Battery pack and power consuming device

Abstract

The utility model discloses a kind of battery pack and electric device, battery pack includes metal plate and soft package battery, soft package battery group includes shell and electric core, shell includes first edge portion and second edge portion, second edge portion is oppositely arranged with metal plate;Tab is led out from first edge portion, insulating layer is arranged between tab and first edge portion, insulating layer exceeds first edge portion edge;Second edge portion includes bending portion, the end face of second edge portion away from shell is first outer end face, tail end of second edge portion is between first outer end face and shell main body;The total length of second edge portion along unfolding direction is L, the minimum spacing between first outer end face and metal plate is d, the size that insulating layer exceeds first edge portion edge is m, satisfy, 6mm 2 ≤(L+d)*m≤200mm 2 Thus, tail end and metal plate lap joint short circuit risk can be reduced, space utilization can be improved, and the volume energy density of battery pack can be improved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to battery packs and electrical devices. Background Technology

[0002] With the development of new energy technologies, batteries are being widely used in various electrical devices. For example, batteries are now installed in vehicles in the form of battery packs.

[0003] In battery packs, the sealing edge of the pouch cell casing (such as an aluminum-plastic casing) and its nearby metal plate are prone to creepage or overlap, leading to the risk of external short circuits in the battery. Utility Model Content

[0004] In view of this, the present invention provides a battery pack and an electrical device to solve the problem that when the metal layer in the casing is close to the metal plate, creepage or contact can easily occur, leading to a short circuit in the battery.

[0005] In a first aspect, this utility model provides a battery pack, comprising: a metal plate; a battery, including a casing and a battery cell, the casing including a shell body for accommodating the battery cell and a sealing edge portion, the casing including an adhesive layer, a metal layer and a protective layer disposed sequentially, the adhesive layer being disposed close to the battery cell; the sealing edge portion including a first sealing edge portion and a second sealing edge portion, the second sealing edge portion being disposed opposite to the metal plate along a first direction; a tab electrically connected to the battery cell, the tab extending from the first sealing edge portion along a second direction, an insulating layer disposed between the tab and the first sealing edge portion, the insulating layer extending beyond the edge of the first sealing edge portion along the second direction. The direction is perpendicular to the second direction; wherein, the second sealing portion includes a bent portion, the bent portion causing the second sealing portion to bend and form at least two overlapping sealing segments, the end face of the second sealing portion away from the shell is the first outer end face, the tail end of the second sealing portion away from the cell is located between the first outer end face and the shell body; the length of the second sealing portion along the unfolding direction is L, the minimum distance between the first outer end face and the metal plate along the first direction is d, and the dimension of the insulating layer extending beyond the edge of the first sealing portion along the second direction is m, satisfying that, the units of L, d, and m are all mm, 6mm 2 ≤ (L+d)*m≤200mm 2 .

[0006] Beneficial effects: (L+d)*m is greater than or equal to 6mm 2 This can reduce the risk of battery short circuit caused by creepage or contact between the tail end and the metal plate, but (L+d)*m is too large, greater than 200mm. 2 This would lead to low space utilization, which is not conducive to improving battery energy density. Therefore, 6mm 2≤ (L+d)*m≤200mm 2 This can reduce the risk of short circuit when the tail end connects to the metal plate, and also improve space utilization and increase the volumetric energy density of the battery pack.

[0007] Secondly, this utility model provides an electrical device, including the aforementioned battery pack. Attached Figure Description

[0008] To more clearly illustrate the specific embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0009] Figure 1 This is a schematic diagram of the battery structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the battery cell structure according to an embodiment of the present invention; Figure 3 This is a partial structural diagram of the battery according to an embodiment of the present utility model; Figure 4 This is a partial structural schematic diagram of the battery pack according to an embodiment of the present utility model; Figure 5 This is a schematic diagram of the structure of the bent portion of the battery according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the bent portion of the battery in the bent state (solid line) and the unfolded state (dashed line) according to an embodiment of the present utility model. Figure 7 This is a cross-sectional view of the battery at the tab position according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the off-center bending portion of a battery according to another embodiment of the present invention. Figure 9 This is a schematic diagram of a structure in which an insulating element is provided between the bent portion and the metal plate in an embodiment of the present utility model. Figure 10 This is a schematic diagram of the welding structure of the electrode body and the connecting piece in an embodiment of the present utility model; Figure 11 This is a schematic diagram of the structure of the battery with a fastening strap according to an embodiment of the present invention; Figure 12 This is a schematic diagram of the battery pack structure according to an embodiment of the present invention; Figure 13 This is a schematic diagram of the battery pack according to another embodiment of the present invention.

[0010] Explanation of reference numerals in the attached figures: 10-Box body; 11-Metal plate; 12-Side wall; 20-Battery; 21-Shell; 201-Adhesive layer; 202-Metal layer; 203-Protective layer; 21a-First shell; 21b-Second shell; 211-First sealing edge; 212-Second sealing edge; 212a-First outer end face; 2121-Bending part; 2121a-First bending section; 2121b-Second bending section; 2122-Main body; 2122a-Sealing section; 213-Third sealing edge; 2 13a - First outer edge; 213b - Second outer edge; 214 - Shell body; 222 - Electrode; 222a - Electrode body; 222b - Connecting piece; 22 - Battery cell; 2221 - First electrode; 2222 - Second electrode; 30 - Insulating layer; 40 - Insulating component; 50 - Fastening band; C - Solder mark; O - Center; X - First direction; Y - Second direction; Z - Third direction; a1 - First connecting end; a2 - Tail end; a3 - First bent end; a4 - Second bent end. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0012] In battery packs, when the sealing edge of the soft-pack battery casing (such as an aluminum-plastic casing) is close to the metal plate opposite it, creepage or overlap can easily occur, causing a risk of battery short circuit.

[0013] Research has revealed that the primary cause of battery short circuits lies in the electrified metal layer at the edge of the casing seal, posing a short circuit risk. Although the metal layer of the pouch battery casing is protected by insulating layers on both the top and bottom, further investigation shows that when the distance between the current lead-out terminal tab and the sealing edge of the lead-out tab is too close, or when there are conductive foreign objects inside the battery pack, or when the insulating layer between the tab and the sealing edge exceeds the tab's allowable size and is insufficient to isolate the tab from the metal layer, creepage or overlap occurs between the tab and the metal layer of the sealing edge. This results in the entire metal layer of the pouch battery casing becoming electrified. After the batteries are assembled, this eventually leads to creepage or overlap between the sealing edge and the metal plate opposite it, causing multiple batteries to pass through the metal plate, resulting in a risk of a short circuit in the entire battery pack, triggering internal thermal runaway, and affecting battery safety.

[0014] To address this, this application bends the sealing edge opposite the metal plate, concealing the tail end of the sealing edge (the end with the exposed metal layer) between the first outer end face of the sealing edge away from the shell and the shell body. This reduces the risk of creepage or overlap between the metal layer of the sealing edge and the metal plate; by meeting the 6mm requirement... 2 ≤ (L+d)*m≤200mm 2 This design reduces the risk of creepage or overlap between the metal layer and the metal plate at the sealing edge, prevents overlap between the tail end and the metal plate, increases the creepage distance between the metal plate and the sealing edge, and improves the volumetric energy density of the battery pack. Wherein, L is the length of the second sealing portion 212 along the unfolding direction, d is the minimum distance between the first outer end face and the metal plate 11, and m is the dimension of the insulating layer 30 extending beyond the edge of the first sealing portion 211.

[0015] The following is combined Figures 1 to 13 The embodiments of this utility model will be described in detail below.

[0016] This utility model provides a battery pack, including a metal plate 11 and a pouch battery 20. The pouch battery 20 includes a casing 21 and a cell 22. The casing 21 may include a first casing 21a and a second casing 21b, which are disposed opposite to each other and sealed together along a third direction Z, forming a casing body 2143 for accommodating the cell 22 and a sealing edge portion. The sealing edge portion includes a first sealing edge portion 211 and a second sealing edge portion 212, which is disposed opposite to the metal plate 11 along a first direction X.

[0017] In this embodiment of the invention, the first direction X can be the width direction of the battery 20, the second direction Y can be the length direction of the battery 20, and the third direction Z can be the thickness direction of the battery 20. The first direction X, the second direction Y, and the third direction Z are all perpendicular to each other.

[0018] The aforementioned metal plate 11 can be the bottom wall of the housing 10, or a water-cooling plate between the bottom wall of the housing and the battery 20, etc. The material of the metal plate 11 can be at least one or more of the following materials or alloys: aluminum, aluminum alloy, copper, copper-aluminum alloy, steel, stainless steel, and nickel. This application does not impose any particular restrictions on the metal plate 11.

[0019] As an example, the housing 21 can be an aluminum-plastic housing. The housing body 2143 can be a recessed portion of the housing 21 for accommodating the battery cell, including a bottom wall and side walls of the recess. The sealing portion is a flange portion of the housing 21, with one end of the flange portion near the battery cell 22 connected to the edge of the recess, and the other end extending along the side away from the battery cell 22. The housing 21 is sealed by bonding or heat-fusion of the upper and lower flange portions.

[0020] A battery cell is the component in a battery where electrochemical reactions occur; it is the smallest unit in a battery capable of carrying out electrochemical reactions such as charging and discharging.

[0021] A battery cell is the basic unit of a battery, typically consisting of a positive electrode, a negative electrode, and a separator. Lithium-ion 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.

[0022] The positive electrode is one of the core components in a battery that carries the positive electrode active material. During charging, metal ions (e.g., lithium ions) are released from 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 released from the negative electrode and intercalated into the positive electrode active material (reduction reaction), thus realizing the storage and release of lithium ions.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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 the 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 negative electrode through the external circuit to maintain charge balance, thus achieving energy storage and release.

[0027] 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 polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc.). The negative electrode active layer includes a negative electrode active material, conductive components, and adhesives.

[0028] 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-ammonia composites. The conductive agent can be conductive carbon black, carbon nanotubes, etc., and the binder can be styrene-butadiene rubber, polyacrylic acid, etc.

[0029] The tab is located on one side of the positive / negative current collector cell and is separately or integrally formed with the current collector. It is electrically connected to the current collector to conduct the current on the corresponding current collector. When the tab and the current collector are separately set, the tab and the current collector can be connected by welding.

[0030] The tabs are made of a metal material with good electrical conductivity (such as copper, aluminum, copper or nickel).

[0031] The tab 222 and the cell 22 are integral structural components. For example, the cell 22 may include a cell body 221 and a tab 222. The cell body 221 includes a positive electrode, a negative electrode, and a separator. The tab 222 is electrically connected to the cell body 221 and extends from the first sealing edge 211 along the second direction Y. An insulating layer 30 is provided between the tab 222 and the first sealing edge 211. Along the second direction Y, the insulating layer 30 extends beyond the edge of the first sealing edge 211.

[0032] The tab 222 can be a separate structural component from the cell 22. For example, the cell 22 can include a cell body 221, which includes a positive electrode, a negative electrode, and a separator. The cell body 221 has a tab lead-out portion, and the tab 222 is electrically connected to the tab lead-out portion, such as by welding. The tab 222 is led out from the first sealing edge portion 211 as a transition component.

[0033] The battery cell 22 can be a wound core or a stacked core. The battery cell body 221 includes a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate. The insulating layer 30 can be made of insulating materials such as polypropylene (CPP), polyethylene (PE), polyethylene terephthalate (PET), polybutylene succinate (PBS), and polyimide (PI).

[0034] The second edge sealing portion 212 includes a bent portion 2121, which causes the second edge sealing portion 212 to bend and form at least two overlapping edge sealing segments. The end face of the second edge sealing portion 212 away from the shell 21 is the first outer end face 212a. Figure 4 As shown), the tail end a2 of the second edge sealing portion 212 is located between the first outer end face 212a and the shell body 2143. This can be understood as follows: after the second edge sealing portion 212 is bent, its tail end a2 is hidden between the first outer end face 212a and the shell body 2143. That is, the exposed metal layer of the tail end a2 of the second edge sealing portion 212 does not directly face the metal plate 11; the two are separated by the bent portion 2121. The number of bends of the second edge sealing portion 212 is unlimited, such as two folds, three folds, four folds, etc.

[0035] You can start bending from a position a certain distance away from the root of the second edge 212 (e.g.) Figure 12 As shown), it can also be bent from the root of the second sealing edge 212 (as shown). Figure 13 (As shown).

[0036] The total length of the second sealing part 212 along the unfolding direction is L ( Figure 6 As shown), along the first direction X, the minimum distance between the first outer end face 212a and the metal plate 11 is d ( Figure 4 As shown), along the second direction Y, the dimension by which the insulating layer 30 extends beyond the edge of the first sealing portion 211 is m ( Figure 3As shown), the units of L, d, and m are all mm, which satisfies 6mm. 2 ≤ (L+d)*m≤200mm 2 (L+d)*m can be 6mm. 2 10mm 2 20mm 2 30mm 2 40mm 2 80mm 2 100mm 2 120mm 2 130mm 2 150mm 2 200mm 2 Any one of the values, or any value in between. Preferably, 18mm. 2 ≤ (L+d)*m≤70mm 2 .

[0037] The larger the length L of the second sealing part 212 along the unfolding direction and the larger the minimum distance d between the bent part 2121 and the metal plate 11, the better it is to reduce the risk of short circuit when the tail end a2 and the metal plate 11 overlap. However, if L and d are too large, it will result in a large space occupation and low space utilization. After the battery is assembled, it will occupy a large space of the battery pack, which is not conducive to improving the volumetric energy density of the battery pack and will affect the overall range of the battery pack.

[0038] The larger the dimension m of the insulating layer 30 extending beyond the edge of the first sealing portion 211, the larger the size of the electrode tab 222 covered. The lower the risk of creepage and overlap between the electrode tab 222 and the intermediate metal layer 202 of the first sealing portion 211, thereby reducing the risk of creepage or overlap between the second sealing portion 212 and the metal plate 11. However, if the dimension m of the insulating layer 30 extending beyond the edge of the first sealing portion 211 is too large, it will encroach on the exposed size of the electrode tab 222, which is not conducive to the reliability of the connection between the electrode tab 222 and external components (such as busbars).

[0039] Therefore, by adjusting the size of (L+d), the risk of short circuit between the tail end a2 and the metal plate 11 can be directly controlled, and by adjusting the size of m, the risk of short circuit between the tail end a2 and the metal plate 11 can be indirectly controlled.

[0040] When 6mm 2 ≤ (L+d)*m≤200mm 2 This not only reduces the risk of short circuit when the tail end a2 connects to the metal plate 11, but also improves space utilization, increases the volumetric energy density of the battery pack, and is beneficial to the reliability of the connection between the tab 222 and external components.

[0041] In some embodiments, refer to Figure 4The second sealing portion 212 also includes a main body portion 2122, which connects the shell body 2143 and the bending portion 2121. Along the first direction X, the main body portion 2122 has a first connecting end a1 that connects to the shell body 2143. The distance between the first connecting end a1 and the metal plate 11 is H1, satisfying 2.1mm ≤ H1 ≤ 19mm. H1 can be any value among 2.1mm, 5mm, 8mm, 13mm, 16mm, 18mm, and 19mm, or any value between two of these.

[0042] A larger H1 is more conducive to increasing the minimum distance d between the bent portion 2121 and the metal plate 11, reducing the risk of short circuit when the tail end a2 overlaps with the metal plate 11. However, an excessively large H1 will result in a large space occupation and low space utilization, which is not conducive to improving the volumetric energy density of the battery pack. Therefore, 2.1mm≤H1≤19mm can both reduce the risk of short circuit when the tail end a2 overlaps with the metal plate 11 and improve space utilization, thereby increasing the volumetric energy density of the battery pack.

[0043] In some embodiments, the second sealing portion 212 further includes a main body portion 2122, which connects the shell body 214 and the bending portion 2121. Along the first direction X, the main body portion 2122 has a first connecting end a1 connected to the shell body 2143, and the bending portion 2121 has a first bent end a3 connected to the main body portion 2122. Along the first direction X, the distance between the first bent end a3 and the first connecting end a1 is L1, satisfying 0.1mm ≤ L1 ≤ 4mm. L1 can be any value among 0.1mm, 0.5mm, 1mm, 2mm, 2.5mm, 3mm, and 4mm, or any value between two of these.

[0044] A larger L1 makes bending easier, improving manufacturing efficiency and yield, and reducing the risk of gas generated during cell 22 cycling breaking through the main body 2122. However, an excessively large L1 occupies more space, resulting in low space utilization and hindering the improvement of the battery pack's volumetric energy density. Therefore, a value of 0.1mm ≤ L1 ≤ 4mm facilitates bending, improves processing efficiency and yield, reduces the risk of gas generated during cell 22 cycling breaking through the main body 2122 and causing cracking, and also improves space utilization, thereby increasing the battery pack's volumetric energy density.

[0045] In some embodiments, along the first direction X, the distance between the first bent end a3 and the metal plate 11 is H2, satisfying 1.5mm ≤ H2 ≤ 12mm. H2 can be any value among 1.5mm, 3mm, 4mm, 4.5mm, 5.5mm, 7mm, 8mm, 9mm, 10mm, 10.5mm, 11mm, and 12mm, or any value between any two. As an example, refer to... Figure 4The bending portion 2121 includes a first bending segment 2121a and a second bending segment 2121b. The first bending segment 2121a connects the main body portion 2122 and the second bending segment 2121b. The first bending segment 2121a bends relative to the main body portion 2122 along a third direction Z. The second bending segment 2121b bends relative to the first bending segment 2121a along the other side of the third direction Z. The second bending segment 2121b is located on the side of the first bending segment 2121a away from the metal plate 11 along a first direction X. The end of the second bending segment 2121b away from the first bending segment 2121a is the tail end a2.

[0046] A larger H2 is more conducive to increasing the minimum distance d between the bent portion 2121 and the metal plate 11, reducing the risk of short circuit when the tail end a2 overlaps with the metal plate 11. However, an excessively large H2 will result in a large space occupation and low space utilization, which is not conducive to improving the volumetric energy density of the battery pack. Therefore, 1.5mm≤H2≤12mm can both reduce the risk of short circuit when the tail end a2 overlaps with the metal plate 11 and improve space utilization, thereby increasing the volumetric energy density of the battery pack.

[0047] In some embodiments, the bending portion 2121 includes a first bending segment 2121a and a second bending segment 2121b. The first bending segment 2121a connects the main body portion 2122 and the second bending segment 2121b. The first bending segment 2121a bends relative to the main body portion 2122 along a third direction Z, and the second bending segment 2121b bends relative to the first bending segment 2121a along the other side of the third direction Z. The second bending segment 2121b is located on the side of the first bending segment 2121a away from the metal plate 11 along a first direction X. The end of the second bending segment 2121b away from the first bending segment 2121a is the tail end a2. Along the third direction Z, the distance between the second bending end a4 and the first bending end a3 is L2, which satisfies 3mm ≤ L2 ≤ 8mm. L2 can be any value among 3mm, 4mm, 4.5mm, 5mm, 6mm, 7mm, and 8mm, or any value between two of them. As an example, the second bend segment 2121b has a second bend end a4 connected to the first bend segment 2121a.

[0048] A larger L2 is more conducive to reducing stress concentration in the first bending segment 2121a, reducing the risk of the first bending segment 2121a springing open, and in the event that gas is generated during the cycle of the cell 22 and breaks through the main body 2122, a longer first bending segment 2121a can reduce the risk of further cracking caused by gas. However, if L2 is too large, it will result in a large space occupation and low space utilization, which is not conducive to improving the volumetric energy density of the battery pack. Therefore, 3mm≤L2≤8mm can reduce stress concentration in the first bending segment 2121a, reduce the risk of the first bending segment 2121a springing open, reduce the risk of cracking caused by gas being generated during the cycle of the cell 22 and breaking through the first bending segment 2121a, and improve space utilization and increase the volumetric energy density of the battery pack.

[0049] In some embodiments, the bending portion 2121 includes a first bending segment 2121a and a second bending segment 2121b. The first bending segment 2121a connects the main body portion 2122 and the second bending segment 2121b. The first bending segment 2121a bends relative to the main body portion 2122 along a third direction Z. The second bending segment 2121b bends relative to the first bending segment 2121a along the other side of the third direction Z. The second bending segment 2121b is located on the side of the first bending segment 2121a away from the metal plate 11 along a first direction X. The end of the second bending segment 2121b away from the first bending segment 2121a is the tail end a2. Along the third direction Z, the distance between the second bending end a4 and the tail end a2 is L3, satisfying 2mm ≤ L3 ≤ 6mm. L3 can be any value among 2mm, 4mm, 5mm, 5.5mm, and 6mm, or any value between two of them.

[0050] A larger L3 is more conducive to reducing stress concentration in the second bending segment 2121b, reducing the risk of the second bending segment 2121b springing open, and in the event that gas is generated during the cycle of cell 22 and breaks through the first bending segment 2121a, a longer second bending segment 2121b can reduce the risk of further cracking caused by gas. However, an excessively large L3 will result in a large space occupation and low space utilization, which is not conducive to improving the volumetric energy density of the battery pack. Therefore, 2mm≤L3≤6mm can reduce stress concentration in the first bending segment 2121a, reduce the risk of the first bending segment 2121a springing open, reduce the risk of cracking caused by gas being generated during the cycle of cell 22 and breaking through the second bending segment 2121b, and improve space utilization and increase the volumetric energy density of the battery pack.

[0051] In some embodiments, along the first direction X, the distance between the tail end a2 and the metal plate 11 is H3, which satisfies 1.9mm≤H3≤17mm. H3 can be any value among 1.9mm, 2.5mm, 3mm, 3.5mm, 5.5mm, 7mm, 8mm, 9mm, 12mm, 14mm, 16mm, and 17mm, or any value between two of them.

[0052] A larger H3 is more conducive to increasing the distance between the tail end a2 and the metal plate 11, reducing the risk of short circuit due to contact between the tail end a2 and the metal plate 11. However, an excessively large H3 will result in a large space occupation and low space utilization, which is not conducive to improving the volumetric energy density of the battery pack. Therefore, 1.9mm≤H3≤17mm can both reduce the risk of short circuit due to contact between the tail end a2 and the metal plate 11 and improve space utilization, thereby increasing the volumetric energy density of the battery pack.

[0053] In some embodiments, the second sealing portion 212 is formed by a sealing connection between the first housing 21a and the second housing 21b, and the main body portion 2122 has a sealing section 2122a ( Figure 5 (As shown). The entire main body 2122 is a sealing section 2122a, or it may be partially a sealing section 2122a.

[0054] By having a sealing section 2122a in the main body 2122, the sealing effect of the second sealing section 212 can be improved, reducing the risk of leakage caused by gas generation during the battery cell 22 cycle breaking through the second sealing section 212.

[0055] In some embodiments, refer to Figure 5 Along the first direction X, the distance H4 between the edge of the sealing section 2122a near the shell body 2143 and the first connecting end a1 satisfies 0.5mm≤H4≤6mm. H4 can be any value among 0.5mm, 2mm, 3mm, 4mm, 5mm, and 6mm, or any value between two of them.

[0056] The larger H4 is, the longer the sealing section 2122a is, which is more conducive to improving the sealing effect of the second sealing edge 212 and reducing the risk of leakage caused by gas generation during the cycle of the battery cell 22 breaking through the second sealing edge 212. However, if H4 is too large, the utilization rate of the housing space will be reduced. Therefore, 0.5mm≤H4≤6mm can improve both the sealing effect of the second sealing edge 212 and the utilization rate of the housing space.

[0057] In some embodiments, the length of the sealing segment 2122a along the unfolding direction of the second sealing portion 212 is L4, satisfying 0.3≤L4 / L≤0.96. L4 / L can be any value among 0.3, 0.4, 0.5, 0.6, 0.75, and 0.96, or any value between two of them. L4 can be 6mm to 15mm.

[0058] The larger the L4 / L ratio, the higher the proportion of the sealing section 2122a, which is more conducive to improving the sealing effect of the second sealing edge 212 and reducing the risk of leakage caused by gas generation during the battery cell 22 cycle breaking through the second sealing edge 212. However, if the L4 / L ratio is too large, it will encroach on the size of the bending part 2121, causing the bending part 2121 to easily spring open, resulting in the risk of short circuit between the middle metal layer of the tail end a2 and the metal plate 11. Therefore, 0.3≤L4 / L≤0.75 can both improve the sealing effect of the second sealing edge 212 and reduce the risk of short circuit between the middle metal layer of the tail end a2 and the metal plate 11 caused by the bending part 2121 springing open.

[0059] In some embodiments, along the third direction Z, the distance between the tail end a2 and the end where the sealing section 2122a connects to the first connecting end a1 is L5, satisfying 0mm≤L5≤5mm. L5 can be any value among 0mm, 1mm, 2mm, 3mm, 4mm, and 5mm, or any value between two of them.

[0060] A larger L5 is more conducive to preventing the tail end a2 from rubbing against the sealing section 2122a, thus reducing the risk of wear. However, if L5 is too large, it will encroach on the size of the second bending section 2121b, resulting in a high risk of the second bending section 2121b springing open, which could cause the middle metal layer of the tail end a2 to overlap and short-circuit with the metal plate 11. Therefore, 0mm≤L5≤5mm can both prevent the tail end a2 from rubbing against the sealing section 2122a and reduce the risk of the second bending section 2121b springing open, which could cause the middle metal layer of the tail end a2 to overlap and short-circuit with the metal plate 11.

[0061] In some embodiments, the length L of the second sealing portion 212 along the unfolding direction satisfies 8mm≤L≤20mm. L can be any value among 8mm, 9mm, 11mm, 13mm, 15mm, 16mm, 18mm, and 20mm, or any value between two of them.

[0062] The distance d between the bent part 2121 and the metal plate 11 satisfies 2mm≤d≤15mm. d can be any value among 2mm, 4mm, 6mm, 10mm, 12mm, 14mm, and 15mm, or any value between two of them.

[0063] The greater the length L of the second sealing portion 212 along the unfolding direction, and / or the greater the minimum distance d between the bent portion 2121 and the metal plate 11, the better it is to reduce the risk of short circuit when the tail end a2 overlaps with the metal plate 11. However, if L and / or d are too large, it will result in a large space occupation and low space utilization, which is not conducive to improving the volumetric energy density of the battery pack. Therefore, 8mm≤L≤20mm and / or 2mm≤d≤15mm are beneficial to both reducing the risk of short circuit when the tail end a2 overlaps with the metal plate 11 and improving the volumetric energy density of the battery pack.

[0064] In some embodiments, refer to Figure 7 Both the first housing 21a and the second housing 21b include an adhesive layer 201, a metal layer 202, and a protective layer 203. The metal layer 202 is disposed between the adhesive layer 201 and the protective layer 203. A portion of the adhesive layer 201 of each of the first housing 21a and the second housing 21b located at the first sealing portion 211 is bonded to the insulating layer 30, and the other portion is bonded to each other. The adhesive layers 201 of each of the first housing 21a and the second housing 21b located at the second sealing portion 212 are bonded to each other. The bonding can be achieved by heat fusion or by adhesive.

[0065] The protective layer 203 serves as an outer insulating layer, and its material can be one or more of the following: polycaprolactam (nylon 6), PET (polyethylene terephthalate), polybutylene succinate, etc. The metal layer 202 can be one or more of the following metals or alloys: aluminum, aluminum alloy, copper, nickel, etc. The adhesive layer 201 serves as the inner insulating layer, and its material can be one or more of materials such as polypropylene film (PP) and cast polypropylene film (CPP).

[0066] The nylon layer is responsible for maintaining the shape stability of the aluminum-plastic film, ensuring that the film does not deform during the manufacturing process of lithium-ion batteries.

[0067] The primary function of the 202 metal layer is waterproofing. Lithium batteries are extremely sensitive to moisture, and the packaging film must effectively prevent water vapor intrusion. Nylon itself is not waterproof and cannot meet this requirement, while aluminum, after reacting with oxygen in the air, forms a dense oxide film, thus preventing water vapor penetration and protecting the inside of the battery cell. In addition, the aluminum layer also provides the necessary plasticity during the aluminum-plastic film molding process to meet the requirements of the perforation process.

[0068] The PP layer, or polypropylene layer, has the property of melting at high temperatures and being adhesive. The battery's thermal sealing process mainly relies on the PP layer melting and bonding together when the end caps are heated, followed by curing and bonding during cooling.

[0069] The sealing effect of the battery is improved by bonding a portion of the adhesive layer 201 of the first housing 21a and the second housing 21b to the insulating layer 30.

[0070] In some embodiments, refer to Figure 5 The first bend end a3 has a rounded corner with a radius of R, satisfying 0.5mm≤R≤3mm. R can be any value among 0.5mm, 0.7mm, 1mm, 1.5mm, 2.5mm, and 3mm, or any value between two of them.

[0071] A larger R value reduces stress concentration at the first bending end a3, thus lowering the risk of fracture. However, an excessively large R value occupies more space, resulting in low space utilization and hindering the improvement of the battery pack's volumetric energy density. Therefore, a value of 0.5mm ≤ R ≤ 3mm can both reduce stress concentration at the first bending end a3, lowering the risk of fracture, and reduce space occupation, thereby improving the battery pack's volumetric energy density.

[0072] In some embodiments, refer to Figure 7 The thickness of the metal layer is D1, and the total thickness of the first sealing portion 211 or the second sealing portion 212 is D2, satisfying 0.075 ≤ D1 / D2 ≤ 0.25. D1 / D2 can be any value from 0.075, 0.1, 0.12, 0.2, 0.25, or any value between two of these. The total thickness of the first sealing portion 211 or the second sealing portion 212 can be twice the thickness of the unheated portion of the shell. D1 can be 0.03mm to 0.1mm. D2 can be 0.06mm to 0.4mm.

[0073] The smaller the ratio of D1 to D2, the thinner the metal layer, which is more conducive to bending. However, if D1 / D2 is too small, the strength of the metal layer will be low. Therefore, 0.075≤D1 / D2≤0.25 is convenient for bending while ensuring the strength of the first sealing part 211 or the second sealing part 212.

[0074] In some embodiments, refer to Figure 5 The second sealing portion 212 also includes a main body portion 2122, which connects the shell body 2143 and the bending portion 2121; the bending portion 2121 has a first bending end a3 connected to the main body portion 2122; along the first direction X, the cell body 221 includes an electrode, and the distance between the edge of the electrode near the metal plate 11 and the first bending end a3 is H5, which satisfies 0.3mm≤H5≤7mm.

[0075] Since the first bending end a3 is the first crack risk point of the bending part 2121, the larger H5 is, the lower the risk of gas in the shell 21 breaking through the first bending end a3, thus improving the bonding reliability of the bending part 2121. However, if H5 is too large, the electrode space will be small, resulting in low space utilization, which is not conducive to improving the volumetric energy density. Therefore, 0.3mm≤H5≤7mm can reduce the risk of gas in the shell 21 breaking through the first bending end a3, reduce space occupation, and improve volumetric energy density.

[0076] In some embodiments, the closest distance between the first connecting end a1 and the shell body 2143 is L6, and the first bending segment 2121a of the bending portion 2121 bends toward the surface opposite to the nearest shell body 2143, satisfying 2mm≤L6≤10mm. L6 can be any value of 2mm, 3mm, 4mm, 5mm, 7mm, 8mm, 9mm, or 10mm, or any value between two of them.

[0077] Specifically, along the third direction Z, the shell body 2143 has a first outer edge 213a and a second outer edge 213b; the distance L6 between the first connecting end a1 and the first outer edge 213a is less than the distance between the first connecting end a1 and the second outer edge 213b, and the first bent segment 2121a bends in a direction away from the first outer edge 213a.

[0078] The first connecting end a1 can be offset from the center O of the shell body 2143 ( Figure 5 (As shown), it can also be located at the center O of the shell body 2143. When the first connecting end a1 is offset from the center O of the shell body 2143, the length of the bending part 2121 along the unfolding direction can be increased, reducing the risk of the bending part 2121 springing open due to stress. When the first connecting end a1 is located at the center O of the shell body 2143, the gas generated by the cell 22 during circulation is less likely to break through the second sealing part 212, reducing the risk of the second sealing part 212 cracking and leaking.

[0079] In some embodiments, along the third direction Z, the length between the first outer edge 213a and the second outer edge 213b of the shell body 2143 is L7, satisfying 0.08 ≤ L6 / L7 ≤ 0.4. L6 / L7 can be any one of 0.08, 0.1, 0.12, 0.2, 0.25, 0.3, 0.35, 0.4 or any value between two of them. L7 can be 6mm to 25mm.

[0080] The larger L6 / L7 is, the more the first connection end a1 deviates from the center O of the shell body 2143, which can increase the length of the bending part 2121 along the unfolding direction and reduce the risk of the bending part 2121 springing open due to stress. If L6 / L7 is too large, the gas generated by the circulation of the cell 22 is more likely to accumulate on one side, which increases the risk of breaking through the second sealing edge 212. Therefore, 0.08≤L6 / L7≤0.4 can reduce both the risk of the bending part 2121 springing open due to stress and the risk of gas breaking through the second sealing edge 212.

[0081] In some embodiments, along the third direction Z, the first connecting end a1 is offset from the center O of the shell body 2143, and the distance between the first connecting end a1 and the center O of the shell body 2143 is L8, satisfying 0.2mm≤L8≤25mm. L8 can be any value among 0.2mm, 0.5mm, 2mm, 4mm, 6mm, 8mm, 12mm, 15mm, 22mm, 23mm, and 25mm, or any value between two of them.

[0082] The larger L8 is, the longer the bending portion 2121 is along the unfolding direction, reducing the risk of the bending portion 2121 springing open due to stress. If L8 is too large, the gas generated by the cell 22 during circulation will accumulate on one side, causing it to break through the second sealing portion 212. Therefore, 0.2mm≤L8≤25mm can reduce both the risk of the bending portion 2121 springing open due to stress and the risk of the cell 22 generating gas during circulation breaking through the second sealing portion 212, leading to cracking and leakage.

[0083] In some embodiments, along the third direction Z, the distance L9 between the tail end a2 and the first outer edge 213a is less than the distance between the tail end a2 and the second outer edge 213b, satisfying 3mm≤L9≤10mm. L9 can be any value among 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, and 10mm, or any value between two of them.

[0084] The larger L9 is, the greater the distance between the bent portion 2121 and the center O of the shell body 2143, which can increase the length of the bent portion 2121 along the unfolding direction and reduce the risk of the bent portion 2121 springing open due to stress. However, if L9 is too large, the gas generated by the circulating battery cell 22 will accumulate on one side and break through the second sealing edge 212. Therefore, 3mm≤L9≤10mm can reduce both the risk of the bent portion 2121 springing open due to stress and the risk of the gas generated by the circulating battery cell 22 breaking through the second sealing edge 212.

[0085] In some embodiments, refer to Figure 9An insulating member 40 is provided between the metal plate 11 and the bent portion 2121. The thickness of the insulating member 40 along the first direction X is D3, which satisfies 0.1mm≤D3≤2mm. D3 can be any value among 0.1mm, 0.5mm, 1mm, 1.2mm, 1.5mm, and 2mm, or any value between two of them.

[0086] The insulating component 40 can be an insulating layer on the surface of the metal plate 11 facing the bend 2121, or it can be a component independent of the metal plate 11.

[0087] The greater the thickness D3 of the insulating component 40, the better it is to reduce the risk of short circuit when the tail end a2 of the bent portion 2121 overlaps with the metal plate 11; however, if the thickness D3 of the insulating component 40 is too large, it will result in a large space occupation and low space utilization, which is not conducive to improving the volumetric energy density of the battery pack; therefore, 0.1mm≤D3≤2mm can both reduce the risk of short circuit when the tail end a2 of the bent portion 2121 overlaps with the metal plate 11 and improve the volumetric energy density of the battery pack.

[0088] In some embodiments, the insulating member 40 extends beyond at least one end of the bent portion 2121 at opposite ends along the second direction Y.

[0089] Since the metal layers at both ends of the bend 2121 along the second direction Y are exposed to the outside, if the metal layers are charged, there is a risk of short circuit with the adjacent metal parts. By extending the insulating member 40 beyond at least one end of the bend 2121 along the second direction Y, the risk of short circuit between the metal layers at both ends of the bend 2121 and the nearby metal parts can be reduced.

[0090] In some embodiments, along the second direction Y, the extension dimension of the insulating member 40 beyond the bend 2121 on the same side is L10, satisfying 1mm≤L10≤15mm. L10 can be any value among 1mm, 2mm, 5mm, 8mm, 10mm, 12mm, 14mm, and 15mm, or any value between two of them.

[0091] The larger L10 is, the lower the probability of a short circuit between the metal layers at opposite ends of the bending portion 2121 along the second direction Y and the nearby metal parts; however, if L10 is too large, it will result in a large space occupation and low space utilization, which is not conducive to improving the volumetric energy density of the battery pack; therefore, 1mm≤L10≤15mm can both reduce the risk of a short circuit between the metal layers at opposite ends of the bending portion 2121 along the second direction Y and the nearby metal parts, and improve the volumetric energy density of the battery pack.

[0092] In some embodiments, the metal plate 11 extends beyond at least one end of the bent portion 2121 along the second direction Y, and the extension dimension is L11, satisfying 2mm≤L11≤30mm. L11 can be any value among 2mm, 4mm, 10mm, 15mm, 20mm, 25mm, and 30mm, or any value between two of them.

[0093] Typically, structural adhesive is used to fill the space between the metal plate 11 and the battery 20 to secure the battery 20 and suppress expansion during battery cycling. A larger L11 provides better support for the battery 20, but an excessively large L11 will lead to wasted space in the housing 10 and reduce the volumetric energy density of the battery pack. Therefore, 2mm ≤ L11 ≤ 30mm provides good support for the battery 20 while minimizing the volumetric energy density of the battery pack.

[0094] In some embodiments, refer to Figure 12 The battery pack also includes a housing 10, which includes a bottom wall and two side walls 12. The two side walls 12 are connected to opposite sides of the bottom wall along the third direction Z. The bottom wall and the two side walls 12 form a groove for accommodating multiple batteries 20. The bottom wall is a metal plate 11. Along the first direction X, the dimension of the side wall 12 is L12, which satisfies 70mm ≤ L12 ≤ 110mm. L12 can be any value among 70mm, 80mm, 90mm, 100mm, 105mm, 106mm, 107mm, 108mm, 109mm, and 110mm, or any value between two of them. Along the first direction X, the dimension L12 of the side wall 12 can be 80% to 120% of the battery height.

[0095] The larger the size L12 of the side wall 12, the better the effect of suppressing the expansion of the battery 20. However, if L12 is too large, it will lead to wasted space in the housing 10 and reduce the volumetric energy density of the battery pack. Therefore, 70mm≤L12≤110mm can not only effectively suppress the expansion of the battery 20, but also reduce the volumetric energy density of the battery pack.

[0096] In some embodiments, the dimension m of the insulating layer 30 extending beyond the edge of the first sealing portion 211 satisfies 0.5mm ≤ m ≤ 6mm. m can be any value among 0.5mm, 0.8mm, 1.5mm, 2mm, 2.5mm, 4mm, 5mm, and 6mm, or any value between two of them.

[0097] The larger M is, the lower the risk of creepage or overlap between the tab 222 and the metal layer of the first sealing edge 211. However, if M is too large, it will encroach on the exposed size of the tab 222, which is not conducive to the connection between the tab 222 and the external connecting parts. Therefore, 0.5mm≤m≤6mm can reduce the risk of creepage or overlap between the tab 222 and the metal layer of the first sealing edge 211, and also facilitate the connection between the tab 222 and the external connecting parts.

[0098] In some embodiments, refer to Figure 1 The edge sealing portion also includes a third edge sealing portion 213, which is disposed opposite to the first edge sealing portion 211 along the second direction Y; the electrode tab 222 includes a first electrode tab 2221 and a second electrode tab 2222, which are respectively connected to the two sides of the battery cell body 221 along the second direction Y. The first electrode tab 2221 is led out from the first edge sealing portion 211, and the second electrode tab 2222 is led out from the third edge sealing portion 213.

[0099] The first tab 2221 and the second tab 2222 are led out from both sides of the housing 21. Compared with the same-side leading out method, this can alleviate the problem of sealing failure caused by overheating and cracking of the sealing edge on one side.

[0100] In some embodiments, refer to Figure 10 The tab 222 includes a tab body 222a and a connecting piece 222b. The tab body 222a is connected to the cell body 221. The connecting piece 222b is welded to the tab body 222a to form a solder mark C. The connecting piece 222b extends out of the first sealing edge 211 along the second direction Y. The distance between the solder mark C and the insulating layer 30 is m1, which satisfies 0.5mm ≤ m1 ≤ 5mm. m1 can be any value among 0.5mm, 1mm, 2mm, 4mm, 4.5mm, and 5mm, or any value between two of them.

[0101] The larger m1 is, the larger the size of the insulation layer 30 that avoids the solder mark C, reducing the risk of the insulation layer 30 being burned by heat during welding. However, if m1 is too large, it will lead to low space utilization of the casing 21 and reduce the volumetric energy density of the battery. Therefore, 0.5mm≤m1≤5mm can both reduce the risk of the insulation layer 30 being burned by heat during welding and improve the space utilization of the casing 21, thereby increasing the volumetric energy density of the battery.

[0102] In some embodiments, refer to Figure 7 Along the third direction Z, the thickness of the insulating layer 30 is D4, which satisfies 0.03mm≤D4≤0.8mm. D4 can be any value among 0.03mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, and 0.8mm, or any value between two of them.

[0103] The thicker the insulation layer 30 is, the lower the risk of creepage or overlap between the tab 222 and the metal layer of the first sealing edge 211. However, if D4 is too thick, it is not conducive to heat sealing and bonding, and the seal is prone to failure. Therefore, 0.03mm≤D4≤0.8mm can reduce the risk of creepage or overlap between the tab 222 and the metal layer of the first sealing edge 211, and also improve the sealing effect.

[0104] In some embodiments, refer to Figure 3 Along the third direction Z, the insulating layer 30 and the shell 21 have an overlapping portion; along the second direction Y, the size of the overlapping portion is m2, which satisfies 2mm≤m2≤8mm. m2 can be any value among 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, and 8mm, or any value between two of them.

[0105] The larger m2 is, the larger the bonding size between the insulation layer 30 and the shell 21, and the better the sealing effect. However, if m2 is too large, it will encroach on the internal space of the shell 21, reduce the space utilization of the shell 21, and reduce the volumetric energy density of the battery. Therefore, 2mm≤m2≤8mm can improve both the sealing effect and the volumetric energy density of the battery.

[0106] In some embodiments, refer to Figure 12 Multiple batteries 20 are provided, and the multiple batteries 20 are arranged along the third direction Z. The housing 21 includes a first surface, which is the surface with the largest area in the housing 21. The first surfaces of two adjacent batteries 20 are arranged opposite each other.

[0107] Multiple batteries 20 are arranged together in a large area, which can improve the volumetric energy density and the structural strength of the multiple batteries 20.

[0108] In some embodiments, the metal plate 11 is located below the bend 2121 along the first direction X.

[0109] Therefore, the bending part 2121 is protected from the risk of being forced open (unfolded) by stress by the weight of the battery 20 itself.

[0110] In some embodiments, refer to Figure 11 The battery 20 also includes a plurality of fastening straps 50, which are spaced apart along the second direction Y. One end of each fastening strap 50 is connected to the outer surface of the first housing 21a, and the other end of each fastening strap 50 passes around the bend 2121 and is connected to the outer surface of the second housing 21b. The width of the fastening strap 50 along the second direction Y is W, which satisfies 10mm ≤ W ≤ 30mm. W can be any value among 10mm, 12mm, 13mm, 16mm, 20mm, 25mm, and 30mm, or any value between two of them.

[0111] Each battery 20 can be individually secured with a fastening strap 50. Alternatively, multiple batteries 20 can be secured with a single fastening strap 50.

[0112] The bending portion 2121 is restrained by the fastening band 50 to prevent the bending portion 2121 from springing open due to stress. The larger W is, the larger the bonding area between the fastening band 50 and the shell 21, and the better the restraining ability of the bending portion 2121. However, if W is too large, it will lead to waste of the fastening band 50 and increase material costs. Therefore, 10mm≤W≤30mm can effectively prevent the bending portion 2121 from springing open due to stress and also prevent waste of the fastening band 50 and increase material costs.

[0113] In some embodiments, the bend 2121 is located at the top of the battery 20 along the first direction X; the battery pack also includes a limiting member that abuts against the bend 2121. The limiting member may be a fastening band, a limiting pressure plate, etc.

[0114] When the bent portion 2121 is located at the top of the battery 20, the bending portion 2121 is pressed by the limiting member and kept in a bent state to prevent the bending portion 2121 from springing open due to stress.

[0115] In some embodiments, refer to Figure 12 At least the first bent segment 2121a of the bent portion 2121 in at least two adjacent batteries 20 is bent in a direction away from each other. This facilitates the series connection of two adjacent batteries 20.

[0116] In other embodiments, the first bending segment 2121a of the bending portion 2121 in at least two adjacent batteries 20 bends toward the same side.

[0117] In some embodiments, refer to Figure 12 Along the third direction Z, in two adjacent batteries 20, the distance between the tail ends a2 of the two bends is Q, which satisfies 5mm≤Q≤40mm. Q can be any value among 5mm, 6mm, 15mm, 25mm, 35mm, and 40mm, or any value between two of them.

[0118] The larger the distance Q between the tail ends a2 of the two bends, the lower the risk of short circuit between the tail ends a2 of the two adjacent batteries 20. However, if Q is too large, the distance between the two batteries 20 will increase, which will lead to low space utilization of the housing 10 and is not conducive to the volumetric energy density of the battery pack. Therefore, 5mm≤Q≤40mm can reduce the risk of short circuit between the tail ends a2 of the two adjacent batteries 20 and improve the volumetric energy density of the battery pack.

[0119] This utility model also provides an electrical device, including the battery pack mentioned in any of the above embodiments.

[0120] Battery packs can serve as the operating power source for electrical devices, or as the driving power source for electrical devices, replacing or partially replacing fuel or natural gas to provide driving power for vehicles. Electrical devices encompass a wide range of technological fields, including energy storage devices, electric boats, aircraft, laptops, power tools, electric bicycles, electric motorcycles, electric cars, military equipment, and aerospace.

[0121] Preparation of each embodiment of the pouch cell: Preparation of negative electrode: (1) Mix the negative electrode active material, conductive agent, binder and dispersant, add solvent to obtain negative electrode slurry, wherein the mass percentage of negative electrode active material: conductive agent: binder: dispersant is (90-98): (0-5): (1.5-5): (0.3-1.5), coat the negative electrode slurry on at least one surface of the negative electrode current collector, dry, roll and cut to obtain negative electrode sheet; a) The negative electrode active material is selected from carbon materials, silicon-based materials, and lithium titanate (Li4Ti5O4). 12 One or more of the following; Specifically, the carbon material can be selected from one or more of the following: natural graphite, artificial graphite, mesophase carbon microspheres, hard carbon, and soft carbon. Specifically, the silicon-based material can be selected from one or more of elemental silicon, silicon oxides, silicon carbide compounds, and silicon alloys; b) The conductive agent is selected from one or more of the following: superconducting carbon (SP), conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. c) The adhesive is selected from at least one of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resins (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and sodium carboxymethyl methyl ester (CMC); d) The dispersant is selected from at least one of the following: acrylic acid, acrylate, polyether ester, phosphate ester, small molecule alkanolamine, polyurethane, modified styrene / maleic anhydride, HNBR, and PVP; e) The current collector is selected from metal foil or composite current collector; Specifically, the metal foil can be copper or a copper alloy; Specifically, the composite current collector includes an intermediate high-polymer layer and metal layers disposed on both sides of the polymer layer. The polymer layer comprises polymer materials, including polyamide (PA), polyterephthalate, polyimide (PI), polyethylene (PE), polypropylene (PP), polystyrene (PPE), polyvinyl chloride (PVC), aramid, acrylonitrile-butadiene-styrene copolymer (ABS), polybutylene terephthalate (PET), poly(p-phenylene terephthalamide) (PPTA), polypropylene (PPE), polyoxymethylene (POM), epoxy resin, phenolic resin, polytetrafluoroethylene (PTEE), polyvinylidene fluoride (PVDF), silicone rubber, polycarbonate (PC), polyvinyl alcohol (PVA), and polyethylene glycol (PEG). At least one of cellulose, starch, protein, their derivatives, their cross-links and their copolymers; The metal layer is selected from at least one of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy; f) The solvent is selected from water.

[0122] (2) The positive electrode active material is mixed with conductive agent, binder and dispersant, and a solvent is added to obtain positive electrode slurry, wherein the mass percentage of positive electrode active material: conductive agent: binder: dispersant is (90-99%): (0.5-5%): (0.5-5%): (0-2%); the positive electrode slurry is coated on at least one surface of the positive electrode current collector, dried, rolled and cut to obtain positive electrode sheet; a) The positive electrode active material is selected from one or more of lithium cobalt oxide (LCO), nickel cobalt manganese ternary material (NCM), nickel cobalt aluminum ternary material (NCA), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LFP), lithium nickel manganese oxide (LNMO), and lithium manganese iron phosphate (LMFP); b) The conductive agent is selected from at least one of superconducting carbon (SP), acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers. c) The adhesive is selected from at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin; d) Dispersants are selected from acrylic acid, acrylate, polyether ester, phosphate ester, small molecule alkanolamine, polyurethane, modified styrene / maleic anhydride, HNBR, PVP, and polyethylene glycol (PEG); Note: LFP and LMFP will be added, but ternary and lithium nickel manganese oxide are not added at present, mainly because LFP and LFMP particles are small and are prone to agglomeration.

[0123] e) The current collector can be a metal foil or a composite current collector; Specifically, the metal foil can be aluminum or an aluminum alloy; Specifically, the composite current collector includes an intermediate high-polymer layer and metal layers disposed on both sides of the polymer layer. The polymer layer comprises polymer materials, including polyamide (PA), polyterephthalate, polyimide (PI), polyethylene (PE), polypropylene (PP), polystyrene (PPE), polyvinyl chloride (PVC), aramid, acrylonitrile-butadiene-styrene copolymer (ABS), polybutylene terephthalate (PET), poly(p-phenylene terephthalamide) (PPTA), polypropylene (PPE), polyoxymethylene (POM), epoxy resin, phenolic resin, polytetrafluoroethylene (PTEE), polyvinylidene fluoride (PVDF), silicone rubber, polycarbonate (PC), polyvinyl alcohol (PVA), and polyethylene glycol (PEG). At least one of cellulose, starch, protein, their derivatives, their crosslinks and their copolymers; the metal layer may include at least one of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy; f) The solvent is selected from NMP.

[0124] (3) Electrolyte preparation Ethylene carbonate, dimethyl carbonate, and diethyl carbonate are mixed in a volume ratio of 25~35:60~70:2~8, and lithium salt is added to prepare an electrolyte with a concentration of 0.5~2.5 mol / L. a) The lithium salt is selected from at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0125] (4) Selection of diaphragm The diaphragm can be at least one of glass fiber, non-woven fabric, polyethylene (PE), polypropylene (PP) and polyvinylidene fluoride; the diaphragm surface can also be coated, the coating can be an inorganic coating and, or an organic coating, wherein the inorganic coating material includes at least one of alumina, silicon oxide, titanium oxide, magnesium oxide, zirconium oxide and boehmite; the organic coating includes at least one of aramid coating and polyvinylidene fluoride (PVDF) coating.

[0126] (5) Battery manufacturing The above-mentioned positive electrode, separator, negative electrode, and separator are stacked in sequence, and the bare cell is obtained after stacking or winding.

[0127] (6) Electrode welding The bare cell's positive electrode foil is soldered to the positive electrode tab, and the bare cell's negative electrode foil is soldered to the negative electrode tab. Insulating tape is then applied at the soldering points.

[0128] (7) Battery packaging The battery obtained in step (6) is placed in an aluminum-plastic film with pits, and an insulating layer is set between the positive and negative tabs and the aluminum-plastic film. The edges are then sealed with a heat sealer, and an injection port is reserved.

[0129] (8) Injection The battery obtained in step (7) is injected with liquid through the injection hole, and after standing, it is evacuated.

[0130] (9) Formation The battery obtained in step (8) is subjected to formation treatment.

[0131] (10) Final sealing The battery obtained in step (9) is vented, and the venting area is then heat-sealed to obtain the batteries of Examples 1-25, as shown in Table 1: Space utilization test: For each embodiment and comparative example, 10 batteries were taken. The batteries were prepared by the above method. After stacking the batteries with their large surfaces facing each other, the positive and negative tabs of adjacent batteries were welded on. A metal plate was placed on the side with the bend. The minimum distance d between the metal plate and the bend, the length L of the second sealing edge along the unfolding direction, and the dimension m of the insulation layer extending beyond the sealing edge of the shell at the tab are shown in Table 1 below. Except for the other structures, they are the same, including the distance of the tab extending beyond the insulation layer. The battery pack was placed on a horizontal plane parallel to the bottom surface. The maximum height h1 of the battery pack in the direction perpendicular to the bottom surface was measured. At the same time, the maximum length L1 and the maximum width d1 of the battery pack in the direction parallel to the bottom surface were measured. The length direction is the tab lead-out direction, and the width direction is the direction perpendicular to the length direction. The volume of the battery pack was calculated according to the formula V1=L1*d1*h1. The volume of a single battery was measured in the same way and recorded as V2. According to the formula space utilization rate = The space utilization rate is calculated. If the space utilization rate is greater than 85%, it is considered qualified; otherwise, it is considered unqualified.

[0132] Insulation performance test: For each embodiment and comparative example, 50 batteries were used. The batteries were prepared using the method described above. Ten batteries were stacked face-to-face, and a stainless steel plate was placed on one side of the battery bend. The minimum distance d between the plate and the bend, the length L of the second sealing edge along the unfolding direction, and the distance m of the insulation layer extending beyond the casing sealing edge at the tab are shown in Table 1. All other structures were identical, resulting in five battery packs. An insulation withstand voltage test was used to measure only the resistance between the battery and the aluminum alloy plate. One output terminal of the insulation withstand voltage tester was connected to the stainless steel plate, and the other terminal was connected to the battery bend. A DC voltage of 3000V was applied between the two output terminals, and the current was measured. The resistance between the battery bend and the stainless steel plate was calculated using the formula R=U / I. The resistance of the five battery packs in each embodiment and comparative example was measured and averaged to obtain the test results. Specific results are shown in Table 1. If the obtained resistance is greater than or equal to 500MΩ, the insulation between the battery and the aluminum alloy plate is qualified; if the obtained resistance is less than 500 MΩ, the insulation between the battery and the aluminum alloy plate is unqualified.

[0133] Table 1

[0134] As shown in Table 1, (L+d)*m is less than 6mm in Comparative Example 1 and Comparative Example 3. 2 While this method achieves better space utilization, the insulation resistance is significantly lower than that in Examples 1-25 where (L+d)*m is within 6mm. 2 ~200mm 2 The insulation resistance value within the specified range indicates that (L+d)*m is greater than or equal to 6mm. 2 At this time, the risk of battery short circuit is low, and (L+d)*m is less than 6mm. 2 At that time, the risk of battery short circuit is relatively high; in Comparative Example 2 and Comparative Example 4, (L+d)*m is greater than 200mm. 2 While a better insulation effect can be achieved, the space utilization rate is significantly lower than that in Examples 1-25 where (L+d)*m is within 6mm. 2 ~200mm 2 Space utilization rate within the range, indicating that (L+d)*m is less than or equal to 200mm. 2 At that time, the space utilization rate was relatively high, therefore, 6mm 2 ≤ (L+d)*m≤200mm 2 This can reduce the risk of battery short circuits and achieve a high space utilization rate.

[0135] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application, are intended to cover non-exclusive inclusion. In the description of embodiments of this application, technical terms such as "first," "second," etc., are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of embodiments of this application, "a plurality of" means two or more, unless otherwise expressly and specifically defined. The reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0136] In the description of the embodiments of this application, the technical terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "circumferential," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed, operated, or used in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0137] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0138] 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 such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery pack, characterized in that, include: Metal plate (11); A soft-pack battery (20) includes a casing (21) and a battery cell (22). The casing (21) includes a casing body (214) for accommodating the battery cell (22) and a sealing portion. The casing includes an adhesive layer (201), a metal layer (202), and a protective layer arranged sequentially. The adhesive layer is disposed close to the battery cell. The sealing portion includes a first sealing portion (211) and a second sealing portion (212). The second sealing portion (212) is disposed opposite to the metal plate (11) along a first direction (X). A tab (222) is electrically connected to the battery cell. The tab (222) is led out from the first sealing portion (211) along a second direction (Y). An insulating layer (30) is disposed between the tab (222) and the first sealing portion (211). Along the second direction (Y) of the tab's lead-out direction, the insulating layer (30) extends beyond the edge of the first sealing portion (211). The first direction (X) is perpendicular to the second direction (Y). The second sealing portion (212) includes a bending portion (2121), which causes the second sealing portion to bend and form at least two overlapping sealing segments. The end face of the second sealing portion away from the shell is the first outer end face. The tail end (a2) of the second sealing portion (212) away from the cell (22) is located between the first outer end face and the shell body (214). The total length of the second sealing portion (212) along the unfolding direction is L. Along the first direction (X), the minimum distance between the first outer end face and the metal plate (11) is d. Along the second direction (Y), the dimension by which the insulating layer (30) extends beyond the edge of the first sealing portion (211) is m. The units of L, d, and m are all mm, which satisfies the condition 6mm. 2 ≤ (L+d)*m≤200mm 2 .

2. The battery pack according to claim 1, characterized in that, The second edge sealing portion (212) includes a main body portion (2122), which connects the shell body (214) and the bending portion (2121). Along the first direction (X), the main body (2122) has a first connecting end (a1) connected to the shell body (214), and the distance between the first connecting end (a1) and the metal plate (11) is H1, which satisfies 2.1mm≤H1≤19mm.

3. The battery pack according to claim 1, characterized in that, The second edge sealing portion (212) includes a main body portion (2122), which connects the shell body (214) and the bending portion (2121). Along the first direction (X), the main body (2122) has a first connection end (a1) that is connected to the shell body (214). The bending portion (2121) has a first bending end (a3) ​​connected to the main body portion (2122). Along the first direction (X), the distance between the first bending end (a3) ​​and the first connecting end (a1) is L1, which satisfies 0.1mm≤L1≤4mm.

4. The battery pack according to claim 1, characterized in that, The second sealing portion (212) includes a main body portion (2122) that connects the shell body (214) and the bending portion (2121); along the first direction (X), the main body portion (2122) has a first connecting end (a1) that connects to the shell body (214); the bending portion (2121) has a first bending end (a3) ​​that connects to the main body portion (2122); Along the first direction (X), the distance between the first bent end (a3) ​​and the metal plate (11) is H2, which satisfies 1.5mm≤H2≤12mm.

5. The battery pack according to claim 1, characterized in that, The second edge sealing portion (212) includes a main body portion (2122) that connects the shell body (214) and the bending portion (2121); the bending portion (2121) has a first bending end (a3) ​​that connects to the main body portion (2122). The bending portion (2121) includes a first bending segment (2121a) and a second bending segment (2121b). The first bending segment (2121a) connects the main body portion (2122) and the second bending segment (2121b). The first bending segment (2121a) bends relative to the main body portion (2122) along a third direction (Z). The second bending segment (2121b) bends relative to the first bending segment (2121a) along the other side of the third direction. The second bending segment (2121b) is located on the side of the first bending segment (2121a) away from the metal plate (11) along the first direction (X). The first direction (X), the second direction (Y), and the third direction (Z) are perpendicular to each other. The bent portion (2121) has a second bent end (a4) connected to the first bent segment (2121a). Along the third direction (Z), the distance between the second bent end (a4) and the first bent end (a3) ​​is L2, which satisfies 3mm≤L2≤8mm.

6. The battery pack according to claim 1, characterized in that, The second edge sealing portion (212) includes a main body portion (2122) that connects the shell body (214) and the bending portion (2121); the bending portion (2121) has a first bending end (a3) ​​that connects to the main body portion (2122). The bending portion (2121) includes a first bending segment (2121a) and a second bending segment (2121b). The first bending segment (2121a) connects the main body portion (2122) and the second bending segment (2121b). The first bending segment (2121a) bends relative to the main body portion (2122) along a third direction (Z). The second bending segment (2121b) bends relative to the first bending segment (2121a) along the other side of the third direction (Z). The second bending segment (2121b) is located on the side of the first bending segment (2121a) away from the metal plate (11) along the first direction (X). The end of the second bending segment (2121b) away from the first bending segment (2121a) is the tail end (a2). The first direction (X), the second direction (Y), and the third direction (Z) are perpendicular to each other. The bent portion (2121) has a second bent end (a4) connected to the first bent segment (2121a). Along the third direction (Z), the distance between the second bent end (a4) and the tail end (a2) is L3, which satisfies 2mm≤L3≤6mm.

7. The battery pack according to claim 1, characterized in that, Along the first direction (X), the distance between the tail end (a2) and the metal plate (11) is H3, which satisfies 1.9mm≤H3≤17mm.

8. The battery pack according to claim 1, characterized in that, The housing (21) includes a first housing (21a) and a second housing (21b), and the second sealing portion (212) is formed by sealing the first housing (21a) and the second housing (21b); the main body portion (2122) of the second sealing portion has a sealing section (2122a).

9. The battery pack according to claim 8, characterized in that, Along the first direction (X), the main body (2122) has a first connection end (a1) that is connected to the shell body (214). Along the first direction (X), the distance between the sealing section (2122a) near the edge of the shell body (214) and the first connecting end (a1) is H4, which satisfies 0.5mm≤H4≤6mm.

10. The battery pack according to claim 8, characterized in that, The length of the sealing section (2122a) along the unfolding direction of the second sealing portion (212) is L4, which satisfies 0.3≤L4 / L≤0.

96.

11. The battery pack according to claim 8, characterized in that, Along the unfolding direction of the second sealing portion (212), the distance from the edge of the sealing section (2122a) away from the shell body (214) to the tail end (a2) is L5, which satisfies 0mm≤L5≤5mm.

12. The battery pack according to claim 1, characterized in that, The length L of the second sealing portion (212) along the unfolding direction satisfies 8mm ≤ L ≤ 20mm; and / or, The minimum distance d between the bent portion (2121) and the metal plate (11) satisfies 2mm≤d≤15mm.

13. The battery pack according to any one of claims 1-12, characterized in that, The housing (21) includes a first housing (21a) and a second housing (21b). Both the first housing (21a) and the second housing (21b) include an adhesive layer (201), a metal layer (202), and a protective layer (203). The metal layer (202) is disposed between the adhesive layer (201) and the protective layer (203). A portion of the adhesive layer (201) of each of the first housing (21a) and the second housing (21b) located at the first edge sealing portion (211) is bonded to the insulating layer (30), and the other portion is bonded to each other. The adhesive layers (201) of each of the first housing (21a) and the second housing (21b) located at the second edge sealing portion (212) are bonded to each other.

14. The battery pack according to claim 13, characterized in that, The second edge sealing portion (212) includes a main body portion (2122), which connects the shell body (214) and the bending portion (2121); the bending portion (2121) has a first bending end (a3) ​​connected to the main body portion (2122). The first bent end (a3) ​​has a rounded corner, and the radius of the rounded corner is R, which satisfies 0.5mm≤R≤3mm.

15. The battery pack according to claim 13, characterized in that, The thickness of the metal layer is D1, and the total thickness of the first sealing portion (211) or the second sealing portion (212) is D2, satisfying that 0.075≤D1 / D2≤0.

25.

16. The battery pack according to any one of claims 1-12, characterized in that, The second edge sealing portion (212) includes a main body portion (2122), which connects the shell body (214) and the bending portion (2121); the bending portion (2121) has a first bending end (a3) ​​connected to the main body portion (2122). The battery cell (22) includes an electrode sheet. Along the first direction (X), the distance between the edge of the electrode sheet near the metal plate (11) and the first bent end (a3) ​​is H5, which satisfies 0.3mm≤H5≤7mm.

17. The battery pack according to any one of claims 1-12, characterized in that, The second sealing portion (212) includes a main body portion (2122) that connects the shell body (214) and the bending portion (2121); along the first direction (X), the main body portion (2122) has a first connecting end (a1) that connects to the shell body (214). Along the third direction (Z), the shell body (214) has a first outer edge (213a) and a second outer edge (213b) opposite each other; the distance L6 between the first connecting end (a1) and the first outer edge (213a) is less than the distance between the first connecting end (a1) and the second outer edge (213b), and the bent portion (2121) bends in a direction away from the first outer edge (213a), satisfying 2mm≤L6≤10mm.

18. The battery pack according to claim 17, characterized in that, Along the third direction (Z), the length between the first outer edge (213a) and the second outer edge (213b) of the shell body (214) is L7, which satisfies 0.08≤L6 / L7≤0.

4.

19. The battery pack according to claim 17, characterized in that, Along the third direction (Z), the first connecting end (a1) is offset from the center of the shell body (214), and the distance between the first connecting end (a1) and the center of the shell body (214) is L8, which satisfies 0.2mm≤L8≤25mm.

20. The battery pack according to any one of claims 1-12, characterized in that, Along the third direction (Z), the shell body (214) has opposing first outer edge (213a) and second outer edge (213b); Along the third direction (Z), the distance L9 between the tail end (a2) and the first outer edge (213a) is less than the distance between the tail end (a2) and the second outer edge (213b), satisfying 3mm≤L9≤10mm.

21. The battery pack according to any one of claims 1-12, characterized in that, An insulating member (40) is provided between the metal plate (11) and the bent portion (2121). Along the first direction (X), the thickness of the insulating member (40) is D3, which satisfies 0.1mm≤D3≤2mm.

22. The battery pack according to claim 21, characterized in that, The insulating member (40) extends beyond at least one end of the bent portion (2121) along the second direction (Y) at opposite ends.

23. The battery pack according to claim 22, characterized in that, Along the same side of the second direction (Y), the extension dimension of the insulating member (40) beyond the bending portion (2121) is L10, which satisfies that 1mm≤L10≤15mm.

24. The battery pack according to any one of claims 1-12, characterized in that, The metal plate (11) extends beyond at least one end of the bent portion (2121) along the second direction (Y) at opposite ends, and the extension dimension is L11, satisfying 2mm≤L11≤30mm.

25. The battery pack according to claim 1, characterized in that, The battery pack also includes: The housing (10) includes a bottom wall and two side walls (12), the two side walls (12) being connected to opposite sides of the bottom wall along a third direction (Z), the bottom wall and the two side walls (12) forming a groove for accommodating a plurality of batteries (20), the bottom wall including the metal plate (11). Along the first direction (X), the dimension of the sidewall (12) is L12, which satisfies 70mm≤L12≤110mm.

26. The battery pack according to any one of claims 1-12, characterized in that, The dimension m of the insulating layer (30) extending beyond the edge of the first sealing portion (211) satisfies 0.5mm≤m≤6mm.

27. The battery pack according to claim 26, characterized in that, The edge sealing portion further includes a third edge sealing portion (213), which and the first edge sealing portion (211) are disposed opposite to each other along the second direction (Y); The electrode tab (222) includes a first electrode tab (2221) and a second electrode tab (2222), the first electrode tab (2221) being led out from the first sealing portion (211) and the second electrode tab (2222) being led out from the third sealing portion (213).

28. The battery pack according to any one of claims 1-12, characterized in that, The tab (222) includes a tab body (222a) and a connecting piece (222b). The tab body (222a) is electrically connected to the electrode of the battery cell. The connecting piece (222b) is welded to the tab body (222a) to form a solder mark (C). The connecting piece (222b) extends out of the first sealing edge (211) along the second direction (Y). The distance between the solder mark (C) and the insulating layer (30) is m1, which satisfies 0.5mm≤m1≤5mm.

29. The battery pack according to any one of claims 1-12, characterized in that, Along the third direction (Z), the thickness of the insulating layer (30) is D4, which satisfies 0.03mm≤D4≤0.8mm, and the first direction (X), the second direction (Y) and the third direction (Z) are perpendicular to each other.

30. The battery pack according to any one of claims 1-12, characterized in that, Along the third direction (Z), the insulating layer (30) and the housing (21) have overlapping portions, and the first direction (X), the second direction (Y) and the third direction (Z) are perpendicular to each other; Along the second direction (Y), the size of the overlapping portion is m2, which satisfies 2mm≤m2≤8mm.

31. The battery pack according to claim 1, characterized in that, The battery (20) is provided in multiple ways. The housing (21) includes two first surfaces facing each other along the third direction Z. The first surface is the surface with the largest area in the housing (21). The multiple batteries (20) are arranged along the third direction (Z), and the first surfaces of two adjacent batteries (20) are arranged facing each other.

32. The battery pack according to claim 31, characterized in that, The bent portion (2121) is located at the bottom of the battery (20) along the first direction (X).

33. The battery pack according to claim 31, characterized in that, The battery (20) also includes a plurality of fastening straps (50), which are spaced apart along the second direction (Y). One end of each fastening strap (50) is connected to the first outer surface of the housing (21), and the other end of each fastening strap (50) passes around the bend (2121) and is connected to the second outer surface of the housing (21). The second outer surface is opposite to the first outer surface along a third direction. The first direction (X), the second direction (Y), and the third direction (Z) are perpendicular to each other. Along the second direction (Y), the width of the fastening strap (50) is W, which satisfies that 10mm≤W≤30mm.

34. The battery pack according to claim 31, characterized in that, Along the first direction (X), the bend (2121) is located on top of the battery (20); The battery pack also includes a limiting member that abuts against the bent portion (2121).

35. The battery pack according to claim 31, characterized in that, The bends (2121) in at least two adjacent batteries (20) are bent in a direction away from each other.

36. The battery pack according to claim 31, characterized in that, Along the third direction (Z), in two adjacent batteries (20), the distance between the tail ends (a2) of the two bent portions (2121) is Q, which satisfies 5mm≤Q≤40mm.

37. The battery pack according to any one of claims 1-12, characterized in that, 18mm 2 ≤(L+d)*m≤70mm 2 。 38. An electrical appliance, characterized in that, Includes the battery pack as described in any one of claims 1-37.

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