Soft package battery pack and electric device

Abstract

The invention belongs to the technical field of batteries, and discloses a soft package battery pack and a power utilization device.The soft package battery pack comprises at least two batteries, an end plate and an isolation plate, the at least two batteries are arranged in the first direction, each battery comprises a shell, and the shell comprises a first shell part and a second shell part which are oppositely arranged; a sealing edge used for connecting the first shell part and the second shell part in a sealing mode is arranged at the position, facing the end plate, of the shell. The end plate is arranged at at least one end of the battery in the second direction, the second direction is perpendicular to the first direction, at least one through hole is formed in the end plate, and the through hole is opposite to the at least one sealing edge; the isolation plate is arranged between the end plate and the sealing edge, and the isolation plate is provided with a weak part opposite to the through hole. The soft package battery pack can improve the pressure relief rate when the battery is subjected to thermal runaway, realizes external directional pressure relief of the soft package battery pack, ensures that water vapor and foreign matters outside the soft package battery pack cannot enter the soft package battery pack, and realizes insulation safety of the soft package battery pack.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a soft-pack battery pack and an electrical device. Background Technology

[0002] Soft-pack batteries are widely used in the field of new energy batteries due to their advantages such as flexible size and high assembly efficiency. However, the existing soft-pack batteries are mostly made of aluminum-plastic film, which makes it difficult to set explosion-proof valves for directional pressure relief. This makes the battery casing susceptible to abnormal pressure relief. Moreover, the poor air venting after the battery is depressurized affects the safety of adjacent batteries or other electrical components inside the battery pack, and can cause severe thermal runaway of the battery pack. Summary of the Invention

[0003] This invention provides a pouch battery pack and an electrical device. The pouch battery pack can improve the pressure relief rate when the battery experiences thermal runaway, realize external directional pressure relief of the pouch battery pack, and ensure that moisture and foreign objects outside the pouch battery pack do not enter the pouch battery pack, thus achieving insulation safety of the pouch battery pack.

[0004] To achieve this objective, the present invention adopts the following technical solution: A pouch battery pack includes at least two batteries, an end plate, and a separator. The at least two batteries are arranged along a first direction. Each battery includes a housing, which includes a first housing portion and a second housing portion disposed opposite to each other. The housing has a sealing edge for sealingly connecting the first housing portion and the second housing portion at a position facing the end plate. The end plate is disposed at at least one end of the battery along a second direction, which is perpendicular to the first direction. The end plate has at least one through hole, which is disposed opposite to at least one of the sealing edges. The separator is disposed between the end plate and the sealing edge, and the separator has a weak portion disposed opposite to the through hole.

[0005] An electrical device includes at least one pouch battery pack as described above.

[0006] The beneficial effects of this invention are as follows: Arranging at least two batteries along a first direction allows the sealing edges on the casings of multiple batteries to face the same end plate, reducing thermal impact between batteries. Because the end plate has a through-hole and the separator plate has a weak point, when a battery experiences thermal runaway and the sealing edge cracks under the action of high-temperature gas, the gas can break through the weak point and exit through the through-hole from the end plate, increasing the pressure relief rate during thermal runaway and achieving external directional pressure relief of the pouch battery pack. Due to the presence of the separator plate, moisture and foreign objects from outside the pouch battery pack can be effectively prevented from entering the pouch battery pack through the through-hole of the end plate, ensuring insulation safety and better protecting the battery.

[0007] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the structure of a soft-pack battery according to an embodiment of the present invention; Figure 2 This is an exploded structural diagram of the soft-pack battery pack according to an embodiment of the present invention; Figure 3 yes Figure 2 The diagram shows the structure of the end plate. Figure 4 yes Figure 2 The diagram shows the structure of the isolation plate. Figure 5 This is a partial cross-sectional schematic diagram of a soft-pack battery pack according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the battery structure according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of the second type of end plate according to an embodiment of the present invention; Figure 8 Is with Figure 7 A schematic diagram of the corresponding isolation plates; Figure 9 This is a schematic diagram of the structure of the second type of end plate according to an embodiment of the present invention; Figure 10 Is with Figure 9 A schematic diagram of the corresponding isolation plates; Figure label: 100. Battery; 110. Housing; 111. First housing section; 112. Second housing section; 113. Sealing edge; 200. End plate; 210. Through hole; 300. Isolation plate; 310. Weak part; 400. Box body; 410. Bottom plate; 420. Cover plate. Detailed Implementation

[0009] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0010] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0011] In the description of this embodiment, the terms "upper," "lower," "left," "right," "front," and "rear," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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 the present invention. Furthermore, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0012] The applicant's research found that the main reason for the severe thermal runaway of pouch batteries is that when the internal pressure of the pouch battery pack reaches a certain level, it bursts through the casing. The bursting area is mostly the sealing edge of the casing. Because the pouch battery casing is easily deformed, existing technologies generally fix the pouch battery with glue or fasten it with end plates and composite cable ties to prevent battery deformation. This results in insufficient venting space inside the battery pack, causing the cracked sealing edge to quickly transmit heat to adjacent batteries. Since there is no directional venting channel on the outside of the pouch battery pack, heat spreads between adjacent batteries within the pouch battery pack, causing severe thermal runaway and leading to the risk of fire and explosion of the pouch battery pack.

[0013] This invention discloses a pouch battery pack, with reference to Figures 1-6 As shown, the pouch battery pack includes at least two batteries 100, an end plate 200, and a separator plate 300. The batteries 100 are pouch batteries, and at least two batteries 100 are arranged along a first direction. Each battery 100 includes a housing 110 and a cell disposed in the housing 110. The housing 110 includes a first housing portion 111 and a second housing portion 112 disposed opposite to each other. The housing 110 is provided with a sealing edge 113 facing the end plate 200 for sealingly connecting the first housing portion 111 and the second housing portion 112. An end plate 200 is disposed at at least one end of the battery 100 along a second direction, which is perpendicular to the first direction and is the length direction of the battery 100. The end plate 200 is provided with at least one through hole 210, which is disposed opposite to at least one sealing edge 113. An isolation plate 300 is disposed between the end plate 200 and the sealing edge 113, and the isolation plate 300 has a weak portion 310 disposed opposite to the through hole 210, the size of which is smaller than the size of the through hole 210.

[0014] It should be further explained that a battery cell is the component in battery 100 where electrochemical reactions occur; it is the smallest unit in battery 100 capable of performing electrochemical reactions such as charging / discharging. A battery cell typically includes a positive electrode, a negative electrode, and a separator. A battery cell can be a wound core or a stacked core. The separator is located between adjacent positive and negative electrode plates.

[0015] Battery cells primarily function by the intercalation and deintercalation of metal ions between the positive and negative electrodes. In cylindrical cells, the three-layer thin-film structure is wound into a cylindrical shape, while in cuboid cells, the thin-film structure is wound or stacked into a roughly cuboid shape.

[0016] The positive electrode is one of the core components of the battery 100 that carries the positive electrode active material. During charging, metal ions (e.g., lithium ions) are extracted 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 (e.g., lithium ions in a lithium battery) are extracted 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.

[0017] 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 active materials for batteries. These positive active materials can be used alone or in combination. The lithium phosphates include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also abbreviated as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Lithium transition metal oxides include, but are not limited to, at least one of lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, and their modified compounds.

[0018] The positive electrode current collector includes a conductive metal foil, which can be made of stainless steel, copper, aluminum, nickel, carbon electrodes, or titanium with a silver-plated surface. Composite current collectors can also be used, which may include a polymer base layer and a metal layer. Composite current collectors are formed by forming a metal material (aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer substrate (such as polyethylene terephthalate, polyethylene terephthalate, polyethylene, polyethylene, etc.).

[0019] 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, SuperP, etc.), carbon nanotubes, graphene and carbon nanofibers.

[0020] 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.

[0021] The negative electrode sheet includes a negative current collector and a negative active layer disposed on at least one surface of the negative current collector. The negative 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 negative current collector can also be a composite current collector, which may include a polymer base material 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 base material (such as a base material of polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc.). The negative active layer includes a negative active material, conductive components, and adhesives.

[0022] 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, and silicon-carbon composites. The conductive agent can be conductive carbon black, carbon nanotubes, etc., and the binder can be styrene-butadiene rubber, polyacrylic acid, etc.

[0023] The battery cell also includes tabs, which are disposed on one side of the positive / negative current collector and are separately or integrally formed with the current collector. The tabs are electrically connected to the current collector to conduct current through it. When the tabs and current collector are separate, they can be connected by welding. The tabs are made of a highly conductive metal material (such as copper, aluminum, or nickel). The tabs and the battery cell can be an integral structural component. For example, the battery cell may include a battery cell body and tabs. The battery cell body includes a positive electrode, a negative electrode, and a separator. The tabs are electrically connected to the battery cell body. Alternatively, the tabs and the battery cell can be separate structural components. For example, the battery cell may include a battery cell body, which includes a positive electrode, a negative electrode, and a separator. The battery cell body has tab leads, and the tabs are electrically connected to the tab leads, such as by welding.

[0024] Preferably, the tab is located on the side of the cell closest to the end plate 200. The cell on the side where the tab is led out has a multi-layer structure, which facilitates gas discharge in the event of thermal runaway of the battery 100, thereby increasing the gas discharge rate of the battery during thermal runaway.

[0025] Optionally, the battery 100 also includes an electrode plate electrically connected to the tab. The electrode plate passes at least partially through the sealing edge 113, and one end of the electrode plate is electrically connected to the tab, while the other end is electrically connected to other external batteries or electrical devices. The electrode plate may include at least one or more materials or alloys selected from aluminum, aluminum alloy, copper, copper-aluminum alloy, steel, stainless steel, nickel, etc. The electrode plate may also be disposed on the side of the battery 100 near the separator.

[0026] An insulating seal is also provided between the electrode sheet and the housing 110. The insulating seal is provided between the housing 110 and the electrode sheet to insulate the electrode sheet and the housing 110. The insulating seal material may include one or more insulating materials such as polypropylene (CPP) or polyethylene (PE), polyethylene terephthalate (PET), polybutylene succinate (PBS), and polyimide (PI).

[0027] It should be further noted that the material of the casing 110 of the battery 100 differs from that of traditional square and cylindrical casings. The casing 110 includes an outer insulating layer, a metal layer, and an inner insulating layer. The metal layer is disposed between the inner and outer insulating layers. The inner insulating layer of the first casing portion 111 is bonded to the inner insulating layer of the second casing portion 112, forming a sealing edge 113. The outer insulating layer is an outer protective layer, and its material can be one or more of polycaprolactam (nylon 6), PET (polyethylene terephthalate), polybutylene succinate, etc. The metal layer can be one or more of aluminum, aluminum alloy, copper, nickel, etc., or other metals or alloys. The inner protective layer can be one or more of polypropylene film (PP) and cast polypropylene film (CPP), etc. The outer insulating layer is responsible for maintaining the shape stability of the casing 110, ensuring that the casing does not deform during the lithium-ion battery manufacturing process. The main function of the metal layer is waterproofing, as lithium batteries are extremely sensitive to moisture and must effectively prevent the intrusion of water vapor. The outer insulation layer itself is not waterproof and cannot meet this requirement. However, the intermediate metal layer reacts with oxygen in the air to form a dense oxide film, thereby preventing moisture penetration and protecting the inside of the battery cell. In the actual assembly process, the inner insulation layer of the first housing part 111 and the outer insulation layer of the second housing part 112 are bonded together to form a sealing edge 113, or a separate adhesive layer can be used for sealing. Grooves are provided on the first housing part 111 and / or the second housing part 112 to form a space for accommodating the battery cell. Three or four flange edges are formed on the outer periphery of the grooves. The upper and lower opposing flange edges are sealed together to form the sealing edge 113, thereby sealing the housing 110. It is understood that arranging at least two batteries 100 along the first direction allows the sealing edge 113 on the housing 110 to face the same end face, reducing the thermal impact between the batteries 100. Because the end plate 200 has a through hole 210 and the separator 300 has a weak point 310, when the battery 100 experiences thermal runaway and the sealing edge 113 cracks under the action of high-temperature gas, it can break through the weak point 310 and exit the end plate 200 through the through hole 210, thereby increasing the pressure relief rate when the battery 100 experiences thermal runaway and realizing external directional pressure relief of the pouch battery pack. However, the through hole directly on the end plate 200 allows water vapor and foreign objects to enter the pouch battery pack after the inside and outside of the battery pack are connected, which may cause internal short circuit safety risks. Therefore, by setting the separator 300 between the sealing edge 113 of the battery 100 and the end plate 200, it is possible to better prevent water vapor and foreign objects from entering the pouch battery pack through the through hole 210, thereby achieving insulation safety of the pouch battery pack. Furthermore, by providing a weak part 310 between the through hole 210 and the sealing edge 113, the size of the weak part 310 is smaller than the size of the through hole 210, making it difficult for moisture and foreign objects outside the soft-pack battery pack to enter the soft-pack battery pack, ensuring the insulation safety of the soft-pack battery pack, and at the same time improving the venting rate after the battery 100 is depressurized.

[0028] It should be noted that the soft-pack battery pack in this embodiment also includes a housing 400, which includes a bottom plate 410 and a cover plate 420. The bottom plate 410 and the cover plate 420 cover each other and together define a receiving space for accommodating the battery 100. The end plate 200 is connected to the bottom plate 410 and the cover plate 420 respectively.

[0029] Optionally, the end plate 200 can be made of one or more metals or alloys selected from aluminum, aluminum alloy, steel, copper, and nickel. The end plate 200 is disposed at the end of the pouch battery pack, serving two purposes: firstly, to limit the movement of the multiple batteries 100, thereby strengthening the overall strength of the pouch battery pack; and secondly, to protect the batteries 100 from damage to their casings 110 caused by external foreign objects. Further optionally, the thickness of the end plate 200 is 0.3-3 mm.

[0030] Optionally, the weak portion 310 includes a groove formed on the separator 300. The groove extends along a first direction and corresponds to the sealing edges 113 of at least two batteries 100, meaning that the groove and the projection of the sealing edges 113 of at least two batteries 100 onto the plane of the end plate 200 at least partially overlap. It is understood that the weak portion 310 is a groove formed on the separator 300. When the pouch battery pack is working normally, the groove is in a closed state, which can effectively prevent moisture and foreign objects from entering the pouch battery pack through the through hole 210. When a battery 100 experiences thermal runaway, the groove can quickly expand under the impact of high-temperature flue gas, achieving external directional pressure relief of the pouch battery pack. It should be noted that in the embodiments of the present invention, the scribing is in the shape of a straight line. Of course, in other embodiments of the present invention, the scribing can also be one or more shapes such as line, S-shape, rectangle, circle, etc. The scribing can also be a continuous or discontinuous structure, as long as it can ensure that when the battery 100 experiences thermal runaway, the high-temperature flue gas can break through the scribing to achieve pressure relief.

[0031] Optionally, the weak portion 310 includes a gap formed in the separator 300. It is understood that the weak portion 310, formed as a gap in the separator 300, allows high-temperature flue gas to be rapidly discharged through the gap and through the through-hole 210 when the battery 100 experiences thermal runaway, achieving external directional pressure relief of the pouch battery pack. Compared to a notch, the gap, being larger than a notch, allows for faster pressure relief by forming the weak portion 310.

[0032] Further optional, see reference Figures 3-4As shown, the dimension h1 of the gap along the third direction is smaller than the dimension h2 of the through hole 210 along the third direction, and the third direction is perpendicular to both the first and second directions. It is understandable that if the gap is too large, external moisture and contaminants can easily enter the pouch battery pack through the through hole 210 and the gap, thus affecting the normal operation of the pouch battery pack. In this embodiment, setting the dimension h1 of the gap along the third direction to be smaller than the dimension of the through hole 210 along the third direction can reduce the probability of moisture and contaminants entering the battery 100 through the gap, ensuring the normal operation of the pouch battery pack.

[0033] Alternatively, h1 and h2 can satisfy the relationship: h2mm - h1mm ≥ 6mm. It is understood that if the difference between the dimensions h2 of the through hole 210 along the third direction and the dimensions h1 of the gap along the third direction is too small, it will increase the probability of moisture and dirt entering the soft-pack battery 100 through the gap. In this embodiment, the difference between h2 and h1 is controlled within the range of ≥ 6mm, specifically 6mm, 7mm, 8mm, 9mm, 10mm, or other values ​​≥ 6mm. This helps to ensure the blocking effect of the separator 300 on moisture and dirt, thereby reducing the probability of moisture and dirt entering the soft-pack battery 100 through the gap.

[0034] Optional, see reference Figure 4 As shown, the dimension of the weak portion 310 along the first direction is L1mm, and the dimension of the through hole 210 along the first direction is L2mm. L1 and L2 satisfy the relationship: |L1mm-L2mm|≤10mm. The dimension L1mm of the weak portion 310 along the first direction can be greater than the dimension L2mm of the through hole 210 along the first direction, and the dimension L1mm of the weak portion 310 along the first direction can also be less than the dimension L2mm of the through hole 210 along the first direction, as long as the absolute value of the difference between L1 and L2 is ≤10mm. Specifically, the absolute value of the difference between L1 and L2 can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm, or other values ​​≤10mm can be selected according to actual needs. It is understandable that if the difference between the dimension L1mm of the weak portion 310 along the first direction and the dimension L2mm of the through hole 210 along the first direction is too large, it will cause the high-temperature flue gas to be discharged slowly when the battery 100 experiences thermal runaway, thereby reducing the pressure relief and exhaust efficiency of the pouch battery pack. In this embodiment, the difference between the dimension L1mm of the weak portion 310 along the first direction and the dimension L2mm of the through hole 210 along the first direction is controlled within 10mm. The difference between the dimensions of the weak portion 310 and the through hole 210 along the first direction is not large, which is beneficial to improving the speed of high-temperature flue gas discharge when the battery 100 experiences thermal runaway, thereby improving the pressure relief and exhaust efficiency of the pouch battery pack.

[0035] Optionally, the dimension of a single weak section 310 along the first direction ranges from 50mm to 200mm. Specifically, the dimension of a single weak section 310 along the first direction can be 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, or 200mm. Of course, other values ​​within the range of 50mm to 200mm can also be selected according to actual needs. It is understandable that if the dimension of a single weak section 310 along the first direction is too small, the speed of high-temperature flue gas discharge will be slower, thereby reducing the pressure relief and exhaust efficiency of the pouch battery pack. If the size of a single weak part 310 along the first direction is too large, it increases the probability that moisture and dirt will enter the interior of the pouch battery 100 through the gap. In this embodiment, the size of a single weak part 310 along the first direction is controlled within the range of 50mm-200mm. This can increase the speed of high-temperature flue gas discharge when the battery 100 experiences thermal runaway, thereby improving the pressure relief and exhaust efficiency of the pouch battery pack, and also reduce the probability that moisture and dirt will enter the interior of the pouch battery pack through the gap.

[0036] Optional, see reference Figures 7-10 As shown, when the thickness of battery 100 is greater than or equal to 10mm, there are at least two weak points 310, and the at least two weak points 310 are spaced apart along the first direction. It can be understood that the thicker the individual battery 100, the greater the energy density of the individual battery 100, which increases the risk of cracking of the sealing edge 113 of the battery 100. At this time, the internal heat and gas generation of the battery 100 is greater. By setting at least two weak points 310 spaced apart along the first direction, more sealing edges 113 of the battery 100 can be covered, allowing the abnormal battery 100 to vent the internal gas to the outside of the pouch battery pack, thereby improving the overall venting rate of the pouch battery pack.

[0037] Alternatively, the spacing between two adjacent weak points 310 can be 40mm-80mm. Specifically, the spacing between two adjacent weak points 310 can be 40mm, 41mm, 42mm, 43mm, 44mm, 45mm, 46mm, 47mm, 48mm, 49mm, 50mm, 51mm, 52mm, 53mm, 54mm, 55mm, 56mm, 57mm, 58mm, 59mm, 60mm, 61mm, 62mm, 63mm, 64mm, 65mm, 66mm, 67mm, 68mm, 69mm, 70mm, 71mm, 72mm, 73mm, 74mm, 75mm, 76mm, 77mm, 78mm, 79mm, or 80mm. Other values ​​within the 40mm-80mm range can also be selected according to actual needs, and are not limited to the examples mentioned above. It is understandable that if the distance between two adjacent weak points 310 is too large, the thermal runaway of the battery 100 is uncertain, and some batteries 100 will be far from the weak points 310, which will reduce the rate of high-temperature gas discharge during thermal runaway. However, if the distance between two adjacent weak points 310 is too small, the separator 300 will experience stress concentration under normal operating conditions due to the close proximity of the weak points 310, which will increase the probability of the separator 300 cracking. This will allow moisture and foreign objects from outside the pouch battery pack to enter the pouch battery pack through the weak points 310, causing a short circuit risk in the battery 100. In this embodiment, the distance between two adjacent weak points 310 is controlled between 40mm and 80mm, which can both increase the rate of high-temperature gas discharge during thermal runaway and ensure the strength of the separator 300, reducing the probability of the separator 300 cracking, thereby reducing the risk of short circuit failure of the pouch battery pack.

[0038] Alternatively, the weak portion 310 may be offset from the centerline of the separator 300 extending in the first direction. It is understood that during the operation of the pouch battery pack, the center of a single cell 100 along a third direction is where the expansion and deformation are greatest. Since this third direction is perpendicular to both the first and second directions, if the weak portion 310 is aligned with the centerline of the separator 300 extending in the first direction, the weak portion 310 will be directly opposite the area of ​​maximum expansion of the cell 100, potentially causing abnormal cracking of the weak portion 310 and increasing the risk of short-circuit failure in the pouch battery pack. In this embodiment, the weak part 310 and the center line of the separator 300 extending in the first direction are staggered. The weak part 310 corresponds to the area where the number of batteries 100 is relatively small, which reduces the probability of short circuit failure of the soft pack battery pack caused by cracking of the weak part 310 and improves the structural strength of the separator 300 and the end plate 200. Furthermore, the through hole 210 and the center line of the separator 300 in the first direction are also staggered, which can better improve the overall structural strength of the soft pack battery pack while ensuring rapid exhaust of thermal runaway inside the soft pack battery pack.

[0039] Optional, see reference Figure 4 As shown, the distance L3 between the weak part 310 and the center line of the isolation plate 300 extending in the first direction (marked as a in the figure) is 20mm-40mm. Specifically, the distance between the weak part 310 and the center line of the isolation plate 300 extending in the first direction can be 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm, 36mm, 37mm, 38mm, 39mm, or 40mm. Of course, other values ​​within the range of 20mm-40mm can also be selected according to actual needs, and are not limited to the examples mentioned above. It is understandable that if the distance L3 between the weak portion 310 and the center line extending along the first direction of the separator 300 is too large, it will affect the overall exhaust efficiency of the pouch battery pack; if the distance L3 between the weak portion 310 and the center line extending along the first direction of the separator 300 is too small, the weak portion 310 on the separator 300 will be subject to stress concentration due to the large deformation force in the middle, which may lead to abnormal cracking. In this embodiment, the distance L3 between the weak portion 310 and the center line extending along the first direction of the separator 300 is controlled between 20mm and 40mm, which can ensure the overall exhaust efficiency of the pouch battery pack and avoid abnormal cracking of the weak portion 310 due to stress concentration.

[0040] Optionally, at least one end of the weak portion 310 along the first direction is spaced apart from the end of the separator 300 along the first direction. It is understood that the spaced-apart arrangement between the weak portion 310 and the end of the separator 300 can reduce the risk of cracking of the weak portion 310 during normal operation, thereby reducing the probability of short-circuit failure of the pouch battery pack caused by cracking of the weak portion 310.

[0041] Optionally, the separator 300 is an insulating plate, and its thickness is less than that of the end plate 200. It is understandable that choosing an insulating material for the separator 300 provides better insulation protection between the end plate 200 and the battery casing 110, minimizing the probability of short-circuit failure in the pouch battery pack and ensuring its operational stability. The thinner thickness of the separator 300 compared to the end plate 200 facilitates rapid breaching of the weak point 310 in the event of thermal runaway in the battery 100, ensuring that the high-temperature fumes generated by thermal runaway are quickly expelled from the pouch battery pack.

[0042] Further optionally, the material of the isolation plate 300 may include, but is not limited to, one or more of epoxy resin, polyester resin, phenolic resin, polyvinyl chloride, mica board, etc. The overall size of the isolation plate 300 is smaller than the size of the end plate 200 (here, the overall size means that the size of the isolation plate 300 along the first direction is smaller than the size of the end plate 200 along the first direction, and the size of the isolation plate 300 along the third direction is smaller than the size of the end plate 200 along the third direction). The isolation plate 300 and the end plate 200 are fixedly connected, which can be fixed by adhesive, or other fixing methods can be selected according to actual needs.

[0043] Optionally, the thickness of the isolation plate 300 can be 50μm-300μm. Specifically, the thickness of the isolation plate 300 can be 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, 210μm, 220μm, 230μm, 240μm, 250μm, 260μm, 270μm, 280μm, 290μm, or 300μm. Of course, other values ​​within the 50μm-300μm range can also be selected according to actual needs. The solution is that if the thickness of the separator 300 is too large, it will not be conducive to the breakthrough of the weak part 310, and will reduce the exhaust rate of high-temperature gas during thermal runaway. If the thickness of the separator 300 is too small, it will reduce the strength of the separator 300 and increase the probability of the separator 300 cracking, thereby increasing the risk of short circuit failure of the pouch battery pack. In this embodiment, the thickness of the separator 300 is controlled within 50μm-300μm, which can both improve the exhaust rate of high-temperature gas during thermal runaway and ensure the strength of the separator 300, reduce the probability of the separator 300 cracking, and thus reduce the risk of short circuit failure of the pouch battery pack.

[0044] Optionally, the dimension of the through hole 210 along the third direction is 5mm-20mm, and the third direction is perpendicular to both the first and second directions. Specifically, the dimension of the through hole 210 along the third direction can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, or 20mm. Of course, other values ​​within the range of 5mm-20mm can also be selected according to actual needs, and are not limited to the examples mentioned above. It is understandable that if the dimension of the through hole 210 along the third direction is too small, the speed of high-temperature flue gas discharge will be slower, thereby reducing the pressure relief and exhaust efficiency of the soft-pack battery pack. If the size of the through hole 210 along the third direction is too large, it increases the probability that water vapor and dirt will enter the interior of the pouch battery pack through the gap. In this embodiment, the size of the through hole 210 along the third direction is controlled within the range of 5mm-20mm. This can not only increase the speed of high-temperature flue gas discharge when the battery 100 is thermally runaway, thereby improving the pressure relief and exhaust efficiency of the pouch battery pack, but also reduce the probability that water vapor and dirt will enter the interior of the pouch battery 100 through the gap.

[0045] Optionally, the dimension of the through hole 210 along the third direction is smaller than the dimension of the through hole 210 along the first direction. Thus, the through hole 210 can correspond to multiple batteries. At the same time, the third direction is the height direction of the soft-pack battery pack, which has a large vibration amplitude. Reducing the dimension of the through hole 210 along the third direction can better achieve the protection of the end plate 200.

[0046] Optionally, multiple through holes 210 are provided at intervals along the first direction. It is understood that providing multiple through holes 210 can improve the pressure relief and venting efficiency of the pouch battery pack.

[0047] Optionally, along the second direction, the through hole 210 and the weak part 310 are spaced apart. It can be understood that the spaced arrangement of the through hole 210 and the weak part 310 can buffer the high-temperature flue gas when it is discharged, reducing the chance of damage to the end plate 200 on the one hand, and providing space to facilitate the rapid discharge of high-temperature flue gas on the other hand.

[0048] Optionally, the distance between the through hole 210 and the weak portion 310 can be 2mm-10mm. Specifically, the distance between the through hole 210 and the weak portion 310 can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm, or other values ​​within the range of 2mm-10mm, and is not limited to the examples mentioned above. It is understood that if the distance between the through hole 210 and the weak portion 310 is too small, the buffering effect will be reduced, and it will be detrimental to the discharge of high-temperature flue gas. If the distance is too large, it will increase the unused internal space of the pouch battery pack, which is detrimental to improving the energy density of the pouch battery pack. In this embodiment, controlling the distance between the through hole 210 and the weak portion 310 within the range of 1mm-10mm can both facilitate the rapid discharge of high-temperature flue gas and help control the overall volume of the pouch battery pack, thereby improving the energy density of the pouch battery pack.

[0049] Optionally, the dimension of the sealing edge 113 along the second direction is less than or equal to 30 mm, and the dimension of the weak portion 310 along the first direction is ≥60 mm. It is understood that if the sealing edge 113 is too short, the rate of high-temperature gas generated during thermal runaway will be faster, and the high-temperature flue gas will be larger. Therefore, it is necessary to increase the size of the weak portion 310 to ensure that the high-temperature flue gas generated by the thermal runaway of the battery 100 is discharged quickly and to avoid affecting the testing of adjacent batteries 100.

[0050] Optionally, the end plate 200 includes a first end plate and a second end plate, which are respectively disposed on both sides of the battery 100 along the second direction. Thus, the battery 100 can be fixed by the two end plates 200, thereby improving the structural stability of the entire pouch battery pack.

[0051] Optionally, both the first end plate and the second end plate are provided with through holes 210. Thus, when the battery 100 experiences thermal runaway, both the first end plate and the second end plate can vent, ensuring the venting efficiency of the pouch battery pack, reducing the probability of thermal runaway propagation, and reducing the severity of thermal runaway.

[0052] Optionally, the length of the battery 100 is greater than or equal to 400 mm, and the dimension of the through hole 210 along a third direction is greater than or equal to 6.5 mm, with the third direction being perpendicular to both the first and second directions. It is understood that the longer the battery 100, the larger its capacity and the more gas generated by thermal runaway. When the length of the battery 100 is greater than or equal to 400 mm, the dimension of the through hole 210 along a third direction needs to be set to a range greater than or equal to 6.5 mm to ensure that the gas generated by thermal runaway of the battery 100 can be discharged as quickly as possible, ensuring the exhaust efficiency of the pouch battery pack.

[0053] It should be noted that, in addition to the end plate 200, the soft-pack battery pack may also include at least one of a side plate, a top plate, and a bottom plate. The side plates are located at both ends in the first direction of the soft-pack battery pack, and the top plate and bottom plate are located at both ends in the third direction. The end plate 200 is connected to at least one of the side plate, bottom plate, and top plate by riveting, welding, bonding, or by binding with cable ties.

[0054] Optionally, along the second direction, the shortest distance d1mm between the weak part 310 and the sealing edge 113, and the dimension of the weak part 310 along the first direction is L1mm. By adjusting the product of the two, d1 and L1 satisfy the relationship: 250≤d1×L1≤4000, which can optimize the gas space inside the soft-pack battery pack. At the same time, it avoids stress concentration caused by the weak part 310 being too large, which would lead to stress concentration and fracture failure of the separator 300, and thus create a flow path for water vapor and foreign matter between the inside and outside of the soft-pack battery pack, causing a safety risk of internal short circuit in the soft-pack battery pack. Understandably, if the product of d1×L1 is too large, the proportion of the weak part 310 is too long, or the proportion of the shortest distance d1 between the weak part 310 and the sealing edge 113 is too large, the risk of tearing of the separator 300 is increased. The separator 300 is not supported by the end of the battery 100, the weak part 310 on the separator 300 deforms significantly, and the risk of breakage of the separator 300 increases. This causes the inside and outside of the pouch battery pack to become interconnected, allowing external moisture and foreign matter to enter the pouch battery pack through the through-holes, which will increase the risk of breakage. The risk of insulation short circuit in the battery pack is high. If the product of d1×L1 is too small, the size ratio of the weak portion 310 is too small, or the shortest distance d1 between the weak portion 310 and the sealing edge 113 is too small, it will hinder the rapid discharge of gas generated during thermal runaway. By controlling the product of the shortest distance d1 between the weak portion 310 and the sealing edge 113 and the size L1 of the weak portion 310 along the first direction to be within the range of 250-5000, the discharge rate of high-temperature gas during thermal runaway can be increased while reducing the risk of insulation short circuit in the pouch battery pack. Preferably, 525≤d1×L1≤2995.

[0055] Alternatively, the shortest distance d1 between the weak part 310 and the sealing edge 113 can be in the range of 5mm-20mm. The shortest distance d1 between the weak part 310 and the sealing edge 113 can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, or 20mm. Of course, other values ​​in the range of 5mm-20mm can also be selected according to actual needs, and are not limited to the examples mentioned above. It is understandable that if the shortest distance d1 between the weak part 310 and the sealing edge 113 is too large, it will result in too much useless space in the pouch battery pack, which is not conducive to improving the energy density of the pouch battery pack. If the shortest distance d1 between the weak part 310 and the sealing edge 113 is too small, it will not be conducive to the rapid discharge of gas generated by thermal runaway. In this embodiment, the range of the shortest distance d1 between the weak part 310 and the sealing edge 113 is controlled within the range of 5mm-20mm. This can reduce the useless space in the pouch battery pack, improve the space utilization of the pouch battery pack, and improve the energy density of the pouch battery pack. It can also improve the discharge rate of high-temperature gas during thermal runaway.

[0056] Optionally, the dimension L1 of the weak portion 310 along the first direction is 50mm-200mm. The dimension L1 of the weak portion 310 along the first direction can be selected from 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, and 200mm according to actual needs. Of course, other values ​​within the range of 50mm-200mm can also be selected according to actual needs, and are not limited to the examples mentioned above. It should be noted that when there is only one weak portion 310, L1 is the length of that single weak portion 310; when there are multiple weak portions 310, L1 is the total length of all weak portions 310.

[0057] The following describes the exhaust effect of parameters of several specific embodiments of the pouch battery pack.

[0058] First, the battery is manufactured as follows: Method for preparing battery 100: (1) Preparation of positive electrode sheet 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).

[0059] (2) Preparation of negative electrode 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, 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).

[0060] (3) Preparation of electrolyte: 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.

[0061] (4) Preparation of the diaphragm: Polyethylene film is selected as the diaphragm.

[0062] (5) Preparation of battery 100: The positive electrode, separator, and negative electrode are stacked in sequence to form a battery cell. The battery cell is placed in a housing 110, the inner insulating layer of which is cast polypropylene (CPP), the metal layer is aluminum, and the outer insulating layer is polycaprolactam (nylon 6). The edges are sealed using a heat sealer, and an electrolyte injection port is reserved. The battery 100 is dried, and then electrolyte is injected. After standing, formation, volume adjustment, and final sealing, the battery 100 is obtained.

[0063] 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.

[0064] Preparation method of pouch battery pack Nine batteries 100 prepared by the above method are stacked together along a first direction, and a heat insulation pad is placed between adjacent batteries. An end plate 200 is placed at one end of the nine batteries 100 in a second direction. The first direction is perpendicular to the second direction. A through hole 210 is formed on the end plate 200. The through hole 210 is corresponding to the sealing edge 113 of at least one battery 100. An isolation plate 300 is placed between the end plate 200 and the battery 100. A weak part 310 is provided on the isolation plate 300 corresponding to the position of the through hole 210, thereby forming a soft-pack battery pack.

[0065] Performance Test 1: Thermal runaway test of adjacent 100 cells: The pouch battery packs were prepared according to the above-described method. Three pouch battery packs were prepared for each embodiment and comparative example. The values ​​of d1 (distance 113 from the weak point 310 of the separator 300) and L1 (distance 310 of the weak point 310 on the separator 300) in the pouch battery packs of each embodiment and comparative example are shown in Table 1 below. All other structures are identical. Each battery 100 in the pouch battery pack was charged to its upper limit voltage using a 0.33C rate, and a high-temperature resistant steel needle with a diameter of 3mm was used to charge the battery at a rate of 25 ± 1 / 25 rpm. A 5mm speed is applied from a third party to penetrate the middle of battery 100 (i.e., starting from the end battery 100 in the pouch battery pack, the 5th battery 100 is the middle battery 100), causing thermal runaway of battery 100 in the pouch battery pack. The thermal runaway time of adjacent batteries 100 is calculated. The thermal runaway time of the pouch battery pack adjacent to the thermally runaway pouch battery in the three pouch battery packs is measured and the average value is calculated. If the average time is greater than 6 minutes, it is considered good; if it is within 5-6 minutes, it is considered qualified; and if it is less than 5 minutes, it is considered unqualified.

[0066] When the positive electrode active material of the battery is a nickel-cobalt-manganese ternary cathode, the upper limit voltage is 4.25V and the lower limit voltage is 2.5V. When the positive electrode active material of the battery is lithium iron phosphate, the upper limit voltage is 3.6V and the lower limit voltage is 2.5V.

[0067] In this test, the positive electrode active material of battery 100 is selected from lithium iron phosphate. 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. The ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0068] Performance Test 2 300 tear test on the isolation plate; Soft-pack battery packs were prepared according to the above-described method. 100 soft-pack battery packs were prepared for each embodiment and comparative example. The d1 value of the distance between the sealing edge 113 and the weak portion 310 of the separator 300, and the L1 value of the weak portion 310 on the separator 300, are shown in Table 1 below for each embodiment and comparative example. All other structures are identical. The soft-pack battery packs were subjected to random vibration in the Z / Y / X directions and sinusoidal constant-frequency vibration under the conditions described in GB38031-2020.8.2, with each direction undergoing continuous random vibration for 12 hours and sinusoidal constant-frequency vibration for 2 hours. Subsequently, the soft-pack battery packs of each embodiment and comparative example were placed at 50°C for 24 hours, and then... After being placed at ℃ for 30 minutes, the resistance between the first sealing edge 113 of the battery 100 and the separator 300 is tested using an insulation withstand voltage tester. One output terminal of the insulation withstand voltage tester is connected to the sealing edge 113 of the end battery 100 in the soft-pack battery pack, and the other end is connected to the separator 300. A DC voltage of 3000V is applied between the two output terminals, and the current is measured. The resistance value between the sealing edge 113 of the battery 100 and the separator 300 is calculated according to formula (1). The resistance of the three soft-pack battery packs is measured and the average value is taken. If the resistance value is greater than 600MΩ, it is good; if the resistance value is between 500MΩ and 600MΩ, it is qualified; if it is less than 500MΩ, it is unqualified. R=U / I (1).

[0069] In this test, the positive electrode active material of battery 100 is selected from lithium iron phosphate. 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. The ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2. Table 1 According to Table 1, in Examples 1-12, d1×L1 falls within the range of 250-4000 defined in this invention, and both the thermal runaway test of adjacent batteries 100 and the tear test of the separator 300 are qualified. In Comparative Example 1, d1×L1 is smaller, and the thermal runaway test of adjacent batteries 100 is unqualified. In Comparative Example 2, d1×L1 is larger, and the tear test of the separator 300 is unqualified. Therefore, it is demonstrated that within the scope defined in this invention, both the thermal runaway test of adjacent batteries 100 and the tear test of the separator 300 are qualified, proving that controlling d1×L1 can achieve non-obvious effects.

[0070] This invention also discloses an electrical device comprising at least one pouch battery pack as described above. The pouch battery pack can serve as the operating power source for the electrical device, or as the driving power source, replacing or partially replacing fuel or natural gas to provide driving power for a vehicle. The electrical device encompasses devices or equipment in numerous technical fields, including energy storage devices, electric ships, aircraft, laptops, power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, and aerospace.

[0071] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0072] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A pouch battery pack, characterized in that, The device includes at least two batteries, an end plate, and a separator plate. The at least two batteries are arranged along a first direction. Each battery includes a housing. The housing includes a first housing portion and a second housing portion disposed opposite to each other. The housing has a sealing edge for sealingly connecting the first housing portion and the second housing portion at the end plate. The end plate is disposed at at least one end of the battery along a second direction, the second direction being the length direction of the battery, and the second direction being perpendicular to the first direction. The end plate is provided with at least one through hole, and the through hole is disposed opposite to at least one of the sealing edges. The isolation plate is disposed between the end plate and the sealing edge, and the isolation plate has a weak portion disposed relative to the through hole, the size of the weak portion being smaller than the size of the through hole.

2. The soft-pack battery pack according to claim 1, characterized in that, The weak point includes a groove formed on the separator plate, the groove extending along the first direction and corresponding to the sealing edge of at least two of the batteries.

3. The soft-pack battery pack according to claim 1, characterized in that, The weak part includes a gap formed on the isolation plate, the size h1 of the gap along the third direction is smaller than the size h2 of the through hole along the third direction, and the third direction is perpendicular to both the first direction and the second direction.

4. The soft-pack battery pack according to claim 3, characterized in that, h1 and h2 satisfy the relationship: h2mm-h1mm≥6mm.

5. The pouch battery pack according to any one of claims 1-4, characterized in that, Along the second direction, the shortest distance between the weak part and the sealing edge is d1mm, and the dimension of the weak part along the first direction is L1mm. d1 and L1 satisfy the relationship: 250≤d1×L1≤4000.

6. The pouch battery pack according to any one of claims 1-4, characterized in that, The weak part has a dimension of L1mm along the first direction, and the through hole has a dimension of L2mm along the first direction. L1 and L2 satisfy the relationship: |L1mm-L2mm|≤10mm.

7. The pouch battery pack according to any one of claims 1-4, characterized in that, The size of a single weak portion along the first direction ranges from 50mm to 200mm.

8. The pouch battery pack according to any one of claims 1-4, characterized in that, When the thickness of the battery is greater than or equal to 10 mm, there are at least two weak points, and the at least two weak points are spaced apart along the first direction.

9. The soft-pack battery pack according to claim 8, characterized in that, The distance between two adjacent weak points is 40mm-80mm.

10. The soft-pack battery pack according to claim 8, characterized in that, The weak part is offset from the center line of the isolation plate extending in the first direction.

11. The soft-pack battery pack according to claim 10, characterized in that, The distance L3mm between the weak part and the center line of the isolation plate extending along the first direction is 20mm-40mm.

12. The pouch battery pack according to any one of claims 1-4, characterized in that, The weak portion is spaced apart from at least one end of the isolation plate along the first direction.

13. The pouch battery pack according to any one of claims 1-4, characterized in that, The isolation plate is an insulating plate, and the thickness of the isolation plate is less than the thickness of the end plate.

14. The pouch battery pack according to claim 12, characterized in that, The thickness of the isolation plate is 50μm-300μm.

15. The pouch battery pack according to any one of claims 1-4, characterized in that, Along the second direction, the shortest distance d1mm between the weak part and the sealing edge ranges from 5mm to 20mm.

16. The pouch battery pack according to any one of claims 1-4, characterized in that, The through hole has a size of 5mm-20mm along a third direction, and the third direction is perpendicular to both the first direction and the second direction.

17. The pouch battery pack according to any one of claims 1-4, characterized in that, The through holes are arranged at intervals along the first direction.

18. The pouch battery pack according to any one of claims 1-4, characterized in that, Along the second direction, the through hole and the weak part are spaced apart, and the spacing ranges from 2mm to 10mm.

19. The pouch battery pack according to any one of claims 1-4, characterized in that, The housing includes an outer insulating layer, a metal layer, and an inner insulating layer. The metal layer is disposed between the outer insulating layer and the inner insulating layer. The inner insulating layer of the first housing portion and the outer insulating layer of the second housing portion are bonded together to form a sealing edge.

20. The pouch battery pack according to claim 19, characterized in that, The dimension of the sealing edge along the second direction is less than or equal to 30 mm, and the dimension of the weak part along the first direction is ≥ 60 mm.

21. The pouch battery pack according to any one of claims 1-4, characterized in that, The end plate includes a first end plate and a second end plate, which are respectively disposed on both sides of the battery along the second direction.

22. The soft-pack battery pack according to claim 21, characterized in that, Both the first end plate and the second end plate are provided with the through hole.

23. The pouch battery pack according to any one of claims 1-4, characterized in that, The battery has a length of 400 mm or more, the through hole has a dimension of 6.5 mm or more along a third direction, and the third direction is perpendicular to the first direction and the second direction.

24. An electrical appliance, characterized in that, It includes at least one pouch cell battery pack as described in any one of claims 1-23.

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