Power Battery System and Thermal Evaluation Method for Vehicles

Abstract

The present invention relates to a power battery system for a vehicle. The power battery system includes a battery module and a controller. The battery module has at least a plurality of battery cells and a plurality of busbar assemblies. The busbar assemblies are configured to connect adjacent battery cells. Each busbar assembly includes a busbar connected to the battery cell, a flexible circuit board on which a temperature sensor is integrated and outputs a temperature signal, an internal thermal shield insulation layer disposed at least between the busbar and the flexible circuit board, and an external insulation layer configured to cover the busbar and the flexible circuit board. The controller is configured to receive the temperature signal detected by the temperature sensor of each busbar assembly and predict the heat dissipation direction and / or breakdown point of the battery module based on the temperature signal. The present invention further relates to a heat evaluation method, which can determine the degree of heat dissipation, thereby providing a basis for failure cause analysis and effectively improving the safety of rescue operations.

Description

Technical Field

[0001] The present invention relates to the field of batteries, and more particularly to a power battery system for a vehicle. The present invention further relates to a method for thermal evaluation of a power battery system for a vehicle.

Background Art

[0002] In recent years, electric vehicles or hybrid vehicles powered by power batteries have attracted attention due to many advantages such as zero emissions and high efficiency. Here, the safety problem of power batteries has become a particular focus of research.

[0003] In power batteries, the trigger causes of thermal runaway accidents cover a wide range, such as impact or extrusion due to collision, overcharging or over-discharging, inappropriate temperature management, etc. These trigger causes are interrelated and create a positive feedback loop for thermal runaway. When a battery cell of a power battery undergoes thermal runaway, the battery cell enters a thermal runaway state and releases a large amount of heat, thereby causing the temperature to rise rapidly and possibly exceeding 1000°C. In this case, the battery cell material and the busbar may melt and burn, causing insulation failure, which may in turn cause deformation and short-circuit of the busbar, further worsening the thermal runaway and developing into thermal diffusion. Due to this thermal diffusion, heat further spreads to the surrounding battery cells and causes thermal runaway of other battery cells. Furthermore, in the thermal runaway state, the insulating material used for the busbar burns out, the busbar is exposed to the power battery, and there is a possibility of arcing occurring in the copper bar of the busbar and the case of the power battery due to high-temperature gas and ejected fire, which may penetrate the battery case and ultimately cause the entire power battery to catch fire or explode.

[0004] Currently, in the prior art, when thermal runaway occurs in a power battery, only the occurrence of thermal diffusion can be warned, and the thermal diffusion situation of the power battery, especially the thermal diffusion direction and the breakdown point, cannot be evaluated. This is not helpful for analyzing the cause of the failure and may pose potential risks to subsequent rescue operations.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, an object of the present invention is to propose an improved power battery system for a vehicle. When thermal runaway or thermal runaway occurs in the battery cells of the battery module, the thermal diffusion direction and / or the breakdown point of the battery module can be accurately predicted based on a plurality of temperature signals in the battery module, and the degree of thermal diffusion can be determined, thereby providing a basis for analyzing the cause of the failure and effectively improving the safety of the rescue operation.

Means for Solving the Problems

[0006] A first aspect of the present invention provides a power battery system for a vehicle, the power battery system including at least a battery module and a controller, the battery module having at least a plurality of battery cells and a plurality of busbar assemblies, the busbar assemblies being configured to connect adjacent battery cells, the busbar assemblies including at least a busbar connected to the battery cells, a flexible circuit board on which temperature sensors are integrated and which outputs temperature signals detected by the temperature sensors, an internal thermal shield insulation layer disposed between at least the busbar and the flexible circuit board, and an external insulation layer configured to cover the busbar and the flexible circuit board. The controller is configured to receive temperature signals detected by the temperature sensors of each bus bar assembly and predict the heat diffusion direction and / or breakdown point of the battery module based on the temperature signals.

[0007] According to the present invention, a power battery system includes temperature sensors in a plurality of bus bar assemblies of a battery module. The temperature sensors can detect the temperature of each bus bar. When thermal runaway occurs in the battery module, the temperatures at multiple locations within the battery module can be obtained based on the temperature signals detected by each temperature sensor, thereby obtaining a temperature distribution and predicting the heat diffusion direction and / or breakdown point within the thermal battery module, thereby advantageously evaluating the heat diffusion degree and advantageously improving the safety of rescue operations. Further, the internal thermal shield insulation layer between the bus bar and the flexible circuit board can reduce the adverse effects of the heated bus bar on components, particularly the flexible circuit board, and delay the heat diffusion rate.

[0008] According to an exemplary embodiment of the present invention, the controller is disposed in the battery management system or vehicle control unit of the vehicle, or in a remote server for the vehicle.

[0009] According to an exemplary embodiment of the present invention, at least one of the plurality of bus bar assemblies further includes a pneumatic sensor. The pneumatic sensor contacts the gas within the battery module through an opening in the external insulation layer and outputs a pneumatic signal through the flexible circuit board.

[0010] According to an exemplary embodiment of the present invention, the controller evaluates the heat diffusion degree of the battery module and / or the open state of the pressure relief valve for the battery module based on the pneumatic signal.

[0011] According to an exemplary embodiment of the present invention, the internal thermal shield insulating layer is disposed between the bus bar and the flexible circuit board in a layered form, or the internal thermal shield insulating layer wraps the bus bar in the form of a sheath.

[0012] According to an exemplary embodiment of the present invention, the external insulating layer is integrally formed particularly as a heat shrinkable sleeve, or the external insulating layer is configured as a separate first external insulating layer and a second external insulating layer, and the first external insulating layer and the second external insulating layer are fixedly connected to each other in a shape-fitting manner.

[0013] According to an exemplary embodiment of the present invention, the external insulating layer is made of a heat-resistant and fire-resistant material, particularly polyphenylene sulfide, and / or the bus bar assembly further includes an additional heat insulation layer, and the additional heat insulation layer is disposed between the external insulating layer and the flexible circuit board and / or between the external insulating layer and the bus bar, and / or the bus bar is made of copper, aluminum, nickel or an alloy thereof.

[0014] According to an exemplary embodiment of the present invention, the power battery system further includes an interaction unit, and the interaction unit shows the temperature distribution inside the battery module in the form of an image and feeds back the heat diffusion direction and / or the breakdown point of the battery module predicted by the controller.

[0015] According to an exemplary embodiment of the present invention, the controller transmits the temperature signal, or the heat diffusion direction and / or the breakdown point predicted based on the temperature signal, to the Original Equipment Manufacturer of the vehicle through the real-time monitoring system of the vehicle.

[0016] A second aspect of the present invention provides a method for thermal evaluation of a power battery system for a vehicle, and the thermal evaluation method includes at least the following steps: S1: detecting temperature signals of a plurality of busbar assemblies of a battery module of the power battery system; S2: when a temperature signal of at least one busbar assembly among the plurality of busbar assemblies exceeds a temperature threshold, determining that the battery module is in a thermal runaway state; and S3: predicting a heat diffusion direction and / or a breakdown point of the battery module based on the temperature signal of the busbar assembly.

Brief Description of the Drawings

[0017] Hereinafter, the principles, features, and advantages of the present invention will be better understood by describing the present invention in more detail with reference to the accompanying drawings. In the accompanying drawings,

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0018] To more clearly illustrate the technical problems, technical solutions, and advantageous technical effects solved by the present invention, the present invention will be described in more detail below with reference to the accompanying drawings and a plurality of exemplary embodiments. It should be understood that the specific embodiments described herein are used only for the purpose of explaining the present invention and are not used to limit the protection scope of the present invention.

[0019] In the description of this embodiment, the relationships of directions or positions such as "upper" and "lower" are based on the illustrated directions or positions, for the sake of simplifying the description and operation, and are not intended to imply or suggest that the devices or elements mentioned must have a specific particular direction and must be configured and operated in a specific direction. Therefore, it should not be construed as limiting the present invention.

[0020] In this specification, unless specifically defined and limited otherwise, the terms "installation", "connection", and "attachment" should be understood in a broad sense. For example, it can be any of a fixed connection, a detachable connection, or an integral connection, and may be a mechanical connection or an electrical connection. It can be directly connected, indirectly connected through middleware, or internally connected between two components. A person skilled in the art will be able to understand the meanings of the above terms in the present disclosure according to the circumstances.

[0021] FIG. 1 shows a schematic block diagram of a power battery system 100 for a vehicle according to an exemplary embodiment of the present invention. Here, the vehicle can be a pure electric vehicle or a hybrid vehicle.

[0022] As shown in FIG. 1, the power battery system 100 includes a plurality of battery modules 10, and these battery modules are packaged together into a battery pack. Here, each battery module 10 includes a plurality of battery cells 11 or a single battery respectively. The battery cell is the smallest energy storage unit of the power battery system 100 and has a higher energy density. Here, adjacent battery cells 11 are connected in series or in parallel through a busbar assembly 12, whereby the currents of different battery cells 11 are collected and output together. Here, the busbar assembly 12 is fixedly connected to the tab or post terminal of the battery cell 11, thereby deriving the current of the battery cell 11.

[0023] FIG. 2 shows a schematic diagram of the busbar assembly 12 of the power battery system 100 for a vehicle according to an exemplary embodiment of the present invention.

[0024] As shown in FIG. 2, the busbar assembly 12 includes a busbar 1, and the busbar is connected to the tab or post terminal of the battery cell 11 and is configured to derive the current of the battery cell 11. For this purpose, the busbar 1 should have good electrical conductivity and thermal stability. Here, the busbar 1 can be designed as a copper bar, and the copper bar has the advantages of low resistivity and good workability. However, it is also conceivable that the busbar 1 is manufactured from another material considered useful by those skilled in the art, such as aluminum, nickel, or their alloys.

[0025] As shown in FIG. 2, the bus bar assembly 12 further includes an internal thermal shield insulating layer 2, which is arranged to be in direct contact with the bus bar 1 and is configured such that the heat quantity and current of the bus bar 1 do not have an adverse effect on other components of the battery module 10, and can further prevent electrophoretic penetration due to a short circuit in the case of thermal runaway. Here, the internal thermal shield insulating layer 2 is made of a high-temperature resistant and fireproof insulating material such as polyvinyl chloride with a flame retardant added, polyethylene naphthalate, polyphenylene sulfide, etc. Here, the internal thermal shield insulating layer 2 is configured, for example, in a layered form and is in close contact with the bus bar 1. However, it is also conceivable that the internal thermal shield insulating layer 2 is configured in the form of a sheath, a hollow sleeve, or a performance tape and wraps around the entire bus bar 1.

[0026] As shown in FIG. 2, the bus bar assembly 12 further includes a flexible circuit board 3, on which a temperature sensor 4 for detecting temperature is integrated and printed wiring is printed. The printed wiring outputs the temperature signal detected by the temperature sensor 4 to the outside. Here, the temperature sensor 4 is configured, for example, as a thermocouple. Here, the flexible circuit board 3 is communicably connected to a battery management system for the power battery system 100, particularly through the printed wiring. Here, the internal thermal shield insulating layer 2 is arranged between the bus bar 1 and the flexible circuit board 3, thereby preventing the temperature and current of the bus bar 1 from affecting the flexible circuit board 3. Here, compared with the conventional wiring, the flexible circuit board 3 is easy to assemble with the bus bar 1 and has high thermal stability in the case of thermal runaway of the battery cell 11.

[0027] As shown in FIG. 2, the bus bar assembly 12 further includes an external insulation layer 5, and the external insulation layer is configured to cover other components of the bus bar assembly 12, particularly the bus bar 1 and the flexible circuit board 3. Through the external insulation layer 5, the insulation and wear resistance of the entire bus bar assembly 12 can be increased, and the short circuit and breakdown points in the case of thermal runaway of the battery cell 11 can be prevented as much as possible. Here, the external insulation layer 5 is exemplarily integrally formed in the form of a heat shrinkable sleeve, but other forms of configuration are also conceivable. Specifically, refer to FIG. 3. Here, the external insulation layer 5 is manufactured from an insulating material such as polyethylene or polyvinyl chloride. However, it is also conceivable that the external insulation layer 5 is manufactured from a high-temperature resistant and fireproof insulating material to further enhance the heat resistance and fire resistance of the bus bar assembly 12 and delay the heat diffusion rate in the case of thermal runaway. Here, the color of the external insulation layer 5 can be changed to meet the user's color requirements for the bus bar assembly 12.

[0028] Exemplarily, as shown in FIG. 2, the bus bar assembly 12 further includes an additional heat insulation layer 6, and the additional heat insulation layer is disposed between the external insulation layer 5 and the flexible circuit board 3 and / or between the external insulation layer 5 and the bus bar 1. Through the additional heat insulation layer 6, the heat insulation performance of the bus bar assembly 12 can be further improved and the heat diffusion rate can be delayed. The additional heat insulation layer 6 is particularly suitable when the external insulation layer 5 is manufactured from an insulating material that cannot withstand high temperatures. Here, the additional heat insulation layer 6 can wrap the bus bar 1 and the flexible circuit board 3 in the form of a performance tape or a sleeve.

[0029] FIG. 3 shows a schematic diagram of a bus bar assembly 12 of a power battery system 100 for a vehicle according to another exemplary embodiment of the present invention.

[0030] Unlike the bus bar assembly 12 shown in FIG. 2, the bus bar assembly 12 shown in FIG. 3 further includes a pneumatic sensor 7, which is configured to contact the gas in the battery module 10 through an opening 8 in the external insulation layer 5 and detect a pneumatic signal. The pneumatic sensor 7 is integrated, for example, on a flexible circuit board 3, and the pneumatic signal detected by the pneumatic sensor 7 is output externally through the printed wiring of the flexible circuit board 3.

[0031] As shown in FIG. 3, the external insulation layer 5 of the bus bar assembly 12 is configured as a separate first external insulation layer 5.1 and a second external insulation layer 5.2, and the first external insulation layer and the second external insulation layer are injected through an insulating material and fixedly connected to each other in a form-fitting manner such as a snap fit connection or a plug connection.

[0032] As shown in FIG. 1, the power battery system 100 further includes a controller 20, which receives the temperature signal detected by the temperature sensor 4 of each bus bar assembly 12 of the battery module 10 and the pneumatic signal detected by the pneumatic sensor 7. Here, the controller 20 obtains the temperature distribution situation inside the battery module 10 based on the temperature signals of a plurality of bus bar assemblies 12 of the battery module 10. Here, when at least one of the temperature signals received by the controller 20 exceeds a preset temperature threshold, the controller 20 determines that the battery module 10 and the battery cell 11 corresponding to the temperature signal are in a thermal runaway state, and the temperature threshold is stored in the controller 20. The controller 20 predicts the heat diffusion direction from the battery cell 11 where thermal runaway occurs to the battery module 10 based on the plurality of temperature signals of each bus bar assembly 12, and further predicts possible breakdown points in the battery module 10. Here, the algorithm for predicting the heat diffusion direction and / or breakdown points of the battery module 10 can be stored in the controller 20.

[0033] Exemplarily, the controller 20 is directly integrated into the vehicle's battery management system (BMS), and the battery management system is configured to monitor the state of the power battery and intelligently manage and maintain each battery module 10. Here, the flexible circuit board 3 of the bus bar assembly 12 of the battery module 10 is electrically connected to the controller 20 provided in the battery management system. Further, the controller 20 is arranged in the vehicle body control unit (BCU) of the vehicle or the remote server for the vehicle, and the remote server may be installed, for example, in the original equipment manufacturer of the vehicle and communicatively connected to the battery management system through wireless communication technology.

[0034] Exemplarily, the controller 20 can evaluate the heat dissipation degree of the battery module 10 based on the air pressure signal detected by the air pressure sensor 7 of each bus bar assembly 12. The larger the air pressure signal detected by the air pressure sensor 7, the more gas leakage from each battery cell 11 into the battery module 10, which proves that the heat dissipation degree of the battery module 10 is high. Further, the controller 20 can also evaluate the open state of the pressure relief valve for the battery module 10, particularly the opening time and pressure relief effect of the pressure relief valve, based on the air pressure signal. Here, the controller 20 can more accurately evaluate the heat dissipation degree of the battery module 10 and predict the heat dissipation direction and / or breakdown point of the battery module 10 based on a plurality of temperature signals and air pressure signals of the battery module 10.

[0035] Exemplarily, as shown in FIG. 1, the power battery system 100 further includes an interaction unit 30, which receives information from the controller 20, thereby showing the temperature distribution inside the battery module 10 in the form of an image, and feeds back the heat diffusion direction and / or the breakdown point of the battery module 10 predicted by the controller 20. Thereby, when a thermal runaway occurs in the battery module 10, relevant information can be provided to the vehicle occupants and rescue personnel, thereby helping the vehicle occupants to make correct judgments and improving the rescue efficiency.

[0036] Exemplarily, the controller 20 can transmit the temperature signal or the heat diffusion direction and / or the breakdown point predicted by the temperature signal to the original equipment manufacturer of the vehicle through the vehicle's real-time monitoring system, thereby accelerating the accident cause analysis of the battery module 10 and being able to request rescue in a timely manner.

[0037] FIG. 4 shows a schematic flowchart of a heat evaluation method for a power battery system 100 for a vehicle according to an exemplary embodiment of the present invention. The heat evaluation method is implemented based on the power battery system 100 of the present invention.

[0038] As shown in FIG. 4, the heat evaluation method includes the following steps: S1: A step of detecting temperature signals of a plurality of busbar assemblies 12 of the battery module 10 of the power battery system 100; S2: When the temperature signal of at least one busbar assembly among the plurality of busbar assemblies 12 exceeds a temperature threshold, a step of determining that the battery module 10 is in a thermal runaway state; and S3: A step of predicting the heat diffusion direction and / or the breakdown point of the battery module 10 based on the temperature signal of the busbar assembly 12.

[0039] The description of the foregoing embodiments explains the present invention only within the framework of examples. Of course, as long as it makes technical sense, each feature of the embodiments can be freely combined.

[0040] Other advantages and alternative embodiments of the present invention will be apparent to those skilled in the art. Accordingly, the present invention is not limited to the specific details, representative structures, and illustrative examples shown and described herein in its broader aspects. On the contrary, those skilled in the art can make various modifications and substitutions without departing from the basic spirit and scope of the present invention.

Claims

1. A power battery system (100) for a vehicle, wherein the power battery system (100) includes at least a battery module (10) and a controller (20), the battery module (10) has at least a plurality of battery cells (11) and a plurality of busbar assemblies (12), the busbar assemblies (12) are configured to connect adjacent battery cells (11), and the busbar assemblies (12) include at least a busbar (1) connected to the battery cell (11), a flexible circuit board (3) on which a temperature sensor (4) is integrated and which outputs a temperature signal detected by the temperature sensor (4), an internal thermal shield insulation layer (2) disposed between at least the busbar (1) and the flexible circuit board (3), and an external insulation layer (5) configured to cover the busbar (1) and the flexible circuit board (3), the controller (20) is configured to receive the temperature signal detected by the temperature sensor (4) of each busbar assembly (12) and predict the heat dissipation direction and / or breakdown point of the battery module (10) based on the temperature signal. The power battery system (100).

2. The power battery system (100) according to claim 1, wherein the controller (20) is disposed in the battery management system or vehicle control unit of the vehicle, or in a remote server for the vehicle.

3. At least one of the plurality of busbar assemblies (12) further includes a pneumatic pressure sensor (7), the pneumatic pressure sensor contacts the gas in the battery module (10) through an opening (8) in the external insulation layer (5), and outputs a pneumatic pressure signal through the flexible circuit board (3). The power battery system (100) according to claim 1 or 2.

4. The power battery system (100) according to claim 3, wherein the controller (20) evaluates the heat dissipation degree of the battery module (10) and / or the open state of a pressure relief valve for the battery module (10) based on the pneumatic pressure signal.

5. The internal thermal shield insulating layer (2) is arranged between the bus bar (1) and the flexible circuit board (3) in a layered form, or The internal thermal shield insulating layer (2) wraps the bus bar (1) in the form of a sheath, and the power battery system (100) according to any one of the preceding claims is characterized in that.

6. The external insulating layer (5) is integrally formed as a heat shrinkable sleeve, in particular, or The external insulating layer (5) is composed of a separate first external insulating layer (5.1) and a second external insulating layer (5.2), and the first external insulating layer and the second external insulating layer are fixedly connected to each other in a shape-fitting manner. The power battery system (100) according to any one of the preceding claims is characterized in that.

7. The external insulating layer (5) is made of a heat-resistant and fire-resistant material, in particular polyphenylene sulfide, and / or The bus bar assembly (12) further includes an additional heat insulation layer (6), and the additional heat insulation layer is arranged between the external insulating layer (5) and the flexible circuit board (3) and / or between the external insulating layer (5) and the bus bar (1), and / or The bus bar (1) is made of copper, aluminum, nickel or an alloy thereof, and the power battery system (100) according to any one of the preceding claims is characterized in that.

8. The power battery system (100) further includes an interaction unit (30), and the interaction unit shows the temperature distribution inside the battery module (10) in the form of an image and feeds back the heat diffusion direction and / or the breakdown point of the battery module (10) predicted by the controller (20). The power battery system (100) according to any one of the preceding claims is characterized in that.

9. The controller (20) transmits the temperature signal or the heat diffusion direction and / or the breakdown point predicted based on the temperature signal to the original equipment manufacturer of the vehicle through the real-time monitoring system of the vehicle. The power battery system (100) according to any one of the preceding claims is characterized in that.

10. A method for thermal evaluation of a power battery system (100) for a vehicle, the thermal evaluation method comprising at least the following steps: S1: Detecting temperature signals of a plurality of busbar assemblies (12) of a battery module (10) of the power battery system (100); S2: When the temperature signal of at least one busbar assembly among the plurality of busbar assemblies (12) exceeds a temperature threshold, determining that the battery module (10) is in a thermal runaway state; and S3: Predicting a heat dissipation direction and / or a breakdown point of the battery module (10) based on the temperature signal of the busbar assembly (12). The thermal evaluation method, characterized by comprising the above steps.

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