Battery pack

Abstract

The battery pack comprises at least two battery modules and a wire harness for electrically connecting the plurality of battery modules, the battery pack further comprises a battery management unit, and the at least two battery modules comprise a first battery module directly and electrically connected with the battery management unit. Each battery module comprises an integrated busbar and a battery cell, the first battery module comprises a first circuit board, the first circuit board at least comprises a first circuit layer and a second circuit layer, the first circuit layer is used for transmitting a signal of the first battery module to the battery management unit, and the second circuit layer is electrically connected with other battery modules adjacent to the first battery module; signals of other battery modules are transmitted to the battery management unit through the second circuit layer. The first battery module of the battery pack is provided with at least two circuit layers, so that the battery pack transmits signals from the battery module at the farthest signal transmission distance from the battery management unit to the battery module closer to the signal transmission distance from the battery management unit in sequence, the length of a wire harness is reduced, and the wiring mode is optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage, and in particular to a battery pack. Background Art

[0002] A battery management system (Battery Management System - BMS) and multiple battery modules are usually provided in a battery pack. The battery management system (BMS) is used to monitor and manage the operating state of the entire battery system in real time, so as to ensure the safety and stability of the system. However, currently, each battery module needs to be directly electrically connected to the battery management system (BMS) through a wire harness separately, resulting in a messy wiring problem inside the battery pack. Summary of the Invention

[0003] This application provides a battery pack, which is used to solve the problem that each battery module needs to be directly electrically connected to the battery management system (BMS) through a wire harness separately, resulting in a messy wiring problem inside the battery pack.

[0004] This application provides a battery pack, which includes at least two battery modules and a wire harness for electrically connecting the multiple battery modules. The battery pack further includes a battery management unit. The at least two battery modules include a first battery module directly electrically connected to the battery management unit; The battery module includes an integrated busbar and a battery cell electrically connected to the integrated busbar. The integrated busbar includes a circuit board. The first battery module includes a first circuit board. The first circuit board includes at least a first circuit layer and a second circuit layer. The first circuit layer is used to transmit the signal of the first battery module to the battery management unit. The second circuit layer is used to be electrically connected to other battery modules adjacent to the first battery module, so that the signals of other battery modules adjacent to the first battery module are transmitted to the battery management unit through the second circuit layer.

[0005] In this solution, the first electric module of the battery pack is provided with at least two circuit layers, so as to realize the signal transmission of the battery pack from the battery module at the farthest distance from the battery management unit in terms of signal transmission distance to the battery modules with closer signal transmission distances to the battery management unit in sequence. Thus, finally, the status information of the battery modules other than the first battery module is transmitted to the battery management unit layer by layer through the other circuit layers except the first circuit layer in the first battery module, avoiding the problem that multiple battery modules in a traditional battery pack are separately connected to the battery management unit through wire harnesses. This is beneficial to reducing the use length of the wire harness and optimizing the layout method of the wire harness inside the battery pack, thereby improving the assembly efficiency inside the battery pack, reducing the production cost, and being beneficial to improving the space utilization rate inside the battery pack.

[0006] In this solution, the battery pack includes n battery modules, where n≥2, and the first circuit board includes n circuit layers distributed along its own thickness direction.

[0007] In this solution, the integrated busbar further includes connectors. The integrated busbar of the first battery module includes at least 2n - 1 connectors, and each of the circuit layers of the first circuit board is electrically connected to at least one of the 2n - 1 connectors.

[0008] In this solution, at least some of the circuit boards of at least some of the at least two battery modules include n circuit layers distributed along their own thickness directions, and the integrated busbars of at least some of the at least two battery modules include at least 2n - 1 connectors. At least some of the circuit layers of the circuit boards other than the first circuit board are electrically connected to at least one of the 2n - 1 connectors.

[0009] In this solution, the at least two battery modules further include a second battery module, and the second battery module is electrically connected to the battery management unit through all the battery modules other than the second battery module; The second circuit board of the second battery module includes at least one circuit layer, the integrated busbar of the second battery module includes at least one connector, and the at least one connector is electrically connected to the at least one circuit layer; Along the transmission direction of the signal from the second battery module to the battery management unit, the number of circuit layers of the circuit boards of each battery module gradually increases, the number of connectors of the integrated busbars of each battery module gradually increases, and at least some of the connectors of adjacent battery modules are electrically connected.

[0010] In this solution, along the length direction of the battery pack, each of the connectors is located at the end of each battery module; Along the length direction of the battery pack, multiple connectors within the same battery module are staggeredly distributed.

[0011] In this solution, the battery pack includes two battery modules. The first battery module includes at least a first connector, a second connector, and a third connector. Along the thickness direction of the first circuit board, the first connector is located on one side of the first circuit board, and the second connector and the third connector are both located on the other side of the first circuit board. The first connector is electrically connected to the first circuit layer, the second connector and the third connector are both electrically connected to the second circuit layer, and the first connector and the second connector are respectively electrically connected to the battery management unit through the corresponding wire harnesses; The second circuit board includes at least a third circuit layer, and the second battery module includes at least a fourth connector. The third circuit layer is electrically connected to the fourth connector, and the fourth connector is electrically connected to the third connector via the wire harness, so that the signal of the second battery module is transmitted to the battery management unit through the fourth connector, the third connector, and the second connector in sequence.

[0012] In this solution, the battery pack includes three battery modules. A third battery module with electrical connection is arranged between the first battery module and the second battery module, so that the first battery module and the second battery module transmit signals through the third battery module. The first circuit board further includes a fourth circuit layer. The first battery module includes at least a first connector, a second connector, a third connector, a fifth connector, and a sixth connector. Along the thickness direction of the first circuit board, the first connector is located on one side of the first circuit board, and the second connector, the third connector, the fifth connector, and the sixth connector are all located on the other side of the first circuit board. The first connector is electrically connected to the first circuit layer, the second connector and the third connector are electrically connected to the second circuit layer, the fifth connector and the sixth connector are electrically connected to the fourth circuit layer, and the first connector, the second connector, and the fifth connector are electrically connected to the battery management unit via the corresponding wire harnesses respectively; The second circuit board includes at least a third circuit layer, and the second battery module includes at least a fourth connector; The third battery module includes a third circuit board. The third circuit board includes at least a fifth circuit layer and a sixth circuit layer. The third battery module includes at least a seventh connector, an eighth connector, and a ninth connector. Along the thickness direction of the third circuit board, the seventh connector is located on one side of the third circuit board, and the eighth connector and the ninth connector are both located on the other side of the third circuit board. The seventh connector is electrically connected to the fifth circuit layer, the eighth connector and the ninth connector are both electrically connected to the sixth circuit layer, and the seventh connector is electrically connected to the third connector via the wire harness, so that the signal of the third battery module is transmitted to the battery management unit through the seventh connector, the third connector, and the second connector in sequence; The eighth connector is electrically connected to the sixth connector via the wire harness, and the ninth connector is electrically connected to the fourth connector via the wire harness, so that the signal of the second battery module is transmitted to the battery management unit through the fourth connector, the ninth connector, the eighth connector, the sixth connector, and the fifth connector in sequence.

[0013] In this solution, the circuit board further includes a substrate layer. Along the thickness direction of the battery pack, a circuit layer is disposed on the surface of the substrate layer. The material of the circuit layer is copper foil, and the thickness D1 of the circuit layer satisfies: 10um ≤ D1 ≤ 35um, and the thickness D2 of the substrate layer satisfies: 10um ≤ D2 ≤ 25um.

[0014] In this solution, along the thickness direction of the battery pack, a protective layer is disposed on the surface of the circuit layer. The protective layer is a polyimide film and an adhesive layer. The circuit board further includes a top layer and a bottom layer connected to the protective layer, and the top layer and the bottom layer are SMT patch adhesives; The thickness D3 of the protective layer satisfies: 30um ≤ D3 ≤ 50um.

[0015] It should be understood that the above general description and the following detailed description are only exemplary and do not limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of the battery pack provided by the present application in a specific embodiment; Figure 2 is a schematic structural diagram of the integrated busbar and the battery management unit provided by the present application in a specific embodiment; Figure 3 is a schematic structural diagram of the integrated busbar provided by the present application in a specific embodiment; Figure 4 is Figure 2 a partial enlarged view of part A in Figure 5 is Figure 2 a partial enlarged view of part B in Figure 6 is a schematic diagram of the principle of signal transmission between battery modules in the battery pack to the battery pipeline unit. Among them, the battery pack includes a first battery module and a second battery module; Figure 7 is a schematic diagram of the principle of signal transmission between battery modules in the battery pack to the battery pipeline unit. Among them, the battery pack includes a first battery module, a third battery module and a second battery module; Figure 8 is a schematic structural diagram of the circuit board provided by the present application in a specific embodiment, where the circuit board includes two circuit layers; Figure 9 is a schematic structural diagram of the circuit board provided by the present application in a specific embodiment, where the circuit board includes one circuit layer; Figure 10 is a schematic structural diagram of the circuit board provided by the present application in a specific embodiment, where the circuit board includes three circuit layers.

[0017] Description of the reference numerals in the drawings: 1 - Battery pack; 11 - Battery management unit; 12 - First battery module; 121 - First integrated busbar; 1211 - First circuit board; 1211a - First circuit layer; 1211b - Second circuit layer; 1211c - Fourth circuit layer; 1212 - First connector; 1213 - Second connector; 1214 - Third connector; 1215 - Fifth connector; 1216 - Sixth connector; 13 - Battery cell; 14 - Second battery module; 141 - Second integrated busbar; 1411 - Second circuit board; 1411a - Third circuit layer; 1412 - Fourth connector; 15 - Third battery module; 151 - Third integrated busbar; 1511 - Third circuit board; 1511a - Fifth circuit layer; 1511b - Sixth circuit layer; 1512 - Seventh connector; 1513 - Eighth connector; 1514 Ninth connector; 161 - Substrate layer; 162 - Protective layer; 163 - Top layer; 164 - Bottom layer; 17 - Wiring harness; 181 - Metal strip; 182 - Thermistor; 19 - Separator.

[0018] The drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application and used together with the specification to explain the principles of the present application. Detailed description of the specific embodiments

[0019] To better understand the technical solutions of the present application, the embodiments of the present application will be described in detail below with reference to the drawings.

[0020] In a specific embodiment, the present application will be further described in detail through specific embodiments in combination with the accompanying drawings.

[0021] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0022] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0023] It should be understood that the term " / and" used herein is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0024] It should be noted that the orientation terms such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described from the angles shown in the drawings, and should not be construed as a limitation on the embodiments of the present application. In addition, in the context, it should also be understood that when it is mentioned that an element is connected "above" or "below" another element, it can not only be directly connected "above" or "below" another element, but also be indirectly connected "above" or "below" another element through an intermediate element.

[0025] A battery pack is usually provided with a Battery Management Unit (BMU). As the core control module of the Battery Management System (BMS), the Battery Management Unit (BMU) is responsible for real-time monitoring, protecting and managing the operating state of the battery. The battery cells of multiple modules in a traditional battery pack are respectively and electrically connected to the battery management unit located at the end of the battery pack one by one, which is likely to cause the problem of messy wire harnesses in the battery pack. At the same time, due to the messy wire harnesses, the difficulty of assembly in the battery pack is increased, thus greatly reducing the assembly efficiency of the battery.

[0026] To solve the above problems, therefore, the embodiments of the present application provide a battery pack 1, as Figures 1-3 and Figure 8As shown, the battery pack 1 includes at least two battery modules and a wire harness 17 for electrically connecting the multiple battery modules. The battery pack 1 further includes a battery management unit 11. The at least two battery modules include a first battery module 12 directly electrically connected to the battery management unit 11.

[0027] The battery module includes battery cells 13 electrically connected to an integrated busbar (Cells Contact System - CCS). The integrated busbar includes a circuit board. The first battery module 12 includes a first circuit board 1211. The first circuit board 1211 includes at least a first circuit layer 1211a and a second circuit layer 1211b. The first circuit layer 1211a is used to transmit the signals of the first battery module 12 to the battery management unit 11. The second circuit layer 1211b is used to electrically connect to other battery modules adjacent to the first battery module 12, so that the signals of the other battery modules adjacent to the first battery module 12 are transmitted to the battery management unit 11 through the second circuit layer 1211b.

[0028] Specifically, the integrated busbar further includes a partition 19 and a metal row 181 electrically connected to the circuit board. The metal row 181 is a copper row or an aluminum row used to electrically connect to the battery cells 13. The partition 19 is mainly used to isolate metal rows 181 or components with different potentials to prevent short - circuit phenomena and ensure the safe operation of the system. At the same time, the partition 19 also has a supporting function.

[0029] In this embodiment, the first battery module 12 is directly electrically connected to the battery management unit 11 through the wire harness 17. That is, the first battery module 12 refers to the battery module with the shortest signal transmission distance to the battery management unit 11. The first battery module 12 includes at least a first circuit layer 1211a and a second circuit layer 1211b. During the operation of the battery pack 1, the first circuit layer 1211a is used to collect and transmit the status information of the first battery module 12. The second circuit layer 1211b is electrically connected to other adjacent battery modules directly connected to the first battery module 12 through the wire harness 17, so that the second circuit layer 1211b can collect and transmit the status information of the other adjacent battery modules directly connected to the first battery module 12 through the wire harness 17. Furthermore, the status information of the other adjacent battery modules directly connected to the first battery module 12 through the wire harness 17 can be transmitted to the battery management unit 11 through the first battery module 12.

[0030] Therefore, the first electrical module of the battery pack 1 is provided with at least two circuit layers, so as to enable the battery pack 1 to transmit signals from the battery module at the farthest signal transmission distance from the battery management unit 11 to the battery modules with a closer signal transmission distance to the battery management unit 11 in sequence. Thus, the status information of the battery modules other than the first battery module 12 is finally transmitted to the battery management unit 11 layer by layer through each circuit layer other than the first circuit layer 1211a in the first battery module 12, avoiding the problem that multiple battery modules in the traditional battery pack are separately connected to the battery management unit through wire harnesses, which is beneficial to reducing the use length of the wire harness 17 and optimizing the layout of the wire harness 17 in the battery pack 1, thereby improving the assembly efficiency in the battery pack 1, reducing the production cost, and being beneficial to improving the space utilization rate in the battery pack 1.

[0031] In addition, the circuit board provided in the embodiment of the present application can be a flexible printed circuit (Flexible Printed Circuit - FPC) or a rigid printed circuit board (Printed Circuit Board - PCB).

[0032] In a possible implementation manner, as Figure 1 , Figure 2 , Figure 8 and Figure 10 shown, the battery pack 1 includes n battery modules, and satisfies n≥2. The first circuit board 1211 includes n circuit layers distributed along its own thickness direction. Among them, n can be equal to 2, 3, 4, 5, 6, 7, 8, etc.

[0033] Specifically, if the battery pack 1 includes 2 battery modules, the first circuit board 1211 includes 2 circuit layers distributed along its own thickness direction; if the battery pack 1 includes 3 battery modules, the first circuit board 1211 includes 3 circuit layers distributed along its own thickness direction; if the battery pack 1 includes 4 battery modules, the first circuit board 1211 includes 4 circuit layers distributed along its own thickness direction. Therefore, circuit layers corresponding to each battery module in the battery pack 1 are provided in the first battery module 12, along the direction of signal transmission towards the power management unit in the battery pack 1, so that the other battery modules except the first battery module 12 can be respectively electrically connected to each circuit layer except the first circuit layer 1211a in the first battery module 12 one by one, improving the feasibility of other battery modules transmitting signals to the battery management unit 11 through the first battery module 12. At the same time, each circuit layer is spaced apart along the thickness direction of the first circuit board 1211, reducing the risk of signal interference when other battery modules transmit signals through the first battery module 12, improving the reliability and accuracy of data transmission from the battery pack 1 to the battery management unit 11, and being beneficial to reducing the space occupied by the first circuit board 1211 along its length and width directions, further improving the space utilization rate in the battery pack 1.

[0034] In a possible implementation, as Figures 4-6 shown, the integrated busbar further includes connectors. The integrated busbar of the first battery module 12 includes at least 2n - 1 connectors, and each circuit layer of the first circuit board 1211 is electrically connected to at least one of the 2n - 1 connectors.

[0035] Specifically, in this embodiment, the connectors are used to plug in the wire harness 17, so that the connectors are used to ensure communication and power transmission between the battery management unit 11 and the battery module. For example, when n is equal to 2, the integrated busbar of the first battery module 12 includes at least 3 connectors. The first circuit layer 1211a is electrically connected to at least one connector, and this connector is electrically connected to the battery management unit 11 via the wire harness 17, improving the feasibility and reliability of the battery management unit 11 sampling the first battery module 12. The second circuit layer 1211b is electrically connected to at least two connectors. One of the two connectors is electrically connected to the battery module with the farthest signal transmission distance from the battery management unit 11 (in this example, it refers to other battery modules adjacent to the first battery module 12) via the wire harness 17, and the other end is electrically connected to the battery management system, improving the feasibility and reliability of the battery management unit 11 sampling the battery module with the farthest signal transmission distance from the battery management unit 11.

[0036] Therefore, the integrated busbar of the first battery module 12 includes at least 2n - 1 connectors, and each of the n circuit layers of the first circuit board 1211 is electrically connected to at least one of the 2n - 1 connectors, so that each battery module can be electrically connected to the battery management unit 11 via the wire harness 17 and the connectors through the first battery module 12, realizing the sequential transmission from the battery module with the farthest signal transmission distance from the battery management unit 11 in the battery pack 1 towards the battery module closer to the battery management unit 11 until the signal is transmitted to the battery management unit 11. That is, by providing multiple circuit layers and connectors corresponding to each circuit layer on the first battery module 12, the state information of each battery module in the battery pack 1 is evenly divided and transmitted during the process of transmitting to the battery management unit 11, further improving the reliability and accuracy of the battery management unit 11 collecting data from each battery module. At the same time, by quickly plugging in the wire harness 17 with the connectors, the wire harness 17 is shorter, and thus the resistance of the shorter circuit is smaller, making the sampled information more accurate and reliable.

[0037] In a possible implementation, as Figure 2 , Figures 6-8As shown, the circuit boards of at least some of the at least two battery modules include n circuit layers distributed along their own thickness directions, the integrated busbars of at least some of the at least two battery modules include at least 2n - 1 connectors, and at least some of the circuit layers of the circuit boards other than the first circuit board 1211 are electrically connected to at least one of the 2n - 1 connectors.

[0038] In some embodiments, the first battery module 12 includes a first integrated busbar 121. The other battery modules except the first battery module 12 can all include n circuit layers and 2n - 1 connectors, and the way the 2n - 1 connectors in the other battery modules except the first battery module 12 are electrically connected to the corresponding n circuit layers is the same as the electrical connection way between the connectors and the circuit layers in the first battery module 12. That is, the structures of the integrated busbars in the other modules can be the same as that of the first integrated busbar 121, so as to be processed and assembled together during the production process, improving the production efficiency.

[0039] In a possible implementation manner, as Figure 2 and Figures 4-10 shown, the at least two battery modules further include a second battery module 14. The second battery module 14 is electrically connected to the battery management unit 11 through all the battery modules except the second battery module 14. That is, the second battery module 14 refers to the battery module with the farthest signal transmission distance from the battery management unit 11.

[0040] The second circuit board 1411 of the second battery module 14 includes at least one circuit layer. The integrated busbar of the second battery module 14 includes at least one connector, and the at least one connector is electrically connected to the at least one circuit layer. Along the signal transmission direction from the second battery module 14 to the battery management unit 11, the number of circuit layers of the circuit boards of each battery module gradually increases, the number of connectors of the integrated busbars of each battery module gradually increases, and at least some of the connectors of adjacent battery modules are electrically connected.

[0041] In this embodiment, along the signal transmission direction from the second battery module 14 to the battery management unit 11, that is, the direction of transmitting signals from the battery module at the rear end to the battery modules at the front end in sequence, the number of circuit layers of the circuit boards of each battery module gradually increases, so that the battery modules at the front end have enough circuit layers and connectors for electrically connecting to multiple battery modules at the rear end, improving the feasibility and reliability of transmitting signals from the second battery module 14 through multiple battery modules to the battery management unit 11.

[0042] Specifically, along the signal transmission direction from the second battery module 14 to the battery management unit 11, the number of circuit layers of adjacent battery modules increases by one, and the number of connectors also increases by two in sequence, which is beneficial to saving material consumption and reducing the cost of the battery pack 1.

[0043] In a possible implementation, as Figure 1 , Figures 4-7 shown, since the battery modules are arranged in sequence along the length direction of the battery pack 1, along the length direction of the battery pack 1, each connector is located at the end of each battery module, so that the wiring harness 17 is connected between the connectors located at the ends, avoiding the wiring harness 17 directly contacting high-voltage heating components such as the battery cells 13, which is beneficial to improving the use safety and lifespan of the battery pack 1. At the same time, the connectors being located at both ends of the battery module is beneficial to reducing the length of the wiring harness 17 used to connect two connectors, thereby being beneficial to reducing costs and improving the space utilization rate within the battery pack 1.

[0044] In addition, along the length direction of the battery pack 1, multiple connectors within the same battery module are distributed in a staggered manner, reducing the risk of interference between multiple connectors on the same integrated busbar during the assembly process of the connectors, reducing the assembly difficulty, and at the same time being beneficial to improving the firmness and stability of the connectors installed on the battery module, and further being beneficial to improving the structural stability of the battery pack 1.

[0045] In a possible implementation, as Figures 2-6 Figure 8 , and Figure 10 shown, the battery pack 1 includes two battery modules, that is, when n is equal to 2, the first battery module 12 at least includes a first connector 1212, a second connector 1213, and a third connector 1214. Along the thickness direction of the first circuit board 1211, the first connector 1212 is located on one side of the first circuit board 1211, and both the second connector 1213 and the third connector 1214 are located on the other side of the first circuit board 1211, and the first connector 1212 is electrically connected to the first circuit layer 1211a, and both the second connector 1213 and the third connector 1214 are electrically connected to the second circuit layer 1211b. The first connector 1212 and the second connector 1213 are respectively electrically connected to the battery management unit 11 via the corresponding wiring harnesses 17 one by one.

[0046] The second battery module 14 includes a second integrated busbar 141. The second circuit board 1411 at least includes a third circuit layer 1411a, and the second battery module 14 at least includes a fourth connector 1412. The third circuit layer 1411a is electrically connected to the fourth connector 1412, and the fourth connector 1412 is electrically connected to the third connector 1214 via the wiring harness 17, so that the signals of the second battery module 14 are sequentially transmitted to the battery management unit 11 via the fourth connector 1412, the third connector 1214, and the second connector 1213.

[0047] When the battery pack 1 is operating, the third circuit layer 1411a of the second battery module 14 collects the status information of the battery cells 13 in the second battery module 14 and converts it into a signal. Then the signal is transmitted from the fourth connector 1412 through the wire harness 17 to the third connector 1214. Then the signal is transmitted through the third connector 1214 and the second circuit layer 1211b to the second connector 1213. Then the signal is transmitted from the second connector 1213 through the wire harness 17 to the battery management unit 11, realizing the sampling of the second battery module 14 by the battery management unit 11. At the same time, the first circuit layer 1211a of the first battery module 12 collects the status information of the battery cells 13 in the first battery module 12 and converts it into a signal, so that the signal is transmitted from the first connector 1212 through the wire harness 17 to the battery management unit 11, realizing the sampling of the first battery module 12 by the battery management unit 11, thereby realizing the sequential acquisition and output of the signals of the battery cells 13 in the battery module from the back end to the front end, which is beneficial to optimizing the layout of the wire harness 17 in the battery pack 1, improving the neatness of the wiring, further improving the assembly efficiency in the battery pack 1, reducing the production cost, and being beneficial to improving the space utilization rate in the battery pack 1.

[0048] In addition, the first connector 1212 is located on the upper surface of the first circuit board 1211, the second connector 1213 and the third connector 1214 are located on the lower surface of the first circuit board 1211, and the fourth connector 1412 is located on the upper surface of the second circuit board 1411, so that personnel can electrically connect the connector on the upper surface of the second circuit board 1411 in the second battery module 14 at the back end to a connector on the lower surface of the first circuit board 1211 in the first battery module 12 at the front end through the wire harness 17, so that personnel can quickly identify the wiring, further improving the assembly efficiency of the battery pack 1.

[0049] In a possible implementation manner, such as Figures 7-10As shown, the battery pack 1 includes three battery modules. That is, when n equals 3, a third battery module 15 with electrical connection is provided between the first battery module 12 and the second battery module 14, so that the first battery module 12 and the second battery module 14 transmit signals through the third battery module 15. The first circuit board 1211 further includes a fourth circuit layer 1211c. The first battery module 12 includes at least a first connector 1212, a second connector 1213, a third connector 1214, a fifth connector 1215, and a sixth connector 1216. Along the thickness direction of the first circuit board 1211, the first connector 1212 is located on one side of the first circuit board 1211, and the second connector 1213, the third connector 1214, the fifth connector 1215, and the sixth connector 1216 are all located on the other side of the first circuit board 1211. The first connector 1212 is electrically connected to the first circuit layer 1211a, the second connector 1213 and the third connector 1214 are electrically connected to the second circuit layer 1211b, and the fifth connector 1215 and the sixth connector 1216 are electrically connected to the fourth circuit layer 1211c. The first connector 1212, the second connector 1213, and the fifth connector 1215 are respectively electrically connected to the battery management unit 11 through the corresponding wire harnesses 17.

[0050] The second circuit board 1411 includes at least a third circuit layer 1411a, and the second battery module 14 includes at least a fourth connector 1412.

[0051] The third battery module 15 includes a third integrated busbar 151. The third integrated busbar 151 includes a third circuit board 1511. The third circuit board 1511 includes at least a fifth circuit layer 1511a and a sixth circuit layer 1511b. The third battery module 15 includes at least a seventh connector 1512, an eighth connector 1513, and a ninth connector 1514. Along the thickness direction of the third circuit board 1511, the seventh connector 1512 is located on one side of the third circuit board 1511, and the eighth connector 1513 and the ninth connector 1514 are both located on the other side of the third circuit board 1511. The seventh connector 1512 is electrically connected to the fifth circuit layer 1511a, and the eighth connector 1513 and the ninth connector 1514 are both electrically connected to the sixth circuit layer 1511b. The seventh connector 1512 is electrically connected to the third connector 1214 through the wire harness 17, so that the signal of the third battery module 15 is transmitted to the battery management unit 11 through the seventh connector 1512, the third connector 1214, and the second connector 1213 in sequence.

[0052] Meanwhile, the eighth connector 1513 is electrically connected to the sixth connector 1216 via the wire harness 17, and the ninth connector 1514 is electrically connected to the fourth connector 1412 via the wire harness 17, so that the signals of the second battery module 14 are transmitted to the battery management unit 11 through the fourth connector 1412, the ninth connector 1514, the eighth connector 1513, the sixth connector 1216, and the fifth connector 1215 in sequence.

[0053] When the battery pack 1 is operating, the third circuit layer 1411a of the second battery module 14 collects the state information of the battery cells 13 in the second battery module 14 and converts it into signals. Then the signals are transmitted from the fourth connector 1412 via the wire harness 17 to the ninth connector 1514, then from the ninth connector 1514 via the sixth circuit layer 1511b to the eighth connector 1513, then from the eighth connector 1513 via the wire harness 17 to the sixth connector 1216, then from the sixth connector 1216 via the fourth circuit layer 1211c to the fifth connector 1215, and then from the fifth connector 1215 via the wire harness 17 to the battery management unit 11, realizing the sampling of the second battery module 14 by the battery management unit 11. Meanwhile, the fifth circuit layer 1511a of the third battery module 15 collects the state information of the battery cells 13 in the third battery module 15 and converts it into signals. Then the signals are transmitted from the seventh connector 1512 via the wire harness 17 to the third connector 1214, then from the third connector 1214 via the second circuit layer 1211b to the second connector 1213, and then from the second connector 1213 via the wire harness 17 to the battery management unit 11, realizing the sampling of the third battery module 15 by the battery management unit 11. Meanwhile, the first circuit layer 1211a of the first battery module 12 collects the state information of the battery cells 13 in the first battery module 12 and converts it into signals, so that the signals are transmitted from the first connector 1212 via the wire harness 17 to the battery management unit 11, realizing the sampling of the first battery module 12 by the battery management unit 11.

[0054] In summary, by arranging multiple circuit layers on the circuit board and connecting each battery module electrically through connectors in sequence, the signals of the battery cells 13 in the battery module can be collected and output sequentially from the back end to the front end, which is beneficial to optimizing the layout of the wire harness 17 in the battery pack 1, improving the wiring neatness, further improving the assembly efficiency in the battery pack 1, reducing the production cost, and being beneficial to improving the space utilization rate in the battery pack 1.

[0055] In addition, in this embodiment, along the height direction of the battery module, the fifth connector 1215, the sixth connector 1216, the eighth connector 1513, and the ninth connector 1514 are all located at the same height along the height direction of the battery module, which is beneficial to reducing the length of the wire harness 17, reducing the space occupied by the wire harness 17 along the height direction of the battery module, and facilitating the personnel to connect wires layer by layer along the height direction, improving the accuracy and convenience of wiring.

[0056] In addition, as Figure 6 and Figure 7 in the embodiments, other integrated busbars except the first integrated busbar 121 can be provided with the same number of circuit layers and connectors as those in the first integrated busbar 121, which is convenient for centralized production of the integrated busbars. During assembly, the personnel only need to select and connect wires according to the actual number of battery modules set in the battery pack 1, that is, there is no need to add a process of arranging the position order of different battery modules separately, which is beneficial to improving the production efficiency of the battery pack 1.

[0057] In a possible implementation manner, as Figures 8-10 shown, the circuit board further includes a substrate layer 161. Along the thickness direction of the battery pack 1, a circuit layer is provided on the surface of the substrate layer 161. The material of the circuit layer is copper foil, and the thickness D1 of the circuit layer satisfies: 10um ≤ D1 ≤ 35um, and the thickness D2 of the substrate layer 161 satisfies: 10um ≤ D2 ≤ 25um. Among them, D1 can be 10um, 11um, 12um, 13um, 14um, 15um, 16um, 17um, 18um, 19um, 20um, 21um, 22um, 23um, 24um, 25um, 26um, 27um, 28um, 29um, 30um, 31um, 32um, 33um, 34um, 35um, etc. D2 can be 10um, 11um, 12um, 13um, 14um, 15um, 16um, 17um, 18um, 19um, 20um, 21um, 22um, 23um, 24um, 25um, etc.

[0058] When D1 is too large, that is, the circuit layer is too thick, it greatly increases the thickness of the circuit board, causing material waste; when D1 is too small, that is, the circuit layer is too thin, the internal resistance of the circuit layer is too large, which is likely to cause the circuit board to overheat and have a risk of burning out, reducing the safety of the battery pack 1.

[0059] Therefore, satisfying 10um ≤ D1 ≤ 35um is beneficial to improving the use safety of the battery pack 1 and will not cause material waste at the same time.

[0060] When D2 is too large, that is, the substrate layer 161 is too thick, it greatly increases the thickness of the circuit board and causes material waste; when D2 is too small, that is, the substrate layer 161 is too thin, the internal resistance of the substrate layer 161 greatly increases, easily causing the circuit board to overheat and having the risk of burning out, reducing the safety of the battery pack 1. At the same time, it greatly reduces the structural strength of the circuit, and there is a risk of fracture.

[0061] Therefore, satisfying 10um ≤ D2 ≤ 25um is beneficial to improving the use safety of the battery pack 1, and at the same time making the structural strength of the circuit board moderate without causing material waste.

[0062] In a possible implementation manner, as Figure 8 and Figure 10 , along the thickness direction of the battery pack 1, a protective layer 162 is provided on the surface of the circuit layer. The protective layer 162 is a polyimide film (Polyimide - PI film) and an adhesive layer, so that the protective layer 162 has good dielectric properties. Thus, the protective layer 162 can be used to isolate multiple circuit layers arranged along the thickness direction of the circuit board, enabling the battery management system to shunt - collect information of different battery modules. The circuit board further includes a top layer 163 and a bottom layer 164 connected to the protective layer 162. The top layer 163 and the bottom layer 164 are SMT (Surface Mount Technology - surface mount technology) patch adhesives, mainly used for mounting surface - mount devices (Surface Mount Device - SMD) on the surface of the circuit board.

[0063] Specifically, as Figures 8-10 shown, the protective layer 162 is provided between the top layer 163 and the circuit layer, and between the bottom layer 164 and the circuit layer. At the same time, as Figure 10 shown, the protective layer 162 is provided between two adjacent circuit layers to improve the reliability and accuracy of sampling of the battery pack 1.

[0064] Among them, the thickness D3 of the protective layer 162 satisfies: 30um ≤ D3 ≤ 50um. D3 can be 30um, 31um, 32um, 33um, 34um, 35um, 36um, 37um, 38um, 39um, 40um, 41um, 42um, 43um, 44um, 45um, 46um, 47um, 48um, 49um, 50um, etc.

[0065] When D3 is too large, that is, the protective layer 162 is relatively thick, it greatly increases the thickness of the protective layer 162 and causes material waste; when D3 is too small, that is, the protective layer 162 is relatively thin, the dielectric properties of the protective layer 162 are reduced, and there is a risk of short - circuit in the circuit board, greatly reducing the use safety.

[0066] Therefore, satisfying 30um ≤ D3 ≤ 50um is beneficial to improving the usage safety of the battery pack 1 and will not cause material waste.

[0067] In a possible implementation manner, as Figure 5 shown, the integrated busbar further includes a plurality of thermistors 182 and a plurality of metal bars 181. The metal bars 181 are electrically connected to the circuit board via nickel sheets. The thermistors 182 can be arranged on the nickel sheets. The thermistors 182 are used to detect the temperature of the battery module and can protect the battery module from overheating, which is beneficial to further improving the usage safety of the battery pack 1.

[0068] The above are only the specific implementation manners of the embodiments of the present application, but the protection scope of the embodiments of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiments of the present application should be covered within the protection scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application shall be subject to the protection scope of the claims.

Claims

1. A battery pack, characterized in that: The battery pack (1) comprises at least two battery modules and a wiring harness (17) for electrically connecting the plurality of battery modules, the battery pack (1) further comprising a battery management unit (11), the at least two battery modules comprising a first battery module (12) directly electrically connected to the battery management unit (11); The battery module comprises an integrated busbar and a battery cell (13) electrically connected to the integrated busbar, the integrated busbar comprises a circuit board, the first battery module (12) comprises a first circuit board (1211), the first circuit board (1211) comprises at least a first circuit layer (1211a) and a second circuit layer (1211b), the first circuit layer (1211a) being used to transmit signals of the first battery module (12) to the battery management unit (11), and the second circuit layer (1211b) being used to electrically connect to other battery modules adjacent to the first battery module (12), so that signals of other battery modules adjacent to the first battery module (12) are transmitted to the battery management unit (11) via the second circuit layer (1211b).

2. The battery pack according to claim 1, characterized in that: The battery pack (1) comprises n battery modules, and n≥2 is satisfied; the first circuit board (1211) comprises n circuit layers distributed along its own thickness direction.

3. The battery pack according to claim 2, characterized in that: The integrated busbar further comprises a connector, the integrated busbar of the first battery module (12) comprises at least 2n-1 connectors, and each circuit layer of the first circuit board (1211) is electrically connected to at least one of the 2n-1 connectors.

4. The battery pack according to claim 3, characterized in that: The circuit boards of at least some of the battery modules among the at least two battery modules include n circuit layers distributed along the thickness direction thereof, the integrated busbars of at least some of the battery modules among the at least two battery modules include at least 2n-1 connectors, and at least some of the circuit layers of other circuit boards except the first circuit board (1211) are electrically connected to at least one of the 2n-1 connectors respectively.

5. The battery pack according to claim 3, characterized in that: The at least two battery modules further include a second battery module (14), wherein the second battery module (14) is electrically connected to the battery management unit (11) via all battery modules except the second battery module (14); The second circuit board (1411) of the second battery module (14) comprises at least one circuit layer, and the integrated busbar of the second battery module (14) comprises at least one connector, and the at least one connector is electrically connected to the at least one circuit layer; Along the transmission direction of the signal from the second battery module (14) to the battery management unit (11), the number of circuit layers of the circuit board of each battery module gradually increases, the number of connectors of the integrated busbar of each battery module gradually increases, and at least some of the connectors of adjacent battery modules are electrically connected.

6. The battery pack according to claim 3, characterized in that: Along the length direction of the battery pack (1), each of the connectors is located at the end of each of the battery modules; Along the length direction of the battery pack (1), the plurality of connectors in the same battery module are distributed in a staggered manner.

7. The battery pack according to claim 5, characterized in that: The battery pack (1) comprises two battery modules, the first battery module (12) comprising at least a first connector (1212), a second connector (1213) and a third connector (1214); along the thickness direction of the first circuit board (1211), the first connector (1212) is located on one side of the first circuit board (1211), the second connector (1213) and the third connector (1214) are both located on the other side of the first circuit board (1211), and the first connector (1212) is electrically connected to the first circuit layer (1211a), the second connector (1213) and the third connector (1214) are both electrically connected to the second circuit layer (1211b), and the first connector (1212) and the second connector (1213) are respectively electrically connected to the battery management unit (11) via the corresponding wiring harness (17); The second circuit board (1411) includes at least a third circuit layer (1411a), and the second battery module (14) includes at least a fourth connector (1412), the third circuit layer (1411a) is electrically connected to the fourth connector (1412), and the fourth connector (1412) is electrically connected to the third connector (1214) via the wiring harness (17), so that the signal of the second battery module (14) is transmitted to the battery management unit (11) via the fourth connector (1412), the third connector (1214) and the second connector (1213) in sequence.

8. The battery pack according to claim 5, characterized in that: The battery pack (1) comprises three battery modules, a third battery module (15) electrically connected is arranged between the first battery module (12) and the second battery module (14), so that the first battery module (12) and the second battery module (14) transmit signals via the third battery module (15), the first circuit board (1211) further comprises a fourth circuit layer (1211c), the first battery module (12) comprises at least a first connector (1212), a second connector (1213), a third connector (1214), a fifth connector (1215) and a sixth connector (1216), along the thickness direction of the first circuit board (1211), the first connector (1212) is located on one side of the first circuit board (1211), the second connector (1213) is located on one side of the first circuit board (1211), and the third connector (1214) is located on one side of the first circuit board (1216). The first connector (1212), the third connector (1214), the fifth connector (1215) and the sixth connector (1216) are all located on the other side of the first circuit board (1211), and the first connector (1212) is electrically connected to the first circuit layer (1211a), the second connector (1213) and the third connector (1214) are electrically connected to the second circuit layer (1211b), the fifth connector (1215) and the sixth connector (1216) are electrically connected to the fourth circuit layer (1211c), and the first connector (1212), the second connector (1213) and the fifth connector (1215) are electrically connected to the battery management unit (11) via the corresponding wiring harness (17); The second circuit board (1411) comprises at least a third circuit layer (1411a), and the second battery module (14) comprises at least a fourth connector (1412); The third battery module (15) comprises a third circuit board (1511), the third circuit board (1511) comprises at least a fifth circuit layer (1511a) and a sixth circuit layer (1511b), the third battery module (155) comprises at least a seventh connector (1512), an eighth connector (1513) and a ninth connector (1514), and along the thickness direction of the third circuit board (1511), the seventh connector (1512) is located on one side of the third circuit board (1511), and the eighth connector (1513) and the ninth connector (1514) are both located on the third circuit board (1511). On the other side of the board (1511), the seventh connector (1512) is electrically connected to the fifth circuit layer (1511a), the eighth connector (1513) and the ninth connector (1514) are both electrically connected to the sixth circuit layer (1511b), and the seventh connector (1512) is electrically connected to the third connector (1214) via the wiring harness (17), so that the signal of the third battery module (15) is transmitted to the battery management unit (11) via the seventh connector (1512), the third connector (1214), and the second connector (1213) in sequence; The eighth connector (1513) is electrically connected to the sixth connector (1216) via the wiring harness (17), and the ninth connector (1514) is electrically connected to the fourth connector (1412) via the wiring harness (17), so that the signal of the second battery module (14) is transmitted to the battery management unit (11) in sequence via the fourth connector (1412), the ninth connector (1514), the eighth connector (1513), the sixth connector (1216) and the fifth connector (1215).

9. The battery pack according to any one of claims 1 to 8, characterized in that: The circuit board further comprises a substrate layer (161); along the thickness direction of the battery pack (1), the circuit layer is provided on the surface of the substrate layer (161); the material of the circuit layer is copper foil, and the thickness D1 of the circuit layer satisfies: 10um≤D1≤35um; the thickness D2 of the substrate layer (161) satisfies: 10um≤D2≤25um.

10. The battery pack according to any one of claims 1 to 8, characterized in that: Along the thickness direction of the battery pack (1), a protective layer (162) is provided on the surface of the circuit layer, the protective layer (162) is a polyimide film and an adhesive layer, the circuit board further comprises a top layer (163) and a bottom layer (164) connected to the protective layer (162), the top layer (163) and the bottom layer (164) are SMT patch adhesives; The thickness D3 of the protective layer (162) satisfies: 30um≤D3≤50um.

Images