Pouch battery device and electric appliance

Abstract

The application relates to the new energy technology field and discloses a soft package battery device and an electric equipment, the soft package battery device comprising: a battery pack; a fixing strip comprising an extension section and a fixing section, the extension section being oppositely arranged with a second end face; the fixing section being arranged at two ends of the extension section along a first direction and being connected to two first end faces respectively; the extension section being provided with an elastic insulation layer at least partially on the outer periphery, the elastic insulation layer being located at least between the fixing strip and a shell; along a second direction, the size ratio of the fixing strip to the second end face is M; the thickness of the elastic insulation layer is D2 microns; the shell at least comprises an inner metal layer and an outer insulation layer covering the outer surface of the inner metal layer, the thickness of the outer insulation layer is D1 microns; and 14.4<=MxD1xD2<=40850 is satisfied. The soft package battery device provided by the application guarantees the insulation use safety of the battery and simultaneously improves the space utilization rate of the battery pack.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, specifically to a soft-pack battery device and electrical equipment. Background Technology

[0002] A pouch battery pack is formed by stacking multiple pouch battery cells. Because the casing of a pouch battery cell is relatively soft and lacks sufficient rigid support, it is prone to deformation. Therefore, the pouch battery pack needs to be secured during assembly. This is achieved by installing end plates on both sides of the stacking direction of the pouch battery cells, connecting the end plates with fixing strips, and applying pre-tension to ensure stable clamping of the pouch battery cells.

[0003] However, under vibration conditions, pouch battery packs may experience external short circuits, leading to external insulation failure and affecting their safety and lifespan. Summary of the Invention

[0004] In view of this, the present invention provides a pouch battery device and electrical equipment to solve the problem of easy insulation failure of pouch battery packs.

[0005] In a first aspect, the present invention provides a pouch battery device, comprising:

[0006] The battery pack includes multiple pouch battery cells arranged along a first direction; the battery pack includes two first end faces located at both ends of the first direction, and a second end face located between the two first end faces; the first end faces are perpendicular to the first direction; the pouch battery cell includes a housing and a cell disposed within the housing, and the second end face is disposed perpendicular to the first end face;

[0007] The fixing strip includes an extension section and a fixing section. The extension section is disposed opposite to the second end face. The fixing section is disposed at both ends of the extension section along the first direction and is respectively connected to the two first end faces.

[0008] The extension section is provided with an elastic insulating layer at least partially on its outer periphery, and the elastic insulating layer is located at least between the fixing strip and the housing.

[0009] The length direction of the soft-pack battery cell is the second direction, and the first direction is perpendicular to the second direction;

[0010] Along the second direction, the ratio of the dimension of the fixing strip to the dimension of the second end face is M; the thickness of the elastic insulating layer is D2μm;

[0011] The housing includes at least an inner metal layer and an outer insulating layer covering the outer surface of the inner metal layer, the thickness of which is D1μm;

[0012] It satisfies: 14.4≤M×D1×D2≤40850.

[0013] Beneficial effects: When the formula value of M×D1×D2 is too small, the buffering capacity between the fixing strip and the shell is insufficient and the contact area is too small, which increases the risk of stress concentration, weakens the insulation protection effect, and easily causes wear of the outer insulation layer and exposure of the inner metal layer, increasing the safety hazard of short circuit between the shell metal layer and the external metal structure, leading to thermal runaway of the battery. When the formula value of M×D1×D2 is too large, although the buffering and insulation performance is enhanced, the overall thickness of the insulation layer is large, and the fixing strip covers the side of the battery shell, resulting in poor heat dissipation capacity of the outer end face of the battery, uneven battery temperature rise, and redundant structural space, reducing the overall compactness and energy density of the battery pack.

[0014] Secondly, the present invention also provides an electrical appliance, comprising:

[0015] The electrical equipment body and the pouch battery device as described above are electrically connected.

[0016] Since electrical equipment includes pouch battery devices, which have the same effect as pouch battery devices, they will not be elaborated on here. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram showing the bottom view of the soft-pack battery device of the present invention;

[0019] Figure 2 This is a bottom view of the soft-pack battery device of the present invention;

[0020] Figure 3 for Figure 2 Schematic diagram of section AA;

[0021] Figure 4 for Figure 3 A magnified view of a portion of the image;

[0022] Figure 5 This is a schematic diagram of a single soft-pack battery cell of the present invention;

[0023] Figure 6 for Figure 5 Enlarged view of point A in the middle;

[0024] Figure 7 This is an exploded view of a single soft-pack battery cell of the present invention;

[0025] Figure 8 This is a schematic diagram of the unfolded shell of the present invention;

[0026] Figure 9 for Figure 8 Enlarged view of point B;

[0027] Figure 10 This is a cross-sectional view of a single soft-pack battery cell of the present invention;

[0028] Figure 11 This is a detailed enlarged view of the casing of the present invention;

[0029] Figure 12 This is a schematic diagram of the fixing strip of the present invention;

[0030] Figure 13 This is a schematic diagram of the fixing strip wrapping the first elastic insulating layer according to the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. Battery pack; 11. Soft-pack battery cell; 111. Casing; 1111. Outer insulating layer; 1112. Inner metal layer; 1113. Bending section; 1101. First casing surface; 1102. Second casing surface; 112. Battery cell; 113. Second insulating layer;

[0033] 101. First end face; 102. Second end face;

[0034] 2. Fixing strip; 21. Extension section; 22. Fixing section;

[0035] 3. Elastic insulation layer; 31. First elastic insulation layer; 32. Second elastic insulation layer. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] A pouch battery pack is formed by stacking multiple pouch battery cells. Because the casing of a pouch battery cell is relatively soft and lacks sufficient rigid support, it is prone to deformation. Therefore, the pouch battery pack needs to be secured during assembly. This is achieved by installing end plates on both sides of the stacking direction of the pouch battery cells, connecting the end plates with fixing strips, and applying pre-tension to ensure stable clamping of the pouch battery cells.

[0041] Studies have found that because the casing of a pouch battery cell has a multi-layered structure—an outer insulating layer and an inner metal layer—the insulating layer of the casing contacts the fixing strip during normal use, ensuring insulation. However, under long-term vibration conditions, the insulating layer of the casing may wear down due to friction, exposing the inner metal layer. Especially to avoid the fixing strip covering a large portion of the battery's second end face, which could affect the overall heat dissipation rate, when the fixing strip's size is limited, stress concentration at the bottom of the pouch battery cell is more likely. This causes friction between the fixing strip and the battery cell's casing, potentially damaging the outer nylon insulating layer and increasing the risk of the casing's metal layer contacting the fixing strip or other metal structures. This can lead to safety hazards such as short circuits and thermal runaway. Furthermore, when the fixing strip is made of metal, it can cause overlap between the battery casing and the fixing strip, posing a risk of insulation failure.

[0042] To mitigate the aforementioned risks, the pouch battery device provided in this embodiment reduces the risk of casing insulation failure by providing an elastic insulating layer around the outer periphery of the metal fixing strip. Simultaneously, by controlling the thickness of the elastic insulating layer, its proportion along the length of the fixing strip, and the thickness of the outer insulating layer of the pouch battery cell, the device ensures safe insulation during battery use and avoids difficulties in heat dissipation from the battery's interior to the exterior due to excessively large dimensions of the insulating layer and fixing strip, which could lead to poor temperature uniformity across multiple battery end faces. This also improves the space utilization rate of the battery pack.

[0043] To facilitate understanding of the technical solution of this application, several technical terms that may be involved in this application will first be explained:

[0044] Battery Pack 1:

[0045] Multiple battery cells with similar capacity and internal resistance are connected in series or in parallel to form a battery pack.

[0046] Casing 111:

[0047] The casing of a pouch battery is a multi-layered structure consisting of an outer insulating layer, a metal layer, and an inner insulating layer. The outer insulating layer can be made of one or more materials such as polycaprolactam (nylon 6), PET (polyethylene terephthalate), or polybutylene succinate. The metal layer can be made of one or more metals or alloys such as aluminum, aluminum alloy, copper, or nickel. The inner insulating layer can be made of one or more materials such as polypropylene film (PP) or cast polypropylene film (CPP).

[0048] Cell 112:

[0049] A battery cell is the component in a battery where electrochemical reactions occur; it is the smallest unit in a battery capable of performing electrochemical reactions such as charging and discharging. A battery cell is the basic unit of a battery and typically includes a positive electrode, a negative electrode, and a separator. Lithium-ion battery cells primarily function by the movement of lithium ions between the positive and negative electrodes. In cylindrical cells, a three-layer thin-film structure is wound into a cylindrical electrode assembly, while in cuboid cells, the thin-film structure is wound or stacked into an electrode assembly with a roughly cuboid shape.

[0050] Extreme film:

[0051] Including positive and negative electrodes, let's first talk about the positive electrode:

[0052] The positive electrode is one of the core components in a battery that carries the positive electrode active material. During charging, metal ions (such as lithium ions) are released from the crystal lattice of the positive electrode active material (oxidation reaction), migrate through the electrolyte, and intercalate into the negative electrode. During discharging, metal ions (such as lithium ions in a lithium battery) are released from the negative electrode and intercalated into the crystal lattice of the positive electrode active material (reduction reaction), thus realizing the storage and release of lithium ions.

[0053] A positive electrode generally includes a positive current collector and a positive active material layer. The positive active material layer is coated on at least one surface of the positive current collector and includes: a positive active material, a conductive agent, and a binder. The positive active material includes, but is not limited to, at least one of the following: lithium phosphates, lithium transition metal oxides and their respective modified compounds, or other conventional materials that can be used as positive electrode active materials in batteries. These positive active materials can be used alone or in combination. Lithium phosphates include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (also abbreviated as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (e.g., LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (e.g., LiNi). 1 / 3 Co 1 / 3Mn 1 / 3 O2 (also known as NCM333), LiNi 0.5 Co 0.2 Mn 0.3O2 (Also known as NCM523), LiNi 0.5 Co 0.25 Mn 0.25O2 (Also known as NCM211), LiNi 0.6 Co 0.2 Mn 0.2O2 (Also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1O2 (Also known as NCM811)), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05O2 At least one of the following: ) and its modified compounds.

[0054] The positive electrode conductive agent includes, but is not limited to, one or more combinations of graphite, superconducting carbon, carbon black (such as acetylene black, Ketjen black, Super P, etc.), carbon nanotubes, graphene and carbon nanofibers.

[0055] The positive electrode binder includes, but is not limited to, one or more combinations of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, carboxymethyl chitosan, etc.

[0056] Secondly, regarding the negative electrode:

[0057] During battery charging, active ions (such as Li) from the positive electrode are embedded in the negative electrode, while electrons from the positive electrode are transferred to the negative electrode through an external circuit to maintain charge balance. During discharge, active ions (such as Li) previously embedded in the negative electrode can be released, while electrons from the negative electrode are transferred to the positive electrode through an external circuit to maintain charge balance, thus achieving energy storage and release.

[0058] The negative electrode sheet includes a negative electrode current collector and a negative electrode active layer disposed on at least one surface of the negative electrode current collector. The negative electrode current collector is a conductive metal foil, which can be made of stainless steel, copper, aluminum, nickel, carbon electrodes, or titanium with a silver-plated surface. 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 alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). The negative electrode active layer includes a negative electrode active material, a conductive agent, and a binder.

[0059] The negative electrode active material can be carbon-based materials such as graphite, porous carbon, hard carbon, soft carbon, and mesophase carbon microspheres, or silicon-based materials such as elemental silicon, silicon oxides, silicon-carbon composites, and silicon-nitrogen composites. The conductive agent can be conductive carbon black, carbon nanotubes, etc., and the binder can be styrene-butadiene rubber, polyacrylic acid, etc.

[0060] The molding and sealing process of housing 111 is as follows:

[0061] (1) Molding process. Cut the initial sheet material according to the design dimensions of the shell 111. Using a molding die, under heating, punch out recesses on the initial sheet material to accommodate the core, forming the initial packaging shell. The depth and number of recesses need to be determined according to the thickness of the battery cell. Generally, a single recess is chosen when the battery cell is thin, and a double recess is chosen when the battery cell is thick. (2) Top and side sealing process. First, place the wound core into the punched recesses, and then fold the initial packaging shell in half along the fold line. Place the packaging shell and the core together in the fixture, and perform top and side sealing in the top and side sealing machine. During sealing, the two sealing heads have a certain temperature. When they are closed, they are pressed on the packaging shell, and the PP layer of the packaging shell melts and sticks together to complete the sealing.

[0062] The following is combined Figures 1 to 13 The following describes embodiments of the present invention.

[0063] According to an embodiment of the present invention, in one aspect, a pouch battery device is provided, comprising:

[0064] The battery pack 1 includes a plurality of pouch battery cells 11 arranged along a first direction; the battery pack 1 includes two first end faces 101 located at both ends of the first direction, and a second end face 102 located between the two first end faces 101; the first end faces 101 are perpendicular to the first direction; the pouch battery cell 11 includes a housing 111 and a cell 112 disposed in the housing 111, and the second end face 102 is disposed perpendicular to the first end face 101;

[0065] The fixing strip 2 includes an extension section 21 and a fixing section 22. The extension section 21 is disposed opposite to the second end face 102. The fixing section 22 is disposed at both ends of the extension section 21 along the first direction and is respectively connected to the two first end faces 101.

[0066] At least a portion of the outer periphery of the extension section 21 is provided with an elastic insulating layer 3, and the elastic insulating layer 3 is located at least between the fixing strip 2 and the housing 111;

[0067] The length direction of the soft-pack battery cell 11 is the second direction, and the first direction is perpendicular to the second direction;

[0068] Along the second direction, the ratio of the size of the fixing strip 2 to the size of the second end face 102 is M; the thickness of the elastic insulating layer 3 is D2μm;

[0069] The housing 111 includes at least an inner metal layer 1112 and an outer insulating layer 1111 covering the outer surface of the inner metal layer 1112, wherein the thickness of the outer insulating layer 1111 is D1μm;

[0070] It satisfies: 14.4≤M×D1×D2≤40850.

[0071] The battery pack 1 in this embodiment includes a plurality of pouch battery cells 11 arranged along a first direction. A pouch battery cell 11 refers to a battery that uses a soft outer shell as the encapsulation material. For example, the shell 111 of the pouch battery cell 11 includes an aluminum-plastic film, which comprises a multi-layer structure composed of an outer nylon layer, an intermediate metal layer, and an inner heat-sealing layer. In this embodiment, the inner metal layer 1112 is the intermediate metal layer, typically aluminum foil, which has good thermal and electrical conductivity.

[0072] The soft-pack battery cell 11 has a battery cell inside its casing 111. The battery cell includes multiple electrode sheets stacked along a first direction. A separator is provided between the electrode sheets to achieve electrical isolation. The battery cell is connected to an external circuit through tabs.

[0073] In this embodiment, the pouch cell 11 is constructed in a cuboid shape, and multiple pouch cells 11 are arranged along a first direction, wherein the first direction may be consistent with the thickness direction of the pouch cell 11, thereby effectively improving the energy density of the battery pack when stacked.

[0074] The battery pack 1 includes two first end faces 101 located at both ends of a first direction and a second end face 102 connecting the two first end faces 101. The first end face 101 corresponds to the large surface of the soft-pack battery cell 11, and the second end face 102 corresponds to the small surface of the long side of the soft-pack battery cell 11. The first direction is perpendicular to the large surface, and the second direction is the length direction of the soft-pack battery cell 11.

[0075] By setting a fixing strip 2, multiple soft-pack battery cells 11 can be fixed into an integral structure. The fixing strip 2 extends along the first direction, and its extension section 21 is attached to the outside of the second end face 102. The fixing section 22 is respectively connected to the two first end faces 101 to achieve clamping and fixing of the soft-pack battery cells 11.

[0076] In this embodiment, the fixing strip 2 can be U-shaped or U-shaped, surrounding the battery pack 1. A fixing plate can also be provided around the outer periphery of the battery pack 1. The battery pack 1 includes two opposite sides along a first direction. The fixing plate includes a first fixing plate and a second fixing plate (not shown in the figure), which are respectively disposed on the two opposite sides of the battery pack 1 along the first direction. The two ends of the fixing strip 2 are respectively fixedly connected to the first fixing plate and the second fixing plate. The connection method between the fixing strip 2 and the first fixing plate and / or the second fixing plate is riveting. Riveting technology can achieve a high-strength, high-reliability connection, suitable for mass production scenarios, and does not require additional anti-loosening structures. As a variation, the connection method between the fixing strip 2 and the first fixing plate and / or the second fixing plate can also be bolted, welded, or adhesive.

[0077] It should be noted that the fixing plate is disposed on at least one surface of the battery pack 1 to constrain the battery pack 1. The pouch battery casing has a thin-film structure with relatively low strength. During charging and discharging, the fixing plate is needed to constrain the pouch battery and prevent excessive expansion. In addition, the fixing plate also protects the individual pouch battery cells from external impacts and pressure directly acting on the low-strength pouch battery casing, thus reinforcing the safety of the battery pack. The fixing plate can be made of copper, iron, aluminum, steel, stainless steel, aluminum alloy, plastic, etc., or other metallic materials or composite materials of metals and non-metals; it can be made of engineering plastics, fiberglass, or carbon fiber; it can be made from aluminum alloy sheets through extrusion and / or machine processing. A common structure is a flat plate structure with a certain thickness, typically 2mm to 25mm, to meet the strength requirements of the battery device. A thinner thickness cannot meet the structural strength requirements, while a thicker thickness affects the energy density of the battery device.

[0078] It should be noted that the fixing strip 2 is used to fix the surface of the pouch battery pack where no fixing plate is installed. The fixing strip 2 does not completely cover the surface; it is also used when a portion of the pouch battery casing needs to be exposed for subsequent installation of a heat exchange structure. The fixing strip 2 is fixed to the fixing plate, and the fixing methods include, but are not limited to, welding, riveting, and screwing. The fixing strip 2 is usually made of a strip of metal, and the material can be copper, iron, aluminum, steel, stainless steel, aluminum alloy, etc., preferably the same material as the fixing plate.

[0079] To prevent short circuits between the fixing strip 2 and the soft-pack battery casing, an insulating protective layer can be provided at least at the end of the fixing strip 2 facing the soft-pack battery casing. This can be achieved by providing an insulating component, an insulating film, or using insulating spraying or other processes to create the insulating protective layer.

[0080] Examples of insulating film components: polyester film (PET, Polyethylene Terephthalate), polyimide (PI), polypropylene (PP), or polyethylene (PE). Examples of insulating coating components: (1) modified epoxy resin; (2) polyacrylate; (3) polyethylene phthalate (PET); (4) insulating materials include oil-based insulating resin or water-based insulating resin as the main material. The main material of insulating resin includes epoxy resin, acrylic resin, polyurethane resin, hydroxyl acrylic resin, and other multifunctional resins; various additives may also be included in the insulating material, such as photoinitiators, reactive diluents, flame retardants, wetting agents, leveling agents, defoamers, etc.; (5) polyimide coating or insulating coating formed by polymers such as polyimide (PI) and epoxy resin; (6) styrene-butadiene rubber latex.

[0081] In this embodiment, the elastic insulating layer 3 can specifically be the aforementioned insulating protective layer. The elastic insulating layer 3 can include one or more of the following: an insulating component, an insulating film, and an insulating spray coating.

[0082] In addition, the elastic insulating layer can also be composed of an adhesive layer, used to bond and fix adjacent structural components, or have a certain thermal conductivity. Materials / Composition: (1) The structural adhesive can use insulating materials as the base material, that is, non-conductive adhesives, such as epoxy resin, silicone rubber, polyurethane, etc. (2) The structural adhesive can also be epoxy resin structural adhesive and polyurethane structural adhesive. (3) The structural adhesive can be a two-component epoxy resin structural adhesive, a two-component acrylic structural adhesive, a two-component polyurethane structural adhesive or a two-component silane structural adhesive.

[0083] The thickness of the fixing strip 2 can range from 1.2mm to 10mm.

[0084] The thickness of the elastic insulating layer 3 can range from 0.03mm to 5mm.

[0085] The extension section 21 and the second end face 102 form a buffer contact through the elastic insulating layer 3, which effectively reduces the risk of damage to the surface of the housing 111 caused by friction of the fixing strip 2, and avoids stress concentration caused by vibration or thermal expansion and contraction.

[0086] It should be noted that, along the second direction, the ratio of the size of the fixing strip 2 to the size of the second end face 102 is M; where, considering that there are multiple fixing strips 2, the size of the fixing strip 2 along the second direction specifically refers to the sum of the sizes of all fixing strips 2 along the second direction.

[0087] Along the second direction, when the ratio M between the size of the fixing strip 2 and the size of the second end face 102 is too small, the contact area between the fixing strip 2 and the shell 111 of the soft-pack battery cell 11 is insufficient, which makes it easier for stress concentration to occur at the bottom of the soft-pack battery cell 11, thereby aggravating the wear of the outer insulating layer 1111 of the shell 111 and increasing the risk of contact between the inner metal layer 1112 of the shell 111 and the fixing strip 2 or other metal structures, thus causing safety hazards such as short circuit and thermal runaway; while when the ratio M between the size of the fixing strip 2 and the size of the second end face 102 is too large, it will cause the fixing strip 2 to cover an excessively large area in the second direction, affecting the overall structural compactness, increasing the volume redundancy of the battery pack, and reducing the space utilization rate.

[0088] When the thickness D2 of the elastic insulating layer 3 is too small, the buffering effect is weakened, making it difficult to effectively absorb the stress generated by vibration or thermal expansion and contraction. This leads to an increase in the contact pressure between the shell 111 and the fixing strip 2, exacerbating the wear of the outer insulating layer 1111 and increasing the risk of exposure of the inner metal layer 1112. When the thickness D2 of the elastic insulating layer 3 is too large, although the buffering performance is enhanced, it increases the overall size of the battery pack 1, reduces the space utilization, and may cause the fixing strip 2 to deform during assembly, affecting the uniform distribution of clamping force. This leads to a decrease in the stability of the fixing structure, resulting in a reduction in the positioning accuracy of the soft-pack battery cell 11 in the first direction and affecting the stacking consistency.

[0089] When the thickness D1 of the outer insulating layer 1111 is too small, its insulation performance decreases and it is easily damaged due to mechanical friction or stress concentration, which in turn exposes the inner metal layer 1112, making it difficult to effectively isolate the electrical contact between the inner metal layer 1112 and the external structure, increasing the risk of short circuit. When the thickness D1 of the outer insulating layer 1111 is too large, although the insulation reliability is improved, it will compress the internal cell space and reduce the energy density.

[0090] In summary, the ratio M between the dimensions of the fixing strip 2 and the second end face 102 along the second direction, the thickness D2 of the elastic insulating layer 3, and the thickness D1 of the outer insulating layer 1111 need to be optimized in a coordinated manner. When the formula value of M×D1×D2 is too small, the buffering capacity between the fixing strip 2 and the shell 111 is insufficient and the contact area is too small, leading to an increased risk of stress concentration, weakened insulation protection, and easy wear of the outer insulating layer 1111 and exposure of the inner metal layer 1112. This increases the safety hazard of short circuits between the shell metal layer and the external metal structure, potentially causing thermal runaway of the battery. Conversely, when the formula value of M×D1×D2 is too large, although the buffering and insulation performance is enhanced, the overall thickness of the insulating layer is large, and the fixing strip covers the side of the battery shell, resulting in poor heat dissipation capacity of the outer end face of the battery, uneven battery temperature rise, and poor overall heat dissipation effect of the battery. This also leads to poor heat dissipation consistency of individual batteries and redundant structural space, reducing the overall compactness and energy density of the battery pack. By reasonably controlling the range of values ​​for M×D1×D2, the contradiction between insulation performance and space utilization can be effectively balanced.

[0091] In this embodiment, the value of M is in the range of 0.03≤M≤0.45.

[0092] In this embodiment, the value range of D1um is 10μm≤D1um≤40μm.

[0093] In this embodiment, the value of D2um ranges from 30μm ≤ D2um ≤ 2500μm. It should be noted that the value of D2um can include the thickness of the insulating tape used alone, or it can include the sum of the thicknesses of the insulating tape and the thermally conductive adhesive.

[0094] In this embodiment, the value range of the formula M×D1×D2 is 14.4≤M×D1×D2≤40850.

[0095] As a further optimization, the value range of the formula M×D1×D2 is 56≤M×D1×D2≤28296.

[0096] For example, in this embodiment, the value of M×D1×D2 can be 14.4 or 56 or 210 or 540 or 1043 or 2840 or 5347 or 9875 or 10258 or 13687 or 18752 or 28296 or 31850 or 36421 or 40850, etc., or it can be any range formed by any two of the above values.

[0097] It should be noted that the measurement methods for D1um and D2um are as follows: Use measuring instruments such as micrometers or calipers to measure parameters such as length, width, distance, and thickness.

[0098] The fabrication method of the soft-pack battery device in this embodiment is as follows:

[0099] (1) Preparation of the positive electrode:

[0100] The positive electrode active material, conductive agent acetylene black, and binder PVDF are mixed, and solvent NMP is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, air-dried at room temperature, and then transferred to an oven for further drying. Finally, it is cold-pressed and slit to obtain the positive electrode sheet. Specifically, the mass ratio of positive electrode active material: conductive agent: binder satisfies (92~98):(4~1):(4~1).

[0101] (2) Preparation of negative electrode:

[0102] The negative electrode active material, conductive agent acetylene black, thickener CMC, and binder SBR are mixed, and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector copper foil, air-dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the negative electrode sheet is obtained. The ratio of negative electrode active material: conductive agent: thickener: binder satisfies (90~96): (4~2): (2~1): (4~1).

[0103] (3) Preparation of electrolyte:

[0104] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0105] (4) Preparation of the diaphragm:

[0106] Polyethylene film is selected as the diaphragm.

[0107] (5) Preparation of pouch cells:

[0108] The positive electrode, separator, and negative electrode are stacked in sequence to form a bare battery cell. This bare cell is then placed in a pouch battery casing made of aluminum-plastic film. The first inner insulating layer of the aluminum-plastic film casing is made of cast polypropylene film (CPP), the second metal layer is made of aluminum, and the third outer insulating layer is made of polycaprolactam (nylon 6). The battery is dried, injected with electrolyte, and then encapsulated, allowed to stand, formed, and volume-adjusted to obtain the pouch battery.

[0109] The positive electrode active material can be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate; the negative electrode active material can be selected from one or more negative electrode active main materials, such as artificial graphite, natural graphite, silicon carbide, silicon oxide, and lithium titanate.

[0110] (6) Assembly of the pouch battery device:

[0111] After connecting multiple pouch batteries in series or parallel to form a battery pack, the battery pack is combined with a fixing strip to assemble a pouch battery device.

[0112] Referring to Table 1 below, through several embodiments and comparative tests, the number of batteries in the shell and fixing strip of the provided soft-pack battery device was tested, as well as the maximum temperature difference of the soft-pack battery device was tested to verify its qualification.

[0113] Table 1

[0114]

[0115] Regarding Table 1 above, the explanation is as follows:

[0116] Performance 1: Test the number of batteries with conductive connection between the casing and the fixing strip, using the following method:

[0117] Following the battery fabrication method described above, corresponding pouch cells were prepared for each embodiment and comparative example. Twenty pouch cells were connected in series to form a pouch cell device, with all other test conditions remaining consistent. The pouch cell device was mounted on a vibration table according to GB / T2423.43. The testing process was conducted according to GB / T2423.56. Random and fixed-frequency vibration loads were applied in each direction, preferably in the following order: random z-axis, fixed-frequency z-axis, random y-axis, fixed-frequency y-axis, random x-axis, fixed-frequency x-axis (the line connecting the front and rear of the pouch cell device is the x-axis direction, and another horizontal direction perpendicular to the x-axis is the y-axis direction). The vibration frequency, power spectral density (PSD), and vibration time are shown in the table below.

[0118]

[0119] After vibration, the pouch battery assembly was placed at room temperature for 1 hour. Then, the elastic insulation layer on the second end face of the fixing strip away from the battery pack was scraped off, exposing the metal part as the first test point. In the pouch battery assembly, the outer insulation layer on the side of the shell of each pouch battery not opposite the fixing strip was scraped off, exposing the metal layer as the second test point. Using the resistance setting of a Fluke 17B+ digital multimeter, the resistance between the second test point of each pouch battery and the first test point on the fixing strip was measured. If the resistance is close to infinity, it indicates no insulation failure. If the resistance value can be read, it is considered an insulation failure. If more than two batteries have insulation failures, the assembly is considered unqualified; if two or fewer batteries have insulation failures, the assembly is considered qualified; if no batteries have insulation failures, the assembly is considered good.

[0120] Performance 2: The test method for whether the maximum temperature difference of the soft-pack battery device meets the requirements is as follows:

[0121] Following the battery fabrication method described above, corresponding pouch cells were prepared for each embodiment and comparative example, with the cell dimensions remaining consistent across all pouch cells. Twelve pouch cells were connected in series to form a pouch cell device. Temperature sensors were installed on the outermost two pouch cells, one at the center of the large side facing outwards from the battery device, and the other at the center of the side surface opposite the fixing strip; a total of four temperature sensors were installed in each battery device. Then, a heat exchange plate was installed on the side of the battery device where the fixing strip was located. The heat exchange plate was made of double-layer brazed stainless steel cold plate and contained liquid-cooled channels through which a heat exchange medium, ethylene glycol aqueous solution, was circulated. The heat exchange plate was bonded to the surface of the pouch cell device using thermally conductive structural adhesive.

[0122] All other test conditions remained consistent. The pouch battery device was placed at room temperature (20°C) until thermal equilibrium was reached. At room temperature, the pouch battery device was charged at a constant current of 0.33C to the upper limit voltage, then charged at a constant voltage of 0.33C until the current dropped to 0.05C. After standing for 30 minutes, the pouch battery device was discharged at a constant current of 0.33C to the lower limit voltage. The temperature measured by the temperature sensor during this process was recorded. The difference between the highest and lowest recorded temperatures at the same time point was calculated as the maximum temperature difference of the pouch battery device. If the maximum temperature difference of the pouch battery device was greater than 5°C, it was considered unqualified; if the maximum temperature difference was less than or equal to 5°C but greater than 3°C, it was considered qualified; if the maximum temperature difference was less than or equal to 3°C, it was considered good.

[0123] When the positive electrode active material of the pouch battery is nickel-cobalt-manganese ternary, the upper limit voltage of the pouch battery device is 4.25V×12=51V, and the lower limit voltage is 2.5V×12=30V; when the positive electrode active material of the pouch battery is lithium iron phosphate, the upper limit voltage of the pouch battery device is 3.6V×12=43.2V, and the lower limit voltage is 2.5V×12=30V.

[0124] In this test, the active material for the positive electrode of the pouch battery was selected from a nickel-cobalt-manganese ternary LiNi alloy. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and the ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0125] Regarding the test results, referring to Table 1 above, the explanation is as follows:

[0126] As can be seen from Examples 1-18, when the formula value of M×D1×D2 satisfies the range 9≤M×D1×D2≤45000, the test results of the number of batteries connected between the shell and the fixing strip are all good or qualified, and no unqualified results are found; the test results of whether the maximum temperature difference of the soft-pack battery device is qualified are all good or qualified, and no unqualified results are found; the performance requirements are met.

[0127] In Comparative Examples 1 and 2, the value of the formula M×D1×D2 was below the lower limit. The test result for the number of batteries connected between the casing and the fixing strip was unqualified, failing to meet performance requirements. In Comparative Example 3, the value of the formula M×D1×D2 exceeded the upper limit. The test result for the maximum temperature difference of the pouch battery device was unqualified, failing to meet performance requirements.

[0128] In some embodiments, combined with Figure 5 , Figure 6 , Figure 8 , Figure 9 As shown, the housing 111 includes a first housing surface 1101 opposite to the second end face 102, and the first housing surface 1101 is formed with a bent portion 1113;

[0129] The bent portion 1113 is formed by partially overlapping the first housing surface 1101; the bent portion 1113 extends along the second direction.

[0130] The housing 111 includes a first housing surface 1101 opposite to the second end face 102. The first housing surface 1101 is also the long side face of the housing 111. The first housing surface 1101 is adapted to be fitted with the fixing strip 2.

[0131] The first housing surface 1101 has a bent portion 1113, which is formed by partial overlap of the first housing surface 1101. That is, the bent portion 1113 can be formed by a portion of the first housing surface 1101 protruding or recessing in a third direction to form a partial double-layer structure. On the one hand, it acts as a reinforcing rib to enhance the mechanical strength of the housing 111 in the area of ​​the first housing surface 1101; on the other hand, it makes the first housing surface 1101 form an uneven area, reducing the contact area between the first housing surface 1101 and the fixing strip 2, thereby increasing the insulation distance between the battery cell 112 and the fixing strip 2.

[0132] Specifically, when the bent portion 1113 protrudes, a gap is formed between it and the fixing strip 2, increasing the insulation distance between the first housing surface 1101 and the fixing strip 2, thereby improving insulation reliability; when the bent portion 1113 is recessed, the bent portion 1113 can support the internal battery cell 112, increasing the insulation distance between the battery cell 112 and the fixing strip 2, thereby further reducing the risk of short circuit.

[0133] In some embodiments, the bent portion 1113 is located at the middle of the first housing surface 1101 along a first direction.

[0134] Combination Figure 8 As shown, the housing 111 of this embodiment includes two punched holes of the same depth, which facilitates the housing 112 to be accommodated in the housing 111. When the mold is closed, the two punched holes are symmetrically pressed together, so that the housing 111 forms a closed cavity to stably accommodate the housing 112. In order to facilitate the mold closing of the two punched holes, the bending part 1113 is arranged in the middle of the first housing surface 1101 along the first direction, so that the punched holes on both sides are precisely aligned at the bending part 1113 during the mold closing process, thereby improving the symmetry of the housing structure and the assembly accuracy.

[0135] In some other embodiments, the bent portion 1113 is disposed off the centerline of the first housing surface 1101 along the first direction, satisfying: D2μm≥30μm.

[0136] As a variation, the housing 111 may also include two punches of different depths, or have punches on only one side and a flat surface on the other side. In this case, the bending part 1113 is set off from the centerline along the first direction, which can realize asymmetrical mold positioning, ensure guidance during assembly, and adapt to different cell layouts or installation space requirements.

[0137] At this time, the thickness D2 of the elastic insulation layer 3 needs to be appropriately increased to compensate for the assembly gap caused by the offset of the bending part 1113, and to ensure that the battery cell 112 and the fixing strip 2 maintain reliable insulation performance; at the same time, stress concentration caused by the asymmetry of the housing mold is avoided, and the risk of the fixing strip 2 causing damage to the surface of the housing 111 due to friction is reduced.

[0138] In some embodiments, the bent portion 1113 is formed by the first housing surface 1101 protruding toward the second end surface 102.

[0139] The bending portion 1113 is specifically a protruding structure formed along the middle of the first housing surface 1101 toward the second end surface 102. The protruding structure increases the bending stiffness of the housing while increasing the insulation distance between the first housing surface 1101 and the fixing strip 2, thereby improving the insulation reliability.

[0140] Optionally, the cross-sectional shape of the protruding structure can be arc-shaped, trapezoidal, or U-shaped, etc.

[0141] In some embodiments, combined with Figure 10 As shown, the housing 111 includes a first housing surface 1101 opposite to the second end face 102, and the first housing surface 1101 is provided with a second insulating layer 113 in at least a portion of its area;

[0142] The housing 111 also includes a second housing surface 1102 that is perpendicular to the first direction and adjacent to the first housing surface 1101, and the second insulating layer 113 extends to the second housing surface 1102.

[0143] The first housing surface 1101, which is the long side face of the housing 111, is effectively covered by a second insulating layer 113 in at least a part of the first housing surface 1101. This increases the insulation effect between the first housing surface 1101 and the fixing strip 2, effectively preventing safety risks caused by partial discharge or short circuit. At the same time, the second insulating layer 113 extends to the adjacent second housing surface 1102, which can avoid local insulation weakness caused by contact between the fixing strip 2 and the edge of the housing 111 during the assembly process.

[0144] The second insulating layer 113 can be a restraining tape pasted on the outside of the housing 111, or an outer insulating film.

[0145] In some embodiments, along a third direction, the second insulating layer 113 at least partially overlaps with the fixing strip 2 in projection;

[0146] The third direction is perpendicular to the first and second directions.

[0147] Along the third direction, the second insulating layer 113 at least partially overlaps with the fixing strip 2 in projection, thereby ensuring that the critical contact area between the fixing strip 2 and the housing 111 is effectively covered, separating the fixing strip 2 from the housing 111, and improving the overall insulation safety.

[0148] The third direction can specifically be the width direction of the soft-pack battery cell 11.

[0149] In some embodiments, the following conditions are met: 10μm≤D1μm≤40μm, and / or, 30μm≤D2μm≤2500μm.

[0150] When the thickness D2 of the elastic insulating layer 3 is too small, the buffering effect is weakened, making it difficult to effectively absorb the stress generated by vibration or thermal expansion and contraction. This leads to an increase in the contact pressure between the shell 111 and the fixing strip 2, exacerbating the wear of the outer insulating layer 1111 and increasing the risk of exposure of the inner metal layer 1112. When the thickness D2 of the elastic insulating layer 3 is too large, although the buffering performance is enhanced, it increases the overall size of the battery pack 1, reduces the space utilization, and may cause the fixing strip 2 to deform during assembly, affecting the uniform distribution of clamping force. This leads to a decrease in the stability of the fixing structure, resulting in a reduction in the positioning accuracy of the soft-pack battery cell 11 in the first direction and affecting the stacking consistency.

[0151] When the thickness D1 of the outer insulating layer 1111 is too small, its insulation performance decreases and it is easily damaged due to mechanical friction or stress concentration, which in turn exposes the inner metal layer 1112, making it difficult to effectively isolate the electrical contact between the inner metal layer 1112 and the external structure, increasing the risk of short circuit. When the thickness D1 of the outer insulating layer 1111 is too large, although the insulation reliability is improved, it will compress the internal cell space and reduce the energy density.

[0152] For example, in this embodiment, the value of D1μm can be 10μm, 14μm, 18μm, 22μm, 28μm, 32μm, or 40μm, or it can be any range formed by any two of the above values.

[0153] For example, in this embodiment, the value of D2μm can be 30μm or 100μm or 300μm or 600μm or 900μm or 1200μm or 1600μm or 2000μm or 2500μm, or it can be any range formed by any two of the above values.

[0154] In some embodiments, combined with Figure 10As shown, the housing 111 includes a first housing surface 1101 opposite to the second end face 102. The first housing surface 1101 has a dimension of C mm along the first direction, which satisfies: 4 mm ≤ C mm ≤ 31 mm.

[0155] The dimension C of the first housing surface 1101 along the first direction is the thickness of the soft-pack battery cell 11. By limiting the range of C, we avoid C being too small, which would result in the first housing surface of the battery housing being too small, causing local stress concentration. This would lead to the metal layer being exposed after the outer insulating layer of the housing is rubbed, increasing the risk of short circuit between the housing and the external metal structure. At the same time, we avoid the thickness of the soft-pack battery cell 11 being too large, which would reduce the overall assembly efficiency of the battery housing. With the increase in cell thickness, the housing would be difficult to seal, posing a risk of seal failure.

[0156] For example, in this embodiment, the value of Cmm can be 4mm or 7mm or 10mm or 13mm or 16mm or 19mm or 22mm or 25mm or 28mm or 31mm, or it can be a range formed by any two of the above values.

[0157] In some embodiments, at least one end of the elastic insulating layer 3 extends beyond the outermost pouch cell 11 of the battery pack 1 along a first direction.

[0158] By setting at least one end of the elastic insulating layer 3 beyond the outermost soft-pack battery cell 11 of the battery pack 1, the contact area between the fixing strip 2 and the housing 111 can be effectively covered, reducing the risk of insulation damage caused by local stress concentration; at the same time, it enhances the sealing performance and vibration resistance of the overall structure, and improves the reliability of the battery module in long-term operation.

[0159] Furthermore, the two ends of the elastic insulating layer 3 in the first direction extend beyond the end face of the outermost soft-pack battery cell 11 of the battery pack 1.

[0160] In some embodiments, combined with Figure 4 As shown, along the first direction, the length of one end of the elastic insulating layer 3 extending beyond the outermost soft-pack battery cell 11 of the battery pack 1 at the same end is Emm, satisfying: 3mm≤Emm≤20mm.

[0161] When Emm is too small, the elastic insulation layer 3 does not adequately cover the contact area between the fixing strip 2 and the housing 111, increasing the risk of local stress concentration and making it easy to cause damage to the insulation layer; when Emm is too large, although the insulation protection effect is enhanced, it will increase the material cost and the overall volume of the module, which is not conducive to high-density integration.

[0162] For example, in this embodiment, the value of Emm can be 3mm or 5mm or 7mm or 9mm or 11mm or 13mm or 15mm or 17mm or 19mm or 20mm, or it can be a range formed by any two of the above values.

[0163] In some embodiments, the elastic insulating layer 3 includes a first elastic insulating layer 31 and a second elastic insulating layer 32. The first elastic insulating layer 31 is adhered to the surface of the fixing strip 2, and the second elastic insulating layer 32 is disposed between the first elastic insulating layer 31 and the housing 111.

[0164] The first elastic insulating layer 31 is adhered to the surface of the fixing strip 2. Optionally, the first elastic insulating layer 31 may only cover the surface of the fixing strip 2 facing the housing 111, or it may cover all sides of the fixing strip 2.

[0165] In this embodiment, the first elastic insulating layer 31 includes surface insulating tape adhered to the fixing strip 2, which can effectively isolate the electrical contact between the fixing strip and the shell; the second elastic insulating layer 32 can be a thermally conductive adhesive, which has both good insulation and thermal conductivity after curing, and can effectively transfer the heat generated by the soft-pack battery cell, while avoiding electrical connection between the fixing strip and the shell.

[0166] The second elastic insulating layer 32 fills the space between the first elastic insulating layer 31 and the housing 111, which can accommodate dimensional tolerances during assembly and improve structural compactness. When the battery pack experiences vibration or thermal expansion and contraction, the elastic properties of the thermally conductive adhesive help buffer stress transmission and reduce the risk of interface delamination.

[0167] As a variation, the second elastic insulation layer 32 can also be an elastic foam material, disposed between the first elastic insulation layer 31 and the shell 111, which can undergo elastic deformation during the fastening process, buffer assembly stress, and further improve insulation reliability and structural sealing.

[0168] In some embodiments, the projected area of ​​the second elastic insulating layer 32 on the second end face 102 is greater than the projected area of ​​the first elastic insulating layer 31 on the second end face 102.

[0169] By making the projected area of ​​the second elastic insulating layer 32 on the second end face 102 larger than the projected area of ​​the first elastic insulating layer 31 on the second end face 102, the insulation coverage area can be effectively expanded, especially at the corner where the edge of the fixing strip 2 contacts the housing 111, forming extended protection to avoid the edge of the fixing strip 2 rubbing against the housing 111 and causing wear of the insulation layer.

[0170] In some embodiments, along a first direction, the end of the second elastic insulating layer 32 extends beyond the end face of the outermost pouch cell 11 of the battery pack 1.

[0171] Along the first direction, the end of the second elastic insulating layer 32 extends beyond the end face of the outermost pouch cell 11 of the battery pack 1 to ensure that the edge area of ​​the battery pack still has sufficient insulation protection when subjected to external impact or compression. This effectively protects the insulation structure between all pouch cells 11 and the fixing strip 2, preventing insulation failure caused by localized stress.

[0172] In some embodiments, along a third direction, the thickness of the second elastic insulating layer 32 is greater than the thickness of the first elastic insulating layer 31.

[0173] The elastic modulus of the second elastic insulating layer 32 is less than that of the first elastic insulating layer 31.

[0174] The third direction is perpendicular to the first and second directions.

[0175] By making the thickness of the second elastic insulating layer 32 greater than that of the first elastic insulating layer 31, the buffering performance and deformation tolerance of the second elastic insulating layer 32 can be further improved, effectively reducing the risk of damage to the surface of the housing 111 caused by friction of the fixing strip 2.

[0176] The elastic modulus can be regarded as an indicator of how easily a material undergoes elastic deformation; the higher the value, the smaller the elastic deformation. Therefore, a lower elastic modulus makes the second elastic insulating layer 32 more prone to elastic deformation under pressure, enabling it to better conform to the microscopic unevenness of the shell surface and improve the interfacial bonding stability.

[0177] In this embodiment, the thickness of the first elastic insulating layer 31 ranges from 0.03mm to 1mm. The thickness of the second elastic insulating layer 32 ranges from 0.5mm to 5mm.

[0178] In some embodiments, the melting temperature of the first elastic insulating layer 31 is greater than or equal to 150°C.

[0179] For example, in this embodiment, the melting temperature of the first elastic insulating layer 31 can be 150°C, 180°C, or 200°C, or it can be a range formed by any two of the above values.

[0180] In some embodiments, the first elastic insulating layer 31 is disposed around the outer periphery of the fixing strip 2.

[0181] The first elastic insulating layer 31 is arranged around the outer periphery of the fixing strip 2, which provides a better covering effect for the fixing strip 2. In the case of vibration or impact, it can effectively prevent wear caused by relative displacement between the fixing strip 2 and adjacent components, and increase the creepage distance.

[0182] In some embodiments, a first elastic insulating layer 31 is continuously disposed around the outer periphery of the fixing strip 2. The first elastic insulating layer 31 includes a first end and a second end, and at least one of the first end and the second end is disposed on the surface of the fixing strip 2 away from the housing 111.

[0183] It should be noted that the first end and the second end are the two ends of the first elastic insulating layer 31. Preferably, the two ends are overlapped and disposed on the surface of the fixing strip 2 away from the shell, so as to avoid the insulation layer overlapping and affecting the heat dissipation of the battery cell shell and the increase of friction due to the uneven surface after overlapping, which could cause the outer insulating layer of the shell to fail.

[0184] The first elastic insulating layer 31 can specifically be an insulating tape wrapped around the outer periphery of the fixing strip 2. By having at least one of the first end and the second end positioned on the surface of the fixing strip 2 facing away from the housing 111, the flatness of the surface of the fixing strip 2 facing the housing 111 can be effectively ensured, avoiding stress concentration caused by the protrusion of the end of the first elastic insulating layer 31, thereby reducing the risk of local pressure damage to the surface of the housing 111 of the soft-pack battery cell 11. At the same time, it can effectively prevent the end from lifting or falling off.

[0185] In some embodiments, the fixing strip 2 extends along a first direction, and the length direction of the second end face 102 is parallel to the second direction.

[0186] That is, the extension direction of the fixing strip 2 is perpendicular to the length direction of the second end face 102, so that the fixing strip 2 can effectively span and fix multiple soft-pack battery cells 11, thereby enhancing structural stability.

[0187] In some embodiments, the length direction of the second end face 102 is parallel to the second direction, and at least two fixing strips 2 are provided at intervals along the second direction.

[0188] By having at least two fixing strips 2 spaced apart along the length of the battery pack 1, the constraint force can be distributed more evenly, resulting in a better constraint effect. This effectively suppresses uneven expansion of the battery pack at different locations and avoids structural failure caused by local stress concentration. At the same time, the multi-point distribution of fixing strips 2 can improve the overall stiffness and enhance the resistance to vibration and impact.

[0189] In some embodiments, along the second direction, the interval between adjacent fixing bars 2 is Fmm, satisfying: 80mm≤Fmm≤250mm.

[0190] If the spacing F between adjacent fixing bars 2 is too small, although it can further improve the uniformity of constraint, it will increase the assembly complexity and cost and affect the heat dissipation effect; if the spacing F is too large, it will be difficult to effectively suppress the local deformation of the battery pack 1 along the length direction and reduce the structural stability.

[0191] For example, in this embodiment, the value of Fmm can be 80mm or 100mm or 120mm or 140mm or 160mm or 180mm or 200mm or 220mm or 240mm or 250mm, or it can be a range formed by any two of the above values.

[0192] In some embodiments, the following condition is satisfied: 0.03 ≤ M ≤ 0.45;

[0193] and / or, combined Figure 2 As shown, along the second direction, the width of the fixing strip 2 is Gmm, which satisfies: 10mm≤Gmm≤60mm.

[0194] Along the second direction, when the ratio M between the size of the fixing strip 2 and the size of the second end face 102 is too small, the contact area between the fixing strip 2 and the shell 111 of the soft-pack battery cell 11 is insufficient, which makes it easier for stress concentration to occur at the bottom of the soft-pack battery cell 11, thereby aggravating the wear of the outer insulating layer 1111 of the shell 111 and increasing the risk of contact between the inner metal layer 1112 of the shell 111 and the fixing strip 2 or other metal structures, thus causing safety hazards such as short circuit and thermal runaway; while when the ratio M between the size of the fixing strip 2 and the size of the second end face 102 is too large, it will cause the fixing strip 2 to cover an excessively large area in the second direction, affecting the overall structural compactness, increasing the volume redundancy of the battery pack, and reducing the space utilization rate.

[0195] When the width G of the fixing strip 2 is too small, it is more likely that the fixing strip 2 will squeeze the casing 111 of the pouch battery cell 11, causing local stress concentration, which in turn squeezes the cell 112 and causes the electrode to fall off, posing a safety risk. Moreover, if the width G of the fixing strip 2 is too small, it will result in insufficient constraint on the battery pack, affecting the overall structural stability. When the width G of the fixing strip 2 is too large, although it can reduce the risk of squeezing the casing 111 of the pouch battery cell 11 and increase the constraint, it will significantly block the contact area between the heat exchange plate and the pouch battery cell 11, reducing heat dissipation efficiency.

[0196] For example, in this embodiment, the value of M can be 0.03 or 0.06 or 0.09 or 0.12 or 0.15 or 0.18 or 0.21 or 0.24 or 0.27 or 0.30 or 0.33 or 0.36 or 0.39 or 0.42 or 0.45, or it can be any range formed by any two of the above values.

[0197] For example, in this embodiment, the value of Gmm can be 10mm or 15mm or 20mm or 25mm or 30mm or 35mm or 40mm or 45mm or 50mm or 55mm or 60mm, or it can be a range formed by any two of the above values.

[0198] In some embodiments, combined with Figure 2 As shown, the center line of the fixing strip 2 and the second end face 102 in the length direction are offset by a distance of J mm, which satisfies the condition: 15 mm ≤ J mm ≤ 65 mm.

[0199] Since the expansion is most pronounced in the middle of the length direction of the soft-pack battery cell 11, when the fixing strip 2 is set at the center line position of the length direction of the soft-pack battery cell 11, the fixing strip 2 will cause excessive restraint on the soft-pack battery cell 11, resulting in regional stress concentration, which can easily cause shell deformation or cell damage, and is not conducive to long-term reliability.

[0200] Therefore, by avoiding the centerline of the length of the soft-pack battery cell 11 and offsetting it to both sides, the constraint pressure in the high-stress area in the middle can be effectively relieved, and the risk of local deformation of the casing and damage to the battery cell can be reduced.

[0201] When the distance J between the fixing strip 2 and the center line of the soft-pack battery cell 11 in the length direction is too small, the fixing strip 2 is still close to the expansion core area and cannot effectively disperse the stress; while when the distance J is too large, the fixing strip 2 is too far away from the center of force, reducing the constraint effect and making it difficult to effectively suppress expansion deformation.

[0202] For example, in this embodiment, the value of Jmm can be 15mm or 20mm or 25mm or 30mm or 35mm or 40mm or 45mm or 50mm or 55mm or 60mm or 65mm, or it can be a range formed by any two of the above values.

[0203] In some embodiments, the fixed segment 22 is not provided with an elastic insulating layer 3.

[0204] Since the fixed section 22 is located at both ends of the extension section 21 along the first direction and is used to connect with the first end face 101, there is no need to provide an elastic insulating layer on the fixed section 22 to avoid unnecessary assembly interference, avoid affecting the fixing strength, and reduce space occupation.

[0205] Two first end faces 101 along the first direction of the battery pack 1 can be respectively provided with fixing plates, and fastening straps 4 are connected and fixed to the fixing plates. The connection method can be welding, screwing, riveting or buckle engagement.

[0206] In some embodiments, the battery pack 1 is located above the fixing bar 2 along the direction of gravity, satisfying: 56≤M×D1×D2≤40850.

[0207] The battery pack 1 is located above the fixing strip 2 along the direction of gravity. Under the action of gravity, the friction between the battery pack 1 and the fixing strip 2 is enhanced, thereby increasing the risk of damage to the surface of the housing 111 caused by the fixing strip 2 due to friction. At this time, it is necessary to improve the insulation protection effect by reasonably controlling the product of M, D1 and D2 within the set range, so as to reduce the risk of housing damage.

[0208] For example, in this embodiment, the value of M×D1×D2 can be 56 or 200 or 500 or 1000 or 2000 or 5000 or 10000 or 20000 or 30000 or 40000 or 40850, or it can be any range formed by any two of the above values.

[0209] In some embodiments, the following condition is satisfied: 56≤M×D1×D2≤28296.

[0210] For example, in this embodiment, the value of M×D1×D2 can be 56 or 200 or 500 or 1000 or 2500 or 5000 or 10000 or 15000 or 20000 or 25000 or 28296, or it can be any range formed by any two of the above values.

[0211] According to an embodiment of the present invention, in another aspect, an electrical appliance is also provided, comprising:

[0212] The electrical equipment body and the pouch battery device as described above are electrically connected.

[0213] In this embodiment, the electrical equipment can specifically be electronic devices, electric vehicles, or energy storage systems. Among them, electronic devices include smartphones, tablets, or laptops; electric vehicles include pure electric vehicles, hybrid electric vehicles, or electric motorcycles, etc.; and energy storage systems are used for grid energy storage or home energy management.

[0214] In some embodiments, the electrical equipment further includes:

[0215] The heat exchange plate has a channel inside for the passage of heat exchange medium. The heat exchange plate is arranged opposite to the second end face 102 of the battery pack 1 and is heat exchanged. The fixing strip 2 is arranged between the heat exchange plate and the battery pack 1.

[0216] It should be noted that the heat exchange plate is also called the cold plate. The cold plate is used to dissipate heat from the soft-pack battery cell 11 in order to regulate the temperature of the soft-pack battery cell 11.

[0217] Material / Composition of Cold Plate: (1) The cold plate can be constructed as a liquid cooling plate or a phase change cold plate and is thermally connected to the battery. (2) A refrigerant can be stored in the cold plate. The cooling of the battery cell is achieved through the phase change of the refrigerant. The refrigerant can be a gas (pure water, ethylene glycol aqueous solution, silicone oil, etc.), solid and liquid. A liquid with a high specific heat capacity, such as water, can also be set in the liquid refrigerant as a coolant to achieve liquid cooling heat dissipation of the battery cell. (3) The air-cooled plate is set at the bottom of the box, that is, connected to the bottom of the side wall to form a closed box structure. The air-cooled plate can be fixed to the side wall of the box using nuts and other methods. In order to form an airflow cavity in the box, the bottom plate is set in the barrel-shaped structure. Since the bottom of the battery is flat, the bottom plate also needs to be set parallel to the air-cooled plate. There is a gap between the air-cooled plate and the bottom plate so that the bottom plate, the side wall and the air-cooled plate together form an airflow cavity. (4) The liquid cooling plate has liquid cooling channels. Specifically, the shape of the liquid cooling channels can be various, such as "U", "U-shaped", or "S" shaped. Optionally, the liquid cooling plate also includes an inlet and an outlet, both of which are connected to the current collector for the inlet and outlet of the heat exchange medium. The liquid cooling plate can be made of a material with a certain hardness and strength (such as stainless steel). This makes the liquid cooling plate less prone to deformation when the battery cell is subjected to compression and impact, allowing the battery cell to have higher structural strength and improved safety performance. The materials of the liquid cooling plate can be various, including but not limited to: copper, iron, aluminum, stainless steel, aluminum alloy, etc. The materials of the liquid cooling plate can also be nylon, plastic, etc.

[0218] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and all such modifications and variations fall within the scope defined by the present invention.

Claims

1. A pouch battery device, characterized in that, include: The battery pack (1) includes a plurality of pouch battery cells (11) arranged along a first direction; the battery pack (1) includes two first end faces (101) located at both ends of the first direction, and a second end face (102) located between the two first end faces (101); the first end faces (101) are perpendicular to the first direction; the pouch battery cell (11) includes a housing (111) and a cell (112) disposed in the housing (111), and the second end face (102) is disposed perpendicular to the first end face (101); The fixing strip (2) includes an extension section (21) and a fixing section (22). The extension section (21) is disposed opposite to the second end face (102). The fixing section (22) is disposed at both ends of the extension section (21) along the first direction and is respectively connected to the two first end faces (101). The extension section (21) is provided with an elastic insulating layer (3) at least partially on its outer periphery, and the elastic insulating layer (3) is located at least between the fixing strip (2) and the housing (111); The length direction of the soft-pack battery cell (11) is the second direction, and the first direction is perpendicular to the second direction; Along the second direction, the ratio of the size of the fixing strip (2) to the size of the second end face (102) is M; the size of the fixing strip (2) refers to the sum of the sizes of all the fixing strips (2) along the second direction; The elastic insulating layer (3) includes a first elastic insulating layer (31) and a second elastic insulating layer (32). The first elastic insulating layer (31) is adhered to the surface of the fixing strip (2), and the second elastic insulating layer (32) is disposed between the first elastic insulating layer (31) and the housing (111). The thickness of the elastic insulating layer (3) located between the fixing strip (2) and the housing (111) along a third direction is D2μm. The third direction is perpendicular to the first direction and the second direction. The housing (111) includes at least an inner metal layer (1112) and an outer insulating layer (1111) covering the outer surface of the inner metal layer (1112), wherein the thickness of the outer insulating layer (1111) is D1μm; Satisfies: 56 ≤ M × D1 × D2 ≤ 28296; The range of values ​​for M satisfies 0.08 ≤ M ≤ 0.36; The value range of D1um satisfies 10μm≤D1um≤40μm; The value range of D2um satisfies 70μm≤D2um≤1965μm; Along the first direction, the length of one end of the elastic insulating layer (3) extending beyond the outermost soft-pack battery cell (11) of the battery pack (1) at the same end is Emm, satisfying: 3mm≤Emm≤20mm; Along the second direction, the width dimension of the fixing strip (2) is Gmm, which satisfies: 10mm≤Gmm≤60mm.

2. The soft-pack battery device according to claim 1, characterized in that, The housing (111) includes a first housing surface (1101) opposite to the second end face (102), and the first housing surface (1101) has a bent portion (1113). The bent portion (1113) is formed by partially overlapping the first shell surface (1101); the bent portion (1113) extends along the second direction.

3. The soft-pack battery device according to claim 2, characterized in that, The bent portion (1113) is located at the middle of the first housing surface (1101) along the first direction.

4. The soft-pack battery device according to claim 2, characterized in that, The bent portion (1113) is offset from the centerline of the first housing surface (1101) along the first direction, satisfying: D2μm≥30μm.

5. The soft-pack battery device according to claim 2, characterized in that, The bent portion (1113) is formed by protruding from the first housing surface (1101) toward the second end surface (102).

6. The soft-pack battery device according to claim 1, characterized in that, The housing (111) includes a first housing surface (1101) opposite to the second end face (102), and the first housing surface (1101) is provided with a second insulating layer (113) in at least a portion of its area. The housing (111) further includes a second housing surface (1102) that is perpendicular to the first direction and adjacent to the first housing surface (1101), and the second insulating layer (113) extends to the second housing surface (1102).

7. The soft-pack battery device according to claim 6, characterized in that, Along a third direction, the second insulating layer (113) at least partially overlaps with the fixing strip (2) in projection.

8. The soft-pack battery device according to claim 1, characterized in that, The housing (111) includes a first housing surface (1101) opposite to the second end face (102), and the first housing surface (1101) has a dimension of C mm along the first direction, satisfying: 4 mm ≤ C mm ≤ 31 mm.

9. The soft-pack battery device according to claim 1, characterized in that, The projected area of ​​the second elastic insulating layer (32) on the second end face (102) is greater than the projected area of ​​the first elastic insulating layer (31) on the second end face (102).

10. The pouch battery device according to claim 9, characterized in that, Along the first direction, the end of the second elastic insulating layer (32) extends beyond the end face of the outermost pouch cell (11) of the battery pack (1).

11. The pouch battery device according to claim 1, characterized in that, Along the third direction, the thickness of the second elastic insulating layer (32) is greater than the thickness of the first elastic insulating layer (31); The elastic modulus of the second elastic insulating layer (32) is less than that of the first elastic insulating layer (31); The third direction is perpendicular to the first direction and the second direction.

12. The pouch battery device according to claim 1, characterized in that, The melting temperature of the first elastic insulating layer (31) is greater than or equal to 150°C.

13. The pouch battery device according to claim 1, characterized in that, The first elastic insulating layer (31) is disposed around the outer periphery of the fixing strip (2).

14. The pouch battery device according to claim 13, characterized in that, The first elastic insulating layer (31) is continuously disposed around the outer periphery of the fixing strip (2). The first elastic insulating layer (31) includes a first end and a second end, at least one of which is disposed on the surface of the fixing strip (2) away from the housing (111).

15. The pouch battery device according to any one of claims 1 to 8, characterized in that, The fixing strip (2) extends along the first direction, and the length direction of the second end face (102) is parallel to the second direction.

16. The pouch battery device according to any one of claims 1 to 8, characterized in that, The length direction of the second end face (102) is parallel to the second direction, and at least two fixing strips (2) are provided at intervals along the second direction.

17. The pouch battery device according to claim 16, characterized in that, Along the second direction, the interval between adjacent fixing strips (2) is Fmm, which satisfies: 80mm≤Fmm≤250mm.

18. The pouch battery device according to claim 15, characterized in that, The fixing strip (2) is offset from the center line of the second end face (102) in the length direction, and the offset distance is Jmm, which satisfies: 15mm≤Jmm≤65mm.

19. The pouch battery device according to any one of claims 1 to 8, characterized in that, The fixed section (22) is not provided with the elastic insulating layer (3).

20. The pouch battery device according to any one of claims 1 to 8, characterized in that, The battery pack (1) is located above the fixing bar (2) along the direction of gravity.

21. An electrical appliance, characterized in that, include: The device body and the pouch battery device as described in any one of claims 1 to 20, wherein the device body is electrically connected to the pouch battery device.

22. The electrical equipment according to claim 21, characterized in that, Also includes: A heat exchange plate is provided inside the heat exchange plate for passing through a heat exchange medium. The heat exchange plate is arranged opposite to and heat-exchange connected to the second end face (102) of the battery pack (1). The fixing strip (2) is arranged between the heat exchange plate and the battery pack (1).

Images