Sandwich type liquid-cooled electric box and control method thereof

Abstract

The present application relates to a kind of sandwich type liquid-cooled electric box, including electric box base and electric box shell, the electric box base is fixed with several electric core;The electric box shell includes the inner metal layer, outer metal layer, heat preservation layer and insulating layer sequentially arranged from inside to outside, the cooling sandwich of liquid cooling medium can be formed between the inner metal layer and outer metal layer, the fire inlet is opened in the inner metal layer, the fire inlet is equipped with fire inlet valve, the fire inlet valve can be automatically opened after electric box internal pressure reaches set value.The sandwich type liquid-cooled electric box of the present application can increase the cooling area of electric core, and is equipped with the fire extinguishing mechanism that can make liquid cooling medium enter electric box, the electric box fire risk is limited in single electric box to the greatest extent;Under the condition that cooling area and fire extinguishing mechanism are guaranteed, its mass and volume can be significantly reduced, the economic cost of electric box is reduced, and the use scene is expanded.

Description

Technical Field

[0001] This invention relates to the field of energy storage battery technology, and in particular to a sandwich-type liquid-cooled battery box. Background Technology

[0002] With the continuous adjustment of my country's energy structure, clean energy, represented by solar energy and photovoltaics, is increasingly accounting for a larger proportion of my country's energy consumption, which has also driven the explosive growth of the energy storage industry. Electrochemical energy storage is one of the main forms of future energy storage applications, and the safety and stability of energy storage systems are attracting increasing attention from all sectors of society. Electrochemical energy storage batteries generate a large amount of heat during operation. How to effectively control this heat and maintain the energy storage battery at a suitable temperature directly affects the lifespan and safety of the energy storage system. Currently, the mainstream fire suppression systems for energy storage batteries mainly use gases such as heptafluoropropane and perfluorohexanone. There are two main types of cooling for energy storage systems: one is air cooling, which uses air as the cooling medium to remove heat from the energy storage battery through air convection. The advantages of this method are its simple structure and flexible configuration. The disadvantages are low cooling efficiency and the inability to achieve precise temperature control of the battery. The other method uses water-cooled pipes arranged at the bottom of the energy storage battery to achieve temperature control. Its advantages are high cooling efficiency and precise temperature control, but the disadvantages are complex structure and limited cooling area. Besides the two technical solutions mentioned above, another method involves immersing the energy storage battery in an inert, non-conductive liquid, such as a fluorinated liquid. While this method can effectively ensure that the cell temperature is controlled within an ideal range, it is often too costly and reduces the energy density per unit mass of the energy storage battery.

[0003] Chinese Patent CN202011035109.0, belonging to the field of vehicle battery technology, discloses a liquid-cooled battery system comprising: a battery module; and a cooling support component including a bottom protective plate and a liquid-cooling plate disposed on the upper surface of the bottom protective plate. The battery module is located on the upper surface of the liquid-cooling plate. The liquid-cooling plate has a plurality of cooling channels arranged sequentially along a first direction, each cooling channel having an inlet and an outlet, and the flow rate within each cooling channel being the same. The control method for the liquid-cooled battery system is used to control the cooling of the aforementioned liquid-cooled battery system. This invention can improve the integration efficiency of the liquid-cooled battery system while reducing the risk of coolant leakage, thereby improving the safety performance of the liquid-cooled battery system.

[0004] Chinese patent CN202111663031.1 discloses an immersion liquid-cooled battery energy storage system comprising a battery cabinet and a circulation system module. The battery cabinet includes at least one battery module, which comprises a battery box filled with a temperature-regulating insulating fluid and a battery pack located within the battery box and immersed in the temperature-regulating insulating fluid. The circulation system module is connected to the battery box and includes a fire suppression system adapted to spray fire-fighting coolant onto the battery cabinet in the event of a fire. The temperature-regulating insulating fluid and the fire-fighting coolant are the same medium and are jointly circulated by the circulation system module. This invention integrates battery cooling and fire suppression into a single system, significantly improving the safety, stability, and adaptability of the battery energy storage system, and solving the problems of low capacity density in existing cooling technologies and system complexity and high cost in existing fire suppression technologies.

[0005] Battery module cooling technology based on liquid cooling plates has a limited cooling coverage area, often only cooling the top or bottom surface of the battery module. This results in a significant temperature difference between the side of the battery cell in contact with the cooling plate and the side not in contact with it, making it impossible to precisely control the cell temperature at the cell level. Furthermore, when a cell experiences thermal runaway, it will continuously release flammable gases. Since the module lacks a fire suppression system, the fire risk can only be temporarily controlled using flame-retardant materials and explosion-proof valves.

[0006] The main problem with battery module cooling technology based on immersion technology is its high cost. Furthermore, the high density of inert coolants significantly increases the mass and volume of the battery module, impacting its application scenarios and practicality. These two factors prevent its widespread adoption. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a sandwich-type liquid-cooled electrical box with low manufacturing cost and good cooling effect, equipped with a fire extinguishing mechanism that allows liquid cooling medium to enter the electrical box, thereby limiting the risk of electrical box fire to a single electrical box to the greatest extent.

[0008] The present invention is implemented using the following scheme: a sandwich-type liquid-cooled electrical box, including an electrical box base and an electrical box shell, wherein a plurality of battery cells are fixed on the electrical box base; the electrical box shell includes an inner metal layer, an outer metal layer, a heat insulation layer and an insulating layer arranged sequentially from the inside to the outside, wherein a cooling sandwich layer capable of accommodating liquid cooling medium is formed between the inner metal layer and the outer metal layer, wherein a fire water inlet is provided on the inner metal layer, and a fire water inlet valve is provided at the fire water inlet, wherein the fire water inlet valve can automatically open after the air pressure inside the electrical box reaches a set value.

[0009] Furthermore, the side of the electrical box shell is provided with an inlet pipe and an outlet pipe that communicate with the cooling jacket. The inlet pipe and the outlet pipe are connected to the water-cooled unit through pipes. The side of the electrical box shell is also provided with an outlet pipe for passing through positive and negative leads and a communication pipe for passing through communication lines.

[0010] Furthermore, the battery cell is equipped with a temperature sensor electrically connected to the battery management system (BMS), and the fire hydrant valve is equipped with a sensing contact electrically connected to the BMS.

[0011] Furthermore, a conductivity sensor is fixedly installed on the inner side of the outer metal layer.

[0012] Another technical solution of the present invention: a control method for a sandwich-type liquid-cooled battery box as described above, comprising the following steps: (1) The battery management system (BMS) reads the temperature signals of each temperature sensor arranged on the battery cell and transmits them to the water-cooled unit for flow management; (2) When each temperature sensor arranged on the battery cell detects a temperature difference Δ≥5℃, the battery management system (BMS) issues a first-level alarm signal, and the water-cooled unit increases the flow rate of the cooling medium; (3) When any temperature sensor on the battery cell detects a temperature rise ≥1℃ / 1s, the battery management system (BMS) issues a second-level alarm signal, and the water-cooled unit operates at peak power; (4) When the battery cell temperature continues to rise until a combustible gas leak occurs, the fire inlet valve at the fire inlet of the battery box shell is opened, and the cooling medium in the cooling sandwich of the battery box shell enters the battery box through the fire inlet. The battery management system (BMS) issues a third-level alarm signal, the water-cooled unit stops operating, and the high-voltage circuit is de-energized; (5) The battery management system (BMS) informs the fire alarm controller, reports the location of the faulty battery box, and triggers the fire audible and visual alarm to alert staff of the fire risk.

[0013] Furthermore, in step (4), when the fire inlet valve is opened, the sensing contact transmits a signal to the battery management system (BMS), which can detect that the battery box is in a serious fault.

[0014] Compared with the prior art, the present invention has the following beneficial effects: the sandwich liquid-cooled electrical box of the present invention can increase the cooling area of ​​the battery cells and is equipped with a fire extinguishing mechanism that allows the liquid cooling medium to enter the electrical box, thereby limiting the risk of electrical box fire to a single electrical box to the greatest extent; while ensuring both the cooling area and the fire extinguishing mechanism, its mass and volume can be significantly reduced, thereby reducing the economic cost of the electrical box and expanding the application scenarios.

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through specific embodiments and related drawings. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the internal structure of the sandwich-type liquid-cooled electrical box according to an embodiment of the present invention;

[0017] Figure 2 This is a perspective view of the electrical box casing according to an embodiment of the present invention;

[0018] Figure 3 This is a cross-sectional view of the outer casing of the electrical box according to an embodiment of the present invention;

[0019] Figure 4 This is a flowchart of the control method according to an embodiment of the present invention;

[0020] The labels in the diagram are as follows: 1-Electric box outer shell, 2-Battery cell, 3-Inner metal layer, 4-Outer metal layer, 5-Insulation layer, 6-Insulation layer, 7-Cooling jacket, 8-Inlet pipe, 9-Outlet pipe, 10-Lead-out pipe, 11-Communication pipe, 12-Fire water inlet. Detailed Implementation

[0021] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0022] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0023] like Figures 1-4As shown, a sandwich-type liquid-cooled electrical box includes a box base and a box shell 1. The box shell 1 can be of various shapes, such as square or round. Several battery cells 2 are fixed on the box base. The box shell 1 includes an inner metal layer 3, an outer metal layer 4, a heat insulation layer 5, and an insulating layer 6 arranged sequentially from the inside out. A cooling sandwich 7 that can accommodate liquid cooling medium is formed between the inner metal layer and the outer metal layer. The liquid cooling medium can be a variety of non-conductive inert liquids, such as deionized water. To ensure the cooling effect, the innermost metal layer should be as close as possible to the internal battery cells. A fire inlet 12 is provided on the inner metal layer. There can be multiple fire inlets 12. A fire inlet valve is provided at each fire inlet. The fire inlet valve can be a pressure relief valve. The fire inlet valve can automatically open when the air pressure inside the electrical box reaches a set value. When the battery cells in the electrical box experience thermal runaway and release flammable gases, the pressure inside the box will gradually increase until it forces open the fire hydrant valve. At this point, liquid cooling medium will enter the box, submerging the battery cells and preventing the accident from escalating. The insulation layer uses materials such as rock wool to isolate the internal temperature of the box from the external environment, ensuring that the temperature of the liquid cooling medium in the cooling interlayer is not lost. The outermost layer of the box casing is an insulation layer, mainly composed of insulating and flame-retardant materials such as polyethylene. This ensures maximum safety for the interior of the box even in the event of an electrical accident or ignition source outside.

[0024] Compared to liquid-cooled plate type, this sandwich-type liquid-cooled electrical box can increase the cooling area of ​​the battery cells and is equipped with a fire extinguishing mechanism that allows coolant to enter the electrical box, thus limiting the risk of electrical box fire to a single box to the greatest extent. Compared to immersion type, it can significantly reduce its mass and volume while ensuring both cooling area and fire extinguishing mechanism, thereby reducing the economic cost of the electrical box and expanding its application scenarios.

[0025] In this embodiment, the side of the electrical box housing is provided with an inlet pipe 8 and an outlet pipe 9 that communicate with the cooling jacket. The inlet pipe 8 and the outlet pipe 9 are connected to the water-cooled unit through pipes. The side of the electrical box housing is also provided with an outlet pipe 10 for passing through positive and negative leads and a communication pipe 11 for passing through communication lines.

[0026] An electrochemical energy storage system typically consists of energy storage batteries and corresponding power conversion systems (PCS). The PCS converts direct current (DC) to alternating current (AC) for human use and vice versa, storing the AC power in the batteries. Within an energy storage system, the energy storage cells progress to battery modules and then to battery cabinets. Multiple battery cabinets can be further combined to form energy storage containers or other forms. Generally, a battery cabinet contains N battery modules, and each battery module contains N cells, which are typically connected in series. In addition, a battery management system (BMS) is needed to monitor battery temperature, voltage, current, state of charge (SOC), state of health (SOH), fault status, and other information, determining the allowable charge and discharge current and whether the battery meets operational requirements based on this information.

[0027] In this embodiment, a temperature sensor electrically connected to the battery management system (BMS) is arranged on the battery cell, and an inductive contact electrically connected to the BMS is provided at the fire inlet valve.

[0028] In this embodiment, a conductivity sensor is fixedly installed on the inner side of the outer metal layer. The conductivity sensor monitors the conductivity of the liquid cooling medium and can transmit the conductivity information to the battery management system (BMS). When the conductivity does not meet the operating parameters, the BMS can issue an alarm signal.

[0029] Another technical solution of the present invention: such as Figure 4 As shown, a control method for a sandwich-type liquid-cooled battery box as described above includes the following steps: (1) The battery management system (BMS) reads the temperature signals of each temperature sensor arranged on the battery cell and transmits them to the water-cooled unit for flow management; (2) When each temperature sensor arranged on the battery cell detects a temperature difference Δ≥5℃, the battery management system (BMS) issues a first-level alarm signal, and at the same time, the water-cooled unit increases the flow rate of the cooling medium (which can be deionized water) to prevent the accident from escalating before the alarm is cleared; (3) When any temperature sensor on the battery cell detects a temperature rise ≥1℃ / 1s, At that time, the battery management system (BMS) issued a level 2 alarm signal, and the water-cooled unit operated at peak power to prevent the accident from escalating; (4) When the cell temperature continued to rise until a flammable gas leak occurred, the fire water inlet valve at the fire water inlet of the outer shell of the electrical box was opened, and the cooling medium in the cooling interlayer of the outer shell of the electrical box entered the interior of the electrical box through the fire water inlet. The battery management system (BMS) issued a level 3 alarm signal, the water-cooled unit stopped operating, and the high-voltage circuit was de-energized; (5) The battery management system (BMS) informed the fire alarm controller, reported the location of the faulty electrical box, and triggered the fire sound and light alarm to alert the staff of the fire risk.

[0030] In this embodiment, in step (4), when the fire inlet valve is opened, the sensing contact transmits a signal to the battery management system (BMS), and the BMS can detect that the battery box is in a serious fault.

[0031] Temperature sensors detect changes in cell temperature and transmit this information to the Battery Management System (BMS) to adjust the flow rate of the liquid cooling medium within the interlayer. When the flow rate is at its maximum, if the fire extinguishing valve is opened by flammable gas, the coolant can enter the electrical box at the fastest speed, preventing the accident from escalating.

[0032] Unless otherwise stated, if any of the technical solutions disclosed in this invention specify a numerical range, then the disclosed numerical range is a preferred numerical range. Anyone skilled in the art should understand that the preferred numerical range is merely one among many feasible numerical values ​​that has a more obvious or representative technical effect. Because there are many numerical values, it is impossible to list them all. Therefore, this invention discloses only some numerical values ​​to illustrate the technical solutions of this invention. Furthermore, the numerical values ​​listed above should not constitute a limitation on the scope of protection of this invention.

[0033] If this invention discloses or relates to mutually fixedly connected components or structural parts, then, unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured in one piece using a casting process) (except where it is obviously impossible to use an integral molding process).

[0034] In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in this invention to indicate positional relationships or shapes include states or shapes that are similar to, close to, or approximate with those states or shapes.

[0035] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured by a one-piece molding process.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A control method for a sandwich-type liquid-cooled electrical box, characterized in that: The sandwich-type liquid-cooled electrical box includes an electrical box base and an electrical box shell. Several battery cells are fixed on the electrical box base. The electrical box shell includes an inner metal layer, an outer metal layer, a heat insulation layer and an insulating layer arranged sequentially from the inside to the outside. A cooling sandwich layer that can accommodate liquid cooling medium is formed between the inner metal layer and the outer metal layer. A fire water inlet is provided on the inner metal layer. A fire water inlet valve is provided at the fire water inlet. The fire water inlet valve can automatically open after the air pressure inside the electrical box reaches a set value. An inlet pipe and an outlet pipe communicating with the cooling sandwich layer are provided on the side of the electrical box shell. The inlet pipe and the outlet pipe are connected to the water-cooled unit through pipes. An outlet pipe for passing through positive and negative leads and a communication pipe for passing through communication lines are also provided on the side of the electrical box shell. A temperature sensor electrically connected to the battery management system (BMS) is arranged on the battery cell. An induction contact electrically connected to the battery management system (BMS) is provided at the fire water inlet valve. The control method includes the following steps: (1) The battery management system (BMS) reads (1) The temperature signals of each temperature sensor arranged on the battery cell are transmitted to the water-cooled unit for flow management; (2) When each temperature sensor arranged on the battery cell detects a temperature difference Δ≥5℃, the battery management system (BMS) issues a first-level alarm signal, and the water-cooled unit increases the flow rate of the cooling medium; (3) When any temperature sensor on the battery cell detects a temperature rise ≥1℃ / 1s, the battery management system (BMS) issues a second-level alarm signal, and the water-cooled unit operates at peak power; (4) When the battery cell temperature continues to rise until a combustible gas leak occurs, the fire inlet valve at the fire inlet of the battery box shell is opened, and the cooling medium in the cooling interlayer of the battery box shell enters the battery box through the fire inlet. The battery management system (BMS) issues a third-level alarm signal, the water-cooled unit stops operating, and the high-voltage circuit is de-energized; (5) The battery management system (BMS) informs the fire alarm controller, reports the location of the faulty battery box, and triggers the fire audible and visual alarm to alert staff of the fire risk.

2. The control method for the sandwich-type liquid-cooled electrical box according to claim 1, characterized in that: A conductivity sensor is fixedly installed on the inner side of the outer metal layer.

3. The control method for the sandwich-type liquid-cooled electrical box according to claim 1, characterized in that: In step (4), when the fire inlet valve is opened, the sensing contact transmits a signal to the battery management system (BMS), which can detect that the battery box is in serious fault.

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