Power battery thermal management strategy and system of new energy automobile

Abstract

The invention discloses a thermal management strategy and system for a power battery of a new energy automobile. The strategy comprises the steps that temperature information and voltage information of the power battery are collected from a communication signal of a vehicle-mounted diagnosis interface; calculating a plurality of thermal runaway evaluation indexes according to the temperature information and the voltage information of the power battery; judging whether thermal runaway early warning conditions are met or not according to the plurality of thermal runaway evaluation indexes; if yes, thermal runaway early warning is given out. The thermal runaway judgment is performed in real time by detecting the temperature and voltage information of the power battery, the thermal runaway tendency of the power battery can be found in time, early warning is performed, and the early warning time advance is prolonged.

Description

Technical Field

[0001] The present application relates to the field of power battery technology, and more specifically, to a power battery thermal management strategy and system for new energy vehicles. Background Art

[0002] Fires in new energy vehicles are mainly caused by thermal runaway of the power battery. The spontaneous combustion of vehicles caused by thermal runaway of the power battery poses a great threat to personal safety and property losses. Therefore, both customers and vehicle developers have high requirements for the safety of the vehicle's power battery. Common power battery thermal runaway solutions are to perform thermal management control on the power battery or to provide early warning and control of power battery abnormalities to reduce property losses and casualties.

[0003] Current prevention and control strategies for thermal runaway of vehicle power batteries include:

[0004] 1. Install a smoke sensor or ultrasonic sensor inside the power battery pack to analyze the gas characteristics in the power battery pack and realize thermal runaway warning.

[0005] However, installing sensors inside power batteries is not easy to implement and is difficult to promote, and changes to the power batteries themselves may cause additional safety hazards. In addition, when smoke sensors or ultrasonic sensors issue warnings, the battery has already experienced relatively large side reactions, and the warning time is not long enough.

[0006] 2. When the vehicle is driving and a high-rate charge and discharge condition and a harsh thermal environment are detected, the battery output power is controlled and the heat dissipation is increased to prevent thermal runaway of the battery. However, excessive prevention strategies may affect the normal driving of the vehicle and result in a poor driving experience. Summary of the invention

[0007] The present application provides a power battery thermal management strategy and system for new energy vehicles. By detecting the temperature and voltage information of the power battery to perform real-time thermal runaway judgment, the thermal runaway tendency of the power battery can be discovered in time, and an early warning can be issued, thereby extending the lead time of the early warning.

[0008] This application provides a thermal management strategy for a power battery of a new energy vehicle, including:

[0009] Collecting the temperature and voltage information of the power battery from the communication signal of the on-board diagnostic interface;

[0010] Calculate multiple thermal runaway evaluation indicators based on the temperature and voltage information of the power battery;

[0011] Determine whether the thermal runaway warning conditions are met based on multiple thermal runaway evaluation indicators;

[0012] If the conditions are met, a thermal runaway warning is issued.

[0013] Preferably, the thermal management strategy of the power battery of the new energy vehicle also includes:

[0014] Calculate multiple thermal runaway risk coefficients based on multiple thermal runaway evaluation indicators;

[0015] Determine the thermal runaway risk level based on multiple thermal runaway risk coefficients;

[0016] Determine the heat dissipation solution for the power battery based on the thermal runaway risk level.

[0017] Preferably, the thermal runaway evaluation index includes the maximum temperature, the temperature rise rate of the maximum temperature, the temperature rise rate after the maximum temperature exceeds the temperature threshold, and the drop rate of the battery terminal voltage.

[0018] Preferably, the thermal runaway warning condition is that the maximum temperature, the temperature rise rate of the maximum temperature, and the decrease rate of the battery terminal voltage are all greater than the corresponding first threshold, or the maximum temperature, the temperature rise rate after the maximum temperature exceeds the temperature threshold, and the decrease rate of the battery terminal voltage are all greater than the corresponding first threshold.

[0019] Preferably, when the thermal runaway risk level is level one, the heat dissipation solution for the power battery is that the water pump and cooling fan of the power battery cooling system and the air conditioning compressor of the vehicle work at full load;

[0020] When the thermal runaway risk level is level 2, the power battery cooling solution is to adjust the control parameters of the water pump and cooling fan of the power battery cooling system and the vehicle's air conditioning compressor to preset multiples of the current parameters;

[0021] Among them, when the thermal runaway risk level is level one, the thermal runaway risk of the power battery is higher than level two, and the preset multiple is greater than 1.

[0022] The present application also provides a power battery thermal management system for a new energy vehicle, including a controller, a display module and a sound module;

[0023] The controller is used for the above-mentioned power battery thermal management strategy;

[0024] The display module and the sound module are respectively connected with the controller signal.

[0025] Preferably, the power battery thermal management system of the new energy vehicle also includes an SD storage module, and the SD storage module is connected to the controller signal.

[0026] Preferably, the display module is a vehicle-mounted display screen, and the sound module is a vehicle-mounted audio system.

[0027] Preferably, the controller, display module, sound module and SD storage module are all arranged on a circuit board, and the circuit board is also provided with a first communication interface, a communication module, a power supply and a first power supply interface.

[0028] Preferably, the power battery thermal management system of the new energy vehicle also includes a shell, the circuit board is arranged in the shell, and a second power interface and a second communication interface are provided on the shell, the second power interface is connected to the first power interface, and the second communication interface is connected to the first communication interface.

[0029] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0031] Figure 1 A flow chart of the thermal management strategy of the power battery of the new energy vehicle provided in this application;

[0032] Figure 2 A structural diagram of an embodiment of a power battery thermal management system for a new energy vehicle provided in this application;

[0033] Figure 3 A structural diagram of an embodiment of a circuit board of a power battery thermal management system for a new energy vehicle provided in this application. DETAILED DESCRIPTION

[0034] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0035] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0036] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0037] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0038] The present application provides a power battery thermal management strategy and system for new energy vehicles. By detecting the temperature and voltage information of the power battery and making a real-time thermal runaway judgment, the thermal runaway tendency of the power battery can be discovered in time and an early warning can be issued, which prolongs the advance time of the early warning. The early warning allows the driver to intuitively understand the battery status and respond to the thermal runaway of the battery in time. Furthermore, the present application classifies the thermal runaway risk into different levels and adopts corresponding heat dissipation solutions to avoid the transition of the prevention strategy and affect the normal driving and driving experience of the vehicle. Finally, the present application uses an SD storage module to store the configuration file of the vehicle model, which is used to match different vehicle models and has strong versatility.

[0039] like Figure 1 As shown, the thermal management strategy of the power battery of the new energy vehicle provided in this application includes:

[0040] S110: Collecting temperature information and voltage information of the power battery from a communication signal (eg, a CAN signal).

[0041] As an embodiment, the vehicle CAN signal of the vehicle's on-board diagnostic interface (OBD diagnostic interface) is collected through the CAN bus, and the temperature information and voltage information of the power battery are extracted from the vehicle CAN signal, including the maximum battery temperature, battery terminal voltage, current, etc.

[0042] S120: Calculating a plurality of thermal runaway evaluation indicators based on the temperature information and voltage information of the power battery.

[0043] As an example, the thermal runaway evaluation index includes the maximum temperature T max (Unit: °C), the maximum temperature rise rate V Tmax (unit: °C / s), the temperature rise rate after the maximum temperature exceeds the temperature threshold (for example, 38 °C) (for example, V T38 ) (unit: °C / s) and the rate of decrease of the battery terminal voltage V Vpack (Unit: V / s).

[0044] Specifically, read the battery maximum temperature data column, intercept the data according to the first preset period (for example, 1s), and find the maximum value within the first preset period as the maximum temperature T max .

[0045] Read the battery maximum temperature data column, intercept the data according to the first preset period (for example, 1s), and calculate the value according to the formula V Tmax =(T i -T i-1 ) / (t i -t i-1 ) Calculate the temperature rise rate V of the maximum temperature Tmax , where T i(i=1, 2, 3, 4...) is the highest temperature data point in the ith cycle, t i T i The corresponding time point.

[0046] Read the battery maximum temperature data column, intercept the data within the first preset period (e.g. 1s), and extract the data point T38 with a temperature value ≥ 38°C i , through the formula V T38 =(T38 i -T38 i-1 ) / (t38 i -t38 i-1 ) Calculate the temperature rise rate V after the maximum temperature reaches 38°C T38 , of which T38 i (i=1, 2, 3, 4...) is the data point with the highest temperature ≥38℃ in the i-th cycle, t38 i For T38 i The corresponding time point.

[0047] Read the battery terminal voltage data column, intercept the data points according to the first preset period (for example, 1s), and calculate the value according to the formula V Vpack =(V i -V i-1 ) / (t i -t i-1 ) Calculate the rate of decrease of the battery terminal voltage V Vpack , where V i (i=1, 2, 3, 4...) is the voltage value of the ith battery terminal voltage data point, t i V i The corresponding time point.

[0048] S130: Determine whether the thermal runaway warning condition is met based on multiple thermal runaway evaluation indicators. If so, execute S140; otherwise, return to S110.

[0049] As an embodiment, a thermal runaway warning condition judgment is performed once in a second preset period (eg, 1S).

[0050] As an embodiment, the thermal runaway warning condition is that the maximum temperature, the temperature rise rate of the maximum temperature, and the decrease rate of the battery terminal voltage are all greater than the corresponding first threshold, or the maximum temperature, the temperature rise rate after the maximum temperature exceeds the temperature threshold, and the decrease rate of the battery terminal voltage are all greater than the corresponding first threshold.

[0051] As an embodiment, the first threshold conditions of each thermal runaway evaluation indicator are as follows:

[0052] Condition 1: Maximum temperature T max >42℃;

[0053] Condition 2: Maximum temperature rise rate V Tmax >1℃ / s;

[0054] Condition 3: Temperature rise rate V after the maximum temperature exceeds 38°C T38 >1.2℃ / s;

[0055] Condition 4: Battery terminal voltage drop rate V Vpack >4.5V / s.

[0056] If the above conditions 1, 2, and 4 are met at the same time, or the above conditions 1, 3, and 4 are met at the same time, a thermal runaway warning will be issued.

[0057] As an example, the maximum temperature T max (Unit: °C), the maximum temperature rise rate V Tmax (unit: °C / s), the temperature rise rate after the maximum temperature exceeds the temperature threshold (for example, 38 °C) (for example, V T38 ) (unit: °C / s) and the rate of decrease of the battery terminal voltage V Vpack The corresponding threshold lines can be displayed on the display screen, so that the driver can intuitively understand the changes in various thermal runaway evaluation indicators.

[0058] S140: Issue a thermal runaway warning.

[0059] As an embodiment, a thermal runaway warning is provided by means of a display screen display (e.g., screen flashing) and / or a sound warning (e.g., a buzzer), and the thermal runaway warning enables the driver to intuitively understand the status of the power battery.

[0060] Preferably, the thermal management strategy for the power battery of the new energy vehicle provided in this application also includes:

[0061] S150: Calculating multiple thermal runaway risk coefficients based on multiple thermal runaway evaluation indicators.

[0062] As an example, the plurality of thermal runaway risk factors include a maximum temperature T max The calculated first thermal runaway risk coefficient φ1, the temperature rise rate V based on the maximum temperature Tmax The calculated second thermal runaway risk coefficient φ2 is based on the temperature rise rate V after the maximum temperature exceeds the temperature threshold. T38 The calculated third thermal runaway risk coefficient φ3, based on the battery terminal voltage drop rate V Vpack The fourth thermal runaway risk coefficient φ4 is calculated, and the fifth thermal runaway risk coefficient φ5 is calculated based on the first thermal runaway risk coefficient φ1, the second thermal runaway risk coefficient φ2, the third thermal runaway risk coefficient φ3, the fourth thermal runaway risk coefficient φ4 and the battery health SOH (read through the vehicle CAN signal).

[0063] As an example, the calculation formulas for each thermal runaway risk coefficient are as follows:

[0064] φ1 = 0.1 × T max - 3.5, when φ1<0, φ1 is 0;

[0065] φ2 = 0.35V Tmax - 0.07, when φ2<0, φ2 is 0;

[0066] φ3 = 0.3V T38 - 0.06, when φ3<0, φ3 is 0;

[0067] φ4 = 0.05V Vpack - 0.01, when φ4<0, φ4 is 0;

[0068] φ5=(φ1+φ2+φ3+φ4) / SOH.

[0069] S160: Determine the thermal runaway risk level based on multiple thermal runaway risk coefficients.

[0070] As an embodiment, if any one of the first thermal runaway risk coefficient φ1, the second thermal runaway risk coefficient φ2, the third thermal runaway risk coefficient φ3, the fourth thermal runaway risk coefficient φ4 and the fifth thermal runaway risk coefficient φ5 is greater than the corresponding second threshold, the thermal runaway risk level is level one.

[0071] If the first thermal runaway risk coefficient φ1, the second thermal runaway risk coefficient φ2, the third thermal runaway risk coefficient φ3, and the fourth thermal runaway risk coefficient φ4 are all less than the corresponding second threshold, and the fifth thermal runaway risk coefficient φ5 is between the second threshold and the third threshold, then the thermal runaway risk level is level 2. The second threshold is greater than the third threshold.

[0072] In other cases, the thermal runaway risk level is level three.

[0073] Among them, when the thermal runaway risk level is level one, the thermal runaway risk of the power battery is higher than level two, and when the thermal runaway risk level is level three, there is no thermal runaway risk.

[0074] As an example, if any one of φ1>0.1, φ2>0.35, φ3>0.3, φ4>0.25, and φ5>0.6 is satisfied, the thermal runaway risk level is level 1. If φ1<0.1, φ2<0.35, φ3<0.3, φ4<0.25, and 0.5<φ5<0.6 are satisfied, the thermal runaway risk level is level 2. In other cases than the above, the thermal runaway risk level is level 3.

[0075] S170: Determine the heat dissipation solution for the power battery based on the thermal runaway risk level.

[0076] As an embodiment, when the thermal runaway risk level is level one, the heat dissipation solution for the power battery is that the water pump and cooling fan of the power battery cooling system and the air conditioning compressor of the vehicle work at full load. When the thermal runaway risk level is level two, the heat dissipation solution for the power battery is that the control parameters of the water pump and cooling fan of the power battery cooling system and the air conditioning compressor of the vehicle are adjusted to preset multiples of the current parameters. When the thermal runaway risk level is level three, there is no thermal runaway risk, and the control parameters of the water pump and cooling fan of the power battery cooling system and the air conditioning compressor of the vehicle are not adjusted.

[0077] The preset multiple is greater than 1 (eg, 1.2 times).

[0078] It should be noted that the heat dissipation solution is transmitted to the battery management system (BMS) and the vehicle control unit (VCU) to achieve heat dissipation control.

[0079] Preferably, the CAN signal configuration file of the power battery general data contains the signal protocol of the battery maximum temperature, battery minimum temperature, battery terminal voltage, and battery discharge current. Users can modify the protocol content according to the vehicle model to make the power battery thermal management system suitable for all new energy vehicle models. The protocol file is placed in the memory card that comes with the power battery thermal management system. The software will read and identify the file content during the initialization process as the vehicle's general battery data.

[0080] Based on the above, this application also provides a power battery thermal management system for new energy vehicles. Please refer to Figure 2 The power battery thermal management system includes a controller, a display module and a sound module.

[0081] The controller is used to execute the above-mentioned power battery thermal management strategy.

[0082] The display module and the sound module are respectively connected to the controller signal to issue thermal runaway warning information.

[0083] Preferably, the power battery thermal management system also includes an SD storage module, which is connected to the controller signal and is used to store the configuration file of the vehicle model corresponding to the vehicle in which the power battery thermal management system is located. One vehicle model corresponds to one configuration file. When changing the vehicle model, you only need to replace the configuration file in the SD storage module without re-writing the program. The configuration file is divided into two parts. One is to write the parsing parameters of the power battery data according to DBC; the other is to set the thermal runaway threshold of the vehicle, including the power battery temperature threshold, the power battery voltage threshold, the power battery temperature rise rate threshold, etc.

[0084] As an embodiment, the display module is a vehicle-mounted display screen, and the sound module is a vehicle-mounted audio system, thereby reducing the number of components installed on the vehicle body.

[0085] Preferably, if Figure 2 As shown, the power battery thermal management system is a complete device that is independent of the vehicle body and installed on the vehicle body. It can be installed and disassembled as a whole, which is convenient for expanding the thermal management function of the sold vehicles.

[0086] like Figure 2 and 3 As shown, the power battery thermal management system includes a housing and a circuit board, and the circuit board is arranged in the housing. The controller 1, the display module (including the display interface 2 and the display 3), the sound module 9 (such as a buzzer) and the SD storage module (including the SD memory 4 and the memory base 6) are all arranged on the circuit board, and the circuit board is also provided with a first communication interface 10, a communication module 8, a J-link interface 7 (for burning the control software to the controller), a power module (including a button battery and a crystal oscillator) 12, a first power interface 11, an RS232 interface 13, an RS232 serial port module 14 and a power switch 15. The stud hole 5 is used to fix the circuit board to the housing.

[0087] The housing is also provided with a second power interface and a second communication interface, the second power interface is connected to the first power interface for obtaining electric energy from the outside, and the second communication interface is respectively connected to the first communication interface and the vehicle's OBD diagnostic interface for collecting vehicle signals.

[0088] As an embodiment, the controller is an ARM controller, and the first communication interface and the communication module transmit CAN communication signals. The power supply is a 12V DC power supply.

[0089] As an embodiment, the shell is 3D printed by resin material, and the overall structure is stable and reliable.

[0090] based on Figure 2 and 3 After the thermal management program of the power battery thermal management system is started, each module is initialized first, and then the controller reads the configuration file in the SD storage module and sets the parsing parameters of the bus battery message. Figure 1 The process shown is to perform thermal management of the power battery, wherein the controller parses the voltage, current, temperature and other data of the power battery according to the configuration file, and adds a timestamp to the data by relying on the UTC time obtained by the button battery and the crystal oscillator 12, and then saves the processed data in the SD memory 4, and then synchronously displays it on the display screen 3. When thermal runaway occurs, the controller 1 controls the buzzer to sound an alarm and the display screen 3 to flash.

[0091] This application constructs a method for determining the thermal runaway risk level based on multi-parameter thermal runaway warning conditions and combined with the battery health. The control parameters of the battery water pump, cooling fan, and compressor are corrected by the thermal runaway risk level to achieve reliable battery thermal runaway risk control. It can provide drivers with real-time automatic monitoring tools for power batteries, alarm prompts for power battery thermal runaway, speed up risk response, and improve the driving safety of new energy vehicles. In addition, the power battery thermal management system of this application is small, portable, and easy to wire. It is reliable in operation and can be adapted to all new energy vehicle models, with wide applicability. This application can realize the data collection of the thermal runaway process of the vehicle power battery, analyze the cause of thermal runaway, and provide data support for the improvement of subsequent models.

[0092] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A thermal management strategy for power batteries of new energy vehicles, characterized in that: include: Collecting the temperature and voltage information of the power battery from the communication signal of the on-board diagnostic interface; Calculating a plurality of thermal runaway evaluation indicators according to the temperature information and voltage information of the power battery; Determining whether a thermal runaway warning condition is met according to the multiple thermal runaway evaluation indicators; If the conditions are met, a thermal runaway warning is issued.

2. The thermal management strategy of the power battery of the new energy vehicle according to claim 1 is characterized in that: Also includes: Calculating a plurality of thermal runaway risk coefficients according to the plurality of thermal runaway evaluation indicators; determining a thermal runaway risk level according to the plurality of thermal runaway risk coefficients; A heat dissipation solution for the power battery is determined according to the thermal runaway risk level.

3. The thermal management strategy of the power battery of the new energy vehicle according to claim 2 is characterized in that: The thermal runaway evaluation index includes the maximum temperature, the temperature rise rate of the maximum temperature, the temperature rise rate after the maximum temperature exceeds the temperature threshold, and the drop rate of the battery terminal voltage.

4. The thermal management strategy of the power battery of the new energy vehicle according to claim 3 is characterized in that: The thermal runaway warning condition is that the maximum temperature, the temperature rise rate of the maximum temperature, and the decrease rate of the battery terminal voltage are all greater than the corresponding first threshold, or the maximum temperature, the temperature rise rate after the maximum temperature exceeds the temperature threshold, and the decrease rate of the battery terminal voltage are all greater than the corresponding first threshold.

5. The thermal management strategy of the power battery of the new energy vehicle according to claim 2, characterized in that: When the thermal runaway risk level is level one, the heat dissipation solution for the power battery is that the water pump and cooling fan of the power battery cooling system and the vehicle's air conditioning compressor work at full load; When the thermal runaway risk level is level 2, the power battery cooling solution is to adjust the control parameters of the water pump and cooling fan of the power battery cooling system and the vehicle's air conditioning compressor to preset multiples of the current parameters; Among them, when the thermal runaway risk level is level one, the thermal runaway risk of the power battery is higher than level two, and the preset multiple is greater than 1.

6. A power battery thermal management system for a new energy vehicle, characterized in that: Including controller, display module and sound module; The controller is used to execute the power battery thermal management strategy described in any one of claims 1 to 5; The display module and the sound module are respectively connected to the controller signal.

7. The power battery thermal management system for new energy vehicles according to claim 6, characterized in that: It also includes an SD storage module, and the SD storage module is connected to the controller signal.

8. The power battery thermal management system for new energy vehicles according to claim 6, characterized in that: The display module is a vehicle-mounted display screen, and the sound module is a vehicle-mounted audio system.

9. The power battery thermal management system for new energy vehicles according to claim 7, characterized in that: The controller, the display module, the sound module and the SD storage module are all arranged on a circuit board. The circuit board is also provided with a first communication interface, a communication module, a power supply and a first power supply interface.

10. The power battery thermal management system for new energy vehicles according to claim 9, characterized in that: It also includes a shell, the circuit board is arranged in the shell, and the shell is provided with a second power interface and a second communication interface, the second power interface is connected to the first power interface, and the second communication interface is respectively connected to the first communication interface and the OBD diagnostic interface of the vehicle.

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