Battery cell, battery apparatus and electrical apparatus

Abstract

The embodiments of the present disclosure belong to the technical field of batteries. Provided are a battery cell, a battery apparatus and an electrical apparatus. The battery cell comprises a casing, sealing pouches, electrode assemblies and a buffer layer. The casing has an accommodating space, the sealing pouches being located in the accommodating space, and there being at least two sealing pouches. The sealed space of each sealing pouch is provided with an electrode assembly. The buffer layer is arranged between the at least two adjacent sealing pouches. Since the buffer layer is provided between the at least two adjacent sealing pouches, the impact and collision of the electrode assemblies in the two adjacent sealing pouches are buffered by means of the buffer layer, thereby better alleviating the degree of impact or collision of the electrode assemblies of the two adjacent sealing pouches.

Description

Battery monomer, battery device and electric device TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of batteries, in particular to a battery monomer, a battery device and an electric device. BACKGROUND

[0002] Batteries are increasingly widely used in life and industry. For example, new energy vehicles equipped with batteries have been widely used. In addition, batteries are also increasingly used in the field of energy storage and the like.

[0003] The battery monomers of the battery device are installed in a box body, and energy is stored by charging the battery monomers in the box body or power is supplied to the outside by discharging the battery monomers in the box body. In the related art, mutual impact or collision may occur between adjacent sealing bags in the battery monomers through the electrode assemblies. SUMMARY

[0004] Therefore, the embodiments of the present disclosure aim to provide a battery monomer, a battery device and an electric device, and to alleviate the degree of impact or collision between adjacent electrode assemblies.

[0005] To achieve the above-mentioned purpose, the technical solutions of the embodiments of the present disclosure are as follows:

[0006] The embodiments of the present disclosure provide a battery monomer, comprising:

[0007] a housing having a containing space;

[0008] a sealing bag located in the containing space, the number of the sealing bags being at least two;

[0009] an electrode assembly, the electrode assembly being arranged in each sealing space of the sealing bags;

[0010] a buffer layer, the buffer layer being arranged between at least two adjacent sealing bags.

[0011] In the embodiments of the present disclosure, the buffer layer is arranged between at least two adjacent sealing bags, and the impact and collision of the electrode assemblies between the at least two adjacent sealing bags are buffered by the buffer layer, so that the degree of impact or collision between the at least two adjacent sealing bags through the electrode assemblies can be better alleviated. The buffer layer can also provide a buffer space for the expansion of the electrode assemblies.

[0012] In some embodiments, the material of the buffer layer is foamed polypropylene, rubber, polyurethane, foam or silica gel.

[0013] In the embodiments of the present disclosure, foamed polypropylene, rubber, polyurethane, foam or silica gel can better deform under the action of impact, thereby better buffering external impact or collision.

[0014] In some embodiments, a buffer layer is arranged between every two adjacent sealing bags arranged in a preset direction, and the preset direction is perpendicular to the large face of the electrode assembly.

[0015] In the embodiments of the present disclosure, since the preset direction is perpendicular to the large face of the electrode assembly, the electrode assembly mainly expands along the preset direction during the charging and discharging process, and the expansion can be well released through the buffering of the buffer layer, and a certain force can be provided to the large face of the electrode assembly to inhibit the expansion.

[0016] In some embodiments, the total thickness of all buffer layers between the two adjacent sealing bags is a first thickness, the total thickness of the electrode assembly in each sealing bag and the sealing space of the corresponding sealing bag is a second thickness, the ratio of the first thickness to the second thickness is greater than or equal to 0.15, and the ratio of the first thickness to the second thickness is less than 1.2.

[0017] In the embodiments of the present disclosure, the ratio of the first thickness to the second thickness is greater than or equal to 0.15, so that there is enough buffer space between the two adjacent sealing bags for the electrode assembly to expand and contract during the charging and discharging process. The ratio of the first thickness to the second thickness is less than or equal to 1.2, which can make the thickness of the buffer layer not too thick under the condition that the buffer space is sufficient, which is conducive to improving the volumetric energy density of the battery cell.

[0018] In some embodiments, the ratio of the first thickness to the second thickness is greater than or equal to 0.3, and the ratio of the first thickness to the second thickness is less than 1.

[0019] In the embodiments of the present disclosure, the ratio of the first thickness to the second thickness is greater than or equal to 0.3, so that there is enough buffer space between the two adjacent sealing bags for the electrode assembly to expand and contract during the charging and discharging process. The ratio of the first thickness to the second thickness is less than or equal to 1, which can make the thickness of the buffer layer not too thick under the condition that the buffer space is sufficient, which is conducive to improving the volumetric energy density of the battery cell.

[0020] In some embodiments, the battery cell further comprises a heat insulation layer, the heat insulation layer is arranged between every two adjacent sealing bags, the opposite sides of the heat insulation layer are both provided with the buffer layer located between the corresponding two adjacent sealing bags, and the heat insulation layer comprises a heat insulation main body, and the thermal conductivity of the heat insulation main body is less than the thermal conductivity of the buffer layer.

[0021] In the embodiments of the present disclosure, the buffer layer and the heat insulation layer are arranged between the two adjacent sealing bags, the buffer layer is arranged on both sides of the heat insulation layer, the electrode assembly of the two adjacent sealing bags is buffered by the buffer layer on both sides, and the electrode assembly in the two sealing bags is heat-insulated by the heat insulation layer, thereby reducing the heat transfer of the electrode assembly corresponding to the two sealing bags on both sides of the heat insulation layer. The thermal conductivity of the buffer layer is relatively large, and the buffer layer mainly plays a buffering role and does not need strong heat insulation capacity, which is conducive to reducing the cost.

[0022] In some embodiments, the material of the heat insulation main body is aerogel or phase change material.

[0023] In the embodiments of the present disclosure, both the aerogel and the phase change material are materials with small thermal conductivity, and the use of the aerogel or the phase change material as the material of the heat insulation main body can better play the role of heat insulation.

[0024] In some embodiments, the heat insulation layer further comprises an encapsulating member, and the encapsulating member is sleeved outside the heat insulation main body.

[0025] In the embodiments of the present disclosure, the encapsulating member is sleeved outside the heat insulation main body to encapsulate the heat insulation main body, thereby reducing the possibility of disordered escape of the phase change material in a liquid state or a gaseous state, and the heat insulation main body can be better constrained.

[0026] In some embodiments, the thermal conductivity of the heat insulation main body is greater than or equal to 0.01 W / (m.K), the thermal conductivity of the heat insulation main body is less than or equal to 0.1 W / (m.K), and the thermal conductivity of the buffer layer is greater than 0.1 W / (m.K).

[0027] In the embodiments of the present disclosure, the thermal conductivity of the heat insulation main body is less than or equal to 0.1 W / (m.K), so that the heat insulation main body can basically meet the demand for heat insulation, the heat insulation main body has good heat insulation capacity, the thermal conductivity of the heat insulation main body is greater than or equal to 0.01 W / (m.K), which can inhibit the heat insulation capacity of the heat insulation main body from being too good and causing high cost. The thermal conductivity of the buffer layer is greater than 0.1 W / (m.K), the buffer layer plays a buffering role and does not need to have the function of heat insulation, which is conducive to reducing the cost of the buffer layer.

[0028] In some embodiments, the shell comprises a shell body and an end cover mounted on the shell body, the shell body and the end cover surround a containing space, and the battery monomer further comprises an electrode terminal mounted on the end cover.

[0029] In the embodiments of the present disclosure, the end cover opens or covers an opening at one end of the shell body, so that the sealing bag and the electrode assembly in the sealing bag can be more conveniently mounted into the containing cavity, the electrode terminal is mounted on the end cover, the tab of the electrode assembly is electrically connected with the electrode terminal, and the charging and discharging of the battery monomer is realized through the external connection of the electrode terminal.

[0030] In some embodiments, the end cover is snap-connected or glued to the shell body.

[0031] In the embodiments of the present disclosure, the snap connection makes the end cover and the shell body more conveniently connected, and the glue connection makes the end cover and the shell body more firmly connected.

[0032] In some embodiments, the melting point of the shell body is greater than or equal to 1000℃.

[0033] In the embodiments of the present disclosure, the shell has a high melting point, which is beneficial to inhibit the shell from being damaged at a high temperature.

[0034] In some embodiments, the shell is made of steel, steel alloy, titanium or titanium alloy.

[0035] In some embodiments, the thickness of the shell is greater than or equal to 0.2 mm, and the thickness of the shell is less than 2 mm.

[0036] In the embodiments of the present disclosure, the thickness of the shell is greater than or equal to 0.2 mm, so that the shell has good strength and the possibility of the shell being damaged by external impact can be reduced. The thickness of the shell is less than 2 mm, which is beneficial to limit the thickness of the shell from being too thick, thereby reducing the cost.

[0037] In some embodiments, the shell is made of steel, steel alloy, titanium or titanium alloy.

[0038] In the embodiments of the present disclosure, in the case that the electrode assembly in the shell of the battery monomer occurs thermal runaway, the thermal runaway eruption material in the accommodating cavity is directed to be discharged through the pressure relief port on one side of the shell, so that the eruption material of the electrode assembly in the thermal runaway process is inhibited from erupting in disorder.

[0039] In some embodiments, the shell includes a shell and an end cover mounted on the shell, the shell and the end cover enclose the accommodating space, the battery monomer further includes an electrode terminal mounted on the end cover, and the space in the shell extends through opposite ends of the shell along the arrangement direction of the shell and the end cover. The end cover is located at one end of the shell, and the pressure relief port is located at the other end of the shell.

[0040] In the embodiments of the present disclosure, since the end cover is located at one end of the shell and the electrode terminal is mounted on the end cover, and the pressure relief port is located at the other end of the shell, the thermal runaway eruption material ejected from the pressure relief port is away from the electrode terminal on the end cover, which is beneficial to reduce the thermal runaway eruption material ejected to the electrode terminal to cause the short circuit of the electrode terminal of the adjacent battery monomer and the thermal diffusion between the adjacent battery monomers.

[0041] In some embodiments, the pressure relief port is open, or the battery monomer further includes a shielding piece connected with the shell, the shielding piece covers the pressure relief port, and the pressure resistance of the shielding piece is less than the pressure resistance of the shell.

[0042] In the embodiments of the present disclosure, since the pressure relief port is open, the thermal runaway eruption material in the accommodating space can be smoothly ejected from the pressure relief port to achieve pressure relief. By shielding the pressure relief port with the shielding piece, the objects in the accommodating space can be prevented from falling out of the pressure relief port, and the impurities outside the shell can also be prevented from invading the accommodating space inside the shell. When the electrode assembly in the accommodating space occurs thermal runaway, the thermal runaway eruption material can break through the shielding piece and be ejected from the pressure relief port to achieve pressure relief, since the pressure resistance of the shielding piece is less than the pressure resistance of the shell.

[0043] In some embodiments, the sealing bag is a bag-shaped insulation member or an aluminum plastic film.

[0044] In the embodiments of the present disclosure, the electrolyte used for infiltrating the electrode assembly is sealed by the bag-shaped insulation member or the aluminum plastic film, so that the electrode assembly in the sealing bag can be better infiltrated in the electrolyte.

[0045] In some embodiments, the battery monomer further comprises a heat resistance layer, and the sealing bag containing the electrode assembly is provided with the heat resistance layer between the sealing bag and the shell.

[0046] In the embodiments of the present disclosure, the heat of the electrode assembly in thermal runaway in the sealing bag in the shell is blocked by the heat resistance layer between the shell and the sealing bag, and the possibility of the heat of the electrode assembly in thermal runaway in the shell spreading to the adjacent battery monomer is limited.

[0047] In some embodiments, the sealing bag closest to the shell is provided with the heat resistance layer between the sealing bag and the shell along the arrangement direction of the buffer layer and the sealing bag.

[0048] In the embodiments of the present disclosure, the heat of the electrode assembly in the sealing bag is transmitted to the shell by providing the heat resistance layer between the sealing bag closest to the shell and the shell, so as to reduce the heat generated by the electrode assembly and transmitted to the adjacent battery monomer.

[0049] In some embodiments, the heat resistance layer comprises a heat resistance body and / or a temperature-resistant coating, the thermal conductivity of the heat resistance body is greater than or equal to 0.01 W / (m.K), the thermal conductivity of the heat resistance body is less than or equal to 0.1 W / (m.K), and the melting point of the temperature-resistant coating is greater than 1000℃.

[0050] In the embodiments of the present disclosure, the thermal conductivity of the heat resistance body is less than or equal to 0.1 W / (m.K), so that the heat resistance body has better heat insulation capacity, and the thermal conductivity of the heat resistance body is greater than or equal to 0.01 W / (m.K), so that the heat resistance body can reduce the cost as much as possible while having better heat insulation capacity. The heat generated by the electrode assembly is limited to be transmitted to the adjacent battery monomer by the heat insulation effect of the heat insulation body. The melting point of the temperature-resistant coating is greater than 1000℃, the melting point of the temperature-resistant coating is high, and the temperature-resistant coating can resist high temperature. The temperature-resistant coating is arranged between the shell and the sealing bag, which is conducive to reducing the possibility of the shell being damaged at high temperature.

[0051] In some embodiments, the material of the heat resistance body is ceramic composite material, aerogel, glass fiber, mica or carbon fiber.

[0052] In this embodiment of the disclosure, the ceramic composite material, aerogel, glass fiber, mica or carbon fiber have a low thermal conductivity and good heat insulation ability. The heat-insulating body made of ceramic composite material, aerogel, glass fiber, mica or carbon fiber can effectively limit the heat generated by the electrode assembly from being transferred to the outer shell.

[0053] In some embodiments, the thermal conductivity of the buffer layer is greater than or equal to 0.01 W / (mK), and the thermal conductivity of the buffer layer is less than or equal to 0.1 W / (mK).

[0054] In this embodiment, the thermal conductivity of the buffer layer is less than or equal to 0.1 W / (mK), giving it good thermal insulation capabilities. The buffer layer combines buffering and insulation functions, thus achieving effective buffering and insulation between two adjacent sealed bags. The thermal conductivity of the insulation body is greater than or equal to 0.01 W / (mK), which, while ensuring good insulation capabilities, minimizes the possibility of excessively high costs due to excessive insulation, thereby helping to reduce costs.

[0055] In some embodiments, the buffer layer is made of aerogel, glass fiber, ceramic, or ceramic composite material.

[0056] In this embodiment of the disclosure, aerogel, glass fiber, ceramic and ceramic composite material are all materials with low thermal conductivity, which have both good buffering capacity and good heat insulation capacity. The buffer layer made of aerogel, glass fiber, ceramic or ceramic composite material has both buffering and heat insulation functions.

[0057] A second aspect of this application provides a battery device, comprising:

[0058] Box;

[0059] The battery cell in any of the foregoing embodiments is located inside the housing;

[0060] A third aspect of this application provides an electrical device, comprising:

[0061] Main body of the device;

[0062] The battery device of any of the foregoing embodiments is installed on the main body of the device. Attached Figure Description

[0063] Figure 1 is a schematic diagram of the structure of a battery cell in an embodiment of the present disclosure, where the internal structure of the outer casing is not shown.

[0064] Figure 2 is an exploded view of a single battery cell in one embodiment of this disclosure;

[0065] Figure 3 is a schematic diagram of the structure of a battery cell in one embodiment of the present disclosure. The diagram shows that a buffer layer is provided between two adjacent sealed bags, and no heat insulation layer is provided between two adjacent sealed bags.

[0066] Figure 4 is a schematic diagram of the structure of a battery cell in one embodiment of the present disclosure. A heat-insulating layer is provided between the sealed bag and the outer shell. A buffer layer is provided between two adjacent sealed bags. No heat-insulating layer is provided between two adjacent sealed bags.

[0067] Figure 5 is an enlarged view of position A in Figure 4;

[0068] Figure 6 is a schematic diagram of the structure of a battery cell in one embodiment of the present disclosure. A heat-insulating layer is provided between the sealed bag and the outer shell, and a buffer layer and a heat-insulating layer are provided between two adjacent sealed bags.

[0069] Figure 7 is an enlarged view of position B in Figure 6;

[0070] Figure 8 is a schematic diagram of the structure of the sealing bag and the electrode assembly inside the sealing bag in an embodiment of the present disclosure;

[0071] Figure 9 is a schematic diagram of the structure of a wound electrode assembly in one embodiment of the present disclosure;

[0072] Figure 10 is a schematic diagram of the structure of a stacked electrode assembly in one embodiment of this disclosure.

[0073] Explanation of reference numerals in the attached drawings: 1. Outer shell; 11. Receiving space; 12. Housing; 13. End cap; 15. Pressure relief port; 2. Sealed bag; 3. Electrode assembly; 31. Positive electrode plate; 32. Negative electrode plate; 33. Isolator; 34. Straight area; 35. Corner area; 36. Tab; 4. Buffer layer; 5. Heat insulation layer; 6. Shielding element; 7. Heat-insulating layer. Detailed Implementation

[0074] The embodiments of the technical solutions disclosed herein will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solutions disclosed herein and are therefore intended to limit the scope of protection of this disclosure.

[0075] Unless otherwise defined, 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 disclosure belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure; the terms “comprising” and “having” and any variations thereof in embodiments of this disclosure are intended to cover non-exclusive inclusion.

[0076] In the description of the embodiments of this disclosure, technical terms such as "first," "second," and "third" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.

[0077] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0078] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects are in an "or" relationship.

[0079] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0080] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, the technical term "contact" should be interpreted broadly, and can be direct contact, contact through an intermediate medium layer, contact between two contacting parties with substantially no interaction force, or contact between two contacting parties with interaction force.

[0081] In related technologies, multiple electrode components may be present inside the casing of a single battery cell. The electrode components are immersed in electrolyte, which is sealed by a sealing bag. Since there is no buffer layer between two adjacent sealing bags, they are subject to mutual impact and collision through the corresponding electrode components inside the sealing bags due to external vibration and other environmental factors.

[0082] This embodiment of the invention mitigates the impact and collision between adjacent sealed bags through corresponding electrode assemblies within the sealed bags by providing a buffer layer between two adjacent sealed bags.

[0083] This disclosure provides an electrical device, which includes a device body and a battery device, with the battery device installed on the device body.

[0084] In this embodiment of the disclosure, power is supplied to the main body of the device via a battery device.

[0085] Electrical devices are devices that use electrical energy as their energy source to perform corresponding functions by consuming electrical energy. For example, electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0086] The main body of a device refers to the main structure that consumes electrical energy to perform its corresponding functions. For example, an electrical device can be a mobile phone, where the main body is the part that enables communication and other functions, powered by individual battery cells or battery packs. Similarly, an electrical device can be a car, where the main body is the part that provides seating and allows the vehicle to move on the road, powered by individual battery cells or battery packs.

[0087] In one embodiment, the battery device may be a battery pack.

[0088] In one embodiment, the battery device can be an energy storage device.

[0089] The battery device according to the present disclosure includes a housing and individual battery cells, with the individual battery cells located inside the housing.

[0090] In this embodiment of the disclosure, electrical energy is stored or released through individual battery cells.

[0091] A single battery cell can be a rechargeable battery. A rechargeable battery is a battery cell that can be recharged after it has been discharged, allowing the active materials to be activated and the cell to continue to be used.

[0092] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments disclosed herein are not limited to this.

[0093] A single battery cell includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator disposed between the negative and positive electrodes. During the charging and discharging process of the battery cell, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, disposed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing active ions to pass through. In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0094] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0095] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0096] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this disclosure is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0097] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0098] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0099] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0100] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0101] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this disclosure is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0102] In some embodiments, the negative electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not have a negative electrode active material.

[0103] As an example, negative electrode active materials can be filled or / and deposited within the negative electrode current collector.

[0104] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0105] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0106] In some embodiments, the separator is a separator membrane. This disclosure does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0107] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0108] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0109] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This disclosure does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0110] Liquid electrolytes include electrolyte salts and solvents.

[0111] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0112] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0113] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0114] The gel electrolyte includes a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0115] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0116] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0117] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium-germanium-phosphorus-sulfur, sulfosilium-germanium), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0118] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0119] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0120] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0121] In some implementations, the electrode assembly is a stacked structure.

[0122] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0123] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0124] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0125] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0126] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0127] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0128] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0129] In some embodiments, the battery cell may include a casing. The casing may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the casing may be a sealed structure or a non-sealed structure. As an example, when the casing is a non-sealed structure, the casing serves to protect the electrode assembly, and a sealing bag is included between the casing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating component or an aluminum-plastic film. When the casing is a sealed structure, it is used to encapsulate components such as the electrode assembly and electrolyte.

[0130] The battery cell of this embodiment, as shown in Figures 1 to 8, includes a casing 1, a sealed bag 2, an electrode assembly 3, and a buffer layer 4. The casing 1 has a receiving space 11. The sealed bags 2 are located within the receiving space 11, and there are at least two sealed bags 2. Each sealed bag 2 has an electrode assembly 3 disposed within its sealed space. A buffer layer 4 is disposed between at least two adjacent sealed bags 2.

[0131] The outer casing 1 is a shell-like structure that primarily provides space for housing or mounting most of the other structures of the battery cell.

[0132] The sealing bag 2 is mainly used to seal the electrolyte, and the electrode assembly 3 is immersed in the electrolyte.

[0133] For example, the sealing bag 2 can be an aluminum-plastic film.

[0134] The buffer layer 4 is mainly used to separate two adjacent sealed bags 2 and to buffer the two adjacent sealed bags 2, reducing the hard impact between the two adjacent sealed bags 2.

[0135] For example, the sealed bag 2 and the corresponding electrode assembly 3 inside the sealed bag 2 together constitute the main structure of the pouch cell.

[0136] In this embodiment, since a buffer layer 4 is provided between at least two adjacent sealed bags 2, the impact and collision of the electrode assembly 3 between the two adjacent sealed bags 2 are buffered by the buffer layer 4, thereby effectively mitigating the degree of impact or collision between the two adjacent sealed bags 2 through the electrode assembly 3. The buffer layer can also provide buffer space for the expansion of the electrode assembly.

[0137] In some embodiments, the material of the buffer layer 4 is foamed polypropylene, rubber, polyurethane, foam, or silicone.

[0138] For example, the foamed polypropylene is microcellular polypropylene foam (MPP).

[0139] In this embodiment of the disclosure, foamed polypropylene, rubber, polyurethane, foam or silicone can deform well under impact, thereby effectively buffering external impacts or collisions.

[0140] In some embodiments, please refer to Figures 3, 4, 6, 9 and 10, a buffer layer 4 is provided between every two adjacent sealed bags 2 arranged in a preset direction, the preset direction being perpendicular to the large surface of the electrode assembly 3.

[0141] The "large surface" refers to the surface with the largest area of ​​electrode assembly 3.

[0142] For example, referring to Figure 9, the electrode assembly 3 includes a positive electrode 31, a negative electrode 32, and a separator 33. The positive electrode 31 and the negative electrode 32 are insulated from each other by the separator 33. The positive electrode 31, the negative electrode 32, and the separator 33 are wound together to form a wound structure, and the corresponding electrode assembly 3 is a wound electrode assembly 3. The wound electrode assembly 3 has a flat region 34 and a corner region 35. The preset direction is the direction in which the positive electrode 31 in the flat region 34, the separator 33 in the flat region 34, and the negative electrode 32 in the flat region 34 are alternately stacked.

[0143] For example, referring to Figure 10, the electrode assembly 3 includes a positive electrode 31, a negative electrode 32, and a separator 33. The positive electrode 31 and the negative electrode 32 are insulated from each other by the separator 33. The positive electrode 31, the separator 33, and the negative electrode 32 are alternately stacked to form a stacked structure, and the corresponding electrode assembly 3 is a stacked electrode assembly 3. For the stacked electrode assembly 3, the preset direction is the direction in which the positive electrode 31, the separator 33, and the negative electrode 32 are alternately stacked.

[0144] For example, please refer to Figures 3, 4, 6, 9 and 10. The preset direction is the direction shown by arrow R1 in the figure.

[0145] During the charging and discharging process, the electrode assembly 3 mainly expands along a preset direction. The electrode assembly 3 will also expand in other directions, but the degree of expansion is relatively small.

[0146] In this embodiment, since the preset direction is perpendicular to the large surface of the electrode assembly 3, the electrode assembly 3 mainly expands along the preset direction during the charging and discharging process. The buffer layer 4 can effectively release the expansion and provide a certain force to the large surface of the electrode assembly 3 to suppress the expansion.

[0147] It is understood that the arrangement of the preset direction is not limited. For example, the preset direction can be parallel to the large surface.

[0148] In some embodiments, please refer to Figures 5 and 7. The total thickness of all buffer layers 4 between two adjacent sealed bags 2 is the first thickness, and the total thickness of the electrode assembly 3 in the sealed space of each sealed bag 2 and the corresponding sealed bag 2 is the second thickness. The ratio of the first thickness to the second thickness is greater than or equal to 0.15, and the ratio of the first thickness to the second thickness is less than 1.2.

[0149] The total thickness of all buffer layers 4 between two adjacent sealed bags 2, that is, the total dimension of all buffer layers 4 between two adjacent sealed bags 2 in the arrangement direction of the two adjacent sealed bags 2.

[0150] The total thickness of the electrode assembly 3 in each sealed bag 2 and the corresponding sealed space of the sealed bag 2 is the second thickness, which refers to the dimension of the sealed bag 2 and the electrode assembly 3 in the sealed bag 2 as a whole along the arrangement direction of the two adjacent sealed bags 2.

[0151] For example, please refer to Figure 5. The number of sealing layers between two adjacent sealing bags 2 is one. The first thickness in the figure is D1, the second thickness is D2, and 0.15≤D1 / D2≤1.2.

[0152] For example, please refer to Figure 7. There are two buffer layers 4 between two adjacent sealed bags 2. The thickness of each buffer layer 4 is D3, and the first thickness is D1. The first thickness is the sum of the thicknesses of the two buffer layers 4, that is, D1 = D3 + D3.

[0153] For example, the ratio of the first thickness to the second thickness can be 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.9, 1, 1.1 or 1.2.

[0154] In this embodiment, the ratio of the first thickness to the second thickness is greater than or equal to 0.15, ensuring sufficient buffer space between adjacent sealed bags 2 for the electrode assembly 3 to expand and contract during charging and discharging. The ratio of the first thickness to the second thickness is less than or equal to 1.2, ensuring that the buffer layer 4 is not excessively thick when the buffer space is sufficient, which is beneficial for improving the volumetric energy density of the battery cell.

[0155] In some embodiments, as shown in Figures 5 and 7, the ratio of the first thickness to the second thickness is greater than or equal to 0.3, and the ratio of the first thickness to the second thickness is less than 1.

[0156] For example, the ratio of the first thickness to the second thickness can be 0.3, 0.45, 0.55, 0.65, 0.85, 0.9, 0.95 or 1.

[0157] In this embodiment, the ratio of the first thickness to the second thickness is greater than or equal to 0.3, ensuring sufficient buffer space between adjacent sealed bags 2 for the electrode assembly 3 to expand and contract during charging and discharging. A ratio of the first thickness to the second thickness is less than or equal to 1, ensuring that the buffer layer 4 is not excessively thick when the buffer space is sufficient, which is beneficial for improving the volumetric energy density of the battery cell.

[0158] In some embodiments, please refer to FIG7, the battery cell further includes a heat insulation layer 5, and a heat insulation layer 5 is provided between each two adjacent sealed bags 2. A buffer layer 4 is provided on each of the opposite sides of the heat insulation layer 5 between the corresponding two adjacent sealed bags 2. The heat insulation layer 5 includes a heat insulation body, and the thermal conductivity of the heat insulation body is less than the thermal conductivity of the buffer layer 4.

[0159] The heat insulation layer 5 is mainly used to separate the heat of the electrode assembly 3 inside the sealed bags 2 on both sides, and to suppress the heat transfer between the corresponding electrode assemblies 3 inside the adjacent sealed bags 2 on both sides.

[0160] For example, the insulation layer 5 can be an insulation pad.

[0161] Thermal conductivity refers to the amount of heat transferred through a 1-meter-thick material with a temperature difference of 1 degree Celsius (K, °C) between its two surfaces in 1 second under steady-state heat transfer conditions. The unit is watts per meter-degree (W / (m·K), where K can be replaced by °C). Here, K is the temperature unit Kelvin, °C is the temperature unit Celsius, and W is the power unit watt.

[0162] The higher the thermal conductivity, the easier it is to transfer heat between the two sides; the lower the thermal conductivity, the better the insulation effect.

[0163] In this embodiment, a buffer layer 4 and a heat insulation layer 5 are provided between two adjacent sealed bags 2. Buffer layers 4 are provided on both sides of the heat insulation layer 5. The buffer layers 4 on both sides buffer the electrode assemblies 3 of the adjacent sealed bags 2, and the heat insulation layer 5 insulates the electrode assemblies 3 inside the sealed bags 2, reducing heat transfer to the corresponding electrode assemblies 3 on both sides of the heat insulation layer 5. The buffer layer 4 has a relatively high thermal conductivity and mainly serves a buffering function, without requiring strong heat insulation capabilities, which helps reduce costs.

[0164] It is understood that the specific structure between two adjacent sealed bags 2 is not limited. For example, the heat insulation layer 5 may not be provided between two adjacent sealed bags 2, and the buffer layer 4 between two adjacent sealed bags 2 may be made of a material with low thermal conductivity, so that the buffer layer 4 has both buffering and heat insulation functions.

[0165] In some embodiments, the material of the thermal insulation body is aerogel or phase change material.

[0166] For example, the phase change material can be water.

[0167] In this embodiment, both aerogel and phase change material are materials with low thermal conductivity. Materials using aerogel or phase change material as the main insulation material can effectively perform the function of heat insulation.

[0168] In some embodiments, the insulation layer 5 further includes an encapsulation element, which is sleeved on the outside of the insulation body.

[0169] Some insulation components may be in a liquid or gaseous state. For example, materials that undergo a phase change between a liquid and a gaseous phase, such as water.

[0170] In this embodiment of the disclosure, the heat insulation body is encapsulated by a packaging component sleeved on the outside of the heat insulation body, thereby reducing the possibility of disordered dissipation of the phase change material in the liquid or gaseous state and effectively constraining the heat insulation body.

[0171] It is understood that the specific structure of the insulation layer 5 is not limited. For example, the insulation layer 5 may not have an encapsulation component.

[0172] In some embodiments, the thermal conductivity of the insulation body is greater than or equal to 0.01 W / (mK), the thermal conductivity of the insulation body is less than or equal to 0.1 W / (mK), and the thermal conductivity of the buffer layer 4 is greater than 0.1 W / (mK).

[0173] Thermal conductivity refers to the amount of heat transferred through a 1-meter-thick material with a temperature difference of 1 degree Celsius (K, °C) between its two surfaces in 1 second under steady-state heat transfer conditions. The unit is watts per meter-degree (W / (m·K), where K can be replaced by °C). Here, K is the temperature unit Kelvin, °C is the temperature unit Celsius, and W is the power unit watt.

[0174] For example, the thermal conductivity of the insulation body can be 0.01, 0.011, 0.012, 0.013, 0.015, 0.018, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09 or 0.1.

[0175] For example, the thermal conductivity of the insulation body can be less than or equal to 0.02 and greater than or equal to 0.01.

[0176] In this embodiment, the thermal conductivity of the heat insulation body is less than or equal to 0.1 W / (mK), which allows the heat insulation body to basically meet the heat insulation requirements and has good heat insulation capabilities. The thermal conductivity of the heat insulation body is greater than or equal to 0.01 W / (mK), which can prevent the heat insulation capability of the heat insulation body from being too good and causing excessive cost. The thermal conductivity of the buffer layer 4 is greater than 0.1 W / (mK). The buffer layer 4 plays a buffering role and does not need to have a heat insulation function, which helps to reduce the cost of the buffer layer 4.

[0177] In some embodiments, please refer to Figures 1 to 4 and Figure 6. The housing 1 includes a housing 12 and an end cap 13 mounted on the housing 12. The housing 12 and the end cap 13 enclose a receiving space 11. The battery cell also includes an electrode terminal mounted on the end cap 13.

[0178] The housing 12 is the main structure that provides a space 11 for the electrode assembly 3 and the sealing bag 2, etc.

[0179] For example, the housing 12 can be a steel housing, an aluminum housing, a plastic housing (such as a polypropylene housing), or a composite metal housing (such as a copper-aluminum composite housing 1).

[0180] The end cap 13 is a structure that covers an opening at one end of the housing 12.

[0181] For example, the electrode assembly 3 includes a tab 36, which includes a positive tab 36 and a negative tab 36. The positive tab 36 is formed on the positive electrode plate 31, and the negative tab 36 is formed on the negative electrode plate 32.

[0182] In this embodiment, the opening at one end of the housing 12 is opened or covered by the end cap 13, so that the sealing bag 2 and the electrode assembly 3 inside the sealing bag 2 can be conveniently installed into the receiving cavity. The electrode terminals are installed on the end cap 13, and the tabs 36 of the electrode assembly 3 are electrically connected to the electrode terminals. The charging and discharging of the battery cells are realized through the external connection of the electrode terminals.

[0183] In some embodiments, the end cap 13 and the housing 12 snap together.

[0184] In this embodiment, the end cap 13 and the housing 12 can be connected relatively easily.

[0185] In some embodiments, the end cap 13 is glued to the housing 12.

[0186] In this embodiment of the present disclosure, the end cap 13 is glued to the housing 12, making the connection between the end cap 13 and the housing 12 more secure.

[0187] In some embodiments, the melting point of the housing 12 is greater than or equal to 1000°C.

[0188] In this embodiment, the shell 12 has a relatively high melting point, which helps to prevent the shell 12 from being damaged at higher temperatures.

[0189] In some embodiments, the housing 12 is made of steel, steel alloy, titanium, or titanium alloy.

[0190] In some embodiments, as shown in Figures 2 to 7, the thickness of the housing 12 is greater than or equal to 0.2 mm, and the thickness of the housing 12 is less than 2 mm.

[0191] For example, the thickness of the housing 12 can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.9mm, 1.1mm, 1.2mm, 1.5mm, 1.8mm or 2mm.

[0192] In this embodiment of the disclosure, the thickness of the housing 12 is greater than or equal to 0.2 mm, which gives the housing 12 good strength and reduces the possibility of the housing 12 being damaged by external impact. The thickness of the housing 12 is less than 2 mm, which helps to limit the thickness of the housing 12 from being too thick, thereby reducing costs.

[0193] In some embodiments, please refer to Figures 2 to 4 and Figure 6, a pressure relief port 15 is formed on one side of the housing 1, and the pressure relief port 15 communicates with the receiving space 11.

[0194] The pressure relief port 15 is an opening formed on the outer casing 1, used to allow the gas in the containment cavity to be discharged outward.

[0195] In this embodiment of the present disclosure, when the electrode assembly 3 inside the casing 1 of the battery cell experiences thermal runaway, the thermal runaway ejection material in the accommodating cavity is directionally depressurized through the pressure relief port 15 on one side of the casing 1, thereby effectively suppressing the disorderly ejection of ejection material from the electrode assembly 3 during the thermal runaway process.

[0196] It is understood that the specific structure of the outer casing 1 is not limited. For example, the outer casing 1 may not have a pressure relief port 15.

[0197] In some embodiments, please refer to Figures 2 to 4 and Figure 6. The housing 1 includes a housing 12 and an end cap 13 mounted on the housing 12. The housing 12 and the end cap 13 enclose a receiving space 11. The battery cell also includes an electrode terminal mounted on the end cap 13. The space inside the housing 12 extends through the opposite ends of the housing 12 along the arrangement direction of the housing 12 and the end cap 13. The end cap 13 is located at one end of the housing 12, and the pressure relief port 15 is located at the other end of the housing 12.

[0198] For example, the melting point of the housing 12 is greater than or equal to 1000°C. The high melting point of the housing 12 makes it less likely to be damaged during the thermal runaway of the electrode assembly 3, thereby better confining the thermal runaway ejected material in the containment space 11 to release pressure from the pressure relief port 15, which is beneficial for the better directional ejection of the thermal runaway ejected material.

[0199] In this embodiment, since the end cap 13 is located at one end of the housing 12 and the electrode terminals are mounted on the end cap 13, and the pressure relief port 15 is located at the other end of the housing 12, the thermal runaway ejected from the pressure relief port 15 is away from the electrode terminals on the end cap 13, which helps to reduce the thermal runaway ejected from the electrode terminals and short-circuit the electrode terminals of adjacent battery cells, causing thermal diffusion between adjacent battery cells.

[0200] It is understood that the arrangement of the pressure relief port 15 is not limited. For example, the pressure relief port 15 and the end cap 13 may be located on the same side of the housing 12.

[0201] In some embodiments, the pressure relief port 15 is open.

[0202] In this embodiment of the disclosure, since the pressure relief port 15 is open, it is beneficial for the thermal runaway ejected material in the containment space 11 to be ejected more smoothly from the pressure relief port 15 to achieve pressure relief.

[0203] In some embodiments, please refer to Figures 2 to 4 and Figure 6, the battery cell also includes a shield 6 connected to the housing 1, the shield 6 covering the pressure relief port 15, and the pressure bearing capacity of the shield 6 is less than that of the housing 1.

[0204] For example, the shield 6 is a flame-retardant cover.

[0205] For example, the flame-retardant cap is made of a mother-of-pearl material.

[0206] Gas is continuously introduced into the containment space 11 to increase the pressure inside the containment space 11. When the shield 6 breaks before the outer shell 1, the pressure-bearing capacity of the shield 6 is less than that of the outer shell 1.

[0207] In this embodiment, the pressure relief port 15 is blocked by the shielding member 6. This prevents objects inside the containment space 11 from falling out of the pressure relief port 15 while the battery cell is operating normally. It also prevents impurities outside the outer casing 1 from entering the containment space 11 inside the outer casing 1 through the pressure relief port 15. When the electrode assembly 3 inside the containment space 11 experiences thermal runaway, the pressure-bearing capacity of the shielding member 6 is less than that of the outer casing 1. The thermal runaway ejection then breaks through the shielding member 6 and ejects from the pressure relief port 15, thus releasing pressure.

[0208] In some embodiments, the sealing bag 2 is a bag-shaped insulating component or an aluminum-plastic film.

[0209] In this embodiment of the disclosure, the electrolyte used to wet the electrode assembly 3 is sealed by a bag-shaped insulating component or an aluminum-plastic film, so that the electrode assembly 3 inside the sealed bag 2 can be well wetted in the electrolyte.

[0210] It is understandable that the specific structure of the sealing bag 2 is not limited, and the sealing bag 2 can also be other structures that can seal the electrode assembly 3 and the electrolyte.

[0211] In some embodiments, referring to Figures 2 to 8, the mass energy density of the structure formed by the sealed bag 2 and the electrode assembly 3 within the sealed bag 2 is greater than or equal to 300 Wh / kg. The mass energy density of the structure formed by the sealed bag 2 and the electrode assembly 3 within the sealed bag 2 is less than or equal to 550 Wh / kg.

[0212] In some embodiments, please refer to Figures 5 and 7, the battery cell further includes a heat-insulating layer 7, and a heat-insulating layer 7 is disposed between the sealed bag 2 containing the electrode assembly 3 and the outer casing 1.

[0213] The heat-insulating layer 7 is a structure that limits the transfer of heat from the electrode assembly 3 inside the outer casing 1 of the battery cell to adjacent battery cells during thermal runaway.

[0214] In this embodiment of the disclosure, by providing a heat-insulating layer 7 between the outer shell 1 and the sealing bag 2, the heat of the thermally runaway electrode assembly 3 inside the sealing bag 2 inside the outer shell 1 is blocked, thereby limiting the possibility of the thermally runaway heat of the electrode assembly 3 inside the outer shell 1 spreading to adjacent battery cells.

[0215] It is understood that the structure of the battery cell is not limited. For example, the heat-insulating layer 7 may not be provided between the outer casing 1 and the sealing bag 2 of the battery cell.

[0216] In some embodiments, please refer to Figures 5 and 7, along the direction in which the buffer layer 4 and the sealing bag 2 are arranged, a heat-insulating layer 7 is provided between the sealing bag 2 closest to the outer shell 1 and the outer shell 1.

[0217] For example, please refer to Figures 5 and 7. The buffer layer 4 and the sealing bag 2 are arranged along a preset direction. The heat generation of the electrode assembly 3 is mainly concentrated on the large surface. A heat-insulating layer 7 is provided between the sealing bag 2, which is closest to the outer shell 1, and the outer shell 1 along the preset direction, which can effectively block the heat inside the outer shell 1 from being transferred to the adjacent battery cells.

[0218] In this embodiment of the present disclosure, by providing a heat-insulating layer 7 between the sealing bag 2 closest to the outer shell 1 and the outer shell 1, the heat of the electrode assembly 3 inside the sealing bag 2 is restricted from being transferred to the outer shell 1, thereby reducing the transfer of heat generated by the electrode assembly 3 to adjacent battery cells.

[0219] It is understood that the arrangement of the heat-insulating layer 7 is not limited. For example, the heat-insulating layer 7 may be provided between the sealing bag 2 closest to the outer shell 1 and the outer shell 1 in the direction intersecting the direction of the arrangement of the buffer layer 4 and the sealing bag 2.

[0220] In some embodiments, the heat-insulating layer 7 includes a heat-insulating body, the thermal conductivity of which is greater than or equal to 0.01 W / (mK) and the thermal conductivity of which is less than or equal to 0.1 W / (mK).

[0221] In this embodiment, the thermal conductivity of the heat-insulating body is less than or equal to 0.1 W / (mK), giving it good heat insulation capabilities. The thermal conductivity of the heat-insulating body is greater than or equal to 0.01 W / (mK), allowing it to minimize cost while still providing good heat insulation. The heat insulation effect of the heat-insulating body restricts the transfer of heat generated by the electrode assembly 3 to adjacent battery cells.

[0222] In some embodiments, the heat-insulating layer 7 includes a heat-resistant coating with a melting point greater than 1000°C.

[0223] For example, a heat-resistant coating is applied to the inner wall of the housing 1.

[0224] For example, the melting point of the heat-resistant coating may be greater than the melting point of the housing 12.

[0225] In this embodiment, the heat-resistant coating has a melting point greater than 1000°C. The high melting point of the heat-resistant coating enables it to withstand high temperatures. The heat-resistant coating is disposed between the outer shell 1 and the sealing bag 2, which helps to reduce the possibility of the outer shell 1 being damaged at high temperatures.

[0226] In some embodiments, the heat-insulating layer 7 includes a heat-insulating body and a heat-resistant coating.

[0227] In some embodiments, the heat-insulating body is made of ceramic composite material, aerogel, glass fiber, mica or carbon fiber.

[0228] In this embodiment, the ceramic composite material, aerogel, glass fiber, mica or carbon fiber have low thermal conductivity and good heat insulation ability. The heat-insulating body made of ceramic composite material, aerogel, glass fiber, mica or carbon fiber can effectively limit the heat generated by the electrode assembly 3 from being transferred to the outer shell 1.

[0229] In some embodiments, the thermal conductivity of the buffer layer 4 is greater than or equal to 0.01 W / (mK), and the thermal conductivity of the buffer layer 4 is less than or equal to 0.1 W / (mK).

[0230] In this embodiment, the thermal conductivity of the buffer layer 4 is less than or equal to 0.1 W / (mK), giving it good thermal insulation capabilities. The buffer layer 4 combines buffering and thermal insulation functions, thus effectively achieving both buffering and thermal insulation between two adjacent sealed bags 2. The thermal conductivity of the insulation body is greater than or equal to 0.01 W / (mK). This minimizes the risk of excessive cost due to overly good thermal insulation while ensuring the buffer layer 4 itself has good thermal insulation capabilities, thereby helping to reduce costs.

[0231] In some embodiments, the material of the buffer layer 4 is aerogel, glass fiber, ceramic or ceramic composite material.

[0232] For example, the thermal conductivity of the aerogel, glass fiber, ceramic or ceramic composite material is greater than or equal to 0.01 W / (mK) and less than or equal to 0.1 W / (mK).

[0233] In this embodiment, aerogel, glass fiber, ceramic and ceramic composite material are all materials with low thermal conductivity, which have both good buffering capacity and good heat insulation capacity. The buffer layer 4 made of aerogel, glass fiber, ceramic or ceramic composite material has both buffering and heat insulation functions.

[0234] In some embodiments, referring to Figures 1-10, the battery cell includes a casing 1, a sealed bag 2, an electrode assembly 3, and a buffer layer 4. The casing 1 has a receiving space 11. The sealed bags 2 are located within the receiving space 11, and there are at least two sealed bags 2. An electrode assembly 3 is disposed within the sealed space of each sealed bag 2. A buffer layer 4 is disposed between at least two adjacent sealed bags 2. The casing 1 has a pressure relief port 15. The electrode assembly 3 can be a wound electrode assembly 3 or a stacked electrode assembly 3. The casing 1 includes a housing 12 and an end cap 13 mounted on the housing 12. The housing 12 and the end cap 13 enclose the receiving space 11, and the battery cell also includes electrode terminals mounted on the end cap 13. The sealed bag 2 is an aluminum-plastic film, and the aluminum-plastic film and the electrode assembly 3 within the aluminum-plastic film together constitute the main structure of the pouch cell. The mass energy density of the structure formed by the sealed bag 2 and the electrode assembly 3 within the sealed bag 2 is ≥300Wh / kg. The melting point of the housing 12 is greater than 1000°C, and the material of the housing 12 can be steel, steel alloy, titanium, or titanium alloy. The thickness of the casing 12 is greater than or equal to 0.2 mm. The total thickness of all buffer layers 4 between two adjacent sealed bags 2 is the first thickness, and the total thickness of the electrode assembly 3 in each sealed bag 2 and the corresponding sealed space of the sealed bag 2 is the second thickness. The ratio of the first thickness to the second thickness is greater than or equal to 0.15 and less than 1.2. The end cap 13 is snapped or glued to the casing 12. The battery cell also includes a heat-insulating layer 7, which is disposed between the sealed bag 2 containing the electrode assembly 3 and the outer casing 1. Along the direction of the arrangement of the buffer layers 4 and the sealed bags 2, the heat-insulating layer 7 is disposed between the sealed bag 2 closest to the outer casing 1 and the outer casing 1. The heat-insulating layer 7 includes a heat-insulating body and / or a temperature-resistant coating. The thermal conductivity of the heat-insulating body is greater than or equal to 0.01 W / (mK), the thermal conductivity of the heat-insulating body is less than or equal to 0.1 W / (mK), and the melting point of the temperature-resistant coating is greater than 1000℃. The heat-insulating body is made of ceramic composite materials, aerogel, glass fiber, mica, or carbon fiber. The heat-resistant coating can be an organic or inorganic heat-resistant coating.

[0235] The thermal conductivity of the buffer layer 4 is greater than or equal to 0.01 W / (mK), and the thermal conductivity of the buffer layer 4 is less than or equal to 0.1 W / (mK). The material of the buffer layer 4 is aerogel, glass fiber, ceramic or ceramic composite material.

[0236] The battery cell also includes a heat insulation layer 5. A heat insulation layer 5 is provided between every two adjacent sealed bags 2. A buffer layer 4 is provided on each of the opposite sides of the heat insulation layer 5 between the corresponding two adjacent sealed bags 2. The heat insulation layer 5 includes a heat insulation body. The thermal conductivity of the heat insulation body is less than that of the buffer layer 4.

[0237] The pressure relief port 15 is open.

[0238] The battery cell also includes a shield 6 connected to the outer casing 1. The shield 6 covers the pressure relief port 15. The pressure-bearing capacity of the shield 6 is less than that of the outer casing 1.

[0239] The above are merely preferred embodiments of this disclosure and are not intended to limit the scope of this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A battery cell, comprising: a housing having an accommodation space; a plurality of sealed bags located in the accommodation space; an electrode assembly arranged in a sealed space of each of the sealed bags; and a buffer layer arranged between at least two adjacent sealed bags. The buffer layer is made of foamed polypropylene, rubber, polyurethane, foam or silica gel. The buffer layer is arranged between every two adjacent sealed bags arranged in a preset direction, and the preset direction is perpendicular to a large surface of the electrode assembly. A total thickness of all the buffer layers between the two adjacent sealed bags is a first thickness, a total thickness of each of the sealed bags and the electrode assembly in the sealed space of the corresponding sealed bag is a second thickness, a ratio of the first thickness to the second thickness is greater than or equal to 0.15, and the ratio of the first thickness to the second thickness is less than 1.

2. The ratio of the first thickness to the second thickness is greater than or equal to 0.3, and the ratio of the first thickness to the second thickness is less than 1.

2. The battery cell of claim 1, wherein, The battery cell further comprises a thermal insulation layer arranged between every two adjacent sealed bags, and opposite sides of the thermal insulation layer are provided with the buffer layer arranged between the corresponding two adjacent sealed bags.

3. The battery cell of claim 1 or 2, wherein, The thermal insulation layer comprises a thermal insulation main body, and a thermal conductivity of the thermal insulation main body is less than a thermal conductivity of the buffer layer.

4. The battery cell according to any one of claims 1 to 3, wherein, The thermal insulation main body is made of aerogel or phase change material.

5. The battery cell of claim 4, wherein, The thermal insulation layer further comprises an encapsulating member sleeved on an outer side of the thermal insulation main body.

6. The battery cell according to any one of claims 1 to 5, wherein, The thermal conductivity of the thermal insulation main body is greater than or equal to 0.01 W / (m.K), the thermal conductivity of the thermal insulation main body is less than or equal to 0.1 W / (m.K), and the thermal conductivity of the buffer layer is greater than 0.1 W / (m.K).

7. The battery cell of claim 6, wherein, The housing comprises a shell and an end cover mounted on the shell, the shell and the end cover surround the accommodation space, and the battery cell further comprises an electrode terminal mounted on the end cover.

8. The battery cell of claim 6 or 7, wherein, The end cover is clamped or glued to the shell.

9. The battery cell according to any one of claims 6 to 8, wherein, The melting point of the shell is greater than or equal to 1000 DEG C.

10. The battery cell according to any one of claims 1 to 9, wherein, The shell is made of steel, steel alloy, titanium or titanium alloy.

11. The battery cell of claim 10, wherein, The thickness of the shell is greater than or equal to 0.2 mm, and the thickness of the shell is less than 2 mm.

12. The battery cell of claim 10 or 11, wherein, One side of the housing is formed with a pressure relief port in communication with the accommodation space.

13. The battery cell of any one of claims 10-12, wherein, The housing comprises a shell and an end cover mounted on the shell, the shell and the end cap surround the accommodation space, and the battery cell further comprises an electrode terminal mounted on the end cover, the space in the shell penetrates through opposite ends of the shell along the arrangement direction of the shell and the end cover, the end cover is located at one end of the shell, and the pressure relief port is located at the other end of the shell.

14. The battery cell of any one of claims 10-13, wherein, The pressure relief port is open, or the battery cell further comprises a shielding member connected to the housing, the shielding member covers the pressure relief port, and a pressure bearing capacity of the shielding member is less than a pressure bearing capacity of the housing.

15. The battery cell of any one of claims 1-14, wherein, The sealed bag is a bag-shaped insulating member or an aluminum plastic film.

16. The battery cell of claim 15, wherein, The battery cell further comprises a heat resistance layer arranged between the sealed bag containing the electrode assembly and the housing.

17. The battery cell of claim 15 or 16, wherein, ​ 18. The battery cell of any one of claims 1-17, wherein, ​ 19. The battery cell of any one of claims 1-18, wherein, ​ 20. The battery cell of claim 19, wherein, The heat-resistant layer is arranged between the sealing bag closest to the shell and the shell along the arrangement direction of the buffer layer and the sealing bag.

21. The battery cell of claim 19 or 20, wherein, The heat-resistant layer comprises a heat-resistant body and / or a temperature-resistant coating, the heat-resistant body has a thermal conductivity greater than or equal to 0.01 W / (m.K), the heat-resistant body has a thermal conductivity less than or equal to 0.1 W / (m.K), and the temperature-resistant coating has a melting point greater than 1000 DEG C.

22. The battery cell of claim 21, wherein, The heat-resistant body is made of ceramic composite material, aerogel, glass fiber, mica or carbon fiber.

23. The battery cell of any one of claims 1-5 or any one of claims 10-22, wherein, The buffer layer has a thermal conductivity greater than or equal to 0.01 W / (m.K), and the buffer layer has a thermal conductivity less than or equal to 0.1 W / (m.K).

24. The battery cell of any one of claims 1-5 or any one of claims 10-23, wherein, The buffer layer is made of aerogel, glass fiber, ceramic or ceramic composite material.

25. A battery device, comprising: a box body; a battery cell according to any one of claims 1-24, located in the box body.

26. An electric device, comprising: a device body; a battery device according to claim 25, mounted on the device body.

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