Bunching-free battery pack circuit breaking unit

Abstract

The invention provides a bunching-free battery pack circuit breaking unit, which belongs to the technical field of battery packs, and comprises a positive circuit, a negative circuit, a third circuit and a fourth circuit, a second contact of the main positive relay is connected with a first contact of a quick-charge positive relay, a battery pack positive output voltage, a front-drive positive voltage and a rear-drive positive voltage, and a second contact of the quick-charge positive relay is connected with a quick-charge positive voltage and a battery pack charging positive voltage; and the cathode circuit comprises a shunt, one end of the shunt is connected with battery cathode voltage and battery pack ground voltage, the other end of the shunt is connected with a first contact of a fast charge negative relay, front-drive negative voltage and rear-drive negative voltage, and a second contact of the fast charge negative relay is respectively connected with fast charge negative voltage and battery pack charge negative voltage. The beneficial effects are that battery fast charging and fast charging protection are realized and a power input power supply is provided for a front-drive system and a rear-drive system of an electric vehicle by controlling on-off of a switch of the relay.

Description

Technical Field

[0001] This invention relates to the field of battery pack technology, and more particularly to a wireless battery pack circuit breaker unit. Background Technology

[0002] The Battery Disconnect Unit (BDU) is a crucial component of the battery pack, capable of disconnecting the battery from external circuits when necessary to protect the battery and vehicle electrical system from damage caused by short circuits, overcurrent, and other abnormal conditions. With the rapid development of the electric vehicle industry, the safety, reliability, and intelligence of the BDU are receiving increasing attention.

[0003] Traditional battery pack circuit breaker units typically use negative temperature coefficient (NTC) resistors for current sensing. Since the resistance of an NTC resistor changes with temperature, calibration is required to ensure accurate current sensing. However, this calibration process is complex and tedious, involving extensive calibration work, and temperature factors still significantly interfere with the accuracy of current sensing, leading to inaccurate results. Furthermore, traditional battery pack circuit breaker units cannot provide power input to the front-wheel drive and rear-wheel drive systems of electric vehicles. Summary of the Invention

[0004] To address the above technical problems, this invention provides a wireless battery pack circuit breaker unit.

[0005] The technical problem solved by this invention can be achieved by the following technical solutions:

[0006] A non-beam-based battery pack circuit breaker unit includes:

[0007] The positive circuit includes a fuse, a main positive relay, and a fast-charging positive relay. The first contact of the main positive relay is connected to the positive voltage of the battery pack and the positive voltage of the battery through the fuse. The second contact of the main positive relay is connected to the first contact of the fast-charging positive relay, the positive output voltage of the battery pack, the front-drive positive voltage, and the rear-drive positive voltage. The second contact of the fast-charging positive relay is connected to the fast-charging positive voltage and the charging positive voltage of the battery pack.

[0008] The negative electrode circuit includes a shunt and a fast-charging negative relay. One end of the shunt is connected to the battery negative voltage and the battery pack ground voltage, respectively. The other end of the shunt is connected to the first contact of the fast-charging negative relay, the front negative voltage, and the rear negative voltage, respectively. The second contact of the fast-charging negative relay is connected to the fast-charging negative voltage and the battery pack charging negative voltage, respectively.

[0009] Preferably, the main positive relay is a case-removing relay, which includes a relay body and high-voltage contact terminals and low-voltage contact terminals exposed on the relay body. The high-voltage contact terminals are welded to the copper busbar assembly, and the low-voltage contact terminals are welded to the circuit board.

[0010] Preferably, the positive circuit further includes a pre-charge branch, which includes a pre-charge relay and a pre-charge resistor. The first contact of the pre-charge relay is connected to the first contact of the main positive relay, and the second contact of the pre-charge relay is connected to the second contact of the main positive relay through the pre-charge resistor.

[0011] Preferably, it further includes:

[0012] The device comprises a lower housing, a circuit board, and an upper housing. The lower housing is detachably connected to the upper housing. The positive and negative circuits are integrated on the circuit board, which is located within the space enclosed by the upper and lower housings.

[0013] Preferably, a copper busbar assembly and a high-voltage sampling column assembly are injection molded on the lower housing, and the copper busbar assembly and the high-voltage sampling column assembly are electrically connected to reserved pins on the circuit board;

[0014] The lower housing also has reserved assembly spaces that correspond one-to-one with and are separated from the fuse, main positive relay, shunt, precharge relay and precharge resistor. The fuse, main positive relay, shunt, precharge relay and precharge resistor are installed in the assembly space and are electrically connected to the corresponding copper busbar in the copper busbar group and the corresponding high voltage sampling column in the high voltage sampling column group, respectively.

[0015] Preferably, it further includes a thermal pad, which is disposed below the lower housing, and the copper busbar assembly exchanges heat with the water cooling system of the battery pack through the thermal pad.

[0016] Preferably, it further includes: a thermally conductive insulating adhesive layer disposed between the lower housing and the thermally conductive pad, and the thermally conductive insulating adhesive layer is in contact with the copper busbars in the copper busbar assembly.

[0017] Preferably, it further includes: a protective cover, the protective cover being disposed on one side of the upper housing, and the protective cover being detachably connected to the lower housing.

[0018] Preferably, the circuit board is further provided with a high and low voltage control module, and the high and low voltage control module is provided with a high and low voltage output interface.

[0019] Preferably, the high and low voltage control module includes a high voltage control module and a low voltage control module, wherein the high voltage control module is provided with a high voltage output interface and the low voltage control module is provided with a low voltage output interface.

[0020] The advantages or beneficial effects of the technical solution of this invention are as follows:

[0021] This invention achieves fast charging and fast charging protection functions by controlling the opening and closing of relays, and can also provide power input to the front-wheel drive and rear-wheel drive systems of electric vehicles. The battery circuit breaker unit is equipped with a shunt. Since the shunt has no NTC resistor, there is no need to calibrate the resistance value of the NTC resistor, avoiding the interference of temperature factors on the accuracy of current detection and saving a lot of calibration work for NTC calibration. Attached Figure Description

[0022] Figure 1 The electrical schematic diagram of the wireless battery pack circuit breaker unit is shown in a preferred embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the structure of the wireless beam-free battery pack circuit breaker unit in a preferred embodiment of the present invention.

[0024] Figure 3 An exploded view of the wireless beam-free battery pack circuit breaker unit in a preferred embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the structure of the lower housing and the thermal pad in a preferred embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the circuit board structure in a preferred embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of the structure of the unpacking relay in a preferred embodiment of the present invention.

[0028] Explanation of reference numerals in the attached figures:

[0029] 100, positive circuit; 200, negative circuit;

[0030] 1. Fuse; 2. Main positive relay; 201. Relay body; 202. High-voltage contact terminal; 203. Low-voltage contact terminal; 3. Fast-charging positive relay; 4. Pre-charge relay; 5. Pre-charge resistor; 6. Shunt; 7. Fast-charging negative relay; 8. Lower housing; 9. Upper housing; 10. Circuit board; 11. Thermal pad; 12. Protective cover; 13. High and low voltage control modules; 131. Low-voltage control module; 132. High-voltage control module; 14. Copper busbar assembly; 15. High-voltage sampling column assembly; 16. Heat sink; 17. Low-voltage sampling pin; 18. Thermally conductive insulating adhesive layer. Detailed Implementation

[0031] 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. 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.

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0034] See Figure 1 In a preferred embodiment of the present invention, based on the above-mentioned problems existing in the prior art, a non-beam-based battery pack circuit breaker unit is provided, comprising:

[0035] The positive circuit 100 includes a fuse 1, a main positive relay 2, and a fast-charging positive relay 3. The first contact of the main positive relay 2 is connected to the positive voltage VPack+ of the battery pack and the positive voltage VBAT+ of the battery through the fuse 1. The second contact of the main positive relay 2 is connected to the first contact of the fast-charging positive relay 3, the positive output voltage VLink+ of the battery pack, the front positive voltage Vfd+, and the rear positive voltage Vrd+. The second contact of the fast-charging positive relay 3 is connected to the fast-charging positive voltage Vfc+ and the charging positive voltage VCharge+ of the battery pack.

[0036] The negative circuit 200 includes a shunt 6 and a fast-charging negative relay 7. One end of the shunt 6 is connected to the battery negative voltage VBAT- and the battery pack ground voltage VGND_H, respectively. The other end of the shunt 6 is connected to the first contact of the fast-charging negative relay 7, the front negative voltage Vfd-, and the rear negative voltage Vrd-, respectively. The second contact of the fast-charging negative relay 7 is connected to the fast-charging negative voltage Vfc- and the battery pack charging negative voltage VCharge-, respectively.

[0037] Specifically, in this embodiment, the opening and closing states of the main positive relay 2, the fast charging positive relay 3, and the fast charging negative relay 7 are controlled by the ECU logic to realize the functions of fast charging of the battery, fast charging protection, and providing front-wheel drive and rear-wheel drive power input to the electric vehicle.

[0038] By controlling the opening and closing state of the main positive relay 2, the main DC current of the battery pack can be turned on or off.

[0039] The main positive relay 2 and the fast charging positive relay 3 are connected in series. During fast charging, the main positive relay 2 and the fast charging positive relay 3 must be closed simultaneously to realize the battery fast charging function.

[0040] When the vehicle is fast charging, the battery system's discharge bus is directly connected to the electronic control unit. At this time, although the electronic control unit is energized, it is not in drive mode.

[0041] The BDU has an internal shunt 6 for measuring and calculating the battery pack capacity. This shunt 6 has no NTC resistor, has a low temperature coefficient of resistance, and eliminates the need for NTC resistor calibration. This reduces the impact of temperature on current accuracy and saves the system a lot of calibration work.

[0042] In a preferred embodiment, such as Figure 1 As shown, the positive circuit 100 also includes a pre-charge branch, which includes a pre-charge relay 4 and a pre-charge resistor 5. The first contact of the pre-charge relay 4 is connected to the first contact of the main positive relay 2, and the second contact of the pre-charge relay 4 is connected to the second contact of the main positive relay 2 through the pre-charge resistor 5.

[0043] Specifically, in this embodiment, by controlling the opening and closing state of the pre-charge relay 4, in conjunction with the pre-charge resistor 5, the high-voltage circuit can be protected from the instantaneous large current surge generated when the power supply charges the capacitor.

[0044] In this embodiment, when a suitable voltage is applied between the two coil pins of the relay, the coil generates a magnetic field, thereby actuating the contacts. For example, applying a voltage between the first coil positive pin K1+ and the first coil negative pin K1- of the main positive relay 2 closes the main positive relay 2; if the voltage is stopped, the main positive relay 2 opens. Similarly, applying a voltage between the second coil positive pin K2+ and the second coil negative pin K2- of the fast-charging positive relay 3 closes the fast-charging positive relay 3. Applying a voltage between the third coil positive pin K3+ and the third coil negative pin K3- of the pre-charge relay 4 closes the pre-charge relay 4. Applying a voltage between the fourth coil positive pin K4+ and the fourth coil negative pin K4- of the fast-charging negative relay 7 closes the fast-charging negative relay 7. Conversely, if the voltage is stopped, the corresponding relay opens.

[0045] In a preferred embodiment, such as Figure 2 and Figure 3 As shown, it also includes:

[0046] The lower housing 8, the circuit board 10, and the upper housing 9 are included. The lower housing 8 is detachably connected to the upper housing 9. The positive and negative circuits are integrated on the circuit board 10, which is located within the space enclosed by the upper housing 9 and the lower housing 8.

[0047] More specifically, the lower housing 8 is located inside the battery pack. The lower housing 8 can be fixedly connected to the battery pack using fasteners such as bolts.

[0048] The circuit board 10 of this invention can refer to a printed circuit board assembly (PCBA). PCBA refers to a type of printed circuit board assembly 10. In the manufacturing of electronic devices, PCBA includes the soldering and assembly of components such as printed circuit boards (PCBs), through-hole components, and surface mount technology (SMT) components, which are completed through various processes such as solder paste printing, SMT, through-hole assembly, and AOI (automatic optical inspection).

[0049] The PCB board is the carrier of the entire BDU signal interaction, such as Figure 5 As shown, the pre-charge relay 4 and pre-charge resistor 5 in the pre-charge branch, and the connectors for the low-voltage output and high-voltage output of the high-low voltage control plug-in 13 are soldered using wave soldering. The PCBA also has a low-voltage sampling pin 17. Moving key manufacturing processes forward can reduce the number of steps on the production line and increase the production cycle time of the BDU assembly.

[0050] The BDU with a wireless design of the present invention can realize wireless design within the BDU. The signal interaction between the various electronic components inside the BDU and the battery pack is realized by the plug-in on the PCB board, which is beneficial to improving the space utilization of the battery pack and the versatility of the BDU.

[0051] In a preferred embodiment, such as Figure 4 As shown, the lower housing 8 is injection molded with a copper busbar assembly 14 and a high-voltage sampling column assembly 15, which are electrically connected to the reserved pins on the circuit board 10.

[0052] The lower housing 8 also has reserved assembly spaces that correspond one-to-one with and are separated from the fuse 1, main positive relay 2, shunt 6, precharge relay 4, and precharge resistor 5. The fuse 1, main positive relay 2, shunt 6, precharge relay 4, and precharge resistor 5 are installed in the assembly space and are electrically connected to the corresponding copper busbar in the copper busbar group 14 and the corresponding high-voltage sampling column in the high-voltage sampling column group 15, respectively.

[0053] Specifically, the lower housing 8 and the copper busbar are integrally injection molded from plastic, providing the necessary support and installation strength for the copper busbar to be locked, which can improve the problem of obvious plastic deformation of the lower housing 8.

[0054] The positive and negative circuits are encased in plastic, which effectively solves the creepage distance and clearance safety issues of the 800V high-voltage platform. At the same time, the volume of the lower housing 8 can be reduced by more than 30%, lowering the installation space requirements of the BDU and significantly reducing the cost of raw materials.

[0055] More specifically, the lower housing 8 is also provided with a heat sink 16, which can be made of aluminum, to dissipate heat from the electronic components on the lower housing 8. More preferably, two heat sinks can be provided, with the two heat sinks located at both ends of the fuse 1 respectively, to dissipate the heat generated by the fuse 1, so as to avoid heat accumulation around the fuse and cause the component temperature to become too high.

[0056] In a preferred embodiment, the system further includes a thermal pad 11, which is disposed below the lower housing 8, and the copper busbar assembly 14 exchanges heat with the water cooling system of the battery pack through the thermal pad 11.

[0057] Specifically, in this embodiment, the thermal pad 11 is located between the lower shell 8 of the BDU body and the water-cooling plate of the battery pack, and is used to conduct the heat generated by the copper busbar to the water-cooling plate of the battery pack, thereby achieving the purpose of cooling down the BDU and reducing its load.

[0058] The wireless BDU of this invention mainly serves 800V high-voltage platforms and is a platform-based product. It utilizes the water cooling system of the battery pack to achieve water cooling of the BDU. The copper busbar can exchange heat with the cooling water through the heat transfer medium, improving the heat dissipation of the pack and the whole vehicle, and comprehensively improving the operating environment and service life of the components.

[0059] It also includes a thermally conductive insulating adhesive layer 18, which is disposed between the lower housing 8 and the thermally conductive pad 11, and the thermally conductive insulating adhesive layer 18 is in contact with the copper busbars in the copper busbar assembly 14.

[0060] Specifically, the thermally conductive insulating adhesive layer 18 is made using a vacuum potting process. The thermally conductive insulating adhesive layer 18 has the characteristics of insulating material, which can ensure that there are no electrical safety issues between the positive and negative high-voltage copper busbars and meet the requirements of electrical clearance and creepage distance. At the same time, the thermally conductive insulating adhesive layer 18 has the characteristics of thermally conductive material, which can directly contact the copper busbars and directly conduct the heat generated by the copper busbars to the thermal pad 11, and the heat is carried away by the battery pack cooling water.

[0061] In a preferred embodiment, the device further includes a protective cover 12, which is disposed on one side of the upper housing 9 and is detachably connected to the lower housing 8.

[0062] Specifically, with the protective cover 12, when the BDU body needs to be repaired, the protective cover 12 can be removed from the lower housing 8 to expose a maintenance window. The battery pack input and output interfaces can be disassembled and maintained without disassembling the entire battery pack. This simplifies the troubleshooting and component replacement process and avoids the cumbersome operation of disassembling the entire battery pack when replacing electronic components in traditional designs.

[0063] It should be noted that the implementation of detachable connections in the shell-related structures is a relatively mature technology, and will not be described in detail here.

[0064] In a preferred embodiment, the circuit board 10 is further provided with a high and low voltage control plug-in 13.

[0065] Specifically, in this embodiment, the high and low voltage control plug-in 13 is soldered onto the circuit board 10, and the output interface of the high and low voltage control plug-in 13 is exposed from the lower housing 8 and the upper housing 9 to facilitate connection with the battery pack, thereby enabling flexible switching between quick-swap battery packs and non-quick-swap battery packs and improving mass production automation.

[0066] In a preferred embodiment, the high and low voltage control plug-in 13 is provided with high and low voltage output interfaces.

[0067] Specifically, in this embodiment, when the battery pack is a quick-swap battery pack, high-voltage power output and low-voltage control signal transmission can be completed simultaneously through the high and low voltage output interfaces.

[0068] In another preferred embodiment, the high and low voltage control plug-in 13 includes a high voltage control plug-in 132 and a low voltage control plug-in 131. The high voltage control plug-in 132 is provided with a high voltage output interface, and the low voltage control plug-in 131 is provided with a low voltage output interface.

[0069] Specifically, in this embodiment, when the battery pack is not a fast-swap battery pack, high-voltage output can be achieved through the high-voltage output interface, and low-voltage output can be achieved through the low-voltage output interface.

[0070] In a preferred embodiment, such as Figure 6 As shown, the main positive relay 2 is a case-removing relay, which includes a relay body 201 and high-voltage contact terminals 202 and low-voltage contact terminals 203 exposed on the relay body 201. The high-voltage contact terminals 202 are welded to the copper busbar group 14, and the low-voltage contact terminals 203 are welded to the circuit board 10.

[0071] Specifically, in this embodiment, the main positive relay 2 is a 400A high-current DC relay. Compared with conventional relay structures, the main positive relay 2 in this embodiment adopts a shell-less structure, which requires less installation space and makes the internal structure of the BDU more compact. The shell-less relay has no external plastic casing or mounting feet, and the volume of the shell-less structure is reduced by about 50% compared to relays of the same specifications, increasing the adaptability of the BDU in small spaces. The internal structure and electrical performance of the relay can also be effectively protected by the plastic structure of the lower housing 8 and the protective cover 12.

[0072] The high-voltage contact terminal 202 is connected to the current-carrying copper busbar on the lower housing 8 by laser welding. The welding tensile strength can reach over 4000N, resulting in good connection strength. Moreover, the contact impedance between the copper busbar and the high-voltage contact terminal 202, which are conventionally screw-fastened, is ≤0.02mΩ, while the contact impedance between the copper busbar and the high-voltage contact terminal 202, which are laser-welded, can reach ≤0.007mΩ. This lower contact impedance is more conducive to improving the thermal issues of BDU power devices.

[0073] The low-voltage contact terminal 203 is made of nickel sheet and is soldered to the PCB board. This can effectively absorb the Z-axis height deviation caused by the manufacturing and assembly of the relay and the lower housing 8, and improve the feasibility of the manufacturing process.

[0074] The advantages or beneficial effects of adopting the above technical solution are as follows: This invention realizes the functions of fast charging and fast charging protection of the battery by controlling the opening and closing of the relay switch, and at the same time can provide power input to the front drive and rear drive systems of the electric vehicle; the battery circuit breaker unit is equipped with a shunt, and since the shunt has no NTC resistor, there is no need to calibrate the resistance value of the NTC resistor, avoiding the interference of temperature factors on the accuracy of current detection, and saving a lot of calibration work for NTC calibration; it greatly reduces manual assembly work and improves the automation rate of production line assembly.

[0075] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made using the content of this specification and illustrations should be included within the protection scope of the present invention.

Claims

1. A wireless battery pack circuit breaker unit, characterized in that, include: The positive circuit includes a fuse, a main positive relay, and a fast-charging positive relay. The first contact of the main positive relay is connected to the positive voltage of the battery pack and the positive voltage of the battery through the fuse. The second contact of the main positive relay is connected to the first contact of the fast-charging positive relay, the positive output voltage of the battery pack, the front-drive positive voltage, and the rear-drive positive voltage. The second contact of the fast-charging positive relay is connected to the fast-charging positive voltage and the charging positive voltage of the battery pack. The negative electrode circuit includes a shunt and a fast-charging negative relay. One end of the shunt is connected to the battery negative voltage and the battery pack ground voltage, respectively. The other end of the shunt is connected to the first contact of the fast-charging negative relay, the front negative voltage, and the rear negative voltage, respectively. The second contact of the fast-charging negative relay is connected to the fast-charging negative voltage and the battery pack charging negative voltage, respectively.

2. The wireless battery pack circuit breaker unit according to claim 1, characterized in that, The main positive relay is a case-removing relay, which includes a relay body and high-voltage and low-voltage contact terminals exposed on the relay body. The high-voltage contact terminals are welded to the copper busbar assembly, and the low-voltage contact terminals are welded to the circuit board.

3. The wireless battery pack circuit breaker unit according to claim 1, characterized in that, The positive circuit also includes a pre-charge branch, which includes a pre-charge relay and a pre-charge resistor. The first contact of the pre-charge relay is connected to the first contact of the main positive relay, and the second contact of the pre-charge relay is connected to the second contact of the main positive relay through the pre-charge resistor.

4. The wireless battery pack circuit breaker unit according to claim 3, characterized in that, Also includes: The device comprises a lower housing, a circuit board, and an upper housing. The lower housing is detachably connected to the upper housing. The positive and negative circuits are integrated on the circuit board, which is located within the space enclosed by the upper and lower housings.

5. The wireless battery pack circuit breaker unit according to claim 4, characterized in that, The lower housing is injection molded with a copper busbar assembly and a high-voltage sampling column assembly, which are electrically connected to reserved pins on the circuit board. The lower housing also has reserved assembly spaces that correspond one-to-one with and are separated from the fuse, main positive relay, shunt, precharge relay and precharge resistor. The fuse, main positive relay, shunt, precharge relay and precharge resistor are installed in the assembly space and are electrically connected to the corresponding copper busbar in the copper busbar group and the corresponding high voltage sampling column in the high voltage sampling column group, respectively.

6. The wireless battery pack circuit breaker unit according to claim 5, characterized in that, Also includes: A thermal pad is disposed below the lower housing, and the copper busbar assembly exchanges heat with the water cooling system of the battery pack through the thermal pad.

7. The wireless battery pack circuit breaker unit according to claim 6, characterized in that, Also includes: A thermally conductive insulating adhesive layer is disposed between the lower housing and the thermally conductive pad, and the thermally conductive insulating adhesive layer is in contact with the copper busbars in the copper busbar assembly.

8. The wireless battery pack circuit breaker unit according to claim 5, characterized in that, Also includes: A protective cover is disposed on one side of the upper housing and is detachably connected to the lower housing.

9. The wireless battery pack circuit breaker unit according to claim 4, characterized in that, The circuit board is also equipped with a high and low voltage control module, which has a high and low voltage output interface.

10. The wireless battery pack circuit breaker unit according to claim 9, characterized in that, The high and low voltage control module includes a high voltage control module and a low voltage control module. The high voltage control module is provided with a high voltage output interface, and the low voltage control module is provided with a low voltage output interface.

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