Battery management system, battery system and electric equipment

Abstract

The utility model provides a battery management system, a battery system and electric equipment. The battery management system comprises a pre-charging circuit and a heating circuit, the pre-charging circuit is connected between a battery pack and a load capacitor, the heating circuit is connected to the two ends of the battery pack in parallel, and the heating circuit comprises a heating element used for heating the battery pack; the pre-charging circuit comprises a first switch element and a heating element, and the first switch element and the heating element are connected in series to form a pre-charging branch circuit which is used for charging the load capacitor. According to the utility model, by multiplexing the heating element, the heating characteristic of the heating element can be utilized to heat the battery pack, the original pre-charging resistor in the pre-charging circuit can be replaced in the pre-charging process, and the pre-charging of the load capacitor is realized by utilizing the resistance characteristic of the heating element; therefore, a pre-charging resistor is not needed any more, the space area can be saved, and the cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to power battery technical field especially relates to a battery management system, battery system and electric equipment. BACKGROUND

[0002] Battery management system (BMS) is one of the core systems for monitoring and controlling the running state of battery pack in new energy vehicles. Its main functions include battery charge and discharge management, thermal management, safety protection, etc. to ensure that the battery works stably and efficiently under various working conditions.

[0003] In the related art, a pre-charging circuit is considered to be arranged in the battery management system, and the load capacitor is pre-charged through the pre-charging relay and the pre-charging resistor to avoid large current impact in the power-on moment. However, since the pre-charging resistor is mostly traditional cement resistor or aluminum shell resistor, etc., not only the space area is occupied, which is not conducive to structure optimization, but also mechanical damage is easily caused in the assembly process, thereby affecting the safety and reliability of vehicle operation. UTILITY MODEL CONTENT

[0004] The utility model embodiment provides a battery management system, battery system and electric equipment, not only can improve the instantaneous impact current, but also can reduce the circuit volume and cost, improve the safety and reliability of vehicle operation.

[0005] The technical scheme of the utility model embodiment is implemented as follows:

[0006] In a first aspect, the utility model embodiment provides a battery management system, which comprises a pre-charging circuit and a heating circuit, the pre-charging circuit is connected between the battery pack and the load capacitor, and the heating circuit is connected in parallel across the battery pack, wherein: the heating circuit comprises a heating element for heating the battery pack; the pre-charging circuit comprises a first switching element and a heating element, and the first switching element and the heating element are connected in series to form a pre-charging branch for charging the load capacitor.

[0007] By the above technical means, the heating element is reused, which not only utilizes the heating characteristics of the heating element to heat the battery pack, but also replaces the original pre-charging resistor in the pre-charging circuit to utilize the resistance characteristics of the heating element to realize current-limiting pre-charging of the load capacitor. In this way, since the pre-charging resistor is no longer needed, the pre-charging and heating functions are realized by reusing the heating element, so that the instantaneous impact current is improved, the circuit volume and cost are reduced, the space layout of the high-voltage box is optimized, the space of the high-voltage box is saved, and the safety and reliability of vehicle operation are improved.

[0008] In some embodiments, the battery management system further includes a second switching element and a third switching element, wherein: the second switching element is connected in parallel across the two ends of the pre-charge circuit; and the third switching element is connected in series between the negative terminal of the battery pack and the load capacitor.

[0009] By using the above-mentioned technical means, a second switching element is set in parallel on the pre-charging circuit, and a third switching element is set in series between the negative terminal of the battery pack and the load capacitor. This allows for a quick switch to the main circuit after pre-charging is completed, enabling the battery pack to provide high-voltage electricity to the load capacitor. This further optimizes the electrical path between the battery pack and the load capacitor, preventing the load capacitor from being powered by high voltage before pre-charging is complete, and improving the safety of the battery management system.

[0010] In some embodiments, the heating circuit further includes a fourth switching element, wherein the fourth switching element and the heating element are connected in series; the heating circuit is used to heat the battery pack when the fourth switching element, the second switching element and the third switching element are all closed.

[0011] Through the aforementioned technical means and the coordinated control of multiple switching elements, the heating process can be precisely managed, avoiding simultaneous heating and pre-charging, and reducing the mutual interference between heating and pre-charging.

[0012] In some embodiments, the battery management system further includes a protection device, wherein the protection device is connected in series on the connection between the battery pack and the precharge circuit.

[0013] By using the above-mentioned technical means and setting up protective devices, the current path can be cut off in time under abnormal conditions to prevent damage caused by overcurrent or short circuit, thereby improving the safety protection capability of the battery management system.

[0014] In some embodiments, the battery management system further includes a first voltage detection circuit and a second voltage detection circuit, wherein: the first voltage detection circuit is connected to the connection between the positive terminal of the battery pack and the pre-charge circuit; and the second voltage detection circuit is connected to the connection between the pre-charge circuit and the load capacitor.

[0015] By employing the aforementioned technical means and setting up two voltage detection circuits, it is possible to monitor changes in battery pack voltage and load terminal voltage in real time, providing accurate judgment basis for the battery management system and ensuring the safety and accuracy of the pre-charging process.

[0016] In some embodiments, the battery management system further includes a current detection circuit, wherein the current detection circuit is connected in series on the connection between the negative terminal of the battery pack and the load capacitor.

[0017] By employing the aforementioned technical means and setting up a current detection circuit, the current in the circuit can be monitored in real time, which helps to identify potential faults and take timely measures, thereby improving the operational stability of the battery management system.

[0018] In some embodiments, the battery management system further includes a fifth switching element and a sixth switching element, wherein: the fifth switching element is connected in series on the connection between the positive terminal of the battery pack and the charging port; the sixth switching element is connected in series on the connection between the negative terminal of the battery pack and the charging port; wherein, when the fifth switching element and the sixth switching element are turned on, the battery pack charges the device to be charged connected to the charging port.

[0019] By using the aforementioned technical means and setting up switching elements related to the charging port, the battery management system not only has pre-charging and heating functions, but can also serve as a power output interface for the device to be charged, thus expanding the functionality of the battery management system and improving its overall utilization rate.

[0020] In some embodiments, the heating element includes a heating film, wherein: the heating circuit includes the entire heating film; and the pre-charging circuit includes a portion of the heating film.

[0021] By employing the aforementioned technical means and rationally dividing the use of the heating film in pre-charging and heating modes, it can both meet the current limiting function required for pre-charging and provide full heating function when needed, thus achieving efficient resource utilization. At the same time, it can also overcome the problem of excessively small pre-charging current and excessively long pre-charging time caused by using the entire heating film as a pre-charging resistor, thereby improving pre-charging efficiency.

[0022] In a second aspect, embodiments of the present invention provide a battery system, the battery system including a battery pack and a battery management system as described in any one of the first aspects above.

[0023] Thirdly, this utility model embodiment provides an electrical device, which includes the battery system described in the second aspect above. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a battery management system in related technologies;

[0025] Figure 2 This is a schematic diagram of the structure of a battery management system provided in an embodiment of the present invention. Figure 1 ;

[0026] Figure 3 This is a schematic diagram of the structure of a battery management system provided in an embodiment of the present invention. Figure 2 ;

[0027] Figure 4This is a schematic diagram of the structure of a battery management system provided in an embodiment of the present invention. Figure 3 ;

[0028] Figure 4 This is a schematic diagram of the structure of a battery management system provided in an embodiment of the present invention. Figure 6 ;

[0029] Figure 5 This is a schematic diagram of the structure of a battery management system provided in an embodiment of the present invention. Figure 7 ;

[0030] Figure 6 This is a schematic diagram of the structure of a battery management system provided in an embodiment of the present invention. Figure 8 ;

[0031] Figure 7 This is a schematic diagram of the structure of a battery management system provided in an embodiment of the present invention. Figure 9 ;

[0032] Figure 8 This is a schematic diagram of the structure of a battery management system provided in an embodiment of the present invention. Figure 10 ;

[0033] Figure 9 This is a schematic diagram of the structure of a battery management system provided in an embodiment of the present invention. Figure 11 ;

[0034] Figure 10 This is a schematic diagram of the structure of a battery management system provided in an embodiment of the present invention. Figure 12 ;

[0035] Figure 1 This is a flowchart illustrating a control method for a battery management system provided in an embodiment of the present invention. Figure 2 ;

[0036] Figure 3 This is a flowchart illustrating a control method for a battery management system provided in an embodiment of the present invention. Figure 4 ;

[0037] Figure 1 This is a flowchart illustrating a control method for a battery management system provided in an embodiment of the present invention. Figure 2 ;

[0038] Figures 3-11 This is a schematic diagram of the structure of a battery system provided in an embodiment of this utility model. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on the present utility model. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing embodiments of the invention only and is not intended to limit the invention.

[0041] In the following description, references to "some embodiments," "this embodiment," "this utility model embodiment," and examples, etc., describe a subset of all possible embodiments. However, it is understood that "some embodiments" may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0042] The descriptions such as "first," "second," and "third" appearing in the embodiments of this utility model do not have a specific meaning (such as no order, nor do they indicate a special limitation on the number of devices in the embodiments of this utility model), but are merely for the purpose of clearly describing the embodiments of this utility model and do not constitute any limitation on the embodiments of this utility model.

[0043] To facilitate understanding of the technical solutions of the embodiments of this utility model, the relevant technologies or terms of the embodiments of this utility model are described below. The following relevant technologies or terms are optional solutions and can be combined with the technical solutions of the embodiments of this utility model in any way, and all of them fall within the protection scope of the embodiments of this utility model.

[0044] Figures 4-11 This is a schematic diagram of the structure of a battery management system in related technologies, such as... Figure 4 As shown, the battery management system includes a first pre-charging circuit 101, a heating circuit 202, a load capacitor C1, a third switching element K3, a fifth switching element K5, a sixth switching element K6, a first voltage detection circuit V1, a second voltage detection circuit V2, a third voltage detection circuit V3, a current detection circuit A2, and a protection device F1.

[0045] The first pre-charging circuit 101 includes a pre-charging resistor R1, a first switching element K1, and a second switching element K2; the heating circuit 202 includes a fourth switching element K4 and a heating film A1.

[0046] Among them, the first switching element K1 can be used as a pre-charge relay; the second switching element K2 can be used as a main positive relay; the third switching element K3 can be used as a main negative relay; the fourth switching element K4 can be used as a heating relay; the fifth switching element K5 can be used as a charging positive relay; and the sixth switching element K6 can be used as a charging negative relay.

[0047] Specifically, the positive terminal U1+ of the battery pack is connected to the anode plate of the load capacitor C1, and the negative terminal U1- of the battery pack is connected to the cathode plate of the load capacitor C1; a second switching element K2 is connected in series on the line between the positive terminal U1+ of the battery pack and the anode plate of the load capacitor C1; a third switching element K3 is connected in series on the line between the negative terminal U1- of the battery pack and the cathode plate of the load capacitor C1.

[0048] The pre-charge resistor R1 and the first switching element K1 are connected in series and then in parallel across the two ends of the second switching element K2; the fourth switching element K4 and the heating film A1 are connected in series and then in parallel across the two ends of the battery pack; the charging port 30 is connected in parallel across the two ends of the battery pack, and the fifth switching element K5 is connected in series on the line between the positive terminal U1+ of the battery pack and the charging port 30, and the sixth switching element K6 is connected in series on the line between the negative terminal U1- of the battery pack and the charging port 30.

[0049] A protection device F1 is connected in series on the line between the positive terminal U1+ of the battery pack and the second switching element K2; a current detection circuit A2 is connected in series on the line between the negative terminal U1- of the battery pack and the third switching element K3; the sampling port of the first voltage detection circuit V1 is connected on the line between the protection device F1 and the second switching element K2; the sampling port of the second voltage detection circuit V2 is connected on the line between the second switching element K2 and the anode plate of the load capacitor C1; and the sampling port of the third voltage detection circuit V3 is connected on the line between the fifth switching element K5 and the charging port 30.

[0050] Since there are a large number of load capacitors C1 at the high-voltage electrical load end of the vehicle, in order to avoid the large current generated when the battery pack is powered on and impacting other electrical components such as relays, it is necessary to precharge the load capacitors C1 in the circuit through the precharge resistor R1; when the voltage of the load capacitors C1 at the load end is precharged to the preset voltage range, the power supply will start.

[0051] When pre-charging is required, the first switch element K1 and the third switch element K3 are closed to form a pre-charging circuit from the battery pack to the load capacitor C1, thus pre-charging the load capacitor C1. When the voltage of the load capacitor C1 is pre-charged to a preset voltage range, the second switch element K2 is closed and the first switch element K1 is opened, signifying the end of pre-charging. The battery pack then begins to officially supply power to the load, enabling the vehicle drive motor 40 to start working and drive the vehicle.

[0052] After the pre-charging is completed, if it is necessary to charge the device connected to the charging port 30, the fifth switch element K5 and the sixth switch element K6 are closed to enable the battery pack to supply power to the device connected to the charging port 30.

[0053] Since battery packs have poor charging / discharging performance when operating in low-temperature environments, they need to be heated first. Among them, the solution of heating the battery pack using heating film A1 is simple, easy to implement, and low in cost, and is widely used.

[0054] When it is necessary to heat the battery, the second switch element K2, the fourth switch element K4 and the third switch element K3 are all closed so that the heating film A1 heats the battery pack.

[0055] However, as Figures 5-11 The pre-charging scheme including the pre-charging resistor R1 has the following shortcomings: Firstly, the pre-charging resistor R1 is relatively large, occupying a significant amount of space when placed inside the high-voltage box. Secondly, since most pre-charging resistors R1 currently used in vehicles are cement resistors / aluminum shell resistors, their dimensional tolerances are difficult to minimize. This makes it difficult to control the assembly interference force caused by the large dimensional tolerance of the pre-charging resistor during the actual production and assembly of the high-voltage box. This may cause mechanical damage to the pre-charging resistor R1 during installation. If the pre-charging resistor R1 is damaged, it may lead to problems in actual use. There are risks of short circuits, open circuits, and even explosions, threatening the safe operation of the entire vehicle, and the material cost of the pre-charge resistor R1 is relatively high. On the other hand, since the heating film A1 is a high-voltage device with a large resistance value, the high-voltage pre-charge time of the pre-charge circuit will be exceeded during the heating process, and the pre-charge resistor R1 bears a large amount of energy under long-term operation. After a long-term start-up impact, the pre-charge resistor R1 may burn out due to excessive temperature. The first pre-charge circuit 101 and the heating circuit 202 are both controlled by the BMS. Under low temperature conditions, the first pre-charge circuit 101 and the heating circuit 202 will affect each other.

[0056] Based on this, this utility model provides a battery management system, a battery system, and an electrical device. The battery management system includes a pre-charging circuit and a heating circuit. The pre-charging circuit is connected between the battery pack and the load capacitor, and the heating circuit is connected in parallel across the two ends of the battery pack. The heating circuit includes a heating element for heating the battery pack. The pre-charging circuit includes a first switching element and a heating element, which are connected in series to form a pre-charging branch for charging the load capacitor. By reusing the heating element, not only can the heating characteristics of the heating element be used to heat the battery pack, but also, when pre-charging is required, it can replace the original pre-charging resistor in the pre-charging circuit, utilizing the resistive characteristics of the heating element to achieve current-limited pre-charging of the load capacitor. In this way, since the pre-charging resistor is no longer needed, the pre-charging and heating functions can be achieved by reusing the heating element. Therefore, while improving the instantaneous inrush current, the circuit volume and cost can also be reduced, thereby optimizing the spatial layout of the high-voltage box and saving space in the high-voltage box. In addition, since the pre-charging resistor is no longer needed in the pre-charging circuit, there is no problem of mechanical damage to the pre-charging resistor when it is installed in the high-voltage box, which can also improve the safety and reliability of the vehicle operation.

[0057] The battery management system provided in the embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0058] Figures 6-11 This is a schematic diagram of the structure of a battery management system provided in an embodiment of the present invention. Figures 7-11 ,like Figure 7 As shown. The battery management system 20 provided in this embodiment of the present invention includes a pre-charging circuit 201 and a heating circuit 202. The pre-charging circuit 201 is connected between the battery pack and the load capacitor C1, and the heating circuit 202 is connected in parallel across the two ends of the battery pack.

[0059] The heating circuit 202 includes a heating element for heating the battery pack; the pre-charging circuit 201 includes a first switching element K1 and a heating element, and the first switching element K1 and the heating element are connected in series to form a pre-charging branch for charging the load capacitor C1.

[0060] For example, the heating element may be a film heating element, such as a heating film.

[0061] In this embodiment, the battery management system 20 may or may not include the load capacitor C1, and the present invention does not impose any particular limitation on this.

[0062] The first switching element K1 can be a push-button switch, an electronic switch, a metal-oxide-semiconductor field-effect transistor (MOSET) (referred to as "MOS transistor"), a bipolar junction transistor (BJT) (referred to as "BJT transistor"), a relay, etc. This utility model does not make any special limitation in this regard. The following description will take the first switching element K1 as a relay as an example.

[0063] In one example, the first switching element K1 can function as a pre-charge relay, controlled by the battery management system 20. When pre-charging is required, the battery management system 20 controls the first switching element K1 (i.e., the pre-charge relay) in the pre-charge circuit 201 to close. At this time, current flows out from the positive terminal U1+ of the battery pack, through the heating circuit 202 and the first switching element K1, through the load capacitor C1, and finally to the negative terminal U1- of the battery pack.

[0064] In one example, the heating circuit 202 can be connected in parallel across the two ends of the battery pack. When heating is required, the battery management system 20 controls the heating circuit 202 to heat the battery pack.

[0065] It is understandable that in this embodiment, by reusing the heating element, not only can the heating characteristics of the heating element be used to heat the battery pack, but also, when pre-charging is required, it can replace the original pre-charging resistor in the pre-charging circuit, using the resistive characteristics of the heating element to achieve current-limited pre-charging of the load capacitor. Thus, since the pre-charging resistor is no longer needed, and the pre-charging and heating functions are achieved by reusing the heating element, the circuit size and cost are reduced while improving the instantaneous inrush current, thereby optimizing the spatial layout of the high-voltage box and saving space. Furthermore, since the pre-charging resistor is no longer needed in the pre-charging circuit, there is no issue of mechanical damage to the pre-charging resistor when it is installed in the high-voltage box, which also improves the safety and reliability of the entire vehicle operation.

[0066] As another alternative embodiment, such as Figure 9 As shown, the battery management system 20 provided in this embodiment of the present invention may further include a second switching element K2 and a third switching element K3.

[0067] Specifically, the second switching element K2 is connected in parallel across the two ends of the pre-charging circuit 201; the third switching element K3 is connected in series between the negative terminal U1- of the battery pack and the load capacitor C1.

[0068] In one alternative embodiment, the second switching element K2 may be connected at one end to the first switching element K1 in the pre-charging circuit 201, and at the other end to the positive terminal U1+ of the battery pack.

[0069] The second switching element K2 can be a push-button switch, an electronic switch, a MOSFET, a BJT, a relay, etc. This utility model does not make any special limitation in this regard. The following description will take the second switching element K2 as a relay as an example.

[0070] The third switching element K3 can be a push-button switch, an electronic switch, a MOSFET, a BJT, a relay, etc. This utility model does not make any special limitation in this regard. The following description will take the third switching element K3 as a relay as an example.

[0071] In one example, the second switching element K2 can act as the main positive relay, and the third switching element K3 can act as the main negative relay. When pre-charging is required, the battery management system 20 controls the first switching element K1 (i.e., the pre-charge relay) in the pre-charge circuit 201 to close, and controls the third switching element K3 (i.e., the main negative relay) to close. At this time, current flows out from the positive terminal U1+ of the battery pack, flows through the heating circuit 202 and the first switching element K1, then flows through the load capacitor C1 and the third switching element K3, and finally reaches the negative terminal U1- of the battery pack. When the voltage of the load capacitor C1 is pre-charged to the preset voltage range, the second switching element K2 (i.e., the main positive relay) is controlled to close, and the first switching element K1 (i.e., the pre-charge relay) is controlled to open, so that the battery pack can officially supply power to the downstream load.

[0072] For example, the back-end load can be the vehicle drive motor.

[0073] For example, the preset voltage range can be 90% to 95% of the battery pack voltage.

[0074] In one example, the heating circuit 202 can be connected in parallel across the two ends of the battery pack. When heating is required, the battery management system 20 controls the heating circuit 202 to heat the battery pack.

[0075] It is understood that in this embodiment, the second switching element is connected in parallel to the pre-charging circuit, and the third switching element is connected in series between the negative terminal of the battery pack and the load capacitor. This allows for a quick switch to the main circuit after pre-charging is completed, enabling the battery pack to provide high-voltage power to the load capacitor and other downstream loads. This further optimizes the electrical path between the battery pack and the load capacitor, preventing the load capacitor from being powered by high voltage before pre-charging is complete, and improving the safety of the battery management system.

[0076] As another alternative embodiment, such asFigure 11 As shown, the heating circuit 202 provided in this embodiment of the present invention may further include a fourth switching element K4.

[0077] Specifically, the fourth switching element K4 and the heating element are connected in series and then in parallel across the two ends of the battery pack.

[0078] The fourth switching element K4 can be a push-button switch, an electronic switch, a MOSFET, a BJT, a relay, etc. This utility model does not make any special limitation in this regard. The following description will take the fourth switching element K4 as a relay as an example.

[0079] In one example, the fourth switching element K4 can function as a heating relay. When heating is required, the heating phase is executed first, followed by the pre-charge phase: the battery management system 20 controls the second switching element K2 (i.e., the main positive relay), the third switching element K3 (i.e., the main negative relay), and the fourth switching element K4 (i.e., the heating relay) to all close, thereby heating the battery pack. When the temperature of the battery pack is greater than or equal to a preset temperature, the fourth switching element K4 (i.e., the heating relay) is controlled to open to end the heating phase, and the first switching element K1 (i.e., the pre-charge relay) is controlled to close, while the second switching element K2 (i.e., the main positive relay) is controlled to open, thus initiating the pre-charge phase. When the voltage of the load capacitor C1 is pre-charged to within the preset voltage range, the second switching element K2 is controlled to close, and the first switching element K1 is controlled to open, thereby enabling the battery pack to formally supply power to the downstream load.

[0080] In another example, when heating is required, if a pre-charge phase is performed first, followed by a heating phase: the battery management system 20 controls both the first switch element K1 and the third switch element K3 to close to initiate the pre-charge phase. When the voltage of the load capacitor C1 is pre-charged to a preset voltage range, the second switch element K2 and the fourth switch element K4 are both closed, and the first switch element K1 is opened to heat the battery pack. When the temperature of the battery pack is greater than or equal to a preset temperature, the fourth switch element K4 is opened to end the heating phase, and the battery pack officially supplies power to the downstream load.

[0081] It is understood that, when the battery pack needs to be heated, the battery management system 20 provided by this utility model can either execute the pre-charge stage first and then the heating stage, or it can execute the heating stage first and then the pre-charge stage. This utility model does not impose any particular limitation, making the control of the battery management system 20 more flexible, and allowing it to prioritize either the pre-charge stage or the heating stage according to the user's needs. The following explanation will use the example of the battery management system 20 executing the pre-charge stage first and then the heating stage when the battery pack needs to be heated as an example.

[0082] It is understood that, in this embodiment, the heating process can be precisely managed through the coordinated control of multiple switching elements, avoiding simultaneous heating and precharging, and reducing the mutual influence between heating and precharging.

[0083] In one example, the heating element includes a heating film A1. The heating circuit 202 includes the entire heating film A1; the pre-charging circuit 201 includes a portion of the heating film A1.

[0084] The number of heating films A1 included in the pre-charging circuit 201 can be determined by the resistance value of the heating film A1 itself and the preset pre-charging time. For example, the number of heating films A1 connected in the pre-charging circuit 201 can be determined based on the required pre-charging resistance value and pre-charging time.

[0085] It should be noted that, in this embodiment, the heating film A1 is provided with a first end, a second end, and a third end. The first end and the second end are respectively located at opposite ends of the heating film A1, meaning the area between the first and second ends constitutes the entirety of the heating film A1. The third end is located on the film of the heating film A1; that is, the heating film A1 between the first and third ends is the first part of the heating film A1, and the heating film A1 between the second and third ends is the second part of the heating film A1. The first part and the second part of the heating film A1 together constitute the entirety of the heating film A1.

[0086] For example, the portion of the heating film A1 connected to the pre-charging circuit 201 can be one-half, one-quarter, or two-thirds of the entire heating film A1, etc., to prevent the problem of excessively long pre-charging time caused by a very small pre-charging current due to the large resistance value when the entire heating film A1 is used as a pre-charging resistor.

[0087] The circuit connection relationship is explained in detail below when the heating film A1 is provided with a first end, a second end, and a third end.

[0088] A fourth switching element K4 is provided on the first end of the heating film A1, and is connected to the positive electrode U1+ of the battery pack and the anode plate of the load capacitor C1 through the fourth switching element K4; a second switching element K2 is connected in series on the connection line between the positive electrode U1+ of the battery pack and the fourth switching element K4; the second end of the heating film A1 is connected to the second switching element K2 to connect one end of the positive electrode U1+ of the battery pack, the negative electrode U1- of the battery pack and the cathode plate of the load capacitor C1; a third switching element K3 is provided on the connection line between the second end of the heating film A1 and the negative electrode U1- of the battery pack; the third end of the heating film A1 is connected to the connection line between the second switching element K2 and the fourth switching element K4 through the first switching element K1.

[0089] For example, the heating film A1 between the second end and the third end of the heating film A1 is a part of the heating film A1 included in the pre-charging circuit 201. That is, the second part of the heating film A1 is a part of the heating film A1 included in the pre-charging circuit 201. The amount of the second part of the heating film A1 is determined by the resistance of the heating film A1 itself and the preset pre-charging time.

[0090] The following is based on Figure 8 Let's take an example to illustrate the working principle.

[0091] When the battery management system 20 detects that the temperature of the battery pack is greater than or equal to a preset temperature (i.e., the battery pack does not need to be heated), the battery management system 20 controls the first switching element K1 and the third switching element K3 to close, forming a pre-charge branch for the load capacitor C1, and pre-charging the load capacitor C1. The current flow direction of the pre-charge branch is as follows: the current starts from the positive terminal U1+ of the battery pack, flows through the second part of the heating film A1, passes through the first switching element K1 to reach the anode plate of the load capacitor C1, passes through the cathode plate of the load capacitor C1, flows through the third switching element K3, and returns to the negative terminal U1- of the battery pack.

[0092] When the voltage of the load capacitor C1 is pre-charged to the preset voltage range, the battery management system 20 controls the second switching element K2 to close and the first switching element K1 to open, forming a formal charging circuit for the load capacitor C1, providing normal high-voltage power supply to the load capacitor C1 and its downstream load. The current flow in the formal charging circuit is as follows: the current starts from the positive terminal U1+ of the battery pack, flows through the second switching element K2 to the anode plate of the load capacitor C1, passes through the cathode plate of the load capacitor C1, flows through the third switching element K3, and returns to the negative terminal U1- of the battery pack.

[0093] If the battery management system 20 detects that the temperature of the battery pack is lower than the preset temperature (i.e., the battery pack does not need to be heated), the battery management system 20 first executes the pre-charging phase, then the heating phase, and then the formal power supply phase.

[0094] The battery management system 20 controls the first switching element K1 and the third switching element K3 to close, forming a pre-charge branch for the load capacitor C1, thus pre-charging the load capacitor C1. When the voltage of the load capacitor C1 is pre-charged to within a preset voltage range, the battery management system 20 controls the second switching element K2 and the fourth switching element K4 to close, and the first switching element K1 to open, forming a heating circuit for the battery pack. When the temperature of the battery pack rises to a temperature greater than or equal to a preset temperature, the battery management system 20 controls the fourth switching element K4 to open, ending the heating of the battery pack and forming a formal charging circuit for the load capacitor C1, providing normal high-voltage power supply to the load capacitor C1 and its downstream load.

[0095] It is understandable that in this embodiment, by reasonably dividing the use of the heating film in the two modes of pre-charging and heating, the current limiting function required for pre-charging can be met, and the full heating function can be performed when needed, thus achieving efficient use of resources. At the same time, it can also overcome the problem that the pre-charging current is too small when the entire heating film is used as a pre-charging resistor, resulting in an excessively long pre-charging time, thereby achieving the goal of improving pre-charging efficiency.

[0096] As another alternative embodiment, such as Figure 10 As shown, the battery management system 20 provided in this embodiment of the present invention may further include a protection device F1.

[0097] In one example, without the second switching element K2, the protection device F1 can be connected in series in the connection between the battery pack and the pre-charge circuit 201. More specifically, the protection device F1 can be connected in series in the connection between the positive terminal U1+ of the battery pack and the pre-charge circuit 201.

[0098] In another example, with a second switching element K2, the protection device can be connected in series on the connection between the positive terminal U1+ of the battery pack and the second switching element K2.

[0099] In yet another example, the protection device F1 can also be connected in series on the connection between the negative terminal U1- of the battery pack and the third switching element K3.

[0100] This invention does not impose any particular limitation on the position of the protection device F1. The following description will take the connection between the protection device F1 and the positive terminal U1+ of the battery pack and the second switching element K2 as an example.

[0101] For example, the protection device F1 can be a fuse, a circuit breaker, etc., which can cut off the power supply branch in the event of a failure of the device to be protected.

[0102] It is understood that in this embodiment, the protective device can cut off the current path in time under abnormal circumstances, prevent damage caused by overcurrent or short circuit, and improve the safety protection capability of the battery management system.

[0103] As another alternative embodiment, such as Figures 9-11 As shown, the battery management system 20 provided in this embodiment of the present invention may further include a first voltage detection circuit V1 and a second voltage detection circuit V2.

[0104] In one example, without the second switch element K2 and the protection device F1, the acquisition terminal of the first voltage detection circuit V1 is connected to the connection between the positive terminal U1+ of the battery pack and the pre-charge circuit 201; the acquisition terminal of the second voltage detection circuit V2 is connected to the connection between the pre-charge circuit 201 and the load capacitor C1.

[0105] In another example, with the second switching element K2 and the protection device F1, the acquisition terminal of the first voltage detection circuit V1 is connected to the line between the protection device F1 and the second end of the heating film A1; the acquisition terminal of the second voltage detection circuit V2 is connected to the line between the third end of the heating film A1 and the fourth switching element K4.

[0106] The first voltage detection circuit V1 is used to detect the voltage of the battery pack, and the second voltage detection circuit V2 is used to detect the voltage of the load capacitor C1.

[0107] For example, both the first voltage detection circuit V1 and the second voltage detection circuit V2 can be voltage sensors.

[0108] In one example, the voltage of the load capacitor C1 can be pre-charged to a preset voltage range based on the detection results of the first voltage detection circuit V1 and the second voltage detection circuit V2. Exemplarily, in the pre-charging phase, the battery management system 20 controls the first switching element K1 and the third switching element K3 to close, forming a pre-charging branch for the load capacitor C1, and pre-charging the load capacitor C1. When the battery management system 20 detects that the voltage value collected by the second voltage detection circuit V2 is 90% to 95% of the voltage value collected by the first voltage detection circuit V1, it determines that the voltage of the load capacitor C1 has been pre-charged to the preset voltage range, controls the second switching element K2 to close, controls the first switching element K1 to open, and ends the pre-charging phase.

[0109] It is understood that in this embodiment, two voltage detection circuits are set up to monitor changes in battery pack voltage and load terminal voltage in real time, providing accurate judgment basis for the battery management system and ensuring the safety and accuracy of the pre-charging process.

[0110] As an optional embodiment, such as Figure 9 As shown, the battery management system 20 provided in this embodiment of the present invention may further include a current detection circuit A2.

[0111] Specifically, the current detection circuit A2 is connected in series on the line between the negative terminal U1- of the battery pack and the cathode plate of the load capacitor C1. Since the third switching element K3 is also connected in series on the line between the negative terminal U1- of the battery pack and the cathode plate of the load capacitor C1, this invention does not particularly limit the positional relationship between the current detection circuit A2 and the third switching element K3. In one example, such as...Figure 11 , Figure 10 and Figures 9-11 As shown, the current detection circuit A2 is connected in series on the line between the negative terminal U1- of the battery pack and the third switching element K3; in another example, as Figure 11 and Figure 11 As shown, the current detection circuit A2 is connected in series on the line between the third switching element K3 and the cathode plate of the load capacitor C1.

[0112] Among them, the current detection circuit A2 can be used to detect the current on the branch, providing a basis for the battery management system 20 to determine whether there is an abnormality or fault in the system.

[0113] For example, the current detection circuit A2 can be a current sensor.

[0114] It is understood that, in this embodiment, by setting a current detection circuit, the current in the circuit can be monitored in real time, which helps to identify potential faults and take timely measures, thereby improving the operational stability of the battery management system.

[0115] As an optional embodiment, such as Figures 12-14 As shown, the battery management system 20 provided in this embodiment of the present invention may further include a fifth switching element K5 and a sixth switching element K6.

[0116] Specifically, the fifth switching element K5 is connected in series on the line between the positive terminal U1+ of the battery pack and the first terminal of the charging port 30; the sixth switching element K6 is connected in series on the line between the negative terminal U1- of the battery pack and the second terminal of the charging port 30.

[0117] In one example, such as Figure 12 and Figure 13 As shown, a fifth switching element K5 is provided on the first end of the charging port 30, and is connected to the line between the second voltage detection circuit V2 and the fourth switching element K4 through the fifth switching element K5; a sixth switching element K6 is provided on the second end of the charging port 30, and is connected to the line between the third switching element K3 and the load capacitor C1 through the sixth switching element K6.

[0118] In yet another example, such as Figure 13 As shown, a fifth switching element K5 is provided on the first end of the charging port 30, and is connected to the line between the second voltage detection circuit V2 and the fourth switching element K4 through the fifth switching element K5; a sixth switching element K6 is provided on the second end of the charging port 30, and is connected to the line between the third switching element K3 and the current detection circuit A2 through the sixth switching element K6.

[0119] The fifth switching element K5 can be a push-button switch, an electronic switch, a MOSFET, a BJT, a relay, etc. This invention does not impose any particular limitation on it; the following description uses a relay as an example. In one example, the fifth switching element K5 can be used as a positive charging relay.

[0120] The sixth switching element K6 can be a push-button switch, an electronic switch, a MOSFET, a BJT, a relay, etc. This invention does not impose any particular limitation on it; the following description uses K6 as a relay as an example. In one example, K6 can be used as a negative charging relay.

[0121] It is understandable that the charging port 30 is connected to the device to be charged, that is, the item that needs to be charged. After the pre-charging is completed, if the device to be charged needs to be charged, the battery management system 20 can control the fifth switching element K5 (i.e., the positive charging relay) and the sixth switching element K6 (i.e., the negative charging relay) to close, so that the battery pack can charge the device to be charged connected to the charging port 30.

[0122] It is understood that in this embodiment, the charging port-related switching elements are set so that the battery management system not only has pre-charging and heating functions, but can also serve as a power output interface for the device to be charged, thereby expanding the functions of the battery management system and improving the overall utilization rate.

[0123] As another alternative embodiment, such as Figure 2 As shown, the battery management system 20 provided in this embodiment of the present invention may further include a third voltage detection circuit V3.

[0124] Specifically, the acquisition terminal of the third voltage detection circuit V3 is connected to the line between the fifth switching element K5 and the first terminal of the charging port 30. The third voltage detection circuit V3 is used to acquire the voltage at the charging port 30 and report the acquisition result to the battery management system 20, facilitating the battery management system 20 to monitor the voltage of the device to be charged connected to the charging port 30.

[0125] It is understood that, in this embodiment, by setting a third voltage detection circuit, the battery management system 20 can monitor the charging voltage of the device to be charged, thereby improving the safety protection of the device to be charged.

[0126] As another alternative embodiment, such as Figure 13As shown, the device to be charged 50 is connected to the charging port 30; the back-end load may include the vehicle drive motor 40, which is connected in parallel across the load capacitor C1. For example, after pre-charging is completed, the battery management system 20 controls the second switch element K2, the fifth switch element K5, and the sixth switch element K6 to all close, and the battery pack supplies power to the vehicle drive motor 40 and the device to be charged 50 connected to the charging port 30, respectively.

[0127] Understandably, the vehicle can be driven after the vehicle drive motor 40 is powered on; the charging device 50 can start working after it is powered on.

[0128] The following is based on Figure 14 For example, combined with Figure 14 This invention provides a detailed explanation of the working principle of the battery management system 20 provided in this embodiment.

[0129] It should be noted that the protection device F1, current detection circuit A2, first voltage detection circuit V1, second voltage detection circuit V2, third voltage detection circuit V3, first switching element K1, second switching element K2, third switching element K3, fourth switching element K4, fifth switching element K5, sixth switching element K6 and heating film A1 in the battery management system 20 provided in this embodiment of the present invention can all be placed in the high voltage box.

[0130] like Figure 15 As shown, the high-voltage box is powered on at low voltage. After power-on, the BMS hardware is enabled, controlling the high-voltage box to initiate communication. The high-voltage box performs a self-test upon startup. For example, it can detect whether the first switching element K1, the second switching element K2, the third switching element K3, the fourth switching element K4, the fifth switching element K5, and the sixth switching element K6 can receive the control signals transmitted by the BMS and achieve closure or opening. It can also perform insulation testing on these circuits in the high-voltage box to ensure their insulation performance. After the high-voltage box passes the self-test, it reports to the BMS. The BMS detects the battery pack voltage. If the battery pack voltage is low, it sends a pre-charge command to the high-voltage box. After receiving the pre-charge command, the high-voltage box executes the command and uploads the pre-charge status to the BMS. The BMS can determine whether the pre-charge is complete based on the uploaded pre-charge status.

[0131] Specifically, you can refer to Figure 15 . Figure 1 This is a flowchart illustrating a control method for a battery management system provided in an embodiment of the present invention. Figure 11 ,like Figure 13 As shown, the control method of the battery management system 20 includes the following steps:

[0132] S1301, wake up the battery management system and perform a self-test.

[0133] For example, when the battery management system 20 receives the wake-up signal KL15 sent by the high-voltage box, the battery management system 20 is woken up and controls the high-voltage box to perform a self-test.

[0134] Understandably, KL15 is the number 15 of the German abbreviation "Klemme" (terminal), used to identify the power signal when the vehicle is started. When the key is turned to the ignition position or the push-button start is activated, the KL15 signal is activated, providing 11-15V operating voltage to the electronic control unit.

[0135] S1302. Determine whether the self-test has passed.

[0136] For step S1302, if the judgment result is yes, then step S1303 is executed; if the judgment result is no, then step S1309 is executed.

[0137] For example, the high-voltage box performs a self-test, which includes testing the switching performance of the first switching element K1, the second switching element K2, the third switching element K3, the fourth switching element K4, the fifth switching element K5, and the sixth switching element K6, i.e., testing whether these switches can receive the control signals transmitted by the BMS and can achieve closing or opening; it also includes testing the insulation performance of the circuits in the high-voltage box, including the protection device F1, the current detection circuit A2, the first voltage detection circuit V1, the second voltage detection circuit V2, the third voltage detection circuit V3, the first switching element K1, the second switching element K2, the third switching element K3, the fourth switching element K4, the fifth switching element K5, the sixth switching element K6, and the heating film A1.

[0138] If the switching performance of the switching element is not problematic and the insulation performance of the circuit is also not problematic, the self-test is deemed to have passed and step S1303 can be executed; otherwise, the self-test is deemed to have failed and step S1309 can be executed.

[0139] S1303, the battery management system controls the closing of K1 and K3.

[0140] For example, the battery management system 20 sends control commands to the first switching element K1 (i.e., the pre-charge relay) and the third switching element K3 (i.e., the main negative relay) in the high-voltage box to control the first switching element K1 and the third switching element K3 to close. At this time, the battery pack pre-charges the load capacitor C1.

[0141] S1304. Determine whether pre-charging has been completed within the first time period.

[0142] For step S1304, if the judgment result is yes, then step S1305 is executed; if the judgment result is no, then step S1306 is executed.

[0143] The first time is the preset pre-charge time. The size of the first time can be set according to customer needs and system design goals. For example, the first time can be 200 milliseconds (ms).

[0144] For example, the battery management system 20 collects the voltage of the battery pack acquired by the first voltage detection circuit V1 and the voltage of the load capacitor C1 acquired by the second voltage detection circuit V2. It determines whether the voltage of the load capacitor C1 can be precharged to 90%~95% of the voltage of the battery pack within a first time. If it can, it is determined that the precharge is completed within the first time and step S1305 can be executed; if it cannot, it is determined that the precharge is not completed within the first time and step S1306 can be executed.

[0145] S1305, the battery management system controls K2 to close and K1 to open.

[0146] For example, the battery management system 20 sends control commands to the first switching element K1 (i.e., the pre-charge relay) and the second switching element K2 (i.e., the main positive relay) in the high-voltage box to control the second switching element K2 to close and the first switching element K1 to open. At this time, the battery pack no longer pre-charges the load capacitor C1 and begins to supply high-voltage power to the load capacitor C1 and the vehicle drive motor 40.

[0147] In another example, the first switching element K1 can be opened after the second switching element K2 is closed for a period of time to reduce the occurrence of instantaneous power loss and ensure a stable switching between the pre-charging stage and the formal charging stage.

[0148] S1306. Determine whether pre-charging is completed within the second time period.

[0149] For step S1306, if the judgment result is yes, then step S1307 is executed; if the judgment result is no, then step S1309 is executed.

[0150] The size of the second time interval can be set according to customer needs and system design goals, but it must be larger than the first time interval. For example, the second time interval can be 500ms, 1000ms, etc., and this utility model does not make any special limitation in this regard.

[0151] If pre-charging is not completed within the first time, it indicates a pre-charging timeout fault. Understandably, the system cannot stop operating immediately upon detecting a pre-charging timeout fault, as this would be detrimental to vehicle safety. Therefore, in the event of a pre-charging timeout fault, the severity of the fault should be assessed before deciding whether to continue operation. Specifically, it can be determined whether pre-charging is completed within the second time. If pre-charging is completed within the second time, it indicates that although a pre-charging timeout fault exists, it is not severe, and the system can continue operating to complete the pre-charging of the load capacitor C1, proceeding to step S1307. If pre-charging is not completed within the second time, it indicates a more severe pre-charging timeout fault, and the system cannot continue operating, requiring the execution of step S1309.

[0152] In one alternative embodiment, if pre-charging is not completed within the second time period, the battery management system 20 may store a pre-charge timeout fault, and the pre-charge timeout fault is a severe pre-charge timeout fault.

[0153] S1037, The battery management system controls K2 to close and K1 to open.

[0154] For example, the battery management system 20 sends control commands to the first switching element K1 (i.e., the pre-charge relay) and the second switching element K2 (i.e., the main positive relay) in the high-voltage box to control the second switching element K2 to close and the first switching element K1 to open. At this time, the battery pack no longer pre-charges the load capacitor C1 and begins to supply high-voltage power to the load capacitor C1 and the vehicle drive motor 40.

[0155] In another example, the first switching element K1 can be opened after the second switching element K2 is closed for a period of time to reduce the occurrence of instantaneous power loss and ensure a stable switching between the pre-charging stage and the formal charging stage.

[0156] Since step S1037 is performed when the pre-charging circuit 201 completes pre-charging within the second time period, in addition to controlling the second switching element K2 to close and the first switching element K1 to open, the battery management system 20 also needs to store the minor pre-charging timeout fault, i.e., execute step S1308.

[0157] S1308, Battery Management System Storage Precharge Timeout Fault.

[0158] Understandably, when pre-charging is completed within the second time period, the pre-charge timeout fault stored in the battery management system 20 is a minor pre-charge timeout fault.

[0159] For example, the battery management system 20 can report stored precharge timeout faults to the vehicle control unit (VCU), which can take measures such as blocking, powering down, or restarting depending on the severity of the precharge timeout.

[0160] S1309, Fault, power-on failed.

[0161] In one example, the battery management system 20 can also store power-on failure faults and report them to the VCU, which will then implement appropriate protection strategies.

[0162] To avoid overheating and burning of the portion of the heating film A1 that acts as a pre-charging resistor due to excessive and frequent pre-charging, as an alternative embodiment, the battery management system 20 can perform pre-charging management. For example, after repeatedly powering on 10 times within 3 minutes (min), the system stops responding to power-on commands for 5 minutes.

[0163] Understandably, if the battery pack temperature is too low, it will lead to a decrease in output current, or even no current output, resulting in a reduction in the battery pack's power supply efficiency. To ensure the battery pack's power supply efficiency, as an alternative implementation, such as... Figure 14 As shown, the control method of the battery management system 20 can be optimized by incorporating consideration of whether the battery pack needs to be heated.

[0164] Continue as ​ As shown, after the self-test passes, step S103 is no longer executed, but step S1310 is executed instead.

[0165] S1310. Determine if the battery pack temperature is lower than the preset temperature.

[0166] For step S1310, if the judgment result is yes, then step S1312 is executed; if the judgment result is no, then step S1311 is executed.

[0167] Understandably, when the battery pack temperature is lower than the preset temperature, it indicates that the battery pack temperature is too low. If the battery pack continues to supply power at this temperature, the supply current will be significantly reduced compared to the supply current when the battery pack is at its normal temperature. In severe cases, there may even be no supply current output. Therefore, a step to heat the battery pack is required. For example, when a step to heat the battery pack is required, it can be pre-charged first, followed by heating, i.e., step S1312 can be executed.

[0168] If the temperature of the battery pack is greater than or equal to the preset temperature, it means that the temperature of the battery pack is normal and there is no need to turn on the heating. Step S1311 can then be executed.

[0169] For example, the preset temperature can be in the range of [0℃, 45℃].

[0170] S1311, No need to turn on heating.

[0171] S1312. Determine whether the pre-charging is complete.

[0172] For step S1312, if the judgment result is yes, then step S1313 is executed; if the judgment result is no, then step S1312 is executed.

[0173] For example, the battery management system 20 may send control commands to the first switching element K1 (i.e., the pre-charge relay) and the third switching element K3 (i.e., the main negative relay) in the high-voltage box to control the first switching element K1 and the third switching element K3 to close. At this time, the battery pack pre-charges the load capacitor C1.

[0174] In one embodiment, the battery management system 20 collects the voltage of the battery pack from the first voltage detection circuit V1 and the voltage of the load capacitor C1 from the second voltage detection circuit V2. It determines whether the voltage of the load capacitor C1 can be pre-charged to 90%~95% of the voltage of the battery pack within a first time. If it can, it is determined that the pre-charging is completed within the first time, that is, the pre-charging can be considered complete, and step S1313 can be executed, that is, the battery management system 20 controls K4 to close and turns on the heating. If it cannot, it is determined that the pre-charging is not completed within the first time, that is, the pre-charging is considered incomplete, and the pre-charging process needs to continue. Since pre-charging was not completed in the first time period, it is necessary to determine whether pre-charging can be completed in the second time period. If it can, it is determined that pre-charging was completed in the second time period, that is, pre-charging can be considered complete, and step S1313 can be executed, that is, the battery management system 20 controls K4 to close and turns on the heating. If it cannot, it is determined that pre-charging was not completed in the second time period, that is, pre-charging is considered incomplete. Since pre-charging has not been completed in the second time period, the battery management system 20 should not continue to execute the pre-charging process at this time. It can execute step S1309, or at least disconnect the first switching element K1 to cut off the pre-charging circuit of the load capacitor C1.

[0175] S1313, the battery management system controls K4 to close, thus activating the heating function.

[0176] For example, the battery management system 20 sends a control command to the fourth switching element K4 (i.e., the heating relay) in the high-voltage box to control the fourth switching element K4 to close, turn on the heating, and the heating film A1 heats the battery pack.

[0177] Understandably, when the temperature of the battery pack rises to a level greater than or equal to the preset temperature, the battery management system 20 sends a control command to the fourth switching element K4 (i.e., the heating relay) in the high-voltage box to control the fourth switching element K4 to disconnect and end the heating.

[0178] ​ This is a schematic diagram of the structure of a battery system provided in an embodiment of this utility model, as shown below. ​ As shown, the battery system 150 provided in this embodiment of the present invention includes a battery pack 10 and a battery management system 20 as described in any of the foregoing embodiments.

[0179] The battery pack 10 is connected to the battery management system 20 through the positive terminal U1+ and the negative terminal U1- of the battery pack 10.

[0180] It should be noted that for a detailed description of the battery management system 20, please refer to the relevant descriptions in the aforementioned embodiments of the battery management system 20, which will not be repeated here.

[0181] It should be noted that the battery system 150 in this embodiment of the present invention can be a battery pack, or a high-voltage box of a power battery module, etc., and the present invention does not make any special limitation thereto; the battery pack 10 in this invention can be a power battery module.

[0182] It is understood that the battery system provided by this utility model can achieve the same technical effect as the aforementioned battery management system, and will not be described in detail here.

[0183] This utility model embodiment also provides an electrical device, including the battery system 150 as described in the foregoing embodiment.

[0184] In this embodiment of the utility model, the electrical equipment can be a device that is electrically driven by a battery, such as an electric car, an electric motorcycle, an electric bicycle, an electric ship, etc., without any limitation.

[0185] The battery system 150 includes a battery pack 10 and a battery management system 20 as described in any of the foregoing embodiments. The battery pack 10 is connected to the battery management system 20 via its positive terminal U1+ and negative terminal U1-.

[0186] It should be noted that for a detailed description of the battery management system 20, please refer to the relevant descriptions in the aforementioned embodiments of the battery management system 20, which will not be repeated here.

[0187] It is understood that the electrical equipment provided by this utility model can achieve the same technical effect as the aforementioned battery management system, and will not be described in detail here.

[0188] The following examples illustrate possible implementation schemes of the battery management system described in one or more of the above embodiments.

[0189] like ​ As shown, in the relevant battery management system, the second switching element K2 is the main positive relay at the output end, the third switching element K3 is the main negative relay at the output end, the first switching element K1 is the pre-charge relay, and the fourth switching element K4 is the heating relay. The pre-charge resistor R1 and the pre-charge relay (i.e., the first switching element K1) are connected in series and then in parallel across the main positive relay (i.e., the second switching element K2) to form a pre-charge circuit. The high-voltage electricity output from the power battery module (i.e., the battery pack) passes through the fuse (i.e., the protection device F1), the first voltage detection circuit V1, the main positive relay (i.e., the second switching element K2), and the second voltage detection circuit V2 before finally reaching the vehicle drive motor 40 to provide energy for the vehicle drive motor 40.

[0190] When the vehicle drive motor 40 and other high-voltage components need to be powered on, the power battery BMS needs to pre-charge the high-voltage box. First, the BMS controls the main negative relay (i.e., the third switching element K3) to close. After the main negative relay closes, the pre-charge relay (i.e., the first switching element K1) closes. Due to the current-limiting effect of the pre-charge resistor R1 at the front end of the pre-charge relay, the current in the circuit is very small, and the voltage of the load capacitor C1 will "slowly rise." The first voltage detection circuit V1 monitors the voltage across the power battery module, and the second voltage detection circuit V2 monitors the voltage across the load capacitor C1. When the voltage of the load capacitor C1 reaches 90-95% or more of the power battery module voltage, the main positive relay (i.e., the second switching element K2) closes. After the main positive relay is reliably closed, the pre-charge relay is disconnected, completing the entire pre-charge process. This method avoids the problem of a large current impacting the relay contacts at the moment the high-voltage circuit closes.

[0191] However, this pre-charging scheme with a pre-charging resistor R1 also has its drawbacks. On the one hand, the pre-charging resistor itself is relatively large, taking up a lot of space when placed inside the high-voltage box. On the other hand, since most of the pre-charging resistors currently used in vehicles are cement resistors / aluminum shell resistors, their dimensional tolerances are difficult to converge to a low level. During the actual production and assembly of the high-voltage box, the assembly interference force caused by the large dimensional tolerance of the pre-charging resistor is difficult to control, which may cause mechanical damage to the pre-charging resistor during installation.

[0192] Furthermore, lithium batteries exhibit poor charging / discharging performance at low temperatures, necessitating the addition of a heating function to the battery management system (BMS). Common heating methods for power batteries include coolant heating, internal cell self-heating, and heating film heating. Heating film heating, utilizing the high-voltage electrical energy of the power battery, is simple, cost-effective, and widely used. However, as the heating film is a high-voltage electrical component with significant resistance, it can cause the high-voltage pre-charge time in the pre-charge circuit to exceed its limit during heating. The pre-charge resistor bears a large amount of energy during prolonged operation; after prolonged startup stress, the resistor may burn out due to overheating. Both the pre-charge circuit and the heating film circuit are controlled by the power battery management system. At low temperatures, the power battery pre-charge circuit and self-heating circuit can influence each other, indicating room for optimization in the control logic of the power battery management system.

[0193] like ​ As shown, this embodiment provides a battery management system in which the use of a pre-charge resistor is eliminated in the high-voltage box, and the function of the pre-charge resistor is replaced by a heating film A1. The pre-charge relay (i.e., the first switching element K1) and part of the heating film A1 are connected in series, and the heating relay (i.e., the fourth switching element K4) and the entire heating film A1 are connected in series.

[0194] It is understandable that the protection device F1, current detection circuit A2, first voltage detection circuit V1, second voltage detection circuit V2, third voltage detection circuit V3, first switching element K1, second switching element K2, third switching element K3, fourth switching element K4, fifth switching element K5, sixth switching element K6 and heating film A1 can all be placed in the high voltage box.

[0195] like ​ As shown, when the system's wake-up power is applied, it first wakes up the BMS, and the system performs a self-test. If the self-test fails, the BMS directly reports a fault and waits for system processing. If the self-test passes, it enters the high-voltage pre-charge process (i.e., the pre-charge stage). When pre-charging is required, the BMS first controls the main negative relay (i.e., the third switching element K3) to close, and then controls the pre-charge relay (i.e., the first switching element K1) to close. The current output from the power battery module passes through the heating film A1 and the pre-charge relay before reaching the back end of the main positive relay (i.e., the second switching element K2) to charge the load capacitor C1.

[0196] The BMS synchronously detects the voltage values ​​at the voltage sampling points across the main positive relay. When it detects that the voltage of the load capacitor C1 collected by the second voltage detection circuit V2 reaches 90-95% or more of the voltage of the power battery module collected by the first voltage detection circuit V1 within the first time period, the main positive relay is closed and the pre-charge relay is opened to complete the pre-charge process.

[0197] The value of the first timeout can be set according to customer needs and system design goals, generally not exceeding 200ms. If the BMS detects that the high-voltage box has not completed the pre-charging process within the first timeout, it determines whether pre-charging has been completed within the second timeout. If pre-charging is completed within the second timeout, the BMS stores the pre-charging timeout fault, reports it to the VCU, and can continue normal operation. If pre-charging is not completed within the second timeout, the BMS pre-charging process fails, reports the fault to the VCU, and waits for the vehicle to issue a reset command or power-off restart before resuming operation. The duration of the second timeout is longer than that of the first timeout, and the value of the second timeout generally does not exceed 500ms, with a maximum of 1000ms, and can also be manually set according to system requirements.

[0198] It should be noted that since the resistance of the heating film A1 is generally very large, far exceeding the resistance required for high-voltage pre-charging, in order to shorten the waiting time of the pre-charging process as much as possible, only a portion of the resistance of the heating film A1 can be used for pre-charging. For example, the resistance of the heating film A1 used for pre-charging can be determined based on the original resistance of the pre-charging resistor R1, or it can be determined based on the resistance of the heating film A1 itself and the preset pre-charging time.

[0199] like ​ As shown, this is the optimized control logic of this embodiment. After the system passes the power-on self-test, it should actively determine the cell temperature (i.e., battery pack temperature). When the cell temperature of the power battery module is detected to be lower than the target value (i.e., the preset temperature), the BMS outputs a command to first execute the high-voltage pre-charge process. After the high-voltage pre-charge process is completed, the BMS controls the heating relay (i.e., the fourth switching element K4) to close, and performs heating on the power battery module. If the system detects that the cell temperature of the power battery module is higher than the target value after power-on, the BMS will not heat the battery pack. At the same time, in order to avoid the heating film A1 from overheating and burning due to too many frequent and repeated power-on pre-charges, the battery management system performs 10 power-on cycles within 3 minutes, and then stops responding to power-on commands for 5 minutes.

[0200] In this embodiment, on the one hand, the high-voltage box of the power battery is optimized. By reusing the heating film A1, pre-charging can be completed without the need for a pre-charging resistor inside the high-voltage box. This reduces the structural size of the high-voltage box, effectively lowers its material cost, and improves the reliability of the system. On the other hand, the embodiment analyzes the pain point of mutual interference between the power battery pre-charging circuit and the self-heating circuit under low-temperature conditions and proposes an optimized control logic. This ensures that the power battery system pre-charging is completed normally and that the power battery heating is carried out normally. It avoids interference from other high-voltage load electrical appliances during the pre-charging process and solves the problems of pre-charging failure and pre-charging resistor burnout.

[0201] It should be noted that although the steps of the method of this invention are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps; or steps from different embodiments may be combined into a new technical solution.

[0202] It should be noted that the module division in this embodiment is illustrative and represents only one logical functional division; in actual implementation, other division methods may be used. Furthermore, the functional units in each embodiment of this invention can be integrated into one processing unit, exist as separate physical units, or be integrated into one unit from two or more other units. The integrated units can be implemented in hardware, as software functional units, or a combination of both.

[0203] It should be understood that those skilled in the art will recognize that this invention may take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage) containing computer-usable program code.

[0204] It should also be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the present invention. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of the present invention, the sequence number of the above-described steps / processes does not imply the order of execution; the execution order of each step / process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention. The above-described embodiment numbers are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0205] It should be noted that in this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three kinds of relationships. For example, object A and / or object B can represent three cases: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0206] It should also be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0207] In the several embodiments provided by this utility model, it should be understood that the disclosed apparatus and system can be implemented in other ways. The embodiments described above are merely illustrative. For example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple modules or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, and can be electrical, mechanical, or other forms.

[0208] The modules described above as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network units; some or all of the modules may be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the various embodiments of this utility model, all functional modules may be integrated into one processing unit, or each module may be a separate unit, or two or more modules may be integrated into one unit; the integrated modules may be implemented in hardware or in a combination of hardware and software functional units.

[0209] The features disclosed in the several product embodiments provided by this utility model can be arbitrarily combined without conflict to obtain new product embodiments.

[0210] The above description is merely an embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and scope of this utility model are included within the scope of protection of this utility model.

Claims

1. A battery management system, characterized in that, The battery management system includes a pre-charging circuit and a heating circuit. The pre-charging circuit is connected between the battery pack and the load capacitor. The heating circuit is connected in parallel across the two ends of the battery pack, wherein: The heating circuit includes a heating element for heating the battery pack; The pre-charging circuit includes a first switching element and the heating element, and the first switching element and the heating element are connected in series to form a pre-charging branch for charging the load capacitor.

2. The battery management system according to claim 1, characterized in that, The battery management system further includes a second switching element and a third switching element, wherein: The second switching element is connected in parallel across the two ends of the pre-charging circuit; The third switching element is connected in series between the negative terminal of the battery pack and the load capacitor.

3. The battery management system according to claim 2, characterized in that, The heating circuit further includes a fourth switching element, wherein: The fourth switching element and the heating element are connected in series; The heating circuit is used to heat the battery pack when the fourth switching element, the second switching element, and the third switching element are all closed.

4. The battery management system according to claim 1, characterized in that, The battery management system also includes protection devices, wherein: The protection device is connected in series on the connection between the battery pack and the pre-charge circuit.

5. The battery management system according to claim 1, characterized in that, The battery management system further includes a first voltage detection circuit and a second voltage detection circuit, wherein: The first voltage detection circuit is connected to the line between the positive terminal of the battery pack and the pre-charging circuit; The second voltage detection circuit is connected to the line between the pre-charging circuit and the load capacitor.

6. The battery management system according to claim 1, characterized in that, The battery management system further includes a current detection circuit, wherein: The current detection circuit is connected in series on the line between the negative terminal of the battery pack and the load capacitor.

7. The battery management system according to claim 1, characterized in that, The battery management system further includes a fifth switching element and a sixth switching element, wherein: The fifth switching element is connected in series on the line between the positive terminal and the charging port of the battery pack; The sixth switching element is connected in series on the line between the negative terminal of the battery pack and the charging port; When the fifth and sixth switching elements are turned on, the battery pack charges the device to be charged connected to the charging port.

8. The battery management system according to any one of claims 1 to 7, characterized in that, The heating element includes a heating film, wherein: the heating circuit includes the entire heating film; and the pre-charging circuit includes a portion of the heating film.

9. A battery system, characterized in that, The battery system includes a battery pack and a battery management system as described in any one of claims 1 to 8.

10. An electrical appliance, characterized in that, The electrical equipment includes the battery system as described in claim 9.

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