Battery pack with thermoelectric separation active protection and control method for thermal runaway thereof

Abstract

The application discloses a battery pack with thermoelectric separation active protection and a control method for thermal runaway of the battery pack. The battery pack comprises a battery box, a module formed by arranging a plurality of battery cells, and a battery cell protection and isolation device. The battery cell protection and isolation device physically divides the module space in the battery box into a plurality of independent unit spaces, and at least one battery cell is arranged in each unit space. A CCS assembly and a high-temperature-resistant insulation layer are sequentially arranged on the top of the module from bottom to top. The flexible circuit board of the CCS assembly and the high-temperature-resistant insulation layer have pre-holes, and an exhaust passage for thermal runaway gas is formed between the high-temperature-resistant insulation layer and the CCS assembly. A directional exhaust port is arranged on the end face of the battery box. A solid gas-type fire extinguishing device is arranged between the high-temperature-resistant insulation layer and the module and at least two opposite sides of the module in the length direction.

Description

Technical Field

[0001] This invention relates to the field of battery system technology, and in particular to a battery pack with active protection against thermoelectric separation and a method for controlling thermal runaway. Background Technology

[0002] The system safety of battery packs is paramount in the new energy field. In the development of electric vehicles and large-scale energy storage systems, battery pack design must consider the thermal safety indicators of the battery system. However, existing pack designs often employ a relatively simple thermoelectric hybrid layout. Traditional thermoelectric hybrid designs mainly suffer from the following problems: (1) Disorganized layout: The high-voltage busbar and the low-voltage signal acquisition harness are intertwined and overlapped in a limited space; (2) Complex assembly: It usually requires manual or semi-automatic connection of cables to each sampling point, which is cumbersome and prone to errors; (3) Safety risks: When thermal runaway occurs, the runaway of a single cell can easily cause a short circuit in the high-voltage system, or a secondary runaway of other cells. That is, the thermal runaway exhaust of the cell can easily cause high-temperature damage to the high and low voltage systems, leading to internal short circuits and other safety risks.

[0003] As mentioned earlier, a large amount of heat is generated when the battery system experiences thermal runaway. When one cell experiences thermal runaway, it can affect other cells or the high and low voltage systems, posing a risk of causing thermal runaway in other cells or short circuits in the low voltage system. If effective thermal venting and separation are not performed, it can lead to localized high temperatures or short circuits in the battery pack, causing secondary thermal runaway.

[0004] Current battery pack thermal runaway separation and protection technologies are mostly based on early warning, isolation, and suppression techniques. However, these methods are insufficient for effective control in certain situations and lack the attributes of small-cell suppression and isolation, as well as active fire extinguishing, thus failing to guarantee the ultimate safety of the battery system. Furthermore, most existing thermal runaway control methods rely on monitoring of existing data and have not developed into an effective, tiered control approach.

[0005] As the core component of a battery system, the power battery determines key indicators such as energy, lifespan, and safety performance. Therefore, thermal safety design is crucial for ensuring the performance, lifespan, and safety of the power battery. Consequently, it is necessary to optimize existing battery pack systems and design a novel thermoelectric separation battery structure. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings and defects of the prior art and provide a battery pack with thermal runaway protection and a method for controlling thermal runaway. By constructing an independent thermal runaway exhaust channel for the battery pack, the exhaust and high and low voltage connection devices inside the battery pack can be separated. With the corresponding thermal runaway control method, the safety and reliability of the battery system can be guaranteed.

[0007] One aspect of the present invention provides a battery pack with active protection against thermal runaway, comprising a battery box, a module formed by arranging multiple battery cells, and a battery cell protection and isolation device. The battery cell protection and isolation device physically divides the internal module space of the battery box into multiple independent unit spaces, each unit space arranging at least one of the battery cells. A CCS component and a high-temperature resistant insulation layer are sequentially arranged from bottom to top on the top of the module. The flexible circuit board of the CCS component and the high-temperature resistant insulation layer have pre-drilled holes corresponding to the positions of the explosion-proof valves on the top of the battery cells. An exhaust channel for thermal runaway gas generation during thermal runaway is formed between the high-temperature resistant insulation layer and the CCS component. A directional exhaust port is arranged on the end face of the battery box. A solid-generating gas type fire extinguishing device is arranged above the high-temperature resistant insulation layer and between the module and at least two opposite sides along its length and the battery module. These devices are used to spray extinguishing agents at the explosion-proof valve positions of the thermally runaway battery cells in the vertical and / or horizontal directions. The solid-generating gas type fire extinguishing device consists of multiple fire extinguishing units.

[0008] Preferably, the battery cell protection and isolation device is a grid-like structure formed by vertically connecting horizontal and vertical plates.

[0009] Preferably, the CCS assembly includes a high-voltage connection busbar and an insulating separation bracket, wherein the high-voltage connection busbar is fixed by the insulating separation bracket and is separate from the flexible circuit board used for low-voltage connection.

[0010] Preferably, the high-temperature resistant insulation layer is composed of a high-temperature resistant insulation layer and an insulating gasket below it, and the high-temperature resistant layer is made of mica material.

[0011] Preferably, each of the fire extinguishing units includes a trigger interface or switch. When the trigger interface or switch is opened, the fire extinguishing unit sprays extinguishing agent toward the explosion-proof valve of the corresponding thermally runaway battery cell.

[0012] Preferably, one of the unit spaces is configured with at least one top-level fire suppression unit and / or one side fire suppression unit.

[0013] Preferably, the directional exhaust port is equipped with a directional exhaust explosion-proof valve, and a fire extinguishing liquid injection port is arranged on the end face where the exhaust port is located.

[0014] Preferably, a smoke pressure thermal runaway sensor is arranged on one end face of the battery housing and connected to the BMS.

[0015] Preferably, the module has a pressure sensor on its side, which is used to monitor the pressure of the module's fixing strap. The pressure sensor is located between the side fire extinguishing device and the module. The CCS assembly integrates a valve opening warning device.

[0016] Another aspect of the present invention provides a method for controlling thermal runaway of a battery pack, used for controlling thermal runaway of the battery pack with active thermal separation protection, comprising the steps of: When at least one of the cells in the unit space experiences thermal runaway, the gas generated by the thermal runaway is discharged through the cell explosion-proof valve, then discharged upwards through pre-drilled holes on the flexible circuit board and the high-temperature resistant insulation layer, undergoing thermoelectric separation with the high and low voltage circuit components at the top of the module, entering the exhaust channel, and then flowing to the exhaust port on the end face of the battery box for discharge; the liquid cooling unit operates according to the thermal management strategy, cooling the cell through the module liquid cooling plate, and at the same time, the trigger interface or opening of the fire extinguishing unit corresponding to the unit space where the thermal runaway cell is located opens, spraying fire extinguishing agent in the direction or position of the cell explosion-proof valve where the thermal runaway cell occurred, for active fire suppression and extinguishing.

[0017] The battery pack of the present invention can achieve thermoelectric separation when the cell is thermally runaway. At the same time, by adding a directional exhaust channel, it can exhaust and vent explosion. Combined with thermal runaway detection and early warning and fire extinguishing, it can detect the thermal runaway of the cell and actively directionally extinguish the fire, thus ensuring the safety performance of the battery system.

[0018] The battery pack of the present invention has an exhaust channel constructed on the top surface of the module and a directional explosion vent on the end face, which facilitates the flow and discharge of gas. Through thermal runaway detection, it provides active fire protection and graded control, thereby realizing the active safety function of the battery pack.

[0019] In particular, this invention provides comprehensive thermal unit isolation for each spatial unit, forming a complete isolation and fire suppression system for a single thermal runaway unit. Combined with external fire extinguishing access points and BMS integrated control, it can ensure that the thermal runaway of the entire system is suppressed to the smallest unit, guaranteeing the ultimate safety of the product and solving the industry pain point of suppressing, extinguishing and controlling thermal runaway of battery packs under extreme conditions.

[0020] This invention forms a directional explosion-proof channel by reserving an exhaust channel for the battery cell valve. It uses a steel strip pressure sensor to detect module pressure, a CCS temperature sensor and a valve opening sensor to detect battery cell temperature and whether the explosion-proof valve is open. A BMS system integrates multiple early warning and detection devices, including smoke pressure and thermal runaway sensors, for comprehensive monitoring. This provides early warning and detection of thermal runaway, and proactively activates bottom-level liquid cooling thermal management strategies, side-level aerosol directional fire suppression devices, and top-level aerosol directional fire suppression devices. This achieves comprehensive isolation and fire suppression of any thermal runaway unit. Combined with external fire extinguishing access points and BMS integrated control, it ensures that thermal runaway is suppressed to the smallest unit, guaranteeing ultimate product safety. Attached Figure Description

[0021] Figure 1 This is an exploded view of the battery pack of the present invention.

[0022] Figure 2This is a schematic diagram showing the connection between the formed battery module wrapped with steel strip, the cell isolation and protection device, and the side fire extinguishing device of the present invention.

[0023] Figure 3 This is a schematic diagram of the CCS component installed on the battery module of the present invention.

[0024] Figure 4 This is a schematic diagram of the battery module of the present invention after a high-temperature resistant insulating layer has been installed.

[0025] Figure 5 This is a schematic diagram of the pre-drilled holes on the high-temperature resistant insulating layer of the present invention.

[0026] Figure 6 This is a schematic diagram of the exhaust flow direction during thermal runaway inside the battery pack of the present invention.

[0027] Figure 7 This is a schematic diagram of the smoke pressure thermal runaway sensor integrated at the front end of the battery pack housing of the present invention.

[0028] Figure 8 This is a schematic diagram of the front end of the battery pack housing of the present invention.

[0029] Figure 9 This is a schematic diagram of the arrangement of the fire extinguishing device of the battery pack of the present invention.

[0030] Figure 10 This is a side view of the internal structure of the battery pack of the present invention. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0032] To enhance battery system safety and prevent secondary safety issues such as short circuits in other cells and internal high / low voltage short circuits during thermal runaway, proactive graded fire suppression and safety mitigation measures are implemented for products experiencing thermal runaway. (See [link to relevant documentation]). Figures 1 to 9As shown in the exemplary embodiment of this application, a battery pack with active protection against thermal runaway is proposed, including a battery box 7, a module formed by arranging multiple battery cells 10, and a battery cell protection and isolation device 3. The battery cell protection and isolation device physically divides the internal module space of the battery box into multiple independent unit spaces, and at least one battery cell 10 is arranged in each unit space. A CCS component 4 and a high-temperature resistant insulation layer 5 are arranged sequentially from bottom to top on the top of the module. The flexible circuit board 14 of the CCS component and the high-temperature resistant insulation layer have pre-drilled holes 17. A thermal runaway gas exhaust channel for thermal runaway is formed between the high-temperature resistant insulation layer and the CCS component. A directional exhaust port 9 is arranged on the end face of the battery box. Solid gas-generating fire extinguishing devices are arranged above the high-temperature resistant insulation layer and between the module and the battery module at least two opposite sides in the length direction, namely a top fire extinguishing device 6 and a side fire extinguishing device 2, which are used to spray fire extinguishing agent at the explosion-proof valve 22 position of the thermal runaway battery cell in the vertical direction and / or horizontal direction, respectively. The solid gas-generating fire extinguishing device is composed of multiple fire extinguishing units.

[0033] In some embodiments, a fire extinguishing device mounting plate or bracket is located above the high-temperature resistant insulation layer. This can be a top liquid-cooled plate on which multiple fire extinguishing units are arranged. The fire extinguishing agent outlet 18 is aligned with the explosion-proof valve of the battery cell, spraying the fire extinguishing agent from top to bottom toward the explosion-proof valve 22. Figure 10 As shown, the extinguishing agent outlet 21 of the side fire extinguishing device 2 can be configured to discharge the extinguishing agent towards the explosion-proof valve in the horizontal direction, or the top fire extinguishing device and the side fire extinguishing device can be configured as a structure with an internal cavity containing extinguishing agent, each cavity being independent, with a trigger opening corresponding to the explosion-proof valve position, which is connected to the inside of the cavity, so that the extinguishing agent can be sprayed out after triggering to extinguish the fire.

[0034] For example, the pre-drilled holes on the flexible circuit board of the CCS component correspond vertically to the positions of the explosion-proof valve on the top of the cell, and the pre-drilled holes on the high-temperature resistant insulation layer are above the explosion-proof valve on the top of the cell. This facilitates the smooth upward discharge of high-temperature and high-pressure gas generated after runaway, which enters the exhaust channel and is discharged from one side of the end face of the battery box.

[0035] In one embodiment, such as Figure 2 As shown, the battery cell protection and isolation device 3 is a grid-like structure formed by vertically connecting horizontal and vertical plates. This battery cell protection and isolation device constructs a separate thermal runaway unit at the module battery cell level. It is made of integrated nano-protective material to isolate the thermal runaway of the battery cell unit and form an integrated unit protection structure. By arranging aerosol fire extinguishing devices on the side and top of the module, and arranging the nozzle of the fire extinguishing device corresponding to each thermal runaway unit, it is used to actively suppress the runaway unit in the event of thermal runaway, thus forming a small unit structure with comprehensive protection and active fire extinguishing.

[0036] In one embodiment, the CCS assembly includes a high-voltage connection busbar and an integral, insulated separation bracket 13. The high-voltage connection busbar is fixed by the insulated separation bracket 13 and is separate from the flexible circuit board 14 used for low-voltage connection. In this application, the module CCS hierarchical design incorporates a high- and low-voltage separation design. The insulated separation bracket is designed to independently support and insulate the high-voltage busbar. The CCS low-voltage connection flexible circuit features a pre-drilled hole design to retain an independent venting channel.

[0037] In one embodiment, the high-temperature resistant insulation layer is composed of an insulating pad 16 on the lower side and a high-temperature resistant layer 15 on the upper side. The high-temperature resistant layer 15 is made of high-temperature resistant and insulating mica board material. In this application, the module adopts a composite design of mica and insulating pad, and at the same time, the mica is pre-drilled. The opening structure is weakened, that is, a break line is formed at the opening position to ensure that other units are not affected when a unit experiences thermal runaway.

[0038] In one embodiment, each fire extinguishing unit includes a trigger interface or switch. The trigger interface or switch can be controlled by the battery management system to determine whether to open based on temperature, pressure and smoke detection information. When opened, the fire extinguishing unit sprays extinguishing agent at the explosion-proof valve of the corresponding thermally runaway cell to extinguish the fire at the ignition point, thus realizing the minimum unitization of active protection and fire extinguishing.

[0039] In one embodiment, a unit space is configured with at least one top-level fire extinguishing unit and / or one side fire extinguishing unit. One fire extinguishing unit may correspond to one cell, such as a fire extinguishing unit spraying vertically or a fire extinguishing unit spraying horizontally, or both a fire extinguishing unit spraying vertically and a fire extinguishing unit spraying horizontally.

[0040] In one embodiment, see Figure 8 As shown, the directional exhaust port 9 is equipped with a directional exhaust explosion-proof valve, and a fire extinguishing liquid injection port 8 is arranged on the end face where the exhaust port is located. The fire extinguishing liquid injection port is used to inject liquid fire extinguishing agent into the battery box, which is used after the entire box catches fire or multiple internal units catch fire.

[0041] Among them, see Figure 8 As shown, there is also a warning signal interface 20 of the battery management system on the end face of the battery box, so as to output the corresponding warning signal to the battery management system.

[0042] In one embodiment, see Figure 7As shown, a smoke pressure thermal runaway sensor 11 is arranged on one end face of the battery housing and connected to the BMS. This sensor can be integrated into the BMS. In one embodiment, a mica cover is arranged at the front end of the module to protect the high-voltage components 19 of the battery pack and prevent damage to these components from the release of thermal runaway gases.

[0043] In one embodiment, see Figure 2 As shown, the module has a pressure sensor 12 on its side, which is used to monitor the pressure of the module fixing belt (steel belt). The pressure sensor is located between the side fire extinguishing device and the module. The CCS component integrates a valve opening warning device to detect whether the cell explosion-proof valve below it is open. When it is detected that it is open, a warning is issued. Through the pressure sensing device integrated in the module steel belt, the pressure of the steel belt can be monitored in real time during thermal runaway, providing the module's pressure monitoring signal.

[0044] The battery pack of this application can ensure the rapid discharge of thermal runaway gas from the unit without triggering other units and high and low pressure systems, complete the internal depressurization and venting of the system, and form a fire extinguishing unit at the ignition point inside the system by combining data monitoring such as internal temperature, pressure and smoke sensors, thus constructing a complete protection system of early warning, venting, depressurization and active fire suppression to ensure the safety of the entire system.

[0045] Another aspect of this application provides a method for controlling thermal runaway of a battery pack, used for controlling thermal runaway of the battery pack with active thermal separation protection, including: When at least one of the cells in the unit space experiences thermal runaway, the generated gas is discharged through the cell explosion-proof valve, then vertically upwards through pre-drilled holes on the flexible circuit board and high-temperature resistant insulation layer, undergoing thermoelectric separation with the high and low voltage circuit components at the top of the module, entering the exhaust channel, and then flowing to the exhaust port on the end face of the battery box for discharge; the liquid cooling unit operates according to the thermal management strategy, cooling the cell through the module liquid cooling plate; simultaneously, the trigger interface or opening of the corresponding fire extinguishing unit in the unit space for the cell experiencing thermal runaway opens, spraying extinguishing agent towards the direction or location of the cell explosion-proof valve for active fire suppression. In terms of structural design, the battery pack of this invention features a separate comprehensive thermal runaway unit built at the module cell level, an independent exhaust channel designed at the module CCS level to avoid the impact of inter-cell valve thermal runaway, and a pressure relief and exhaust channel built synchronously at the PACK level. It also incorporates an active fire suppression structure at the unit level, combined with thermal runaway detection for temperature, smoke, and pressure early warning and suppression. In terms of control strategy, based on the detection and early warning signals and numerical information of temperature, smoke, and pressure, the smoke and pressure early warning system integrated into the BMS on the battery module transmits alarm signals for graded suppression in control strategies and methods. Simultaneously, it integrates with the container system's shelf control strategy for reporting and control. This solution has strong practicality and universality.

[0046] The technology of this invention enables comprehensive control encompassing isolation, detection, early warning, and fire suppression. In the event of thermal runaway, it predicts and determines whether early intervention is necessary based on thermal models and temperature valve opening data. When the internal temperature and smoke continue to rise above the threshold, and the internal pressure increases, different decision-making modes can be activated in a timely manner. Combined with real-time monitoring conditions, different modes are implemented for liquid cooling plate cooling, side aerosol fire suppression devices, top aerosol devices, and fixed-point / multi-point activation strategies to effectively extinguish fires and provide information feedback. Simultaneously, it can be integrated with the container system's shelving control strategy for reporting and control. The entire process includes early warning, monitoring, and feedback modes. When the monitored values ​​drop to a safe threshold, the control strategy is adjusted to the next higher level in real time, forming a complete set of comprehensive hierarchical control technology encompassing isolation, detection, early warning, and fire suppression.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of the equivalents of the claims be included within the invention.

[0048] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A battery pack with active protection against thermoelectric separation, characterized in that, The battery includes a battery box, a module formed by arranging multiple battery cells, and a battery cell protection and isolation device. The battery cell protection and isolation device physically divides the internal module space of the battery box into multiple independent unit spaces. At least one of the battery cells is arranged in each unit space. From bottom to top, a CCS component and a high-temperature resistant insulation layer are arranged on the top of the module. The flexible circuit board of the CCS component and the high-temperature resistant insulation layer have pre-drilled holes. A thermal runaway gas exhaust channel is formed between the high-temperature resistant insulation layer and the CCS component. A directional exhaust port is arranged on the end face of the battery box. Solid-generating gas-type fire extinguishing devices are arranged above the high-temperature resistant insulation layer and between the module and at least two opposite sides along the length of the module. These devices are used to spray extinguishing agents at the explosion-proof valve positions of thermally runaway battery cells in the vertical and / or horizontal directions. The solid-generating gas-type fire extinguishing devices consist of multiple fire extinguishing units.

2. The battery pack with active thermoelectric separation protection according to claim 1, characterized in that, The battery cell protection and isolation device consists of a grid-like structure formed by vertically connecting horizontal and vertical plates.

3. The battery pack with active thermoelectric separation protection according to claim 1, characterized in that, The CCS assembly includes a high-voltage connection busbar and an insulating separation bracket. The high-voltage connection busbar is fixed by the insulating separation bracket and is separated from the flexible circuit board used for low-voltage connection.

4. The battery pack with active thermoelectric separation protection according to claim 1, characterized in that, The high-temperature resistant insulation layer is composed of a high-temperature resistant insulation layer and an insulating gasket, and the high-temperature resistant layer is made of mica material.

5. The battery pack with active thermoelectric separation protection according to claim 1, characterized in that, Each of the fire extinguishing units includes a trigger interface or switch. When the trigger interface or switch is opened, the fire extinguishing unit sprays extinguishing agent toward the explosion-proof valve of the corresponding thermally runaway cell.

6. The battery pack with active thermoelectric separation protection according to claim 1, characterized in that, Each of the aforementioned unit spaces is configured with at least one top-level fire suppression unit and / or one side fire suppression unit.

7. The battery pack with active thermoelectric separation protection according to claim 1, characterized in that, The directional exhaust port is equipped with a directional exhaust explosion-proof valve, and a fire extinguishing liquid injection port is arranged on the end face where the exhaust port is located.

8. The battery pack with active thermoelectric separation protection according to claim 1, characterized in that, A smoke pressure thermal runaway sensor is arranged on one end face of the battery housing and is connected to the BMS.

9. The battery pack with active thermoelectric separation protection according to claim 1, characterized in that, The module has a pressure sensor on its side, which is used to monitor the pressure of the module's fixing strap. The pressure sensor is located between the side fire extinguishing device and the module. The CCS assembly integrates a valve opening warning device.

10. A method for controlling thermal runaway of a battery pack, used for controlling thermal runaway of a battery pack with active thermal-electric separation protection as described in any one of claims 1-9, characterized in that, Including the following steps: When at least one of the cells in the unit space experiences thermal runaway, the gas generated by thermal runaway is discharged through the cell explosion-proof valve, discharged upward through the pre-opened holes on the flexible circuit board and the high-temperature resistant insulation layer, thermally separated from the high and low voltage line components at the top of the module, enters the exhaust channel, and then flows to the exhaust port on the end face of the battery box for discharge. The liquid cooling unit operates according to the thermal management strategy, cooling the battery cell through the module liquid cooling plate. At the same time, the trigger interface or opening of the fire extinguishing unit corresponding to the cell where the thermal runaway battery cell is located opens, spraying fire extinguishing agent in the direction or position of the explosion-proof valve of the thermal runaway battery cell to actively suppress and extinguish the fire.

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