability, the electronic components on the upper and lower surfaces of the circuit board 2 may be optimally configured. Optionally, the maximum height of each electronic component located on the lower surface of the circuit board 2 may be greater than the maximum height of each electronic component located on the upper surface of the circuit board 2. The "maximum height of each electronic component" here refers to the height of the highest electronic component among the multiple electronic components located on the lower or upper surface of the circuit board 2.

[0034] Relatively speaking, electrical components with large volume and weight are arranged on the lower surface of the circuit board 2. The battery pack will experience comprehensive vibration in three directions of XYZ under operating conditions, among which the Z direction is the direction perpendicular to the bottom plate of the battery pack. Especially when the entire pack vibrates in the Z direction, the arrangement positions of the electronic components in the BDU are controlled, and the components with large height (large volume and heavy weight) are placed under the circuit board to lower the center of gravity of the BDU as a whole, which can make it more stable. In addition, since the electrical components with small volume and light weight are arranged on the upper surface of the circuit board 2, the possibility of damaging the circuit board 2 can be reduced.

[0035] In the case where the maximum height of each electronic component located on the upper surface of the circuit board is less than or equal to the maximum height of each electronic component located on the lower surface of the circuit board, the thickness of the circuit board 2 can be 0.5 mm to 2 mm; for example, but not limited to, the thickness of the circuit board 2 is 0.6 mm, 1.2 mm or 1.8 mm. In this way, on the basis of meeting the carrying capacity of the carrier board, the board thickness is reasonably controlled, the weight of the whole package is reduced, the mass energy density of the whole package is improved to a certain extent, and the component cost of the BDU circuit board itself can be reduced.

[0036] In a specific implementation, the ratio of the maximum height of each electronic component located on the upper surface of the circuit board 2 to the maximum height of each electronic component located on the lower surface of the circuit board 2 can be less than or equal to 1.27 and greater than or equal to 1. In this way, by reasonably controlling the height of the electronic components located on the upper surface of the circuit board 2, the center of gravity of the BDU is prevented from being too high, and the stability of the BDU shell is improved to avoid the problem of fatigue failure of the connection points and solder joints of each electrical component under the vibration condition of the whole package, especially the connection between the high-voltage conductive bus and the main positive relay and the main negative relay, which is generally connected by screw connection or welding. Under repeated vibration of the whole package, it is easy for the bolts to loosen, the connection to be virtual, or the fatigue failure and fracture of the welding position, thereby causing the increase of local resistance and the sudden increase of heat generation, and even the possibility of thermal runaway of the whole package.

[0037] In the case where the maximum height of each electronic component located on the upper surface of the circuit board 2 is greater than the maximum height of each electronic component located on the lower surface of the circuit board 2, the thickness of the circuit board 2 can be 1mm~3mm; for example but not limited to, the thickness of the circuit board 2 is 1.2mm, 2mm or 2.8mm. Due to the external wiring of the BDU and other reasons, when the maximum height of the upper electronic component is greater than the maximum height of the lower electronic component, it is necessary to control the thickness of the circuit board within an appropriate range to compensate for the decrease in stability due to the increase in the center of gravity and the damage to the strength of the BDU circuit board caused by the pressure of the upper electronic components, thereby further improving the stability and reliability of the BDU.

[0038] In other specific implementations, the projections of the electronic components located on the lower surface of the circuit board 2 and the electronic components located on the upper surface of the circuit board 2 on the plane where the circuit board 2 is located at least partially overlap. In this way, the upper and lower layers of electrical components are clamped on the upper and lower surfaces of the circuit board 2, and when the whole package vibrates in the Z direction, the upper and lower layers of electronic components clamp the circuit board together, which is conducive to improving the overall strength of the circuit board 2 and reducing the risk of bending and breaking of the circuit board.

[0039] In order to improve the adaptability of the BDU, the housing 1 serving as the assembly basis of the BDU may be further optimized. Figure 2 and Figure 3As shown, the outer surface of the housing 1 may have an avoidance recess 13 to avoid interference with the reinforcing beam 24 in the electrical compartment. The reinforcing beam 24 is perpendicular to the extension direction of the circuit board 2 and can enhance the overall structural strength of the electrical compartment. At least part of the reinforcing beam 24 in the electrical compartment B can be built into the avoidance recess 13. In this way, the available space in the compartment is adapted without increasing the assembly space in the compartment, thereby improving the space utilization of the entire package.

[0040] For example, Figure 2 The reinforcing beam 24 shown in is a beam structure. In a specific implementation, the avoidance recess 13 and the beam structure can be fixedly connected, such as but not limited to, adhesive fixation, or assembly size interference fixation, or concave-convex structure matching fixation, so as to increase the stability of the BDU shell 1. Under the vibration condition of the whole package, on the one hand, the reinforcing beam 24 is equivalent to adding a fixed rib to the BDU shell, which increases the overall strength of the BDU. On the other hand, the strength of the BDU shell can also be used to improve the strength of the electrical compartment. The two work together to improve the integrity of the electrical compartment, which helps to improve the overall strength. In addition, the specific setting position and size of the avoidance recess 13 can be determined according to the overall design requirements of the product, such as but not limited to the layout of electrical components on the circuit board in the shell 1 and the specific form of the reinforcing beam in the electrical compartment. This is not limited to the embodiments of the present application.

[0041] Please also see Figure 6 and Figure 7 ,in, Figure 6 is a schematic diagram of a layout above the circuit board described in an embodiment of the present invention, Figure 7 A schematic diagram of a layout below the circuit board described in an embodiment of the present invention.

[0042] In a specific implementation, an avoidance recess 13 can be adaptively provided on the outer surface of the housing 1. Figure 6 The position area indicated by mark C shown in the figure can be set accordingly. Figure 3 The avoidance recess 13 below the housing 1 shown in FIG. Figure 6 The position area indicated by the mark D shown in the figure can be set accordingly. Figure 3 The avoidance recess 13 above the housing 1 is shown in FIG.

[0043] In a specific implementation, the projection of the avoidance recess 13 on the plane where the circuit board 2 is located can be staggered with the electronic components on the corresponding side panel to maximize the use of the space in the direction perpendicular to the panel surface and reasonably control the space occupied by the battery pack disconnecting unit. It should be understood that the above-mentioned corresponding position areas where the avoidance recesses can be arranged can be determined according to the design requirements of different products to obtain a shell profile with good assembly adaptability, thereby adapting to electrical compartments of various structures. This is not limited to the embodiments of the present application.

[0044] It should be noted that in actual application scenarios, higher and higher strength requirements are placed on the entire battery pack. Due to the complex and numerous high-voltage wiring in the electrical compartment, a beam structure is usually required in the electrical compartment to obtain better structural strength. Based on the present application, the avoidance recess 13 of the BDU shell 1 provides technical guarantee for meeting the avoidance assembly requirements.

[0045] Optionally, the main positive relay 34 and the main negative relay 35 are located on the same side of the circuit board 2. In this way, the high and low voltage ports of the main positive relay 34 and the main negative relay 35 can be connected on the same side, which is beneficial to the overall layout and compactness. Figure 7 As shown, the main positive relay 34 and the main negative relay 35 are respectively located at opposite ends of the lower surface of the circuit board 2. Based on the physical distance between the two and the physical barrier formed by the beam structure after assembly, the electromagnetic interference between the two can be reduced to the maximum extent.

[0046] In a specific implementation, the main fuse 36 and the pre-charging resistor 37 can be arranged between the main positive relay 34 and the main negative relay 35 to fully utilize the board space of the circuit board 2. At the same time, the copper bus 5 connected to the main positive relay 34 and the main negative relay 35 is arranged on the same side of the circuit board 2 as the two to further fully utilize the board space under the circuit board 2.

[0047] In order to make the internal structure layout more compact, optionally, the battery management system (BMS) mainboard of the battery pack circuit breaker unit 10 can be stacked with the circuit board 2. Please refer to Figure 8 , which is a schematic diagram of the assembly relationship between the circuit board and the BMS mainboard in an embodiment of the present invention.

[0048] The BMS main board 4 is arranged on the other side of the circuit board 2 opposite to the main positive relay 34 and the main negative relay 35, so as to avoid interference between the BMS main board 4 and the copper bus 5. Figure 4 , Figure 6 and Figure 8 As shown, the electronic components such as the heating fuse 31, the heating relay 32 and the pre-charging relay 33 can be centrally arranged on one side of the upper surface of the circuit board 2, and the BMS main board 4 can be mounted on the circuit board 2 beside the heating fuse 31, the heating relay 32 and the pre-charging relay 33. In this way, the overall structure is more compact and reasonable, and the space occupied by the battery pack circuit breaker unit 10 in the battery compartment is reduced.

[0049] In a specific implementation, the projection of the BMS mainboard 4 on the plane where the circuit board 2 is located may at least partially overlap with the circuit board 2. Of course, the projection of the BMS mainboard 4 on the plane where the circuit board 2 is located may also completely overlap with the circuit board 2.

[0050] Correspondingly, a high-voltage sampling connector 6 may be provided on the upper surface of the circuit board 2, and a low-voltage communication connector 7 may be provided on the lower surface of the circuit board 2, and the two may respectively realize corresponding electrical interconnection with the BMS main board 4.

[0051] In other possible implementations, other functional components may be provided on the upper and lower surfaces of the circuit board 2, which will not be described in detail here.

[0052] It should be noted that the other functional components of the battery pack and the battery pack disconnecting unit 10 described in the embodiment of the present application are not the core invention points of the present application, and those skilled in the art can implement them based on the existing technology, which will not be described in detail herein.

[0053] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A battery pack, characterized in that: It includes a box body, a battery pack and a battery pack disconnecting unit, the box body includes a bottom plate and a box body frame, the box body frame is fixed on the bottom plate, and encloses and forms a storage space of the box body; a partition beam is arranged in the box body, and the partition beam divides the storage space into a battery compartment and an electrical compartment; The battery pack is arranged in the battery compartment, and the battery pack disconnecting unit is arranged in the electrical compartment; The battery pack disconnecting unit comprises a housing, a circuit board and electronic components connected to the circuit board, wherein the circuit board is arranged in the housing, and the electronic components are arranged on both side surfaces of the circuit board; The electronic components include a main positive relay, a main negative relay, a heating relay and a pre-charging relay. The main positive relay and the main negative relay are arranged at intervals on the lower surface of the circuit board, and the heating relay and the pre-charging relay are arranged on the upper surface of the circuit board.

2. The battery pack according to claim 1, characterized in that: The maximum height of each of the electronic components located on the lower surface of the circuit board is greater than the maximum height of each of the electronic components located on the upper surface of the circuit board.

3. The battery pack according to claim 1, characterized in that: The ratio of the maximum height of each electronic component located on the upper surface of the circuit board to the maximum height of each electronic component located on the lower surface of the circuit board is less than or equal to 1.

27.

4. The battery pack according to claim 1, characterized in that: The projections of the electronic components located on the lower surface of the circuit board and the electronic components located on the upper surface of the circuit board on the plane where the circuit board is located at least partially overlap.

5. The battery pack according to claim 1, characterized in that: The maximum height of each electronic component located on the upper surface of the circuit board is greater than the maximum height of each electronic component located on the lower surface of the circuit board, and the thickness of the circuit board is 1 mm to 3 mm.

6. The battery pack according to claim 1, characterized in that: The maximum height of each electronic component located on the upper surface of the circuit board is less than or equal to the maximum height of each electronic component located on the lower surface of the circuit board, and the thickness of the circuit board is 0.5mm~2mm.

7. The battery pack according to any one of claims 1 to 6, characterized in that: The outer surface of the shell has an escape recess.

8. The battery pack according to claim 7, characterized in that: The projection of the avoidance recess on the plane where the circuit board is located is staggered with the electronic components on the board surface of the circuit board on the corresponding side.

9. The battery pack according to claim 1, characterized in that: The battery pack disconnecting unit further includes a BMS mainboard, which is mounted on the circuit board and located on the other side of the circuit board opposite to the main positive relay and the main negative relay.

10. The battery pack according to claim 7, characterized in that: The projection area of ​​the electrical compartment on the bottom plate is 5% to 20% of the area of ​​the bottom plate. The electrical compartment is provided with a reinforcing beam, the extension direction of the reinforcing beam is perpendicular to the extension direction of the circuit board, and at least part of the reinforcing beam is built into the avoidance recess.

11. The battery pack according to claim 10, characterized in that: The battery pack disconnecting unit is fixedly connected to the reinforcing beam via the avoidance recess.

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