A low-voltage lithium battery device for automobile and control method thereof

Abstract

The present invention discloses a low-voltage lithium battery device for an automobile and a control method thereof, comprising: a battery device body, comprising at least first and second battery cell groups composed of a plurality of battery cells; a BMS module, comprising at least first and second control units, a voltage and current sensor module, a temperature sensor module, a switch module, and a communication interface module; the first and second control units respectively connect or disconnect the first and second battery modules based on the state of charge and battery health status of the first and second battery cell groups provided by the sensor modules, thereby ensuring normal power supply to the EPS and providing feedback on the status of the low-voltage lithium battery device to the user. The present invention synchronously calculates the battery state of charge (SOC) and battery health (SOH) information based on vehicle speed, acceleration signals, and battery parameters, adjusts three switches within the battery to ensure normal power supply to the EPS, a key safety component, and feeds back the current battery status signal to the vehicle gateway via CAN / LIN.

Description

Technical Field

[0001] The present invention relates to the field of automotive lithium batteries, and in particular to an automotive low-voltage lithium battery device and a control method thereof. Background Art

[0002] Traditionally, 12V lead-acid batteries have been used as starting devices for automotive low-voltage batteries. These batteries can provide sufficient current for the starter motor in a short period of time, while also meeting the basic power requirements of the existing low-voltage system. However, driven by the development of autonomous driving and new energy electric vehicles, corresponding automotive safety laws and regulations are becoming increasingly stringent. Furthermore, the diversification of user needs and the expansion of onboard electrical appliances are increasing the requirements for electrical components related to vehicle safety functions.

[0003] The QM properties of current low-voltage lead-acid batteries cannot fully guarantee the proper power supply of the steering system in critical vehicle conditions such as collisions and low-voltage grid fluctuations. To achieve functional safety, existing OEM technologies primarily incorporate a complete redundant power supply or redundant functional system. A common approach is to use a dual-battery solution, separating the backup power supply from the primary power supply. This ensures that, in the event of a power source failure, the redundant power supply can still power safety-critical systems, such as the EPS system or electronic braking system, thus meeting safety design requirements.

[0004] Figure 1 The diagram shows a dual-battery control schematic. This system includes a first battery 11 and a second battery 12. This dual-battery solution requires ample space for layout. The intelligent isolating switch 13, which can intelligently detect current and voltage anomalies, is part of the intelligent control module. The two battery control systems and the intelligent isolating switch 13 must be separately connected to the vehicle control module system. The dual-battery system must implement low-voltage grid safety isolation and failure mode detection. This system requires high development costs, complex wiring layout, and a large number of system-related parts, increasing vehicle weight and fuel consumption. It also poses a high risk of mechanical failure under abnormal operating conditions.

[0005] According to ISO 26262, sudden loss of assist (SLoA) should be included in steering system hazard and risk analyses. In 2021, legislation GB 17675 and GB / T 34590 revised high-risk limits. From a vehicle system and component-level safety perspective, the new 100fit steering system, designed to meet ASIL C requirements, is required to avoid steering failure risks in certain vehicles. Currently, low-voltage batteries serve as the primary power source, but their inherent QM component properties cannot meet system-level safety requirements. Summary of the Invention

[0006] It is to be understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanatory and are intended to provide further explanation of the disclosure.

[0007] In response to the above problems, the present invention provides an automotive low-voltage lithium battery device and a control method thereof, which can meet ASIL C requirements, simplify the entire low-voltage power supply system structure, and improve the entire steering system function to meet regulatory requirements.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides a low-voltage lithium battery device for an automobile, characterized in that the device comprises:

[0009] The battery device body includes at least a first battery cell group and a second battery cell group composed of a plurality of battery cells;

[0010] A BMS module comprising at least first and second control units, a voltage and current sensor module, a temperature sensor module, a switch module, and a communication interface module;

[0011] The first and second control units adjust the switch module according to the charge status and battery health status of the first and second battery groups provided by the sensor module, respectively, in combination with the current driving conditions, to execute the connection or disconnection status of the first and second battery modules, ensure the normal power supply of EPS, and feedback the status of the low-voltage lithium battery device to the user.

[0012] Preferably, the present invention further provides a low-voltage lithium battery device for an automobile, characterized in that:

[0013] The switch module includes first, second and third switches, the third switch connects the first battery cell group and the second battery cell group, the first switch electrically couples the first battery cell group and the third switch, and together with the first temperature sensor and the first voltage and current sensor, forms the first power module, the second switch electrically couples the second battery cell group and the third switch, and together with the second temperature sensor and the second voltage and current sensor, forms the second power module.

[0014] Preferably, the present invention further provides a low-voltage lithium battery device for an automobile, characterized in that:

[0015] The device further includes a diode connected in parallel with the third switch.

[0016] The present invention also provides a control method for a low-voltage lithium battery device for an automobile, comprising:

[0017] Step 1: When the BMS module detects that the SOC of the low-voltage lithium battery device is less than or equal to 15%, the first and third switches are opened and the second switch is closed to enter a self-protection mode to prevent the first battery module from entering a deep power-loss state due to starting the vehicle and damaging the battery. If the condition is not satisfied, the process proceeds to step 3.

[0018] Step 2: When the sensor module controlling the second battery module recognizes that a large current is connected, the first and third switches are closed, and the device is activated to complete external charging and maintenance;

[0019] Step 3: When the BMS module detects that the SOC of the current lithium battery device is greater than 15%, the first, second, and third switches are closed, and the first and second battery modules jointly participate in the power supply of the low-voltage grid;

[0020] Step 4: The engine starts normally;

[0021] Step 5: When a low-voltage grid abnormality occurs, the first and second switches are closed, and the third switch is opened, and the two independent circuits operate normally;

[0022] Step 6: When a battery abnormality occurs while the vehicle is driving, the BMS module can self-check the real-time status of the battery.

[0023] Preferably, the present invention further provides a control method for a low-voltage lithium battery device for an automobile, wherein the step 1 further comprises:

[0024] When KL15 is in ON state and the BMS module executes the battery to enter the self-protection mode, the vehicle low-voltage energy management system will remind the user to connect an external charging device to maintain the battery through the HMI or ABT.

[0025] Preferably, the present invention further provides a control method for a low-voltage lithium battery device for an automobile, wherein step 6 further comprises:

[0026] When the first battery module is abnormal, the first switch is disconnected and the second and third switches are closed;

[0027] When the second battery module is abnormal, the second switch is disconnected and the first and third switches are closed to ensure that the abnormal module does not interfere with the operation of the normal module;

[0028] When the first battery module and the low-voltage load are abnormal, the BMS module self-checks the real-time status of the battery, opens the second and third switches, and closes the first switch;

[0029] When an abnormality occurs in the first battery module or the second battery module, the first and second switches are disconnected and the third switch is closed. The low-voltage power grid of the entire vehicle and the ASIL C electrical appliances are directly powered by the generator.

[0030] Preferably, the present invention further provides a control method for a low-voltage lithium battery device for an automobile, characterized in that the method further comprises:

[0031] When a short circuit occurs in the low-voltage load line or an abnormal signal, undervoltage or overvoltage occurs on the power supply side while the vehicle is driving, the vehicle's low-voltage energy management system will alert the user of the low-voltage grid abnormality through the HMI or ABT.

[0032] Preferably, the present invention further provides a control method for a low-voltage lithium battery device for an automobile, characterized in that step 4 further comprises:

[0033] During normal engine operation, the device enters either a charging mode to maintain the battery or a discharging mode; when the vehicle is stationary, the engine is allowed to stop and the battery is in a discharging mode to support the entire low-voltage power grid and save fuel.

[0034] Preferably, the present invention further provides a control method for a low-voltage lithium battery device for an automobile, wherein step 5 further comprises:

[0035] The first battery module supplies power to all low-voltage loads of the vehicle, and the second battery module only supplies power to ASIL C systems such as EPS.

[0036] Preferably, the present invention further provides a control method for a low-voltage lithium battery device for an automobile, characterized in that the control method further comprises:

[0037] When the BMS module is in a non-sleep mode, it intermittently self-learns whether the SOC, SOH, etc. of the current battery module are normal.

[0038] The device and control method of the present invention can obtain the current vehicle speed and acceleration signals from the vehicle gateway based on the input signal, detect the battery voltage, current and temperature values ​​in real time according to the sensor module, and synchronously calculate the battery state of charge (SOC) and battery state of health (SOH) information. Combined with the current driving conditions, the BMS module adjusts the three switch states inside the battery to execute whether both modules are fully connected or disconnected, ensuring the normal power supply of the key safety component EPS, and then feeds back the current battery status signal to the vehicle gateway through CAN / LIN to remind the user. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to preferred embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to represent the same or similar parts. In addition, although the terms used in this disclosure are selected from commonly known and commonly used terms, some of the terms mentioned in this disclosure may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description herein. In addition, it is required that the present disclosure be understood not only by the actual terms used, but also by the meaning implied by each term.

[0040] The above and other objects, features and advantages of the present invention will become apparent to those skilled in the art from the detailed description of the present invention with reference to the accompanying drawings below.

[0041] Figure 1 The diagram shows the existing dual-battery control principle diagram;

[0042] Figure 2 The figure shows a signal control block diagram of the lithium battery BMS module 200 of the present invention;

[0043] Figures 3 (1) and 3 (2) are respectively a top view and a three-dimensional view of the structure of a lithium battery device according to a preferred embodiment;

[0044] Figure 4 A schematic diagram illustrating the circuit principle of the lithium battery device of the present invention;

[0045] Figure 5 is a logic flow chart of the lithium battery device control method of the present invention;

[0046] Figure 6 The figure shows a control circuit block diagram of the lithium battery device of the present invention.

[0047] Reference numerals

[0048] 11 - First Battery

[0049] 12--Second battery

[0050] 13-Intelligent isolating switch

[0051] 14 - Generator

[0052] 15--Electrical appliances for vehicles

[0053] 16--EPS system

[0054] 31 - First positive electrode

[0055] 32 - Second positive electrode

[0056] 33 - Negative electrode

[0057] 34-CAN / LIN interface

[0058] 100 - Battery device body

[0059] 101 - First switch

[0060] 102 - Second switch

[0061] 103 - The third switch

[0062] 111 - First temperature sensor

[0063] 112 - Second temperature sensor

[0064] 121 - First battery pack

[0065] 122 - Second battery pack

[0066] 131 - First voltage and current sensor

[0067] 132 - Second voltage and current sensor

[0068] 141 - First control unit

[0069] 142 - Second control unit

[0070] 150 - First battery module

[0071] 151 - Second battery module

[0072] 200-BMS module

[0073] 300 - Vehicle Gateway DETAILED DESCRIPTION

[0074] To more clearly illustrate the technical solutions of the embodiments of this application, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0075] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0076] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0077] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0078] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0079] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is solely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. Furthermore, while the terms used in this application are selected from commonly known and commonly used terms, some terms mentioned in this specification may have been selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of this description. Furthermore, this application should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0080] 3 (1) and 3 (2) are schematic diagrams of a preferred embodiment of the lithium battery device of the present invention, which are shown as a top view and a three-dimensional view respectively.

[0081] As can be seen from this embodiment, the device's external output interface consists of two positive electrodes and one negative electrode. The two positive electrodes are a first positive electrode 31 and a second positive electrode 32, and the negative electrode 33. This indicates that compared to traditional batteries, there is an additional positive electrode terminal 32. The first positive electrode terminal 31 is designated KL30.0, and the newly added second terminal 32 is designated KL30.1.

[0082] Combine Figure 4 , which can help you understand the wiring of the device of the present invention. Based on the vehicle's power distribution, the negative terminal 33 is grounded, similar to a traditional starting battery. The first positive terminal 31 KL30.0 is connected to the vehicle's power distribution box or fuse box, respectively, to power the vehicle's electrical appliances and starter. The vehicle circuits connected to it primarily consist of QM components and ASIL A and B parts with low safety requirements, such as cooling fans, lighting systems, wipers, and airbags. The second positive terminal 32 KL30.1 is connected to the vehicle's circuits primarily for systems with high functional safety requirements, such as the EPS steering system and electronic braking. First, the second positive terminal 32 KL30.1 separates electrical appliances with high functional safety levels from those with low levels through the interface. Second, both positive terminals can be independently powered according to actual operating conditions, without interfering with each other. The components themselves can achieve grid safety isolation, resulting in a highly integrated power supply system that ensures users can safely turn and park within a certain timeframe.

[0083] As shown in Figure 3 (2), the device of the present invention has the same aspect ratio as a common 12V lead-acid battery of the same model. It has three terminals 31 to 33 and a CAN / LIN interface 34. The battery management system module (BMS module) 200 is directly integrated on the upper part of the device, eliminating the need for an additional controller connected to the battery. The device directly interacts with the vehicle gateway 300 through the built-in CAN / LIN interface 34. The device is fully compatible with the layout of batch fuel vehicles and surrounding parts, effectively reducing unknown layout issues caused by structural problems and effectively reducing the complexity of the wiring harness.

[0084] Figure 6 The control circuit block diagram of the low-voltage lithium battery device of the present invention is shown.

[0085] The shaded box contains the battery device body 100 and the BMS module 200 .

[0086] The BMS module 200 includes a first control unit 141 and a second control unit 142. The lithium battery device of the present invention includes a switch module, a temperature sensor module, a cell group, and a voltage and current sensor module. The switch module includes first, second, and third switches 101-103; the temperature sensor module includes first and second temperature sensors 111 and 112; the cell group includes first and second cell groups 121 and 122; and the voltage and current sensor module includes two groups: a first voltage and current sensor 131 and a second voltage and current sensor 132. The first switch 101, the first temperature sensor 111, the first cell group 121, and the first voltage and current sensor module 131 constitute a first battery module 150. The second switch 102, the second temperature sensor 112, the second cell group 122, and the second voltage and current sensor module 132 constitute a second battery module 151. The first switch 101 electrically couples the first cell group 121 and the third switch 103, and the second switch 102 electrically couples the second cell group 122 and the third switch 103. The first battery module 150 and the second battery module 151 are electrically connected via the third switch 103 and controlled by the BMS module 200 .

[0087] from Figure 6 It can be seen that the BMS module 200 obtains the current vehicle speed, acceleration and other signals from the vehicle gateway 300. The sensor modules (including the temperature sensor module and the voltage and current sensor module) in the BMS module 200 in the lithium battery device detect the current battery voltage, current and temperature values ​​in real time, and calculate the current battery state of charge (SOC) and battery health (SOH) value.

[0088] According to the current driving conditions, the BMS module 200 adjusts the status of the three switches 101 to 103 inside the battery to check whether both power modules are connected or disconnected, ensuring the normal power supply of the key safety component EPS, and then feeds back the current battery status signal to the vehicle gateway through CAN / LIN to remind the user.

[0089] Figure 4 The schematic diagram shows the lithium battery circuit principle. The key components of the lithium battery device mainly include:

[0090] The first battery module 150 and its corresponding BMS module 200 have a total capacity of 20Ah, and their connection is controlled by the first switch 101. The second battery module 151 and its corresponding BMS module 200 have a total capacity of 20Ah, and their connection is controlled by the second switch 102. The two battery modules are connected in parallel by default, and the maximum battery capacity of the entire circuit can reach 40Ah. The third switch 103 is located between the first and second battery modules 150 and 151, and its disconnection is controlled by the battery BMS module 200. A diode 401 is also connected in parallel to the circuit, acting as a one-way switch. The entire lithium battery system meets ASIL C requirements. The positive terminals corresponding to the lithium battery system can be reasonably allocated according to the functional safety requirements of the entire vehicle components.

[0091] Figure 5 This is a logic control flow chart of a control method for a lithium battery device according to an embodiment of the present invention, combined with Figure 4 , the control method is as follows:

[0092] In step 501 , when the BMS module 200 in the lithium battery device of the present invention is in a non-sleep mode, it will intermittently self-learn whether the SOC, SOH, etc. of the current battery module are normal.

[0093] Step 502 : When the BMS module 200 detects that the current battery SOC is ≤15%, the BMS module 200 sends a signal to the vehicle low-voltage energy management system or the vehicle gateway 300 .

[0094] In step 503, if the KL15 status is ON, the vehicle low-voltage energy management system will send a signal to the HMI or ABT to remind the user to connect an external charging device to maintain the battery.

[0095] In step 504 , the first and third switches 101 and 103 in the battery are automatically disconnected, and the second switch 102 is closed by default. The battery enters a self-protection mode to prevent the first battery module 150 from being damaged by starting the vehicle and causing the entire battery device to enter a deep power-loss state.

[0096] In step 505, after the battery enters the self-protection mode, when the sensor in the second battery module 151 circuit recognizes that a large external current is connected, the first and third switches 101 and 103 inside the battery will automatically close, activating the entire battery module to complete external charging and maintenance.

[0097] In step 506 , when the BMS module 200 detects that the current battery SOC is greater than 15%, the three switches 101 - 103 in the lithium battery device are closed by default, and both battery modules can now participate in the power supply of the low-voltage grid in the entire loop.

[0098] In step 507, when the battery SOC is greater than 15%, the engine can be started normally. According to the low-voltage energy management strategy, the battery can enter the charging mode to maintain the battery during driving, or enter the discharging mode. When the vehicle is stationary, the engine is allowed to stop and the battery is in the discharging mode to support the power supply of the entire low-voltage grid and save fuel.

[0099] Step 508 , when the vehicle is running, if the low-voltage load (seat heating, air conditioning, etc.) circuit is short-circuited or the power supply (engine, generator, DCDC) has an abnormal signal, undervoltage or overvoltage, etc.

[0100] In step 509 , the vehicle low-voltage energy management system will alert the user of low-voltage grid abnormalities through the HMI or ABT.

[0101] In step 510, the first and second switches 101 and 102 in the low-voltage lithium battery device of the present invention are closed, and the third switch 103 is automatically opened, disconnecting the first and second battery modules 150 and 151 inside the battery. This isolates the high-ASIL C EPS end and the low-voltage load end electrical appliances of the vehicle, forming two circuits. This ensures that the QM components at the abnormally low-voltage load end or the ASIL A and B components do not interfere with the normal operation of the ASIL C end components.

[0102] In step 511, the first battery module 150 can supply power to all low-voltage loads of the vehicle. However, due to the protection of the diode 401 on the third switch 103, the second battery module 151 only supplies power to the ASIL C system, such as the EPS, and does not participate in the power supply of other electrical appliances in the vehicle. The EPS can operate normally for a certain period of time to avoid steering loss of control. At the same time, the HMI or ABT will also remind the user of the current battery status.

[0103] Step 512: When the vehicle is driving, an abnormality may occur at the battery terminal due to a collision, a short circuit of an internal component, etc.

[0104] In step 513, the internal BMS module 200 of the battery performs a self-check of its real-time battery status. When an abnormality occurs in the first battery module 150, the first switch 101 is opened, and the second and third switches 102 and 103 are closed. When an abnormality occurs in the second battery module 151, the second switch 102 is opened, and the first and third switches 101 and 103 are closed. This ensures that the abnormal module does not interfere with the operation of the non-abnormal modules, thereby further ensuring the normal power supply of the ASIL C system. When an abnormality occurs in the first battery module 150 and the low-voltage load, the internal BMS module 200 of the battery performs a self-check of its real-time battery status. The second and third switches 102 and 103 are all opened, and the first switch 101 is closed. When an abnormality occurs in the first battery module 150 and the second battery module 502, the first and second switches 101 and 102 are opened, and the third switch 103 is closed. The low-voltage grid of the entire vehicle and the ASIL C electrical appliances are directly powered by the generator.

[0105] In step 514 , the battery device, through its own stable control strategy, can ensure normal power supply to the EPS within a certain period of time under abnormal conditions, in combination with the vehicle low-voltage grid signal and the real-time detection of the BMS module 200 .

[0106] from Figure 6 As can be seen from the schematic block diagram of the control circuit of the lithium battery device of the present invention, the device includes two battery modules and a BMS control system, wherein the BMS control system mainly consists of a management host (CPU) controller, a voltage and current sensor module, a temperature sensor module, a switch module and a communication interface module.

[0107] Each battery module has its own CPU controller, connected to current and voltage sensors for real-time monitoring. This ensures accurate acquisition of information such as the voltage of individual cells, their maximum and minimum temperatures, and the battery pack's charge and discharge capacity. It can generate alarms and control outputs for extreme conditions such as overcurrent, overvoltage, undervoltage, high temperature, low temperature, and short circuit. The battery BMS control system can detect the total voltage and current of the lithium battery unit and accurately estimate the real-time battery state of charge (SOC) and state of health (SOH).

[0108] The two battery modules are connected via the first to third switches 101 to 103. The BMS module 200 will determine in real time whether the switch module is turned off or on correctly. When the BMS module 200 detects a voltage greater than 16V or less than 9V, the module controls the third switch 103 to disconnect in time; when an overcurrent or short circuit is detected, the third switch 103 will also be disconnected in time.

[0109] The BMS module 200 controls the lithium battery device through the sensor module and the switch module, so that the lithium battery device has the following five voltage control modes:

[0110] (1) Normal mode:

[0111] During vehicle operation, the battery BMS controls the first to third switches 101-103 to a closed state. The first and second battery modules 150 and 151 are simultaneously connected to the low-voltage power grid by default. The default power supply of the entire low-voltage power grid circuit battery is 40Ah. The lithium battery low-voltage battery system functions like a normal starting battery, primarily for starting, lighting, ignition, start & stop, and other functions. The vehicle's generator and the entire battery system can then jointly power the vehicle's low-voltage loads, with the battery system selecting charge and discharge based on its own SOC. Because the two modules each have independent BMS controls and high-precision current sensors, they can monitor the battery voltage and SOC value in real time while driving, ensuring that the batteries are not over-discharged or overcharged, and that the first and second battery modules reach a balanced state of charge.

[0112] (2) Isolation mode:

[0113] During vehicle driving, when the vehicle control module detects an abnormality at the load end, power supply DCDC end, generator end or battery end, and exceeds a certain set threshold, the first to third switches 101 to 103 are closed or opened according to the actual situation to ensure that a circuit is connected to meet the ASIL C system power supply requirements.

[0114] (3) Safe Mode:

[0115] During vehicle driving, when the vehicle collides or a sub-component inside the battery causes an abnormality at the battery end, the BMS system detects through the sensor voltage and temperature module. If it finds that it exceeds a certain set threshold, it will disconnect the abnormal battery module switch and close the non-abnormal module and the third switch 103. At this time, the non-abnormal first or second battery pack and the generator jointly participate in the power supply of the vehicle's low-voltage system, and the battery can provide a maximum capacity of 20Ah.

[0116] (4) Self-protection mode:

[0117] If the vehicle is parked for a long time or in a workshop and is locked, when the BMS detects that the battery SOC is less than 15%, to prevent the battery from entering a deep power loss and causing unnecessary losses, the first and third switches 101 and 103 are automatically disconnected, and the second switch 102 is closed. The BMS will feed back the current battery status to the vehicle's low-voltage power grid management system and provide it to the customer through ABT to indicate that an external charging device is needed for maintenance or additional charging. At this time, the user will not be able to start the vehicle and the battery will enter self-protection mode to extend its service life.

[0118] (5) Activation mode:

[0119] When the battery enters the self-protection mode, the first switch 101 and the third switch 103 are disconnected, and the second switch 102 is closed. If the sensor module detects a large current, the BMS module will compare the status of the first battery module 150 and the second battery module 151, and automatically close the first and third switches 101 and 103 after determining that an external charging device is connected. At this time, the entire lithium battery enters the charging maintenance state. When the battery SOC is greater than 15%, the vehicle can be started.

[0120] The specific switch modules are as follows:

[0121]

[0122] In summary, the device of the present invention obtains the current vehicle speed and acceleration signals from the vehicle gateway based on the input signals, detects the battery voltage, current, and temperature values ​​in real time according to the sensor module, and synchronously calculates the battery state of charge (SOC) and battery state of health (SOH) information. Combined with the current driving conditions, the BMS module adjusts the three internal switch states of the battery to determine whether both modules are fully connected or disconnected, ensuring the normal power supply of the key safety component EPS, and then feeds back the current battery status signal to the vehicle gateway via CAN / LIN to remind the user.

[0123] The basic concepts have been described above. It will be apparent to those skilled in the art that the above disclosures are merely illustrative and do not constitute limitations on this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to this application. Such modifications, improvements, and amendments are suggested in this application and remain within the spirit and scope of the exemplary embodiments of this application.

[0124] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0125] Similarly, it should be noted that, in order to simplify the presentation of this application and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of this application sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not mean that the subject matter of this application requires more features than those recited in the claims. In fact, an embodiment may have fewer features than all of the features of a single embodiment disclosed above.

[0126] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of the individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining the number of digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the settings of such numerical values ​​are as accurate as possible within the feasible range.

[0127] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions can be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A low-voltage lithium battery device for automobiles, characterized in that: The device comprises: The battery device body includes at least a first battery cell group and a second battery cell group composed of a plurality of battery cells; A BMS module comprising at least first and second control units, a voltage and current sensor module, a temperature sensor module, a switch module, and a communication interface module; The first and second control units adjust the switch module according to the state of charge and battery health status of the first and second battery groups provided by the sensor module, respectively, in combination with the current driving conditions, to execute the connection or disconnection of the first and second battery modules to ensure normal power supply to the EPS, and provide feedback to the user on the status of the low-voltage lithium battery device; The switch module includes first, second and third switches, the third switch connects the first battery cell group and the second battery cell group, the first switch electrically couples the first battery cell group and the third switch, and together with the first temperature sensor and the first voltage and current sensor, forms a first power supply module, and the second switch electrically couples the second battery cell group and the third switch, and together with the second temperature sensor and the second voltage and current sensor, forms a second power supply module.

2. The automotive low-voltage lithium battery device according to claim 1, characterized in that: The device further includes a diode connected in parallel with the third switch.

3. A control method for a low-voltage lithium battery device for an automobile according to any one of claims 1 to 2, characterized in that: The method comprises: Step 1: When the BMS module detects that the SOC of the low-voltage lithium battery device is less than or equal to 15%, the first and third switches are opened and the second switch is closed to enter a self-protection mode to prevent the first battery module from entering a deep power-loss state due to starting the vehicle and damaging the battery. If the condition is not satisfied, the process proceeds to step 3. Step 2: When the sensor module controlling the second battery module recognizes that a large current is connected, the first and third switches are closed, and the device is activated to complete external charging and maintenance; Step 3: When the BMS module detects that the SOC of the current lithium battery device is greater than 15%, the first, second, and third switches are closed, and the first and second battery modules jointly participate in the power supply of the low-voltage grid; Step 4: The engine starts normally; Step 5: When a low-voltage grid abnormality occurs, the first and second switches are closed, and the third switch is opened, and the two independent circuits operate normally; Step 6: When a battery abnormality occurs while the vehicle is driving, the BMS module can self-check the real-time status of the battery.

4. The control method of the automotive low-voltage lithium battery device according to claim 3, characterized in that: The step 1 further comprises: When KL15 is in ON state and the BMS module executes the battery to enter the self-protection mode, the vehicle low-voltage energy management system will remind the user to connect an external charging device to maintain the battery through the HMI or ABT.

5. The control method of the automotive low-voltage lithium battery device according to claim 4, characterized in that: The step 6 further comprises: When the first battery module is abnormal, the first switch is disconnected and the second and third switches are closed; When the second battery module is abnormal, the second switch is disconnected and the first and third switches are closed to ensure that the abnormal module does not interfere with the operation of the normal module; When the first battery module and the low-voltage load are abnormal, the BMS module self-checks the real-time status of the battery, opens the second and third switches, and closes the first switch; When an abnormality occurs in the first battery module or the second battery module, the first and second switches are disconnected and the third switch is closed. The low-voltage power grid of the entire vehicle and the ASIL C electrical appliances are directly powered by the generator.

6. The control method of the automotive low-voltage lithium battery device according to claim 5, characterized in that: In step 4, further comprising: When a short circuit occurs in the low-voltage load line or an abnormal signal, undervoltage or overvoltage occurs on the power supply side while the vehicle is driving, the vehicle's low-voltage energy management system will alert the user of the low-voltage grid abnormality through the HMI or ABT.

7. The control method of the automotive low-voltage lithium battery device according to claim 6, characterized in that: The step 4 further comprises: During normal engine operation, the device enters either a charging mode to maintain the battery or a discharging mode; when the vehicle is stationary, the engine is allowed to stop and the battery is in a discharging mode to support the entire low-voltage power grid and save fuel.

8. The control method of the automotive low-voltage lithium battery device according to claim 7, characterized in that: The step 5 further comprises: The first battery module supplies power to all low-voltage loads of the vehicle, and the second battery module only supplies power to the ASIL C system.

9. The control method of the automotive low-voltage lithium battery device according to claim 8, characterized in that: The control method further includes: When the BMS module is in a non-sleep mode, it intermittently self-learns whether the SOC and SOH of the current battery module are normal.

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