Battery pack, energy storage cabinet and energy storage container

Abstract

The utility model discloses a battery pack, energy storage cabinet and energy storage container, relates to immersed battery technical field, including battery pack and shell component, the shell component has cavity, the cavity is equipped with cooling liquid, the battery pack is provided in the cavity and is at least partially immersed in the cooling liquid, and the shell component is equipped with the battery pack. A gap exists between the liquid level of the cooling liquid and the inner cavity wall of the upper portion of the cavity and is filled with inert gas. Only the cooling liquid and the inert gas are arranged in the closed cavity in the battery pack, so that when the battery is in thermal runaway, the gas generated in the battery increases the pressure in the battery and breaks through a safety valve or a weak part at the top of the battery, and a large amount of combustible gas is released; and the combustible gas ejected by the battery assembly cannot be combusted with the inert gas, so that the flame-proof and explosion-proof effects are realized, and the safety of the immersed battery pack is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of submerged battery packs, and in particular to a battery pack, an energy storage cabinet and an energy storage container. Background Art

[0002] Battery PACK, also known as battery module or battery pack, refers to multiple single cells connected in series and parallel, equipped with corresponding thermal management systems and other supporting equipment, and packaged to form an independent, rechargeable and dischargeable energy storage unit.

[0003] The battery thermal management system includes immersion cooling, which cools the battery by immersing it in a coolant. Direct contact between the battery pack and the coolant offers advantages such as low contact thermal resistance, a large heat transfer area, high cooling efficiency, and a compact structure. It also effectively prevents thermal runaway. Fluorocarbons and hydrocarbons (such as mineral oil, synthetic oil, and natural oil) are commonly used coolants for immersion cooling.

[0004] In the prior art, the assembly structure of the battery pack is to first place the battery pack in a box, then fill the box with coolant to immerse the battery pack, and finally seal the box cover. The battery pack has the possibility of explosion and combustion. Utility Model Content

[0005] The present invention aims to solve one of the technical problems in the related art to a certain extent. To this end, the present invention provides a battery module, an energy storage cabinet and an energy storage container.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solution: a battery pack, comprising a battery assembly and a shell assembly, the shell assembly having a chamber, a coolant being provided in the chamber, the battery assembly being arranged in the chamber and at least partially immersed in the coolant, characterized in that there is a gap between the liquid surface of the coolant and the upper inner wall of the chamber, and the gap is filled with an inert gas.

[0007] The application of this application has the following beneficial effects: there is only coolant and inert gas in the closed cavity inside the battery pack. When the battery experiences thermal runaway, the gas generated inside the battery causes the pressure inside the battery to increase and breaks through the safety valve or weak point on the top of the battery, releasing a large amount of gas, mainly including: CO, CO2, CH4, C2H4, C2H6, H2, etc., most of which are combustible substances; the inert gas cannot support the combustion of the gas released by the thermal runaway of the battery component, thereby achieving flame retardancy and explosion protection, and improving the installability of the immersed battery pack.

[0008] Optionally, the shell assembly is provided with a closable suction port and a closable exhaust port, both of which are connected to the chamber; the suction port is arranged on the side of the shell assembly, and the exhaust port is arranged on the top of the shell assembly.

[0009] Optionally, a first valve is provided at the extraction port, and the first valve is used to connect to an external pump to extract air from the chamber and inject inert gas or coolant into the chamber.

[0010] Optionally, a second valve is provided at the exhaust port, and the second valve is used to connect or block the chamber from the outside, so that the inert gas entering the chamber through the injection port can be discharged through the exhaust port.

[0011] Optionally, an explosion-proof valve is provided on the housing assembly, and the explosion-proof valve is located at the top of the housing assembly; a pressure relief port is provided on the top of the housing assembly, and the explosion-proof valve is arranged at the pressure relief port.

[0012] Optionally, the housing assembly includes a box body and a box cover, the box body has an opening, and the box cover is arranged at the opening of the box body and closes the opening; the box cover and the box body are sealed and connected, and the box cover and the box body together define the chamber.

[0013] Optionally, the coolant is mineral oil, silicone oil or transformer oil.

[0014] Optionally, the inert gas is nitrogen, argon, or a mixture of nitrogen and argon.

[0015] The present invention also provides an energy storage cabinet, comprising any one of the aforementioned battery packs.

[0016] In addition, the present invention also provides an energy storage container, which includes the aforementioned energy storage cabinet.

[0017] The reasoning process of the beneficial effects of the energy storage cabinet provided by the present invention and the aforementioned battery pack of the energy storage container is similar and will not be repeated here.

[0018] These features and advantages of the present invention will be fully disclosed in the following detailed description and accompanying drawings. The preferred embodiments or means of the present invention will be fully illustrated in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of the present invention. Furthermore, although multiple features, elements, and components may be present and are labeled with different symbols or numbers for convenience, they all represent components with the same or similar structure or function. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below with reference to the accompanying drawings:

[0020] Figure 1 It is a schematic diagram of the internal structure of the utility model.

[0021] Figure 2 It is a schematic diagram of the three-dimensional structure of the utility model.

[0022] Figure 3 It is a side structural schematic diagram of the present utility model.

[0023] Figure 4 It is a flow chart of the liquid injection method in the utility model embodiment.

[0024] Among them, 1. Inert gas layer; 2. Oil layer; 3. Battery module; 4. Explosion-proof valve; 5. Exhaust port; 6. Liquid inlet. DETAILED DESCRIPTION

[0025] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described in the embodiments are intended to explain the present invention and are not to be construed as limiting the present invention.

[0026] References in this specification to "one embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment itself can be included in at least one embodiment disclosed herein. The appearance of the phrase "in one embodiment" in various places in the specification does not necessarily refer to the same embodiment.

[0027] In related technologies, the application of immersion liquid cooling systems cannot prevent the occurrence of battery thermal runaway disasters. Instead, they can only reduce the degree of thermal runaway to a certain extent and slow down the spread of thermal runaway within the battery pack. The reasons are as follows:

[0028] (1) The existing battery pack assembly structure is to first place the battery pack in a box, then fill the box with coolant to immerse the battery pack, and finally seal the box cover. Due to sealing problems, there is always air inside the battery pack. When the battery experiences thermal runaway, a chemical reaction occurs inside the battery and a large amount of flammable gas is generated. The gas generated inside the battery causes the pressure inside the battery to increase and break through the safety valve or weak point on the top of the battery, releasing a large amount of gas, mainly including: CO, CO2, CH4, C2H4, C2H6, H2, etc., most of which are flammable substances; when the large amount of gas generated inside the battery is ejected and contacts the oxygen in the air, the ejected flammable gas is ignited by the high temperature, thus forming a flame jet phenomenon.

[0029] (2) Thermal runaway occurs when the heat generated by the exothermic reaction cannot be offset by the heat lost to the environment. The heat accumulated inside the battery causes the temperature to rise, which in turn accelerates the reaction rate inside the battery. Due to electrical or mechanical failures, or due to the influence of external heat sources, a temperature rise that we cannot directly observe will occur inside the battery. If the rate of heat generation exceeds the rate of heat loss to the environment, the temperature inside the battery will continue to rise. Once battery thermal runaway occurs, a chain reaction that is difficult to interrupt will occur, and the high temperature generated will be close to 400°C. Considering that the boiling point of most liquid coolants is far below 400°C, the liquid coolant around the lithium-ion battery pack absorbs the large amount of heat generated during thermal runaway and may undergo vaporization, pyrolysis and other reactions. The pyrolysis products of the liquid coolant mix with the gas products generated by the battery thermal runaway. When they accumulate in the enclosed space inside the battery pack and reach the explosion limit, they may explode when exposed to high temperatures, resulting in a secondary explosion disaster.

[0030] In view of this, this embodiment provides a battery pack, referring to the attached Figure 1-3 The battery pack includes a battery assembly 1 and a housing assembly. The housing assembly has a chamber containing a coolant 2. The battery assembly 1 is disposed in the chamber and is at least partially immersed in the coolant 2. A gap exists between the coolant 2 surface and the upper inner wall of the chamber. The gap is filled with an inert gas 3. The inert gas 3 cannot support the combustion of gases released by the battery assembly 1 during thermal runaway, thereby achieving flame retardancy and explosion resistance.

[0031] In this embodiment, the shell assembly is provided with an extraction port 6 and an exhaust port 4, both of which are connected to the chamber; the extraction port 6 is provided on the side of the shell assembly, and the exhaust port 4 is provided on the top of the shell assembly. The extraction port 6 is provided with a first valve, and the first valve is used to connect an external pump to extract air from the chamber and inject inert gas 3 or coolant 2 into the chamber. This embodiment has no special limitation on the first valve, and the first valve is a ball valve or other valves well known to those skilled in the art. The exhaust port 4 is provided with a second valve, and the second valve is used to connect or block the chamber from the outside world, and the inert gas 3 entering the chamber through the extraction port 6 can be discharged through the exhaust port 4. This embodiment has no special limitation on the second valve, and the second valve is a one-way valve or other valves well known to those skilled in the art.

[0032] In this embodiment, an explosion-proof valve 5 is provided on the outer shell assembly, and the explosion-proof valve 5 is located at the top of the outer shell assembly. When the temperature inside the battery assembly 1 is too high, a chemical reaction will occur inside the battery assembly 1, thereby generating gas, causing the pressure inside the battery to continue to increase, resulting in excessive pressure inside the battery. The function of the explosion-proof valve 5 is to disperse the pressure generated inside the battery to the outside world, thereby ensuring the safety of the battery. The principle of the explosion-proof valve 5 is that when the pressure inside the battery suddenly increases or the temperature rises rapidly, the valve will automatically trigger, pop open, and dissipate the high-pressure gas to the outside world. Since the battery explosion-proof valve is set inside the battery container, when the valve pops out, the high-pressure gas can be discharged directly from the top of the battery pack, thereby avoiding the explosion of the battery pack.

[0033] In this embodiment, the housing assembly includes a box body and a box cover, the box body has an opening, and the box cover is arranged at the opening of the box body and closes the opening; the box cover and the box body are sealed and connected, and the box cover and the box body together define the chamber.

[0034] In this embodiment, the coolant 2 is mineral oil, silicone oil, or transformer oil. Mineral oil is odorless and non-volatile, making it a relatively inexpensive coolant. However, due to its high viscosity, it is prone to residue and decomposition, making it flammable. Silicone oil has low electrical conductivity and good temperature resistance at both high and low temperatures, but its viscosity is relatively high. Transformer oil is a mineral oil refined from petroleum. It contains alkanes, cycloalkanes, and aromatic hydrocarbons, which decompose at high temperatures. Transformer oil's main functions are as follows: insulation: It isolates charged parts of different potentials to prevent short circuits; cooling: The flow of oil within the device dissipates heat, preventing abnormal device temperatures; and arc extinguishing: The gas generated during high-temperature decomposition generates high pressure, thereby improving the medium's arc extinguishing performance. Generally, transformer oil is required to have a minimal density, a low freezing point, a low degree of oxidation, and a high flash point. This embodiment does not specifically limit the coolant 2; any coolant for submerged battery packs familiar to those skilled in the art can be used.

[0035] In this embodiment, the inert gas 3 is nitrogen, argon, or a mixture of nitrogen and argon. Nitrogen and argon are colorless, odorless, and non-toxic, and pose no threat to human health or the environment. Furthermore, nitrogen and argon are chemically stable and are not prone to chemical reactions with other substances. The high density of inert gas 3 can form a blanket around the fire source, preventing combustion. The present invention does not specifically limit the choice of inert gas 3; any inert gas familiar to those skilled in the art will suffice.

[0036] In this example, the battery assembly includes battery cells distributed in an array.

[0037] like Figure 4 As shown, an embodiment of the present invention further provides a method for preparing a battery pack, comprising the following steps:

[0038] S1, providing a housing assembly having a box body and a box cover;

[0039] S2, installing the battery assembly in the box, and sealing the box cover at the open end of the box after installation;

[0040] S3, evacuating the housing assembly to a vacuum state, and then introducing an inert gas to a negative pressure state;

[0041] S4, injecting a predetermined amount of coolant into the housing assembly, and discharging excess inert gas during the process of injecting the coolant.

[0042] Specifically, the battery assembly 1 is first installed in the box body, and then the box cover is sealed to form a chamber; specifically, all valves can be closed by welding to make the chamber airtight.

[0043] Connect the injection port 6 to the vacuum pump through the first valve, open the first valve, and then turn on the vacuum pump to evacuate the chamber. When the pressure in the chamber reaches a certain value, turn off the vacuum pump and then close the first valve;

[0044] Then, the extraction port 6 is connected to the gas injection pump through the first valve, the first valve is opened, and the gas injection pump is turned on to introduce inert gas into the chamber. The chamber is still in a negative pressure state. When the pressure in the chamber reaches a certain value, the gas injection pump is turned off, and then the first valve is closed;

[0045] Then, the extraction port 6 is connected to the injection pump through the first valve. The first valve is opened, and the injection pump is turned on to introduce a predetermined amount of coolant into the chamber. It should be noted that in the later stages of the injection process, the second valve, i.e., the exhaust port 4, is slowly opened to expel excess inert gas 3 from the chamber and prevent excessive pressure from causing the explosion-proof valve 5 to open. After the coolant 2 is completely injected, the second valve at the exhaust port 4 and the first valve at the extraction port 6 are closed, and the injection pump is turned off.

[0046] Before injecting the inert gas, the air in the chamber is first evacuated, and then the inert gas is injected. Because the gas filling the chamber is an inert gas, such as nitrogen or argon, these gases are stable, unlikely to react chemically with other substances, and are non-flammable. When the gap between the coolant and the chamber is filled with inert gas, combustion or explosion can be effectively prevented.

[0047] The amount of coolant injected should be enough to completely immerse the battery assembly in the coolant. In this case, the larger the distance between the coolant and the top of the chamber, the more inert gas is contained in the chamber, and the higher the density of the inert gas, which can form a covering layer above the battery assembly to prevent combustion.

[0048] The preparation method of this battery pack is simple and easy, suitable for industrial production, and overcomes the problem that when existing battery packs are assembled, there is an inevitable gap between the cavity and the internal coolant, thereby containing air; when thermal runaway of the battery occurs, combustible gas is released from the battery and undergoes a combustion reaction with the air in the gap. The battery management systems of some energy storage power stations are imperfect and cannot monitor the status of the battery in a timely and accurate manner, making the battery prone to thermal runaway under conditions of overcharging, over-discharging, overheating, etc., and thus causing fire or explosion. Energy storage safety is not only related to the economic benefits of enterprises and the development of the industry, but also to the safety of people's lives and property. Energy storage safety is the foundation of everything. Only by ensuring the safety of energy storage can the energy storage industry develop healthily and sustainably. The immersed battery pack prepared by this method can greatly improve the safety of battery thermal management and reduce the occurrence of safety accidents in energy storage power stations.

[0049] The embodiment of the present invention further provides an energy storage cabinet, comprising a cabinet body, wherein the cabinet body comprises a plurality of storage compartments, each of which is provided with a battery pack as described above. The plurality of storage compartments are arranged in an array within the cabinet body.

[0050] In addition, embodiments of the present invention also provide an energy storage container, including the aforementioned multiple energy storage cabinets. Energy storage technology, a key technology driving new energy and smart grids, has led to the emergence of battery energy storage containers, which integrate battery packs and other electrical equipment within the container. The use of the submerged battery packs provided in the aforementioned embodiments can address the safety risks associated with the high integration of a large number of batteries tightly packed within a limited space, generating significant heat.

[0051] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modifications that do not deviate from the functional and structural principles of the present invention are included within the scope of the claims.

Claims

1. A battery pack comprising a battery assembly (1) and a housing assembly, wherein the housing assembly has a chamber, a coolant (2) is provided in the chamber, the battery assembly (1) is arranged in the chamber and at least partially immersed in the coolant (2), and is characterized in that: There is a gap between the liquid surface of the cooling liquid (2) and the upper inner wall of the chamber, and the gap is filled with inert gas (3).

2. The battery pack according to claim 1, wherein: The shell component is provided with a closable injection port (6) and a closable exhaust port (4), both of which are in communication with the chamber; the injection port (6) is provided on the side of the shell component, and the exhaust port (4) is provided on the top of the shell component.

3. The battery pack according to claim 2, wherein: The extraction port (6) is provided with a first valve, and the first valve is used to connect an external pump to extract air from the chamber and inject inert gas (3) or coolant (2) into the chamber.

4. The battery pack according to claim 3, wherein: The exhaust port (4) is provided with a second valve, which is used to connect or block the chamber with the outside world, and the inert gas (3) entering the chamber through the injection port (6) can be discharged through the exhaust port (4).

5. The battery pack according to any one of claims 1 to 4, characterized in that: An explosion-proof valve (5) is provided on the housing component, and the explosion-proof valve (5) is located at the top of the housing component; a pressure relief port is provided on the top of the housing component, and the explosion-proof valve (5) is arranged at the pressure relief port.

6. The battery pack according to claim 5, characterized in that: The housing assembly includes a box body and a box cover. The box body has an opening. The box cover is arranged at the opening of the box body and closes the opening. The box cover and the box body are sealed and connected, and the box cover and the box body together define the chamber.

7. The battery pack according to claim 4, characterized in that: The cooling liquid (2) is mineral oil, silicone oil or transformer oil.

8. The battery pack according to claim 4, characterized in that: The inert gas (3) is nitrogen, argon or a mixed gas of nitrogen and argon.

9. An energy storage cabinet, characterized in that: A battery pack comprising the battery pack according to any one of claims 1 to 8.

10. An energy storage container, characterized in that: A battery pack comprising the battery pack according to any one of claims 1 to 8.

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