Battery and battery pack

Abstract

The utility model relates to battery technology field discloses a kind of battery and battery pack, battery includes electric core and shell;Shell contains electric core, shell includes first shell and second shell, first shell and second shell are all included edge portion, the edge portion of first shell and the edge portion of second shell are sealed connection and form sealing edge, sealing edge has sealing connection section;Along the extension direction of edge portion, the interval distance between the one end of sealing connection section close to electric core and the pole piece of electric core is L, the length of sealing connection section is A, satisfy, 3mm 2 ≤L*A≤40mm 2 The utility model can reduce the risk of gas breaking through the sealing connection section, and improve the volumetric energy density.

Description

Technical Field

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

[0002] With the development of new energy technologies, batteries are widely used in various electrical devices. For example, pouch batteries, due to their flexible size design and relatively simple manufacturing, have been widely used in passenger vehicles, energy storage, and other fields.

[0003] However, pouch batteries are more prone to deformation and will generate gas during the charge and discharge cycle. As the gas accumulates, it can easily break through the seal, causing the battery seal to fail. Utility Model Content

[0004] In view of this, the present invention provides a battery and battery pack to solve the problem of gas generation in soft-pack batteries breaking through the sealing edge, leading to sealing failure.

[0005] The first aspect of this utility model provides a battery, comprising: a battery cell; and a casing for housing the battery cell. The casing includes a first casing and a second casing, both of which include a sealing edge portion. The sealing edge portion of the first casing and the sealing edge portion of the second casing are sealed together to form a sealing edge. The sealing edge has a sealing connection section. Along the extending direction of the sealing edge portion, the distance between the end of the sealing connection section near the battery cell and the electrode of the battery cell is L, where L and A are both in mm. The length of the sealing connection section is A, which satisfies 3 mm. 2 ≤L*A≤40mm 2 .

[0006] Beneficial effects: When L*A is too small, or L or A is too small, the electrode is too close to the sealed connection section, or the sealed connection section is too small, making it easier for gas to break through the sealed connection section and cause seal failure. When L*A is too large, or L or A is too large, the electrode is too far from the sealed connection section, or the sealed connection section is too large, resulting in low space utilization inside the battery or after battery assembly, which is not conducive to improving volumetric energy density. Therefore, by controlling 3mm... 2 ≤L*A≤40mm 2 This can reduce the risk of gas breaking through the sealed connection section and increase the volumetric energy density.

[0007] A second aspect of this invention provides a battery pack comprising at least two batteries as described in the first aspect, wherein the at least two batteries are arranged along a first direction. 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 cross-sectional view of the battery according to an embodiment of the present invention; Figure 3 This is a cross-sectional view of a battery according to another embodiment of the present invention; Figure 4 This is a cross-sectional view of a battery according to another embodiment of the present invention; Figure 5 This is a cross-sectional view of a battery according to another embodiment of the present invention; Figure 6 This is a partial structural diagram of the shell with a bent portion according to an embodiment of the present utility model; Figure 7 This is a schematic diagram of the battery pack structure according to an embodiment of the present invention; Figure 8 This is a structural schematic diagram of the shell in the unfolded state according to an embodiment of the present invention.

[0010] Explanation of reference numerals in the attached figures: 10-Battery cell; 11-Battery cell body; 12-Electrode tab; 20-Housing shell; 21-First housing shell; 22-Second housing shell; 23-Sealing edge; 23a-First sealing edge; 23b-Second sealing edge; 23c-Third sealing edge; 24-Connecting part; 25-Integral connecting part; 26-Bending part; 121-First electrode tab; 122-Second electrode tab; 201-Inner insulation layer; 202-Intermediate metal layer; 203-Outer insulation layer; 204-Groove; 211-First surface; 221-Second surface; 231-Sealed connecting section; 251-Protruding section; X-First direction; Y-Second direction; Z-Third direction; a2-Tail end; a3-First bending end; a4-First bending 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] The casing of a pouch battery consists of a metal layer and an insulating layer. The sealing edge needs to be heat-fused or bonded together, that is, the two opposing adhesive layers (such as CPP layers) of the casing are heat-fused to form the sealing edge. If the adhesive dimension of the sealing edge is too large, it will occupy too much space when the battery is assembled, which is not conducive to improving the volumetric energy density. If the adhesive dimension is too small, the sealing edge may be broken through as gas accumulates during battery circulation, causing battery sealing failure.

[0013] To address this, the length A of the sealing connection section at the sealing edge and the interval L between the electrode and the sealing connection section are limited to meet the 3mm requirement. 2 ≤L*A≤40mm 2 When L*A is too small, or L or A is too small, the electrode is too close to the sealed connection section, or the sealed connection section is too small, both of which can easily cause gas to break through the sealed connection section, leading to battery seal failure. When L*A is too large, or L or A is too large, the electrode is too far from the sealed connection section, or the sealed connection section is too large, both of which can lead to low space utilization and are not conducive to improving volumetric energy density. Therefore, by controlling 3mm... 2 ≤L*A≤40mm 2 This can reduce the risk of gas breaking through the sealed connection section and also help to improve the volumetric energy density.

[0014] The following is combined Figures 1 to 8 The following describes embodiments of the present invention.

[0015] An embodiment of this utility model provides a battery, including a battery cell 10 and a casing 20. The casing 20 houses the battery cell 10 and includes a first casing 21 and a second casing 22. Both the first casing 21 and the second casing 22 include a sealing edge portion 23. The sealing edge portion of the first casing 21 and the sealing edge portion 23 of the second casing 22 are sealed together to form a sealing edge, and the sealing edge has a sealing connection section 231. Along the extending direction of the sealing edge portion 23 ( Figure 2 In the second direction (Y), the distance between the end of the sealing connection section 231 near the cell 10 and the end of the electrode of the cell 10 is L, and the length of the sealing connection section 231 is A, which satisfies 3mm. 2 ≤L*A≤40mm 2L*A can be any value among 3mm, 5mm, 10mm, 25mm, 30mm, 35mm, and 40mm, or any value between two of them.

[0016] The electrode includes a current collector and an active material layer coated on at least one surface of the current collector, wherein the end of the electrode is the end of the active material layer.

[0017] The sealing portion 23 is a flange structure of the housing 20. The sealing portions 23 of the first housing 21 and the second housing 22 can be connected as a whole by heat fusion sealing, and this whole constitutes a sealing edge. The sealing connection section 231 is the area where the two sealing portions 23 are bonded. The sealing portions 23 extend toward the side away from the battery cell 10.

[0018] Research has found that the main reasons why the sealing edge is easily broken are, in addition to the high risk of deformation of the soft-pack battery itself and the weaker strength of the heat-melted sealing layer of the casing compared to the metal welding layer, that the cell is too close to the sealing section after generating heat and the size of the sealing section is broken too quickly. This leads to the failure of the battery casing seal, causing high-temperature gas, liquid, and solid substances inside the battery to be ejected, which exacerbates the risk of battery thermal runaway and affects the safety of battery use.

[0019] When L*A is too small, or L or A is too small, the electrode is too close to the sealed connection section, or the sealed connection section is too small, making it easier for gas to break through the sealed connection section and cause battery seal failure. When L*A is too large, or L or A is too large, the electrode is too far from the sealed connection section, or the sealed connection section is too large, resulting in low space utilization and hindering the improvement of volumetric energy density. Therefore, by controlling 3mm... 2 ≤L*A≤40mm 2 This can reduce the risk of gas breaking through the sealed connection section and increase the volumetric energy density.

[0020] Reference Figure 4 The housing 20 may include an inner insulating layer 201 (heat-sealing layer), an intermediate metal layer 202 (aluminum foil barrier layer), and an outer insulating layer 203 (protective layer). The thickness of the inner insulating layer 201 (heat-sealing layer) may be 30μm to 100μm. The thickness of the intermediate metal layer 202 (aluminum foil barrier layer) may be 35μm to 70μm. The thickness of the outer insulating layer 203 (protective layer) may be 15μm to 40μm. The sealing portion of the first housing 21 and the sealing portion 23 of the second housing 22 are sealed together by their respective inner insulating layers 201 (heat-sealing layers).

[0021] The outer insulation layer 203 can be made of one or more of the following materials: polycaprolactam (nylon 6), PET (polyethylene terephthalate), polybutylene succinate, etc.

[0022] The intermediate metal layer 202 can be one or more of the following metals or alloys: aluminum, aluminum alloy, copper, nickel, etc.

[0023] The inner insulation layer 201 can be one or more materials such as polypropylene film (PP) and cast polypropylene film (CPP).

[0024] 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.

[0025] The primary function of the intermediate metal layer 202 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.

[0026] 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.

[0027] In some embodiments, at least one of the first housing 21 and the second housing 22 is formed with a groove 204, and the groove sidewall of the groove 204 is transitionally connected to the sealing connection section 231 via a connecting portion 24. The distance L1 along the extending direction between the first end of the connecting portion 24 connected to the groove sidewall and the second end of the connecting portion 24 connected to the sealing connection section 231 satisfies 0.5mm≤L1≤5mm. The groove 204 is used to accommodate the battery cell 10. L1 can be any value of 0.5mm, 1mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, or any value between two of these.

[0028] If L1 is too large, it will occupy too much of the sealing edge size, resulting in an insufficiently small size for the sealing connection section 231. This leads to a smaller effective bonding size at the sealing edge, increasing the risk of gas rupture causing seal failure. Therefore, controlling L1 within the range of 0.5mm≤L1≤5mm can reduce the occupancy of the sealing edge, increase the size of the sealing connection section 231, thereby increasing the effective bonding size at the sealing edge and reducing the risk of seal failure caused by gas rupture.

[0029] In some embodiments, the connecting portion 24 is an arc connecting portion, and the radius corresponding to the arc connecting portion is R, which satisfies 0.5mm≤R≤5mm. R can be any value of 0.5mm, 1mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm or any value between two of them.

[0030] The smaller R is, the smaller the size occupied by the sealing edge, the larger the effective bonding size of the sealing edge, and the lower the risk of gas breaking through the sealing connection section 231 and causing sealing failure. However, if R is too small, the stress concentration of the shell 20 at the connection part 24 is severe, which causes the shell 20 to deform and the risk of the sealing connection section 231 cracking. Therefore, 0.5mm≤R≤5mm can reduce the risk of sealing failure caused by cracking of the sealing connection section 231.

[0031] In some embodiments, 0.2mm ≤ L ≤ 3mm. L can be any one of 0.2mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.5mm, and 3mm, or any value between two of them.

[0032] The larger the value of L, the farther the electrode is from the end of the sealed connection section 231 closest to the cell 10, and the lower the risk of gas breaking through the sealed connection section 231 and causing sealing failure. However, if L is too large, the utilization rate of the battery's internal space will be low, which is not conducive to improving the battery's volumetric energy density, and more electrolyte will be required, increasing costs. Therefore, 0.2mm≤L≤3mm can both reduce the risk of gas breaking through the sealed connection section 231 and improve the battery's volumetric energy density while reducing costs.

[0033] In some embodiments, the total length A of the sealing connection segment 231 satisfies 6mm ≤ A ≤ 15mm. A can be any one of 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, and 15mm, or any value between two of them.

[0034] If A is too small (less than 6mm), the sealed connection section is too small, making it easier for gas to break through the seal and cause battery seal failure. If A is too large (greater than 15mm), the sealed connection section is too large, resulting in low space utilization and hindering the improvement of volumetric energy density. Therefore, by controlling 6mm ≤ A ≤ 15mm, the risk of gas breaking through the sealed connection section can be reduced while improving volumetric energy density.

[0035] In some embodiments, the battery cell 10 includes a battery cell body, which includes a positive electrode, a negative electrode, and a separator. The separator is located between the positive electrode and the negative electrode. The positive electrode, the negative electrode, and the separator are stacked along a first direction X, which is perpendicular to the extension direction.

[0036] The positive electrode, negative electrode, and separator are stacked along the first direction X, and the gas generated during battery cycling is arranged along the extension direction ( Figure 2 Diffusion in the second direction (Y) makes it easier to break through the sealed connection section 231. Therefore, in this structure, by controlling 3mm... 2 ≤L*A≤40mm 2This can effectively reduce the risk of gas breaking through the sealed connection section.

[0037] A battery cell is the component in a battery where electrochemical reactions occur; it is the smallest unit in a battery capable of performing electrochemical reactions such as charging and discharging. A battery cell is the basic unit of a battery and typically includes a positive electrode, a negative electrode, and a separator. Lithium-ion battery cells primarily function by the movement of lithium ions between the positive and negative electrodes. In cylindrical cells, a three-layer thin-film structure is wound into a cylindrical electrode assembly, while in cuboid cells, the thin-film structure is wound or stacked into an electrode assembly with a roughly cuboid shape.

[0038] 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.

[0039] A positive electrode generally includes a positive current collector and a positive active material layer. The positive active material layer is coated on at least one surface of the positive current collector and includes: a positive active material, a conductive agent, and a binder. The positive active material includes, but is not limited to, at least one of the following: lithium phosphates, lithium transition metal oxides and their respective modified compounds, or other conventional materials that can be used as positive electrode active materials in batteries. These positive active materials can be used alone or in combination. Lithium phosphates include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (also abbreviated as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (e.g., LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (e.g., LiNi). 1 / 3 Co 1 / 3Mn 1 / 3 O42 (also known as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM211), LiNi 0.6 Co 0.2Mn 0.2 O2 (also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 A1 0.05 At least one of O2 and its modified compounds.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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. A 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, a conductive component, and a binder. The negative electrode active material can be a carbon-based material such as graphite, porous carbon, hard carbon, soft carbon, or mesophase carbon microspheres, or a silicon-based material such as elemental silicon, silicon oxides, silicon-carbon composites, or 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.

[0044] The tab is located on one side of the positive / negative current collector and is either separate from or integrally formed with the current collector. It is electrically connected to the current collector to conduct current through the corresponding current collector. When the tab and the current collector are separate, they can be connected by welding. The tab is made of a metal material with good electrical conductivity (such as copper, aluminum, or nickel).

[0045] In some embodiments, the total length of the sealing portion 23 along the extension direction is L2, satisfying 0.3≤A / L2≤1.5. A / L2 can be any one of 0.3, 0.4, 0.5, 0.6, 0.7, 0.75, 0.8, 1, 1.5 or any value between two of them. L2 can be 8mm~20mm.

[0046] Reference Figure 2 The total length L2 of the sealing portion 23 is the distance between the end of the sealing portion 23 near the groove opening and the end in the extension direction.

[0047] If A / L2 is too small, the proportion of the length A of the sealing connection section 231 is too small, and the risk of gas breaking through the sealing connection section 231 and causing sealing failure is higher. Therefore, 0.3≤A / L2≤1.5 can make the size proportion of the sealing connection section 231 larger, reducing the risk of gas breaking through the sealing connection section 231 and causing sealing failure.

[0048] In some embodiments, the thickness of the battery cell body is D along the first direction X; the length of the battery cell body is L3 along the second direction Y, satisfying 5mm ≤ D ≤ 24.5mm, 270mm ≤ L3 ≤ 800mm, and the first direction X is perpendicular to the second direction Y. D can be any value of 5mm, 7mm, 10mm, 15mm, 20mm, 21mm, 23mm, 24mm, 24.5mm or any value between two of these. L3 can be any value of 270mm, 300mm, 400mm, 500mm, 600mm, 700mm, 800mm or any value between two of these.

[0049] The larger D and L3 are, the higher the energy density of cell 10. However, if D and L3 are too large, cell 10 will produce more gas, and the risk of gas breaking through the sealing connection section 231 and causing sealing failure will be higher. Therefore, 5mm≤D≤24.5mm and 270mm≤L3≤800mm can improve the energy density of cell 10 while preventing excessive gas production and reducing the risk of gas breaking through the sealing connection section 231 and causing sealing failure.

[0050] In some embodiments, the thickness D of the battery cell body is ≥10mm, the length L3 of the battery cell body is ≥400mm, and the distance L between the end of the sealing connection section 231 near the battery cell 10 and the electrode end of the battery cell 10 is ≥0.3mm.

[0051] When the width and length of the battery cell body meet the above range, the heat generated inside the battery is concentrated. By increasing the distance between the sealing edge and the battery cell, excessive heat generation can be avoided, which may lead to the risk of battery cell seal failure.

[0052] In some embodiments, refer to Figure 6 The sealing edge has a bent portion 26, which bends towards the battery cell 10. The sealing edge has a first bent end a3, a second bent end a4, and a tail end a2. Along the extension direction of the bent portion after it is unfolded, the distance between the second bent end a4 and the tail end a2 is L4, which satisfies 2mm≤L4≤6mm. L4 can be any value of 2mm, 3mm, 4mm, 5mm, or 6mm, or any value between two of them.

[0053] The bend 26 bends towards the cell 10, reducing the risk of short circuits caused by the exposed metal edge of the tail end a2 contacting the nearby metal plate. Since the bend 26 bends towards the cell 10, the portion between the second bend end a4 and the tail end a2 is the most prone to springing open in the bend 26. A larger L4 effectively suppresses this springing open, making it difficult for the gas to impact the bend even if the sealed connection section 231 is ruptured by gas, thus preventing seal failure. However, an excessively large L4 will encroach on the size of the sealed connection section 231, making it more susceptible to rupture and failure. Therefore, a value of 2mm ≤ L4 ≤ 6mm reduces the risk of seal failure at the sealing edge.

[0054] In some embodiments, the thickness of the bent portion 26 at the second bent end a4 is T, satisfying 0.1mm≤T≤0.68mm. T can be any one of 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.68mm, or any value between two of them.

[0055] The greater the thickness T at the second bend end a4, the more sufficient the adhesive allowance during hot melting, resulting in a stronger bond. However, if T is too large, it can easily lead to bending difficulties, greater stress, and a higher risk of the bend 26 springing off. Therefore, 0.1mm≤T≤0.68mm can both improve the adhesive strength and reduce the bending difficulty, thus reducing the risk of the bend 26 springing off.

[0056] In some embodiments, the bending portion 26 includes at least two bending segments, at least a portion of which are stacked to form an overlapping area. Along the first direction X, the width of the overlapping area is N, satisfying 2mm ≤ N ≤ 8mm. N can be any value of 2mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 6mm, 7mm, or 8mm, or any value between two of these.

[0057] Figure 6 The middle bending section 26 includes two bending segments: the portion between the first bending end a3 and the second bending end a4 is the first bending segment, and the portion between the second bending end a4 and the tail end a2 is the second bending segment.

[0058] The larger the width N of the overlapping area, the less likely the bend 26 is to spring open. However, if N is too large, it will encroach on the size of the sealing connection section 231, making the sealing connection section 231 susceptible to failure due to gas rupture. Therefore, 2mm≤N≤8mm can reduce both the risk of the bend 26 springing open and the risk of gas rupture of the sealing connection section 231.

[0059] In some embodiments, the thickness of the sealing connection segment 231 along the first direction X is d, satisfying 0.1mm ≤ d ≤ 0.7mm, where the first direction X is perpendicular to the extension direction. d can be any value of 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, or 0.7mm, or any value between two of these.

[0060] The larger the thickness d of the sealing connection section 231, the more adhesive allowance there is during hot melting, resulting in a stronger bond. However, if d is too large, it will lead to a large space occupation and low space utilization when the battery is assembled. Therefore, 0.1mm≤d≤0.7mm can both make the sealing connection section 231 bond more firmly and improve the space utilization when the battery is assembled.

[0061] In some embodiments, 0.025mm 2 ≤L*d≤2.05mm 2 L*d can be any value among 0.025mm, 0.1mm, 0.2mm, 0.7mm, 1mm, 1.2mm, 1.6mm, 2mm, and 2.05mm, or any value between two of them.

[0062] By making d larger, the sealing connection section 231 can be more firmly bonded, reducing the risk of gas breaking through the sealing connection section 231. Also, by making L larger, the end of the sealing connection section 231 closest to the cell 10 can be further away from the electrode, reducing the risk of gas breaking through the sealing connection section 231.

[0063] A larger L*d reduces the risk of gas rupture through the sealed connection section 231; however, an excessively large L*d will occupy a large space, resulting in low volume utilization and hindering the improvement of volumetric energy density. Therefore, by controlling L*d to 0.025mm... 2 ≤L*d≤2.05mm 2 This can reduce the risk of gas breaking through the sealed connection section 231.

[0064] In some embodiments, along the first direction X, the housing 20 has opposing first surfaces 211 and second surfaces 221. The distance L5 between the sealing connection segment 231 and the first surface 211 is less than the distance between the sealing connection segment 231 and the second surface 221, that is, the sealing connection segment 231 is closer to the first surface 211 of the housing 20. This satisfies the condition 2mm ≤ L5 ≤ 10mm. L5 can be any value among 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, and 10mm, or any value between two of these.

[0065] When the sealing connection section 231 is located in the middle of the housing 20 along the first direction X, the risk of the sealing connection section 231 being ruptured by gas is low because the gas is relatively evenly distributed on both sides of the sealing connection section 231. The larger the distance L5 between the sealing connection section 231 and the first surface 211, the smaller the deviation of the sealing connection section 231 from the middle of the housing 20, and the lower the risk of being ruptured by gas. Conversely, the smaller the distance L5 between the sealing connection section 231 and the first surface 211, the larger the deviation of the sealing connection section 231 from the middle of the housing 20, and the more gas accumulates on one side of the sealing connection section 231, increasing the risk of rupture. The larger the deviation of the sealing connection section 231 from the middle of the housing 20, the longer the bending portion 26 can be, reducing the risk of the bending portion 26 springing open. Therefore, by controlling L5 to 2mm≤L5≤10mm, both the risk of the sealing connection section 231 being ruptured by gas and the risk of the bending portion 26 springing open can be reduced.

[0066] In some embodiments, the housing 20 has a centerline along a first direction X on one side surface of the sealing connection section 231. The sealing connection section 231 is offset from the centerline by a deviation dimension C, satisfying 0.2mm ≤ C ≤ 5mm. C can be any value of 0.2mm, 1mm, 2mm, 2.2mm, 3mm, 3.5mm, 4mm, 4.5mm, or 5mm, or any value between two of them.

[0067] The smaller the deviation of the sealing connection section 231 from the center line, the lower the risk of it being ruptured by gas; the larger the deviation of the sealing connection section 231 from the center line, the more gas accumulates on one side of the sealing connection section 231, and the higher the risk of it rupturing; the larger the deviation of the sealing connection section 231 from the center line, the longer the bending part 26 can be, reducing the risk of the bending part 26 springing open; therefore, by controlling C to 0.2mm≤C≤5mm, both the risk of the sealing connection section 231 being ruptured by gas and the risk of the bending part 26 springing open can be reduced.

[0068] In some embodiments, the sealing edge has a bent portion 26, which bends towards the battery cell 10. The bent portion and the sealing connection section are respectively disposed on opposite sides of the battery cell. (Refer to...) Figure 2The other end of the housing 20 opposite to the bent portion 26 has a protruding section 251. The protruding section 251 has corresponding protrusions and recesses, with the recesses located inside the housing 20. The protruding length of the protruding section 251 is m1, satisfying 0.5mm ≤ m1 ≤ 5mm. m1 can be any value among 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, and 5mm, or any value between any two. The other end of the housing 20 opposite to the bent portion 26 can be the end where the first housing 21 and the second housing 22 are integrally connected.

[0069] The recessed portion of the protruding section 251 can store and disperse a portion of the gas within the casing 20, reducing the risk of gas rupturing the sealing connection section 231. A larger protruding length m1 of the protruding section 251 allows for the storage and dispersion of more gas, further reducing the risk of gas rupturing the sealing connection section 231; however, if m1 is too large, it will result in a large space occupation, low space utilization, and is not conducive to improving volumetric energy density. Therefore, 0.5mm ≤ m1 ≤ 5mm can both reduce the risk of gas rupturing the sealing connection section 231 and avoid excessively affecting space utilization.

[0070] Specifically, the sealing edges include a first sealing edge 23a, a second sealing edge 23b, and a third sealing edge 23c; the housing 20 also includes an integral connecting portion 25, through which the first housing 21 and the second housing 22 are connected, such that the first housing 21 and the second housing 22 are opposite to each other along the first direction X. The two ends of the integral connecting portion 25 along the third direction Z are respectively connected to the second sealing edge 23b and the third sealing edge 23c, and the integral connecting portion 25 is arranged opposite to the first sealing edge 23a along the second direction Y. The bent portion 26 is located on the second sealing edge 23b, and the first direction X, the second direction Y, and the third direction Z are perpendicular to each other. Among them, the protruding section 251 is located on the integral connecting portion 25, and the protruding section 251 protrudes outward along the second direction Y away from the battery cell 10, and is arranged opposite to the sealing connecting section 231.

[0071] In some embodiments, 0.03 ≤ m1 / A ≤ 0.3. m1 / A can be any one of 0.03, 0.1, 0.13, 0.2, 0.21, 0.23, 0.3 or any value between two of them.

[0072] The larger the ratio of m1 / A, the larger m1 becomes, allowing the raised section 251 to store and disperse more gas, thus reducing the risk of gas rupturing the sealed connection section 231. However, if m1 / A is too large, m1 will be too large, leading to wasted space and low space utilization. Therefore, 0.03 ≤ m1 / A ≤ 0.3 can both reduce the risk of gas rupturing the sealed connection section 231 and improve space utilization.

[0073] In some embodiments, along the second direction Y, the closest distance between the edge of the electrode of the cell 10 near the integral connection portion 25 and the protrusion 251 is m2, satisfying 0.5≤m2 / L≤1. m2 / L can be any value of 0.5, 0.6, 0.7, 0.8, 0.9, 1 or any value between two of them.

[0074] The larger the m2 / L ratio, the larger the m2, resulting in more gas being stored near the protruding section 251 and less near the sealing connection section 231, thus reducing the risk of gas breaking through the sealing connection section 231. However, if the m2 / L ratio is too large, the m2 will be too large, leading to wasted space and low space utilization. Therefore, 0.5≤m2 / L≤1 can both reduce the risk of gas breaking through the sealing connection section 231 and improve space utilization.

[0075] In some embodiments, 0.1mm ≤ m2 ≤ 3mm. m2 can be any value of 0.1mm, 0.6mm, 1mm, 1.2mm, 1.7mm, 2mm, 2.5mm, or 3mm, or any value between two of them.

[0076] The larger the m2, the more gas is stored on the side near the protrusion 251, which can reduce the risk of gas breaking through the sealing connection section 231; if the m2 is too large, it will lead to wasted space and low space utilization. Therefore, 0.1mm≤m2≤3mm can both reduce the risk of gas breaking through the sealing connection section 231 and improve space utilization.

[0077] In some embodiments, the sealing edge includes a first sealing edge 23a, a second sealing edge 23b, and a third sealing edge 23c, with the second sealing edge 23b and the third sealing edge 23c disposed opposite to each other along a third direction Z. The first sealing edge 23a includes a sealing connection section 231. The battery cell 10 includes a battery cell body 11 and tabs 12, with the tabs 12 including a first tab 121 and a second tab 122. The first tab 121 and the second tab 122 are respectively connected to the two sides of the battery cell body 11 along a third direction Z. The first tab 121 extends from the second sealing edge 23b, and the second tab 122 extends from the third sealing edge 23c. Along the third direction Z, the distance between the edge of the first tab 121 away from the battery cell body 11 and the edge of the second tab 122 away from the battery cell body 11 is L6, satisfying 320mm≤L6≤880mm; L≥0.25mm. L6 can be any value among 320mm, 400mm, 500mm, 600mm, 700mm, 800mm, and 880mm, or any value between two of them.

[0078] Tab 12 serves as the output terminal for the external current of the battery. It can be integrally connected to the battery cell or electrically connected by welding to the current lead of the battery cell. For example, it can be connected to the current lead of the battery cell via an adapter piece, thus forming the adapter tab 12. The tab is made of a metallic material (such as copper, aluminum, or nickel).

[0079] Therefore, the first tab 121 and the second tab 122 are not led out from the first sealing edge 23a with the sealing connection section 231, further reducing the risk of cracking of the sealing connection section 231. By connecting the first tab 121 and the second tab 122 to both sides of the cell body 11 along the third direction Z, compared to the same-side lead-out method, some heat can be dispersed, reducing the risk of cracking of the second sealing edge 23b and the third sealing edge 23c. A larger L6 results in a longer cell 10, which is beneficial for improving battery energy density. However, if L6 is too large, the cell 10 will produce more gas, increasing the risk of breaking through the sealing connection section 231. Therefore, 320mm≤L6≤880mm can both improve battery energy density and prevent excessive gas production in the cell 10, reducing the risk of gas breaking through the sealing connection section 231. With L≥0.25mm, if the tab size is too large, the battery current transmission path will be too long, increasing the overall internal resistance of the battery and concentrating heat generation, thus preventing the casing sealing section from being broken and causing the risk of seal failure.

[0080] This application also provides a battery pack, including at least two batteries as mentioned in any of the above embodiments, wherein the at least two batteries are arranged along a first direction X.

[0081] Reference Figure 7 The battery pack may include a housing 27, within which at least two batteries are housed. The battery pack may also be a housingless structure, such as being bundled together by cable ties.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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, characterized in that, include: Battery cell (10); A housing (20) is provided to house the battery cell (10). The housing includes an inner insulating layer, an intermediate metal layer and an outer insulating layer. The intermediate metal layer is disposed between the inner insulating layer and the outer insulating layer. The inner insulating layer is disposed close to the battery cell. The housing (20) includes a first housing (21) and a second housing (22). Both the first housing (21) and the second housing (22) include a sealing edge (23). The sealing edge of the first housing (21) and the sealing edge of the second housing (22) are sealed together to form a sealing edge. The sealing edge has a sealing connection section (231). Along the extending direction of the sealing portion (23), the distance between the end of the sealing connection section (231) near the cell (10) and the end of the electrode of the cell (10) is L, and the total length of the sealing connection section (231) is A, where L and A are both in mm, and 3 mm is satisfied. 2 ≤L*A≤40mm 2 .

2. The battery according to claim 1, characterized in that, At least one of the first housing (21) and the second housing (22) has a groove, and the battery cell is at least partially accommodated in the groove. The groove sidewall is transitionally connected to the sealing connection section (231) through a connection part (24). The distance between the first end of the connecting part (24) connected to the side wall of the groove and the second end of the connecting part (24) connected to the sealing connecting section (231) along the extending direction is L1, which satisfies 0.5mm≤L1≤5mm.

3. The battery according to claim 1, characterized in that, At least one of the first housing (21) and the second housing (22) has a groove, and the groove sidewall is connected to the sealing connection section (231) through a connecting part (24); the connecting part (24) is an arc connecting part, and the radius of the arc connecting part is R, which satisfies 0.5mm≤R≤5mm.

4. The battery according to claim 1, characterized in that, 0.2mm≤L≤3mm, and / or, 6mm≤A≤15mm.

5. The battery according to claim 1, characterized in that, The battery cell (10) includes a battery cell body, which includes a positive electrode, a negative electrode and a separator. The separator is located between the positive electrode and the negative electrode. The positive electrode, the negative electrode and the separator are stacked along a first direction (X) which is perpendicular to the extension direction.

6. The battery according to claim 1, characterized in that, Along the extension direction, the total length of the sealing portion (23) is L2, in mm, which satisfies 0.3≤A / L2≤1.

5.

7. The battery according to claim 5, characterized in that, Along the first direction (X), the thickness of the battery cell body is D; along the second direction (Y), the length of the battery cell body is L3, satisfying 5mm≤D≤24.5mm, 270mm≤L3≤800mm, and the first direction (X) is perpendicular to the second direction (Y).

8. The battery according to claim 7, characterized in that, The specified D ≥ 10 mm, the specified L3 ≥ 400 mm, and L ≥ 0.3 mm.

9. The battery according to claim 1, characterized in that, The sealing edge has a bent portion (26) which bends toward the side of the battery cell (10). The sealing edge includes a first bent end (a3), a second bent end (a4) and a tail end (a2). Along the extension direction of the bent portion after it is unfolded, the distance between the second bent end (a4) and the tail end (a2) is L4, which satisfies 2mm≤L4≤6mm.

10. The battery according to claim 9, characterized in that, The thickness of the bent portion (26) at the second bent end (a4) is T, which satisfies 0.1mm≤T≤0.68mm.

11. The battery according to claim 9, characterized in that, The bending portion (26) includes at least two bending segments, at least a portion of the at least two bending segments are stacked and form an overlapping area along the first direction (X), the width of the overlapping area is N, which satisfies 2mm≤N≤8mm.

12. The battery according to any one of claims 1-11, characterized in that, Along the first direction (X), the thickness of the sealing connection section is d, which satisfies 0.1mm≤d≤0.7mm, and the first direction (X) is perpendicular to the extension direction.

13. The battery according to claim 12, characterized in that, 0.025mm 2 ≤L*d≤2.05mm 2 。 14. The battery according to claim 12, characterized in that, Along the first direction (X), the housing (20) has a first surface (211) and a second surface (221) opposite each other. The distance L5 between the sealing connection section (231) and the first surface (211) is less than the distance between the sealing connection section (231) and the second surface (221), satisfying that 2mm≤L5≤10mm.

15. The battery according to claim 12, characterized in that, The housing has a centerline on one side surface of the sealing connection section (231) along the first direction (X), and the sealing connection section (231) is offset from the centerline by a deviation dimension of C, satisfying 0.2mm≤C≤5mm.

16. The battery according to any one of claims 1-11, characterized in that, The sealing edge has a bent portion (26), the bent portion (26) bends toward the side of the battery cell (10), and the bent portion and the sealing connection section are respectively disposed on opposite sides of the battery cell; The other end of the housing (20) opposite to the bent portion (26) has a protruding section (251), the protruding section (251) has a corresponding protruding portion and a recessed portion, the recessed portion is located inside the housing (20); the protruding length of the protruding section (251) is m1, which satisfies 0.5mm≤m1≤5mm.

17. The battery according to claim 16, characterized in that, The housing (20) includes an integral connecting part (25), the first housing (21) and the second housing (22) are connected by the integral connecting part (25), and the integral connecting part (25) and the sealing part (23) are disposed opposite to each other in the second direction (Y); The protruding section (251) is located in the integral connecting part (25) and is disposed opposite to the sealing connecting section (231).

18. The battery according to claim 16, characterized in that, 0.03≤m1 / A≤0.

3.

19. The battery according to claim 17, characterized in that, Along the second direction (Y), the closest distance between the edge of the electrode of the cell (10) near the integral connection part (25) and the protrusion (251) is m2, in mm, and satisfies 0.5≤m2 / L≤1.

20. The battery according to claim 19, characterized in that, 0.1mm≤m2≤3mm.

21. The battery according to any one of claims 1-11, characterized in that, The sealing edge includes a first sealing edge (23a), a second sealing edge (23b), and a third sealing edge (23c), wherein the second sealing edge (23b) and the third sealing edge (23c) are arranged opposite each other in a third direction (Z); the first sealing edge (23a) includes the sealing connection section (231). The battery cell (10) includes a battery cell body (11) and a tab (12). The tab (12) includes a first tab (121) and a second tab (122). The first tab (121) and the second tab (122) are respectively connected to the two sides of the battery cell body (11) along the third direction (Z). The first tab (121) is led out from the second sealing edge (23b), and the second tab (122) is led out from the third sealing edge (23c). Along the third direction (Z), the distance between the edge of the first tab (121) away from the battery cell body (11) and the edge of the second tab (122) away from the battery cell body (11) is L6, which satisfies 320mm≤L6≤880mm, and L≥0.25mm.

22. A battery pack, characterized in that, It includes at least two batteries as claimed in any one of claims 1-21, wherein the at least two batteries are arranged along a first direction.

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