Battery assembly and electrical system
Patent Information
- Application Number
- KR1020267024783
- Authority / Receiving Office
- KR · KR
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-01-29
- Filing Date
- 2024-12-06
- Publication Date
- 2026-09-04
Smart Images
Figure PCT00014_ABST
Abstract
Description
Technology Field
[0001] Cross-reference regarding related applications
[0002] This application claims priority to Chinese Patent Application No. 202410128727.1, filed on January 29, 2024, with the title of the invention "Battery Assembly and Power Consumption System," the entirety of which is incorporated herein by reference.
[0003] This application also claims priority to Chinese patent application No. 202311871144.X, filed on December 29, 2023, with the title of the invention "battery assembly and power consumption system," the entirety of which is incorporated herein by reference.
[0004] Technology field
[0005] This application relates to the field of battery technology, and in particular to battery assemblies and power consumption systems. Background Technology
[0006] Thermal and mechanical abuse of batteries pose safety risks and can even cause thermal runaway in the cells. In related technologies, if thermal runaway occurs in a cell within a battery pack, a large amount of heat is generated internally, causing the cell's temperature to rise rapidly and transfer to adjacent cells. If effective isolation measures are not taken, the temperatures of adjacent cells will rise rapidly, leading to heat propagation.
[0007] The object of the present invention is to provide a battery assembly and a power consumption system. The present invention proposes a parametric design method for a skeleton based on Young's modulus. Cell gaps and pressures are given to determine a selection range of skeleton thickness-related parameters so that the battery assembly has good safety while satisfying functional requirements.
[0008] To achieve the aforementioned objective, one aspect of the present invention provides a battery assembly. The battery assembly comprises a plurality of cells. A heat-absorbing unit is disposed between two adjacent cells. The heat-absorbing unit comprises a heat-absorbing material and a framework of at least one layer. The framework has a plurality of holes penetrating in the thickness direction of the framework. The heat-absorbing material fills the holes. The battery assembly satisfies the following conditions.
[0009]
[0010] Here, x is the thickness of the heat-absorbing unit (in mm);
[0011] d is the gap (in mm) between two adjacent cells;
[0012] a is the ratio of the area of the orthographic projection of the skeleton onto the surface of the heat-absorbing unit in contact with the cell to the area of the surface of the heat-absorbing unit in contact with the cell;
[0013] E1 is the Young's modulus of the skeleton (in GPa units);
[0014] S is the surface area (in mm²) of the heat-absorbing unit in contact with the cell;
[0015] F1 is the pressure (in N units) supported by the skeleton;
[0016] x1 is the thickness of one layer of the skeleton (in mm);
[0017] n is the number of layers of the skeleton, n≥1, and n is an integer.
[0018] Preferably, the energy (Q) of the cell is in the range of 576 to 3456 kJ.
[0019] Preferably, the volume (V) of the heat-absorbing material is 20,000 to 300,000 mm³. The volume (V) of the heat-absorbing material satisfies V = (x - a * n * x1)S.
[0020] Preferably, the thickness (x) of the heat-absorbing unit is in the range of 0.5 to 5 mm.
[0021] Preferably, the gap (d) between two adjacent cells is in the range of 0.3 to 3 mm.
[0022] Preferably, the ratio (a) of the area of the orthographic projection of the frame onto the surface of the heat-absorbing unit in contact with the cell to the area of the surface of the heat-absorbing unit in contact with the cell is in the range of 10% to 50%.
[0023] Preferably, the Young's modulus (E1) of the framework is in the range of 0.0001 to 100 GPa.
[0024] Preferably, the surface area (S) of the heat-absorbing unit in contact with the cell is in the range of 5,000 to 300,000 mm².
[0025] Preferably, the pressure (F1) supported by the frame is in the range of 5,000 to 60,000 N.
[0026] Preferably, the pressure (F1) supported by the frame satisfies the following equation:
[0027]
[0028] Here, F is the total pressure (N) supported by the surface of the heat-absorbing unit in contact with the cell;
[0029] E2 is the Young's modulus (in GPa) of the heat-absorbing material;
[0030] a is the ratio of the orthographic projected area of the framework onto the surface of the heat-absorbing unit in contact with the cell to the surface area of the heat-absorbing unit in contact with the cell.
[0031] Preferably, the thickness (x1) of one layer of the skeleton is in the range of 0.025 to 2 mm.
[0032] Preferably, the number of layers (n) of the skeleton is in the range of 1 to 10.
[0033] Preferably, the thickness (x) of the heat-absorbing unit is greater than the product of the thickness (x1) of one layer of the framework and the number (n) of layers of the framework.
[0034] Preferably, the total thickness of the frame accounts for 1% to 100%, preferably 10% to 80%, of the thickness of the heat-absorbing unit.
[0035] Preferably, the heat-absorbing unit further includes an encapsulation film for encapsulating the framework and the heat-absorbing material.
[0036] Preferably, the holes are evenly spaced in the thickness direction of the frame.
[0037] Preferably, the ratio of the surface area of the heat-absorbing unit in contact with the cell to the surface area of the cell in contact with the heat-absorbing unit is 0.8 or more and 1 or less.
[0038] Preferably, the battery assembly comprises at least two cell groups. A cell group comprises N arranged cells. A heat-absorbing unit is positioned between two adjacent cell groups. The thickness (x) of the heat-absorbing unit satisfies the relationship (0.5 ± b) mm ≤ x ≤ (5 N ± b) mm; where b is a preset correction factor (in mm).
[0039] Preferably, the phase change temperature of the heat-absorbing material is 50°C to 200°C.
[0040] Preferably, the phase change temperature of the heat-absorbing material is 70°C to 160°C.
[0041] Preferably, the heat-absorbing material is a hydrogel.
[0042] Preferably, a plurality of holes are evenly spaced in the direction of extension of the skeleton.
[0043] A second aspect of the present invention provides a power consumption system comprising the aforementioned battery assembly.
[0044] According to the technical solution of the present invention, a battery assembly By ensuring that the value of is between 10 and 1000, the deformation amount of the heat-absorbing unit can be secured within a certain range, thereby preventing damage to the heat-absorbing unit and material overflow caused by squeezing during battery thermal runaway. Brief explanation of the drawing
[0045] Figure 1 is a drawing illustrating the structure of a battery assembly. Figure 2 is a drawing of a heat-absorbing unit including a hexagonal frame. Figure 3 is a drawing of the surface of a hexagonal skeleton. Figure 4 is a drawing of the surface of a square frame. Figure 5 is a drawing of a two-story square frame. Figure 6 is a drawing of a heat-absorbing unit including a single-layer frame. Figure 7 is a drawing of a heat-absorbing unit including a multilayer frame. Figure 8 is a thermal runaway pressure test apparatus. Specific details for implementing the invention
[0046] Specific embodiments of the present invention will be described in detail below with reference to the attached drawings. It should be understood that the specific embodiments described herein are used merely to describe and explain the present invention and are not intended to limit the invention.
[0047] In the description of this application, the terms “first” and “second” are for illustrative purposes only and should not be understood as an indication of relative importance or an implied indication of the quantity of the technical features indicated. Accordingly, unless specifically noted, the feature limited by “first” or “second” may explicitly or implicitly include one or more features, and “plural” means two or more. The term “include” and any variations thereof mean a non-exclusive inclusion that may present or add one or more other features, integers, steps, actions, units, components, and / or combinations thereof.
[0048] Additionally, orientations or positional relationships indicated by terms such as “top,” “bottom,” “inside,” and “outside” are based on the orientations or positional relationships depicted in the attached drawings and are used merely for convenience and brevity of description of the present application, not to indicate that the mentioned devices or elements must have a specific orientation or be configured and operated in a specific orientation. Accordingly, these terms should not be interpreted as a limitation to the present application.
[0049] Furthermore, unless specifically stated or limited otherwise, the terms “mounting,” “interconnection,” and “connection” should be understood in a broad sense. For example, these terms may denote a fixed connection, a detachable connection, or an integral connection, but may denote a mechanical or electrical connection, a direct connection, an indirect connection through an intermediate medium, or an internal connection between two elements. A person skilled in the art can understand the specific meanings of the above terms in this application based on specific cases.
[0050] As illustrated in FIGS. 1 to 7, the battery assembly of the present invention comprises a plurality of cells (2). A heat-absorbing unit (1) is disposed on at least one surface of a cell (2). The heat-absorbing unit (1) comprises a skeleton (11) and a heat-absorbing material (12). The skeleton (11) comprises a plurality of holes (13) penetrating the skeleton (11) in the thickness direction of the skeleton (11). The heat-absorbing material (12) fills the holes (13). The skeleton (11) is a single-layer or multi-layer structure.
[0051] In the present invention, the battery assembly satisfies the following conditions:
[0052]
[0053] Here, x is the thickness (in mm) of the heat-absorbing unit (1);
[0054] d is the gap (in mm) given between the cells (2);
[0055] a is the ratio of the area of the orthographic projection of the frame (11) onto the surface of the heat-absorbing unit (1) in contact with the cell (2) to the area of the surface of the heat-absorbing unit (1) in contact with the cell (2);
[0056] E1 is the Young's modulus (in GPa units) of the skeleton (11);
[0057] S is the surface area (in mm²) of the heat-absorbing unit (1) in contact with the cell (2);
[0058] F1 is pressure (in N units) supported by the frame (11);
[0059] x1 is the thickness (in mm) of one layer of the skeleton (11);
[0060] n is the number of layers of the skeleton (11), n≥1, and n is an integer.
[0061] If the heat-absorbing unit (1) satisfies the above parameter conditions, the battery assembly has good safety. Specifically, in a safety test of the battery assembly, after a nail penetration triggers a thermal runaway in one cell (2), no heat propagation occurs. The battery assembly If the value of is less than 10, the Young's modulus of the frame (11) is excessively low, making the frame (11) prone to significant deformation. Once thermal runaway occurs in the cell (2), the expansion force increases rapidly, causing the heat-absorbing material (12) to rupture its encapsulation and leak, resulting in reduced heat absorption and failure to suppress heat propagation. Of the battery assembly If the value of is greater than 1000, the frame (11) has a very high Young's modulus and is difficult to deform. Since a specific gap needs to be compressed during the design, this compression gap is provided by the heat-absorbing material (12). During the charge / discharge cycle of the cell (2), the heat-absorbing unit (1) is repeatedly compressed, causing the heat-absorbing material (12) to be continuously compressed and overflow from the gap between the cells (2), and consequently, the heat absorbed by the heat-absorbing unit (1) is reduced, which does not suppress heat propagation.
[0062] In a preferred embodiment, the heat-absorbing unit (1) satisfies the following conditions:
[0063]
[0064] In the aforementioned preferred embodiment, the battery assembly has further improved safety.
[0065] In the battery assembly of the present invention, the thickness (x) of the heat-absorbing unit (1) is preferably in the range of 0.5 to 5 mm, and more preferably in the range of 0.5 to 2 mm. When the thickness of the heat-absorbing unit (1) is within the aforementioned preferred range, the safety of the battery assembly is good, and the battery assembly can also secure an appropriate energy density. In the present invention, the thickness of the heat-absorbing unit (1) can be measured using a vernier caliper or a laser distance measuring device. Furthermore, in the present invention, the thickness of the heat-absorbing unit (1) is the thickness measured after removing the heat-absorbing unit (1) from the battery assembly.
[0066] In the battery assembly of the present invention, the gap between the cells (2) is determined based on assembly tolerances and the overall space utilization of the battery pack. Preferably, the gap (d) between the cells (2) is in the range of 0.3 to 3 mm. The gap between the cells (2) can be directly measured by measuring the distance between the opposing surfaces of two adjacent cells (2). A heat-absorbing unit (1) is placed between the opposing surfaces of two adjacent cells (2). Generally, the gap between the cells (2) is the distance between the opposing surfaces of two adjacent cells (2) measured in a resting state when the SOC of the cell (2) is 25%.
[0067] In the battery assembly of the present invention, preferably, the ratio (a) of the area of the projection of the frame (11) onto the surface in contact with the cell (2) of the heat-absorbing unit (1) to the area of the surface in contact with the cell (2) of the heat-absorbing unit (1) is in the range of 10% to 50%. When the area ratio of the frame (11) onto the surface of the heat-absorbing unit (1) is within the aforementioned preferred range, the heat-absorbing unit (1) can provide sufficient support so that the heat-absorbing material (12) is not compressed and comes out, and also secure the heat-absorbing capacity of the heat-absorbing material (12), thereby ensuring that the battery assembly has good safety. When determining a, only the area of the projection of the solid structure of the frame (11) onto the surface of the heat-absorbing unit (1) in contact with the cell (2) is considered. In other words, the area of the hole (13) is not included in the area of the orthographic projection on the surface of the heat-absorbing unit (1) in contact with the cell (2). Additionally, when the projection of the heat-absorbing unit (1) on the surface of the cell (2) in contact with the heat-absorbing unit (1) is on the surface of the cell (2), the area of the orthographic projection on the surface of the heat-absorbing unit (1) in contact with the cell (2) is equal to the area of the surface of the frame (11) facing the heat-absorbing unit (1), and the area of the surface of the heat-absorbing unit (1) in contact with the cell (2) is the area of the surface of the heat-absorbing unit (1) facing the cell (2).
[0068] In the battery assembly of the present invention, the Young's modulus (E1) of the frame (11) is preferably in the range of 0.0001 to 100 GPa. When the Young's modulus of the frame (11) is within the aforementioned preferred range, the frame (11) can provide sufficient support for the heat-absorbing material (12) to ensure that the heat-absorbing material (12) is not compressed, so that the battery assembly has good safety. The Young's modulus (E1) of the frame (11) can be determined based on the material of the frame (11).
[0069] In the battery assembly of the present invention, the surface area (S) in contact with the cell (2) of the heat-absorbing unit (1) is preferably in the range of 5,000 to 300,000 mm². When the heat absorption area on the surface of the heat-absorbing unit (1) is within the aforementioned preferred range, the heat-absorbing unit (1) can provide sufficient heat absorption capacity, thereby suppressing heat propagation in the battery. Generally, the heat absorption area of the heat-absorbing unit (1) may be the surface area attached to the cell (2) of the heat-absorbing unit (1), or the surface area attached to the heat-absorbing unit (1) of a single cell (2).
[0070] In the battery assembly of the present invention, the pressure (F1) supported by the frame (11) is generally applied based on actual conditions. If the pressure is too low, the heat-absorbing unit (1) and the cell (2) cannot be restrained and fixed. If the pressure is too high, the cell (2) may be damaged. Preferably, the pressure (F1) supported by the frame (11) is in the range of 5,000 to 60,000 N.
[0071] More preferably, the pressure (F1) supported by the frame (11) satisfies the following equation:
[0072]
[0073] Here, F is the total pressure (in N units) supported by the surface of the heat-absorbing unit (1) in contact with the cell (2);
[0074] E2 is the Young's modulus (in GPa units) of the heat-absorbing material (12);
[0075] a is the ratio of the area of the orthographic projection of the frame (11) onto the surface of the heat-absorbing unit (1) in contact with the cell (2) to the area of the surface of the heat-absorbing unit (1) in contact with the cell (2).
[0076] The total pressure (F) supported by the surface of the heat-absorbing unit (1) is calculated through the following steps:
[0077] A plan view of the test apparatus is shown in Fig. 8.
[0078] 1. Take one cell (2) and charge the cell (2) to a fully charged state using a standard charging procedure;
[0079] 2. A cell (2) is placed in a test fixture shown in FIG. 8. Here, the large surface of the cell (2) is insulated and appropriately restrained by a heat-absorbing unit (1) and an insulation board (4), and the insulation board (4) may be selected as a calcium silicate board;
[0080] 3. Align the pressure sensor (3) with the center of the wide surface of the cell (2) and the positions on the positive and negative sides of the wide surface. After assembling the entire fixture, maintain the stability of the entire device (i.e., no shaking or detachment of components);
[0081] 4. Triggering thermal runaway of the cell (2) and detecting force conditions fed back by the pressure sensor (3); and
[0082] 5. The total pressure on the surface of the heat-absorbing unit (1) is obtained by summing the force conditions obtained by the three pressure sensors (3).
[0083] In the above-described test method, in addition to placing three pressure sensors (3) at the above-described locations, a plurality of pressure sensors (3) may be optionally placed. The total pressure (F) supported by the surface of the heat-absorbing unit (1) is determined based on the sum of the pressures fed back by the plurality of pressure sensors (3).
[0084] Additionally, in the aforementioned test method, the surface pressure sensor (3), that is, the entire piece of the test film, may be optionally used. The film is attached to the wide surface of the cell (2) (the wide surface of the cell (2) corresponds to the surface of the insulation board (4)) and outputs a total pressure (F) supported by the surface of the heat-absorbing unit (1).
[0085] Additionally, in the aforementioned test method, the pressure sensor (3) may be zeroed after being placed between the fixture baffle (5) and the insulation board (4). Optionally, the pressure sensor (3) may be placed between the fixture baffle (5) and the insulation board (4) to obtain a pressure value. The total pressure supported by the surface of the heat-absorbing unit (1) in contact with the cell (2) during the thermal runaway of the cell (2) may be determined based on the difference between the pressure value determined after the thermal runaway of the cell (2) and the aforementioned pressure value.
[0086] Additionally, in step 3, the test device can simulate the force conditions of the cell (2) inside the battery pack to further improve test accuracy. That is, the test device can be tightened by a pressure load bolt to control the force applied to the battery to match the force of the battery pack (control within the range of 0 to 10 kN, preferably within the range of 1 to 6 kN).
[0087] Thermal runaway of the cell (2) can be triggered by the following two methods:
[0088] 1. Thermal runaway of the cell (2) is triggered by a nail penetration. The nail penetration location is in the middle of the cell (2), for example, at the nail penetration point (6) shown in FIG. 8. Additionally, the nail penetration location may be a positive position and / or a negative position corresponding to the cell (2).
[0089] 2. Based on the apparatus shown in FIG. 8, a heating plate is placed on a wide surface of the cell (2) at a position corresponding to the positive, negative, or intermediate position. The resistance of the heating plate is generally about 45 to 50 Ω. The heating plate is heated to induce thermal runaway of the cell (2).
[0090] In the battery assembly of the present invention, the thickness (x1) of one layer of the frame (11) is preferably in the range of 0.025 to 2 mm. When the thickness of one layer of the frame (11) is within the aforementioned preferred range, the frame (11) can provide sufficient support for the heat-absorbing material (12), and it can also be ensured that the heat-absorbing material (12) in the heat-absorbing unit (1) can provide sufficient heat absorption capacity.
[0091] In the battery assembly of the present invention, the number of layers (n) of the frame (11) increases according to the thickness of the heat-absorbing material (12). However, an excessive number of layers increases the difficulty of production, making it difficult for the material to satisfy design requirements. Preferably, the number of layers (n) of the frame (11) is in the range of 1 to 10, specifically, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. When the number of layers of the frame (11) is within the aforementioned preferred range, the frame (11) can provide sufficient support for the heat-absorbing material (12) and also allow the heat-absorbing unit (1) to provide sufficient heat absorption capacity, thereby suppressing heat propagation of the battery.
[0092] In one embodiment of the present application, the thickness (x) of the heat-absorbing unit (1) is greater than the product of the thickness (x1) of one layer of the frame (11) and the number (n) of layers of the frame (11). When the thickness of the heat-absorbing unit (1) and the total thickness of the frame (11) satisfy the aforementioned range, the volume of the heat-absorbing material (12) can be further increased while securing the support function of the frame (11), thereby preventing problems of heat propagation within the battery assembly and ensuring the safety of the battery assembly.
[0093] In one embodiment of the present application, the holes (13) are evenly spaced in the thickness direction of the frame (11). Specifically, the holes (13) are evenly spaced in the thickness direction of the frame (11) to facilitate the processing and manufacturing of the frame (11) and further to evenly distribute the force on the frame (11), thereby improving the mechanical properties of the frame (11). Even spaced space means that the cross-sections of the holes (13) are all identical in the thickness direction of the frame (11), or that the orthographic projections of the holes (13) onto a plane perpendicular to the thickness direction of the frame (11) completely coincide with each other.
[0094] In addition, in one embodiment of the present application, as illustrated in FIGS. 3 and 4, a plurality of holes (13) are evenly arranged in the extension direction of the frame (11). Specifically, the aforementioned even arrangement means that the spacing between two adjacent holes (13) is the same, so that the heat-absorbing material (12) is evenly arranged at different locations on the surface of the heat-absorbing unit (1) in contact with the cell (2), thereby ensuring heat-absorbing uniformity of the heat-absorbing unit (1). In addition, the frame (11) extends in two mutually orthogonal directions. The holes (13) are evenly arranged in the extension direction of the frame (11), which means that a plurality of holes (13) are evenly arranged in at least one direction. These directions are perpendicular to the thickness direction of the frame (11), and these directions are also perpendicular to each other.
[0095] In one embodiment of the present application, the ratio of the surface area of the heat-absorbing unit (1) in contact with the cell (2) to the surface area of the cell (2) in contact with the heat-absorbing unit (1) is 0.8 or more and 1 or less. By setting the ratio of the contact area between the surface of the adjacent cell (2) and the heat-absorbing unit (1), the heat-absorbing unit (1) can be made to come into complete contact with the surface of the cell (2), thereby ensuring the heat absorption effect of the heat-absorbing unit (1).
[0096] In one embodiment of the present application, the battery assembly comprises at least two groups of cells (2). A group of cells (2) comprises N arranged cells (2). A heat-absorbing unit (1) is positioned between two adjacent groups of cells (2). The thickness (x) of the heat-absorbing unit (1) satisfies the following relationship: (0.5 ± b) mm ≤ x ≤ (5 N ± b) mm, where b is a preset correction factor (mm). Specifically, as the number of cells (2) in a group of cells (2) increases, the thickness of the heat-absorbing unit (1) is increased so that the heat-absorbing unit (1) can completely absorb the heat that may be released during a thermal runaway within the group of cells (2), thereby ensuring the safety of the battery assembly. b is a preset correction factor, which can be determined based on the design requirements of the battery assembly. Generally, the value of b is selected from values such as 0.1, 0.5, and 1, and the value of b increases according to the battery capacity to secure the heat absorption capacity of the heat-absorbing unit (1).
[0097] In one embodiment of the present application, since the heat-absorbing material (12) absorbs heat through a phase change, if a heat-absorbing material (12) with a phase change temperature of 50°C to 200°C is used in a battery assembly, problems such as the phase change material overflowing or being damaged by the large expansion force generated during thermal runaway of the battery may occur. In this case, the heat generated by the cell (2) during thermal runaway cannot be absorbed, causing heat propagation within the battery assembly. Therefore, the battery assembly By satisfying this, the heat absorption effect of the heat-absorbing unit (1) can be secured.
[0098] In addition, if the phase change temperature of the phase change material is within this range, it can more effectively absorb the heat generated in the cell (2) within the battery assembly during charging and discharging, thereby cooling the cell (2) and ensuring normal use of the cell (2).
[0099] In addition, in order to prevent heat propagation in the battery assembly, the phase change temperature of the heat-absorbing material (12) must be between 70°C and 160°C. Specifically, when the phase change temperature of the heat-absorbing material (12) is within this temperature range, the heat-absorbing material (12) does not undergo a phase change during normal operation of the battery, thereby ensuring the amount of heat-absorbing material (12) is secured during thermal runaway of the cell (2). In addition, it can also be ensured that the heat-absorbing material (12) undergoes a complete phase change after thermal runaway occurs within the cell (2) in the battery assembly, thereby completely absorbing the heat generated by the cell (2).
[0100] In one embodiment of the present application, the heat-absorbing material (12) is a composite material comprising a liquid phase change medium. The heat absorption effect is achieved through the phase change of this liquid phase change medium. The liquid phase change medium comprises at least one of a liquid such as water, ethanol, or ethylene glycol. In some embodiments of the present application, the heat-absorbing material (12) may be a hydrogel comprising water, a hydrated salt, or a complex thereof. The phase change temperature of the heat-absorbing material (12) may be controlled by adjusting the water content of the heat-absorbing material (12). The complex may be a complex of a hydrogel or a hydrated salt and another material (e.g., a flame retardant). A hydrogel is used as an example. A polymeric material with a network structure may serve as the matrix of the hydrogel, and water may serve as the liquid phase change medium. In some other embodiments of the present application, the heat-absorbing material (12212) may be a material comprising a liquid such as ethanol or ethylene glycol.
[0101] In the battery assembly of the present invention, the frame (11) comprises a plurality of holes (13) penetrating the frame (11) in the thickness direction of the frame (11), and a heat-absorbing material (12) fills the holes (13). The shape of the holes (13) of the frame (11) is not particularly limited and may be various ordinary regular geometric shapes or irregular shapes, for example, squares, hexagons, or circles. In some embodiments, as shown in FIGS. 2 and 3, the holes (13) of the frame (11) are hexagonal (preferably regular hexagons). In some other embodiments, as shown in FIGS. 4 and 5, the shape of the holes (13) of the frame (11) is square.
[0102] In the battery assembly of the present invention, the frame (11) is a single-layer or multi-layer structure. When the frame (11) is a single-layer structure, as shown in FIG. 6, the heat-absorbing material (12) completely covers the upper and lower surfaces of the frame (11) and fills the holes (13) of the frame (11). When the frame (11) is a multi-layer structure, as shown in FIG. 7, the heat-absorbing material (12) is filled between any two adjacent layers of the frame (11), and the heat-absorbing material (12) also covers the upper surface of the top layer of the frame (11) and the lower surface of the bottom layer of the frame (11).
[0103] In the battery assembly of the present invention, the material forming the frame (11) preferably has the characteristic of withstanding high temperatures of 400°C or higher. In some embodiments, the material forming the frame (11) is polyester, polypropylene (PP), or metal (e.g., aluminum).
[0104] In the battery assembly of the present invention, the heat-absorbing material (12) may be a heat-absorbing material (12) commonly used in the battery field. In some embodiments, the heat-absorbing material (12) is a hydrogel material.
[0105] In the battery assembly of the present invention, the total thickness of the frame (11) is preferably 1% to 100% of the thickness of the heat-absorbing unit (1), and more preferably 10% to 80%. When the ratio of the total thickness of the frame (11) to the thickness of the heat-absorbing unit (1) is within the above range, the heat-absorbing unit (1) can provide sufficient heat absorption capacity, thereby suppressing heat propagation of the battery.
[0106] In the battery assembly of the present invention, the heat-absorbing unit (1) may further include an encapsulation film (14) that encapsulates the frame (11) and the heat-absorbing material (12).
[0107] In the battery assembly of the present invention, preferably, one heat-absorbing unit (1) is disposed for every two cells (2) (as shown in FIG. 1). According to this preferred embodiment, the battery assembly has good safety while satisfying the heat absorption requirements. Specifically, in a safety test of the battery assembly, after a nail penetration triggers a thermal runaway in one cell (2), a distinct heat propagation phenomenon occurs.
[0108] In this embodiment of the present invention, the energy (Q) of the cell (2) is generally in the range of 576 to 3456 kJ, and the volume (V) of the heat-absorbing material (12) is in the range of 20000 to 300000 mm³, ensuring that there is sufficient heat-absorbing material (12) to absorb heat released by the cell (2) and ensuring that the volume energy density reduction rate of the battery assembly is within a specific range, thereby improving the integration level and energy density of the battery assembly. The volume of the heat-absorbing material (12) is V = (x - a * n * x1)S.
[0109] The present invention further provides a power consumption system comprising the aforementioned battery assembly. The power consumption system may be, for example, a vehicle or an energy storage system. Since the battery assembly of the present invention is mounted on the power consumption system, the battery assembly within the power consumption system has good safety while satisfying heat absorption requirements.
[0110] The following embodiments further describe a heat-absorbing unit (1) and a power consumption system according to the present invention. These embodiments are implemented based on the technical solution of the present invention, and detailed implementation and specific operation processes are provided. However, the scope of protection of the present invention is not limited to the following embodiments.
[0111] The experimental methods in the following examples are all conventional methods in the art unless specifically otherwise specified. Unless otherwise specified, all experimental materials used in the following examples are commercially available.
[0112] Examples 1 to 31 and Comparative Examples 1 to 7
[0113] The battery assembly illustrated in FIG. 1 is configured to include a plurality of cells (2) and a heat-absorbing unit (1). One heat-absorbing unit (1) is arranged for every two cells (2). The heat-absorbing unit (1) includes a frame (11) and a heat-absorbing material (12). The heat-absorbing material (12) is a hydrogel. The frame (11) is a single-layer or multi-layer structure. Each layer of the frame (11) includes multiple holes (13) penetrating the frame (11) in the thickness direction of the frame (11). The hydrogel fills the holes (13). The frame (11) and the heat-absorbing material (12) are encapsulated within an encapsulation film (14) (an aluminum-plastic film). Table 1 below shows the thickness (x) of the heat-absorbing unit (1), the gap (d) between the cells (2), the area ratio (a) of the frame (11) on the surface of the heat-absorbing unit (1), the Young's modulus (E1) of the frame (11), the heat absorption area (S) on the surface of the heat-absorbing unit (1), the pressure (F1) supported by the frame (11), the thickness (x1) of one layer of the frame (11), and the number (n) of layers of the frame (11) for each battery pack example.
[0114] x(mm) d(mm) a E1(GPa) S(㎟) F1(N) x1(mm) n Total thickness of the skeleton (11) Example 1 0.5 0.40 0.15 0.3 47790 45000.0 0.40 1.00 0.40 11.948 Example 2 0.5 0.40 0.10 1.5 47790 30000.0 0.20 4.00 0.80 29.869 Example 3 0.4 0.15 0.15 0.3 47790 45000.0 0.40 1.00 0.40 29.869 Example 4 0.1 0.03 0.15 0.3 47790 45000.0 0.10 1.00 0.10 33.453 Example 5 0.6 0.40 0.10 1.5 65762 30000.0 0.50 3.00 1.50 43.841 Example 6 0.5 0.40 0.30 0.3 47790 45000.0 0.10 2.00 0.20 47.790 Example 7 0.5 0.40 0.10 1.5 47790 30000.0 0.25 2.00 0.50 47.790 Example 8 0.5 0.40 0.10 1.5 47790 30000.0 0.40 1.00 0.40 59.738 Example 9 1.0 0.40 0.15 0.3 47790 45000.0 0.40 1.00 0.40 71.685 Example 10 0.5 0.30 0.10 1.5 47790 60000.0 0.25 1.00 0.25 95.580 Example 11 0.6 0.40 0.10 1.5 65762 30000.0 0.25 2.00 0.50 131.524 Example 12 0.5 0.30 0.30 0.3 47790 45000.0 0.10 1.00 0.10 191.160 Example 13 0.4 0.20 0.30 0.3 47790 45000.0 0.10 1.00 0.10 191.160 Example 14 0.6 0.40 0.10 1.5 65762 30000.0 0.03 10.00 0.30 219.207 Example 15 0.5 0.40 0.10 1.5 47790 30000.0 0.10 1.00 0.10 238.950 Example 16 0.6 0.40 0.10 1.5 65762 30000.0 0.13 0.50 0.25 263.048 Example 17 2.5 2.00 0.20 1.5 65762 45000.0 0.25 2.00 0.50 438.413 Example 18 0.5 0.40 0.20 1.5 47790 30000.0 0.10 1.00 0.10 477.900 Example 19 1.5 1.00 0.30 0.3 47790 45000.0 0.10 1.00 0.10 477.900 Example 20 2.5 2.00 0.30 0.3 47790 45000.0 0.10 1.00 0.10 477.900 Example 21 6.5 6.00 0.30 0.3 47790 45000.0 0.10 1.00 0.10 477.900 Example 22 0.5 0.30 0.40 0.75 47790 30000.0 0.05 4.00 0.20 477.900 Example 23 7 4.00 0.10 1.5 65762 30000.0 2.00 3.00 6.00 164.405 Example 24 0.6 0.30 0.20 1.5 65762 45000.0 0.25 1.00 0.25 526.096 Example 25 5 0.40 0.15 0.3 47790 45000.0 0.40 1.00 0.40 549.585 Example 26 0.5 0.40 0.10 1.5 47790 30000.0 0.01 4.00 0.04 597.375 Example 27 10 8.00 0.15 0.3 47790 45000.0 0.50 1.00 0.50 191.160 Example 28 2.5 2.00 0.20 1.5 65762 45000.0 0.25 1.00 0.25 876.827 Example 29 5 2.00 0.15 0.3 47790 45000.0 0.20 1.00 0.20 716.850 Example 30 0.51 0.40 0.15 0.3 47790 45000.0 0.25 2.00 0.50 10.514 Example 31 2.55 2.00 0.20 1.5 65762 45000.0 0.25 1.00 0.25 964.509 Comparative Example 1 2.5 2.00 0.10 0.2 65762 45000.0 2.00 1.00 2.00 7.307 Comparative Example 2 0.55 0.4 0.20 0.15 47790 45000.0 0.25 2.000 0.50 9.558 Comparative Example 3 0.5 0.2 0.50 1.20 65762 45000.0 0.25 1.00 0.25 1052.19 Comparative Example 4 1 0.3 0.50 1.5 47790 45000.0 0.5 1.00 0.50 1115.10 Comparative Example 5 0.6 0.3 0.30 1.5 65762 30000.0 0.025 1.00 0.03 11837.16 Comparative Example 6 0.6 0.4 0.3 1000 47790 45000.0 0.25 1.00 0.25 254880.00 Comparative Example 7 0.5 0.3 0.1 1000 47790 45000.0 0.10 1.00 0.10 212400.00
[0115] Test Example 1: Compression Test
[0116] Compression tests were performed on the cells (2) and heat-absorbing units (1) configured in Examples 1 to 31 and Comparative Examples 1 to 7. Specifically: 1. The battery assembly configured as above was placed in a compression device, and the compression device is a tensile testing machine;
[0117] 2. A compression force is applied to one of the cells (2) using a compression device, and the force is varied from 0 to the value of F1 recorded in Table 1, and the tensile testing machine generates a compression amount (x) corresponding to the pressure (F1) in real time to provide a compression deformation amount of the frame (11);
[0118] 3. The compressive strain of the skeleton (11) was calculated and recorded in Table 2; and
[0119] 4. The condition of the heat-absorbing unit (1) was observed and recorded in the compression test results of Table 2.
[0120] Test Example 2: Thermal Propagation Test
[0121] A nail penetration test was performed on the battery packs composed of Examples 1 to 31 and Comparative Examples 1 to 7 to test whether thermal propagation occurred after a nail penetration-triggered thermal runaway in one cell (2) (based on whether thermal runaway occurred in adjacent cells (2)). In addition, the maximum temperature of the cell (2) where thermal runaway was triggered by the nail penetration was monitored.
[0122] The test conditions are as follows:
[0123] (1) The State of Charge (SOC) was 100%, that is, fully charged;
[0124] (2) The temperature of the sample was 45℃ ± 2℃;
[0125] (3) A 5 mm flat steel needle was inserted into the cell (2) at a speed of 1 mm / s, and the insertion was stopped after thermal runaway occurred in the cell (2), and thermal runaway was determined when the voltage of the cell (2) dropped to 75%;
[0126] (4) After the experiment, observation continued until the temperature of the cell (2) dropped below 100℃; and
[0127] (5) It was determined whether thermal runaway had occurred in the cell (2) and the adjacent cell (2), and if the voltage of the adjacent cell (2) dropped to 75%, it was determined that thermal runaway had occurred, that is, that thermal propagation had occurred.
[0128] The test results are shown in Table 2 below.
[0129] Additionally, Experimental Example 2 can also be performed based on the apparatus shown in FIG. 8, and when applied to such an experimental apparatus, an internal cell (2) in the form of a battery assembly can be added. A thermal runaway test was performed on the battery assembly.
[0130] Test Example 3
[0131] Volume energy density test
[0132] The battery capacity of the battery pack was determined by performing charge and discharge tests on the obtained battery pack. The volumes of the cell (2) and the heat-absorbing unit (1) were measured and calculated. The volume energy density and volume energy density reduction rate of a single cell (2) were calculated using the following formula:
[0133] Volume energy density of a single cell (2) = Capacity of a single cell (2) / Volume of a single cell (2);
[0134] Volume energy density of the new single cell (2) = capacity of the single cell (2) / (volume of the single cell (2) + volume of the heat-absorbing unit (1); and
[0135] Volume energy density reduction rate = Volume energy density of single cell (2) - Volume energy density of new single cell (2).
[0136] The method for measuring the volume of the cell (2) and the volume of the heat-absorbing unit (1) is as follows: for a single cell (2) or heat-absorbing unit (1), the volume of the cell (2) can be obtained by measuring the length, width, and height of the cell (2), and the volume of the heat-absorbing unit (1) can be obtained by measuring the length, width, and height of the heat-absorbing unit (1).
[0137] Battery Capacity Test Method:
[0138] (1) At room temperature, charge the battery with a low current (e.g., 1 / 3C) to the cut-off voltage and leave it for 1 hour;
[0139] (2) Discharge the battery to the cut-off voltage with a constant current of 1 / 3C and leave it for 1 hour; and
[0140] (3) Steps 1 and 2 were repeated a total of 2 times, and the discharge capacity of the second cycle was recorded as the battery capacity.
[0141] In this test example, a lithium iron phosphate battery was used, and the cut-off voltage was 3.75V.
[0142] The results are shown in Table 2 below.
[0143] Example number Compression strain of the skeleton (11) Compression test results Volume of heat-absorbing material (12) Reduction rate of volume energy density of the assembly Thermal propagation test results Example 1 0.02092 No damage 21027.6 2.84% No heat propagation occurs Example 2 0.00418 No damage 20071.8 2.84% No heat propagation occurs Example 3 0.02092 No damage 16248.6 1.08% Heat propagation Example 4 0.02092 No damage 4062.15 0.22% Heat propagation Example 5 0.00304 No damage 29592.9 2.36% No heat propagation occurs Example 6 0.01046 No damage 21027.6 2.84% No heat propagation occurs Example 7 0.00418 No damage 21,505.5 2.84% No heat propagation occurs Example 8 0.00418 No damage 21983.4 2.84% No heat propagation occurs Example 9 0.02092 No damage 44922.6 2.84% No heat propagation occurs Example 10 0.00837 No damage 22,700.25 2.14% No heat propagation occurs Example 11 0.00304 No damage 36169.1 2.36% No heat propagation occurs Example 12 0.01046 No damage 22461.3 2.14% No heat propagation occurs Example 13 0.01046 No damage 17682.3 1.44% Heat propagation Example 14 0.00304 No damage 37484.34 2.36% No heat propagation occurs Example 15 0.00418 No damage 23417.1 2.84% No heat propagation occurs Example 16 0.00304 No damage 37813.15 2.36% No heat propagation occurs Example 17 0.00228 No damage 157828.8 10.78% No heat propagation occurs Example 18 0.00209 No damage 22939.2 2.84% No heat propagation occurs Example 19 0.01046 No damage 70251.3 6.80% No heat propagation occurs Example 20 0.01046 No damage 118041.3 12.74% No heat propagation occurs Example 21 0.01046 No damage 309201.3 30.46% No heat propagation occurs Example 22 0.00209 No damage 20071.8 2.14% No heat propagation occurs Example 23 0.00304 No damage 420876.8 19.46% No heat propagation occurs Example 24 0.00228 No damage 36169.1 1.78% No heat propagation occurs Example 25 0.02092 No damage 236082.6 2.84% No heat propagation occurs Example 26 0.00418 No damage 23703.84 2.84% No heat propagation occurs Example 27 0.02092 No damage 474315.75 36.87% No heat propagation occurs Example 28 0.00228 No damage 161116.9 10.78% No heat propagation occurs Example 29 0.02092 No damage 237516.3 12.74% No heat propagation occurs Example 30 0.02092 No damage 20788.65 2.84% No heat propagation occurs Example 31 0.00228 No damage 164405 10.78% No heat propagation occurs Comparative Example 1 0.03421 encapsulation damage 151252.6 10.78% Heat propagation Comparative Example 2 0.03139 encapsulation damage 21,505.5 2.84% Heat propagation Comparative Example 3 0.00114 Material Overflow 24660.75 1.44% Heat propagation Comparative Example 4 0.00126 Material Overflow 35842.5 2.14% Heat propagation Comparative Example 5 0.00101 Material Overflow 38963.985 2.14% Heat propagation Comparative Example 6 0.00000 Material Overflow 25089.75 2.84% Heat propagation Comparative Example 7 0.00001 Material Overflow 23417.1 2.14% Heat propagation
[0144] From the results of Table 2, it can be seen that, according to Examples 1 to 31, the heat-absorbing unit (1) configured within the parameter range according to the present invention has good mechanical properties. Specifically, the heat-absorbing unit (1) was not damaged in the compression test of the battery assembly. However, in Comparative Examples 1 to 7, the heat-absorbing unit (1) within the battery assembly When the value of is less than 10 or greater than 1000, in a compression test of the battery assembly, the heat-absorbing unit (1) suffers encapsulation damage (the aluminum-plastic film of the heat-absorbing unit (1) is damaged, and material overflows or leaks out from the damaged area) or material overflow (material is compressed out of the gap between the cells (2) due to the expansion of the cell (2), resulting in the heat-absorbing unit (1) being unable to absorb heat. From Examples 3, 4 and 13, it can be seen that when the battery energy is in the range of 537 to 3456 kJ and the volume of the heat-absorbing unit (1) is less than 20000 mm³, heat propagation occurs within the battery. The specific reason is that the amount of heat-absorbing material (12) within the heat-absorbing unit (1) is insufficient to satisfy the heat release of the battery, and thus heat runaway occurs in the adjacent cell (2). Additionally, from Examples 21 and 27, it can be seen that when the battery energy is in the range of 537 to 3456 kJ and the volume of the heat-absorbing unit (1) exceeds 300,000 mm³, heat propagation from adjacent cells (2) did not occur. However, the reduction rate of the volume energy density of the battery assembly exceeded 30%, and the volume energy density of the battery assembly was excessively low. Therefore, when the battery energy is in the range of 537 to 3456 kJ and the volume of the heat-absorbing unit (1) is greater than 20,000 and less than 300,000 mm³, it can be ensured that the heat-absorbing unit (1) has a sufficient volume to absorb heat generated by the cells (2) during thermal runaway, and also ensured that the reduction rate of the volume energy density of the battery assembly is maintained at a specific level (i.e., less than 30%) to maintain the volume energy density of the battery assembly. In addition, if the thickness of the heat-absorbing unit (1) within the battery assembly is adjusted to a desirable range (e.g., 0.1 to 10 mm), it can be ensured that the battery assembly has good safety and that the reduction rate of the volume energy density of the battery assembly is also significantly reduced.
[0145] Preferred embodiments of the present invention are described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications to the technical solutions of the present invention may be made, including combining various technical features in any other suitable manner. Such simple changes and combinations should also be considered as disclosed by the present invention and will all fall within the scope of protection of the present invention. Explanation of the symbols
[0146] 1: Heat-absorbing unit; 2: Cell; 11: Skeleton; 12: Heat-absorbing material; 13: Hole; 14: Encapsulation film; 3: Pressure sensor; 4: Insulation board; 5: Fixture baffle; 6: Nail penetration point.
Claims
Claim 1 As a battery assembly, the battery assembly comprises: a plurality of cells (2); and a heat-absorbing unit (1) — the heat-absorbing unit (1) is disposed between two adjacent cells (2) — and the heat-absorbing unit (1) comprises: a heat-absorbing material (12); and at least one layer of a frame (11) — the frame (11) has a plurality of holes (13) penetrating in the thickness direction of the frame (11), and the heat-absorbing material (12) fills the holes (13) — and the battery assembly satisfies the following conditions, Here, x is the thickness (in mm) of the heat-absorbing unit (1); d is the gap (in mm) between two adjacent cells (2); a is the ratio of the area of the orthographic projection of the frame (11) onto the surface of the heat-absorbing unit (1) in contact with the cell (2) to the area of the surface of the heat-absorbing unit (1) in contact with the cell (2); E1 is the Young's modulus (in GPa) of the frame (11); S is the surface area (in mm²) of the heat-absorbing unit (1) in contact with the cell (2); F1 is the pressure (in N) supported by the frame (11); x1 is the thickness (in mm) of one layer of the frame (11); n is the number of layers of the frame (11), n≥1, and n is an integer, battery assembly. Claim 2 A battery assembly according to claim 1, wherein the energy (Q) of the cell (2) is in the range of 576 to 3456 kJ. Claim 3 A battery assembly according to claim 1 or 2, wherein the volume (V) of the heat-absorbing material (12) is in the range of 20,000 to 300,000 mm³, and the volume (V) of the heat-absorbing material (12) satisfies: V = (x - a * n * x1)S. Claim 4 A battery assembly according to any one of claims 1 to 3, wherein the thickness (x) of the heat-absorbing unit (1) is in the range of 0.5 to 5 mm. Claim 5 A battery assembly according to any one of claims 1 to 4, wherein the gap (d) between two adjacent cells (2) is in the range of 0.3 to 3 mm. Claim 6 A battery assembly according to any one of claims 1 to 5, wherein the ratio (a) of the area of the orthographic projection of the frame (11) onto the surface of the heat-absorbing unit (1) in contact with the cell (2) to the area of the surface of the heat-absorbing unit (1) in contact with the cell (2) is in the range of 10% to 50%. Claim 7 A battery assembly according to any one of claims 1 to 6, wherein the Young's modulus (E1) of the frame (11) is 0.0001 to 100 GPa. Claim 8 A battery assembly according to any one of claims 1 to 7, wherein the surface area (S) of the heat-absorbing unit (1) in contact with the cell (2) is in the range of 5,000 to 300,000 mm². Claim 9 A battery assembly according to any one of claims 1 to 8, wherein the pressure (F1) supported by the frame (11) is in the range of 5,000 to 60,000 N. Claim 10 In any one of claims 1 to 9, the pressure (F1) supported by the frame (11) satisfies the following equation, and Here, F is the total pressure (in N units) supported by the surface of the heat-absorbing unit (1) in contact with the cell (2); E2 is the Young's modulus (in GPa units) of the heat-absorbing material (12); and a is the ratio of the area of the orthographic projection of the frame (11) onto the surface of the heat-absorbing unit (1) in contact with the cell (2) to the area of the surface of the heat-absorbing unit (1) in contact with the cell (2), battery assembly. Claim 11 A battery assembly according to any one of claims 1 to 10, wherein the thickness (x1) of one layer of the frame (11) is in the range of 0.025 to 2 mm. Claim 12 A battery assembly according to any one of claims 1 to 11, wherein the number (n) of the layers of the frame (11) is in the range of 1 to 10. Claim 13 A battery assembly according to any one of claims 1 to 12, wherein the thickness (x) of the heat-absorbing unit (1) is greater than or equal to the product of the thickness (x1) of one layer of the frame (11) and the number (n) of layers of the frame (11). Claim 14 A battery assembly according to any one of claims 1 to 13, wherein the total thickness of the frame (11) accounts for 1% to 100%, preferably 10% to 80%, of the thickness of the heat-absorbing unit (1). Claim 15 A battery assembly according to any one of claims 1 to 14, wherein the heat-absorbing unit (1) further comprises an encapsulating film (14) that encapsulates the frame (11) and the heat-absorbing material (12). Claim 16 A battery assembly according to any one of claims 1 to 15, wherein the holes (13) are evenly spaced in the thickness direction of the frame (11). Claim 17 A battery assembly according to any one of claims 1 to 16, wherein the ratio of the surface area of the heat-absorbing unit (1) in contact with the cell (2) to the surface area of the cell (2) in contact with the heat-absorbing unit (1) is 0.8 or more and 1 or less. Claim 18 A battery assembly according to any one of claims 1 to 17, wherein the battery assembly comprises at least two cell groups, the cell groups comprise N arranged cells (2), the heat-absorbing unit (1) is disposed between two adjacent cell groups, and the thickness (x) of the heat-absorbing unit (1) satisfies the following relationship: (0.5N ± b)mm ≤ x ≤ (5N ± b)mm, where b is a preset correction factor (in mm). Claim 19 A battery assembly according to any one of claims 1 to 18, wherein the phase change temperature of the heat-absorbing material (12) is 50°C to 200°C. Claim 20 A battery assembly according to claim 19, wherein the phase change temperature of the heat-absorbing material (12) is 70°C to 160°C. Claim 21 A battery assembly according to any one of claims 1 to 20, wherein the heat-absorbing material (12) is a hydrogel. Claim 22 A battery assembly according to any one of claims 1 to 21, wherein the plurality of holes (13) are evenly arranged along the extension direction of the frame (11). Claim 23 A power consumption system comprising a battery assembly according to any one of claims 1 to 22.