Battery cell, battery pack, and electric device

Abstract

The application relates to the technical field of batteries, in particular to a battery monomer, a battery pack and a power utilization device. The application provides a battery monomer, which comprises a shell, a first electric core and a connecting sheet. The shell is provided with a first wall, and the first wall is provided with an electrode terminal. The first electric core is arranged in the shell, and the first electric core comprises a first electric core body and a plurality of first tabs. The lengths of at least two first tabs are different. The connecting sheet comprises a connected body part and a first fixing part. The body part is welded with the electrode terminal, and the first fixing part is welded with the plurality of first tabs after being folded. In the thickness direction of the first electric core body, the first electric core body is provided with a first side surface and a second side surface which are oppositely arranged. The first side surface is closer to the body part than the second side surface. The distance between the first fixing part and the second side surface before the first electric core is combined is d1 mm, the thickness of the first electric core body is D1 mm, and the following condition is met: 0.6 <= d1 / D1 <= 0.9. The application can reduce the tearing of the tabs.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a battery cell, a battery pack, and an electrical device. Background Technology

[0002] In related technologies, after the multiple tabs of the battery cell are joined together, they need to be welded together with the adapter plate. If the adapter plate is positioned too low before the battery cell is joined together, the battery cell will flip over to the top of the adapter plate when the cells are joined together, and the tabs will be easily pulled and torn, affecting the current carrying capacity of the tabs. Utility Model Content

[0003] This application provides a battery cell, a battery pack, and an electrical device that can reduce the tearing of the tabs.

[0004] To achieve the above objectives, the main technical solutions adopted in this application include:

[0005] In a first aspect, embodiments of this application provide a battery cell, including a casing, a first cell, and an adapter plate. The casing has a first wall with electrode terminals on the first wall. The first cell is disposed within the casing and includes a first cell body and a plurality of first tabs, at least two of which have different lengths. The adapter plate includes a connected body portion and a first fixing portion. The body portion is welded to the electrode terminals, and the first fixing portion is welded to the plurality of first tabs after they are joined together. Along the thickness direction of the first cell body, the first cell body has a first side and a second side disposed opposite to each other. The first side is closer to the body portion than the second side. Before the first cell is joined together, the distance between the first fixing portion and the second side is d1 mm, and the thickness of the first cell body is D1 mm, satisfying: 0.6≤d1 / D1≤0.9.

[0006] The battery cell proposed in this application reduces misalignment between the multiple first tabs when they are joined together and welded to the adapter plate, thereby reducing the probability of weak welding of some first tabs and reducing the possibility of incomplete soldering caused by some first tabs being inserted between the electrode terminals and the adapter plate. Before the first cell is joined together, if the value of d1 / D1 is too small, it indicates that the distance between the first fixing part and the second side is too small along the thickness direction of the first cell body, and the first tab is easily torn when the first cell is flipped and joined together. If the value of d1 / D1 is too large, it indicates that the distance between the first fixing part and the second side is too large, even exceeding the thickness of the first cell body, indicating that the length of the first tab is too long. After the first cell is flipped and joined together, it may lead to redundancy of the first tab, or even short circuit caused by the first tab contacting the shell.

[0007] Secondly, embodiments of this application also provide a battery pack, including the battery cells described in any of the above embodiments.

[0008] The battery pack of this application has the beneficial effects of the battery cells described in any of the above embodiments.

[0009] Thirdly, embodiments of this application provide an electrical device including a battery cell or a battery pack as described in any of the above embodiments. The electrical device in this application includes both the battery cell and the battery pack as described in any of the above embodiments, and therefore possesses the beneficial effects of the battery cell and battery pack described in any of the above embodiments. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the specific embodiments of this application or 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 application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0011] Figure 1 This is a cross-sectional view of a single battery cell in this application;

[0012] Figure 2 This is a schematic diagram of the structure of the first and second battery cells before they are combined in this application;

[0013] Figure 3 This is a schematic diagram of the structure of the first and second battery cells after they are combined in this application;

[0014] Figure 4 This is a schematic diagram of the structure of the first and second battery cells before they are combined.

[0015] [Explanation of Labels in the Attached Image]

[0016] 1. Outer shell; 11. First wall; 12. Electrode terminals;

[0017] 2. First battery cell; 21. First battery cell body; 211. First side surface; 212. Second side surface; 22. First electrode tab;

[0018] 3. Adapter piece; 31. Main body; 32. First fixing part; 321. First surface; 322. Second surface; 323. Third surface; 33. Second fixing part; 34. Connecting part;

[0019] 4. Second battery cell; 41. Second battery cell body; 411. Third side surface; 412. Fourth side surface; 42. Second electrode tab;

[0020] 5. Strengthening Department;

[0021] X, the thickness direction of the first cell body; Y, the first direction; Z, the second direction. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application 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 description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0024] In this application, the reference to "embodiment" means that a specific 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 throughout 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 in this application can be combined with other embodiments.

[0025] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0027] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0028] The battery in this application is a secondary battery, also known as a rechargeable battery or a storage battery. The battery can store chemical energy and controllably convert chemical energy into electrical energy. In a recyclable battery, the active materials can be activated by charging after discharge so that it can continue to be used.

[0029] Typically, a secondary battery includes a cell, electrolyte, and casing. The cell comprises a positive electrode, a negative electrode, and a separator. The casing is a component that provides a space to house the cell and other components and isolate them from the external environment. The casing generally includes a body with an opening and a receiving cavity at at least one end, as well as a cover plate. The opening of the casing can be closed by the cover plate, sealing and isolating the internal environment of the battery cell from the external environment.

[0030] 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.

[0031] The battery cell and electrolyte are assembled inside the outer casing. During battery charging and discharging, active ions (such as lithium ions) move back and forth between the positive and negative electrode plates, inserting and extracting. A separator is positioned between the positive and negative electrode plates, primarily to prevent short circuits while allowing active ions to pass through. The electrolyte, located between the positive and negative electrode plates, mainly serves to conduct active ions.

[0032] As an example, the preparation process of a secondary battery is as follows: the positive electrode, separator, and negative electrode are stacked in sequence, with the separator acting as a separator between the positive and negative electrodes. Then, the electrodes are wound or stacked to obtain a cylindrical or roughly rectangular cell. The cell is placed in an outer packaging shell, dried, and then injected with electrolyte. After vacuum sealing, settling, formation, and shaping, a secondary battery is obtained.

[0033] A positive electrode typically includes a positive current collector and a positive electrode film layer disposed on at least one side of the positive current collector. The positive electrode film layer includes a positive electrode active material, which can be any existing publicly disclosed positive electrode active material or a positive electrode active material optimized based on existing materials.

[0034] As examples, positive electrode active materials include lithium-containing transition metal oxides (e.g., LiCoO2), phosphides (e.g., LiFePO4), or lithium intercalation compounds (e.g., positive electrode materials for binary lithium batteries such as lithium cobalt oxide and lithium nickel oxide, or positive electrode materials for ternary lithium batteries such as lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide).

[0035] For example, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, rolling, cutting and other processes.

[0036] The binder is used to improve the adhesion between the positive electrode active material particles and the adhesion between the positive electrode active material and the current collector. Specifically, the binder can be at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), styrene-butadiene rubber (SBR), polyacrylonitrile (PAN), polyimide (PI), polyacrylic acid (PAA), polyacrylate, polyolefin, sodium carboxymethyl cellulose (CMC), or sodium alginate.

[0037] The positive electrode current collector is conductive and will not cause adverse chemical changes in the battery. The positive electrode current collector can be stainless steel, aluminum, nickel, titanium, sintered carbon; or aluminum or stainless steel that has been surface treated with one of carbon, nickel, titanium, silver, etc.

[0038] The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one side of the negative electrode current collector. The negative electrode active material layer includes a silicon-based material, which may be a silicon-carbon material and / or a silicon-oxygen material. As an example, the silicon-based material may be one or more of a silicon-carbon composite negative electrode material, a silicon suboxide negative electrode material, a modified silicon suboxide negative electrode material, and nano-silicon materials. The negative electrode active material in the negative electrode active material layer may also optionally include one or more of artificial graphite, natural graphite, and hard carbon.

[0039] For example, the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., water) to form a negative electrode slurry; coating the negative electrode slurry onto a negative electrode current collector, and obtaining the negative electrode sheet after drying, rolling, cutting and other processes.

[0040] As an example, the negative electrode conductive agent can be one or more of the conventional negative electrode conductive agents such as acetylene black and carbon nanotubes; the binder can be one or more of the conventional negative electrode binders such as styrene-butadiene rubber latex (SBR), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), and sodium carboxymethyl cellulose (CMC). The binder is preferably PAA, SBR and CMC, and the mass ratio of PAA, SBR and CMC can be (34.38-74.29):(20-59.38):(5-7.14).

[0041] As an example, the negative electrode current collector can be one of the conventional negative electrode current collectors, such as copper foil. The electrolyte acts as a conductor of ions between the positive and negative electrode plates.

[0042] As an example, the electrolyte can be any electrolyte suitable for electrochemical energy storage devices in the art. The electrolyte includes an electrolyte and a solvent, the electrolyte typically including a lithium salt, and additives may also be added to the electrolyte.

[0043] Specifically, the lithium salt includes at least one selected from 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). The concentration of the electrolyte in the electrolyte solution can be 0.5–5 mol / L.

[0044] Specifically, the solvent includes at least one of ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0045] As an example, the additive can be a conventional electrolyte additive such as fluoroethylene carbonate (FEC), chloroethylene carbonate (CEC), or vinylene carbonate (VC).

[0046] The secondary battery also includes a separator. The separator can be any known porous structure with good chemical and mechanical stability. For example, the separator can be one of PP, PE, or PP / PF; the separator can also be a structure with a coating on the surface of a base membrane, wherein the base membrane coating can be one of PP, PE, or PP / PF, and the coating can be an inorganic coating and / or an organic coating. The inorganic coating can be selected from alumina ceramic layers, osmium silicate, etc., and the organic coating can be selected from PVDF, etc.

[0047] The secondary battery also includes adapter pieces. One end of the adapter piece is used to electrically connect to the output terminal (tab) of the battery cell, and the other end is used to electrically connect to the output terminal (post) of the battery, so that the tab and post form a current conduction. A positive adapter piece is used to electrically connect the positive output terminal of the battery cell to the positive output terminal of the battery. Multiple stacked positive tabs are welded to one end of the positive adapter piece, and the other end of the positive adapter piece is welded to the positive terminal of the post. A negative adapter piece is used to electrically connect the negative output terminal of the battery cell to the negative output terminal of the battery. Multiple stacked negative tabs are welded to one end of the negative adapter piece, and the other end of the negative adapter piece is welded to the negative terminal of the post. The adapter piece can be made of aluminum, copper, or alloy (such as steel), or other conductive materials. The specific material of the adapter piece is selected based on the material of the battery's posts and tabs. Generally, the material of the adapter piece should be the same as the material of the battery's tabs and posts to ensure welding quality.

[0048] After the multiple tabs of the battery cell are joined together, they need to be welded together with the adapter plate. If the adapter plate is located below 1 / 2 the height of the battery cell before the battery cell is joined together, the battery cell will flip when joined together, and the tabs will be easily pulled and torn, affecting the current carrying capacity of the tabs.

[0049] Firstly, reference Figures 1 to 3 This application embodiment also provides a battery cell, which includes a casing 1, a first cell 2, and an adapter plate 3. The casing 1 has a first wall 11, on which electrode terminals 12 are provided. The first cell 2 is disposed inside the casing 1 and includes a first cell body 21 and a plurality of first tabs 22, at least two of the first tabs 22 having different lengths. The adapter plate 3 includes a connected body portion 31 and a first fixing portion 32. The body portion 31 is welded to the electrode terminals 12, and the first fixing portion 32 is welded to the plurality of first tabs 22 after they are closed. Along the thickness direction X of the first cell body 21, the first cell body 21 has a first side surface 211 and a second side surface 212 arranged opposite to each other. The first side surface 211 is closer to the body portion 31 than the second side surface 212. Before the first cell 2 is closed, the distance between the first fixing portion 32 and the second side surface 212 is d1 mm, and the thickness of the first cell body 21 is D1 mm, satisfying: 0.6≤d1 / D1≤0.9.

[0050] The outer casing 1 forms a receiving cavity with an opening at one end. The first battery cell 2 is received in the receiving cavity. The first wall 11 is covered on the opening to encapsulate the first battery cell 2 in the outer casing 1. The first electrode tab 22 is closed and welded to the adapter piece 3. The adapter piece 3 is welded to the first electrode terminal 12 on the first wall 11.

[0051] At least two or more first tabs 22 have different lengths. The length of the first tab 22 closer to the welding position with the adapter piece 3 can be less than the length of the first tab 22 farther away from the welding position with the adapter piece 3. By controlling the length of the multiple first tabs 22, the misalignment between the multiple first tabs 22 can be reduced when the multiple first tabs 22 are closed and welded to the adapter piece 3. This can reduce the probability of weak welding of some first tabs 22 and reduce the cold solder joint caused by some first tabs 22 being inserted between the electrode terminal 12 and the adapter piece 3.

[0052] Here, "before the first cell 2 is assembled" refers to the state of the first cell 2 when multiple first tabs 22 are welded to the adapter piece 3; "after the first cell 2 is assembled" refers to the state of the first cell 2 after it has been rotated 90° from its state before assembly and is now installed in the outer casing 1. (Reference) Figure 2 Before the first battery cell 2 is flipped and joined together, when the first tab 22 after being joined together is welded to the adapter piece 3, the adapter piece 3 is placed on one side of the first battery cell 2. At this time, the thickness direction X of the first battery cell body 21 is parallel to the thickness direction of the adapter piece 3 and the thickness direction of the first wall 11. At this time, the first side 211 of the first battery cell body 21 is closer to the adapter piece 3 than the second side 212. Since the first tab 22 is in a taut state when it is joined together and welded to the adapter piece 3, the first battery cell 2 flips and joins together. The first tab 22 is easily pulled, causing it to tear. Therefore, it is necessary to control the distance between the adapter 3 and the first side 211 and the second side 212 when welding the first tab 22 to the adapter 3. Before the first cell 2 is flipped and joined, the welding position of the first fixing part 32 of the adapter 3 and the first tab 22 should be close to the first side 211 and far away from the second side 212. This reduces the pulling on the first tab 22 when the first cell 2 is flipped and joined, thereby reducing the tearing of the first tab 22. (Reference) Figure 3 After the first cell 2 is flipped and reassembled, the thickness direction X of the first cell body 21 is perpendicular to the thickness direction of the adapter piece 3 and the thickness direction of the first wall 11.

[0053] Before the first cell 2 is assembled, if the value of d1 / D1 is too small, it means that the distance between the first fixing part 32 and the second side 212 along the thickness direction X of the first cell body 21 is too small, and the first electrode tab 22 is easily torn when the first cell 2 is flipped and assembled. If the value of d1 / D1 is too large, it means that the distance between the first fixing part 32 and the second side 212 is too large or even exceeds the thickness of the first cell body 21, which means that the length of the first electrode tab 22 is too long. After the first cell 2 is flipped and assembled, it may cause redundancy of the first electrode tab 22, or even the first electrode tab 22 may come into contact with the outer shell 1 and cause a short circuit. In addition, the second electrode tab 22 receives a large pulling force and is easily torn.

[0054] The value of d1 / D1 can be 0.6, 0.63, 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.81, 0.83, 0.86, 0.87, 0.88 or 0.9, etc.

[0055] Optionally, the distance d1 mm between the first fixing part 32 and the second side 212 satisfies: 18mm≤d1mm≤72mm; the thickness D1 mm of the first battery cell body satisfies: 30mm≤D1mm≤80mm.

[0056] Along the thickness direction X of the first cell body 21, if the distance between the first fixing part 32 and the second side 212 is too small, the first electrode tab 22 is easily torn when the first cell 2 is flipped and reassembled; if the distance between the first fixing part 32 and the second side 212 is too large or even exceeds the thickness of the first cell body 21, it means that the length of the first electrode tab 22 is too long. After the first cell 2 is flipped and reassembled, it may lead to redundancy of the first electrode tab 22, or even the first electrode tab 22 may come into contact with the outer casing 1 and cause a short circuit. In addition, the second electrode tab 22 receives a large pulling force and is easily torn. The distance d1mm between the first fixing part 32 and the second side surface 212 can be 18mm, 20mm, 22mm, 25mm, 28mm, 30mm, 32mm, 35mm, 38mm, 40mm, 42mm, 45mm, 48mm, 50mm, 53mm, 55mm, 58mm, 60mm, 62mm, 64mm, 66mm, 68mm, 70mm or 72mm, etc.

[0057] The thickness dimension D1mm of the first cell body can be 30mm, 32mm, 35mm, 38mm, 40mm, 42mm, 45mm, 48mm, 50mm, 53mm, 55mm, 58mm, 60mm, 62mm, 64mm, 66mm, 68mm, 70mm, 72mm, 74mm, 76mm, 78mm or 80mm, etc.

[0058] Optionally, when the first cell 2 is constructed as a wound cell, and a first tab 22 is led out from the first cell 2 every half turn, the following condition is satisfied: 0.6 ≤ d1 / D1 ≤ 0.85. Wherein, the value of d1 / D1 can be 0.6, 0.62, 0.63, 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.81, 0.83, 0.84, or 0.85, etc.

[0059] It should be noted that after the first cell body 21 is wound, only one first electrode tab 22 is led out for each half-turn of the electrode sheet. That is, with the diameter in the thickness direction X of the first cell body 21 as the center of symmetry, one first electrode tab 22 is led out for each half-turn of the electrode sheet. Multiple first electrode tabs 22 are led out on one side of the thickness direction X of the first cell body 21. Due to the limitation on the number of first electrode tabs 22, before the first cell 2 is flipped and cored, the welding position of the first fixing part 32 and the first electrode tab 22 can be moved toward the second side 212. That is to say, the position of the first fixing part 32 can be closer to the center of the thickness direction X of the first cell body 21, the distance between the first fixing part 32 and the second side 212 is smaller, and the upper limit of the value of d1 / D1 is smaller.

[0060] Optionally, when the first cell 2 is constructed as a wound cell, and a first tab 22 is led out from each turn of the first cell 2, the following condition is satisfied: 0.65≤d1 / D1≤0.9. The value of d1 / D1 can be 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.81, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, or 0.9, etc.

[0061] It should be noted that after the first cell body 21 is wound, only one first electrode tab 22 is led out from each turn of the electrode sheet. That is, with the diameter in the thickness direction X of the first cell body 21 as the center of symmetry, one first electrode tab 22 is led out from each half turn of the electrode sheet, which is called the half electrode tab lead-out method. Multiple first electrode tabs 22 are led out from one side of the thickness direction X of the first cell body 21. Before the first cell 2 is flipped and cored, when the first electrode tab 22 is welded to the first fixing part 32, the position of the first fixing part 32 can be closer to the first side 211. After the first cell 2 is flipped and cored, the distance between the first fixing part 32 and the second side 212 is larger, and the lower limit of the value of d1 / D1 is larger.

[0062] Optionally, when the first electrode 22 leads out the first cell body 21 via a full electrode configuration, the following condition must be met: 0.6 ≤ d1 / D1 ≤ 0.85. The value of d1 / D1 can be 0.6, 0.62, 0.63, 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.81, 0.83, 0.84, or 0.85.

[0063] It should be noted that the full-tab lead-out method refers to the following: when the first cell 2 is a laminated cell, each electrode of the first cell body 21 has a first tab 22 leading out; or when the first cell 2 is a wound cell, with the diameter in the thickness direction X of the first cell body 21 as the center of symmetry, two first tabs 22 are symmetrically arranged on each turn of the electrode of the first cell body 21; this arrangement of the first tabs 22 is also a full-tab lead-out method. Laminated cells must have full-tab lead-out, while wound cells can choose to have full-tab lead-out or not.

[0064] When the first tab 22 leads out the first cell body 21 in a full tab manner, due to the limitation on the number of first tabs 22, before the first cell 2 is flipped and reassembled, the welding position of the first fixing part 32 and the first tab 22 can be moved toward the second side 212. That is to say, the position of the first fixing part 32 can be closer to the center of the thickness direction X of the first cell body 21, the distance between the first fixing part 32 and the second side 212 can be smaller, and the upper limit value of d1 / D1 needs to be appropriately reduced.

[0065] Optionally, the length difference L between the shortest and longest of the multiple first tabs 22 satisfies: 0.5mm ≤ Lmm ≤ 4mm. The shortest first tab 22 is the first tab 22 whose root is closest to the first fixing part 32 when the first tabs 22 are closed and welded to the first fixing part 32. If L is too small, it means that the shortest first tab 22 is too long, which is redundant and may cause the first tab 22 to be inserted backward into the battery cell or overlap with the shell, resulting in a short circuit; if L is too large, the shortest first tab 22 is too short, and the first tab 22 is prone to tearing under tension.

[0066] The value of Lmm can be 0.5mm, 0.8mm, 1.0mm, 1.3mm, 1.5mm, 1.8mm, 2.0mm, 2.2mm, 2.5mm, 2.8mm, 3.0mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, or 4.0mm, etc.

[0067] Optionally, refer to Figure 2The thickness of the multiple first tabs 22 after being joined together is e mm, satisfying: 0.11≤e / D1≤1. The thickness of the multiple first tabs 22 after being joined together is the number of first tabs 22 multiplied by the thickness of a single first tab 22. If the value of e / D1 is too large, it indicates that the thickness of the first tabs 22 after being joined together is too large, resulting in severe misalignment and potentially leading to poor soldering between the first tabs 22 and the first fixing part 32, affecting current transmission and posing a short-circuit risk. If the value of e / D1 is too small, it indicates that the thickness of the first tabs 22 after being joined together is too small, meaning the first tabs 22 are too thin and cannot meet the overcurrent requirements.

[0068] The value of e / D1 can be 0.11, 0.15, 0.2, 0.23, 0.26, 0.28, 0.3, 0.33, 0.35, 0.38, 0.4, 0.43, 0.46, 0.49, 0.5, 0.52, 0.55, 0.58, 0.6, 0.63, 0.66, 0.68, 0.7, 0.73, 0.76, 0.78, 0.8, 0.83, 0.85, 0.88, 0.9, 0.92, 0.95, 0.96, 0.98, or 1, etc.

[0069] Optionally, refer to Figure 4 The width of the first electrode 22 is w mm, which satisfies: 30mm≤w mm≤80mm.

[0070] It should be noted that before the first battery cell 2 and the second battery cell 4 are flipped and joined together, the arrangement direction of the first battery cell 2, the adapter piece 3, and the second battery cell 4 is the first direction Y, the second direction Z, and the first direction Y and the thickness direction X of the first battery cell body 21 are perpendicular to each other. The width of the first electrode 22 is the dimension of the first electrode 22 along the second direction Z. Setting the width of the first electrode 22 to 30mm≤w mm≤80mm improves the current carrying capacity of the first battery cell 2. If the width of the first electrode 22 is too small, it cannot meet the current carrying capacity of the first battery cell 2; if the width of the first electrode 22 is too large, it will affect the packaging of the first battery cell 2.

[0071] The value of w mm can be 30mm, 32mm, 35mm, 38mm, 40mm, 42mm, 45mm, 48mm, 50mm, 53mm, 55mm, 58mm, 60mm, 62mm, 64mm, 66mm, 68mm, 70mm, 72mm, 74mm, 76mm, 78mm, or 80mm, etc.

[0072] Optionally, refer to Figure 3Along the thickness direction of the first wall 11, the first fixing part 32 has a first surface 321 and a second surface 322 disposed opposite to each other. Along the thickness direction X of the first cell body 21, the first fixing part 32 also has a third surface 323 away from the body part 31. The third surface 323 connects the first surface 321 and the second surface 322. The third surface 323 and the first surface 321 are rounded, and the third surface 323 and the second surface 322 are rounded.

[0073] The first fixing part 32, which is welded to the first electrode tab 22 after being closed, has a rounded corner transition, which can reduce the scraping between the first fixing part 32 and the first electrode tab 22 and reduce the tearing of the first electrode tab 22.

[0074] Optionally, the adapter piece 3 also includes a connecting portion 34 that connects the main body portion 31 and the first fixing portion 32, with the main body portion 31 and the first fixing portion 32 spaced apart along the thickness direction of the first wall 11.

[0075] In the thickness direction of the adapter piece 3, the main body 31 and the first fixing part 32 are connected and spaced apart by the connecting part 34, that is, there is a height difference between the main body 31 and the first fixing part 32. Before the first battery cell 2 is flipped and joined, the adapter piece 3 is located on one side of the first battery cell 2, and the first fixing part 32 is closer to the first side 211 than the main body 31. In other words, before the first battery cell 2 is flipped and joined, the position of the main body 31 can be closer to the second side 212. The position of the main body 31 relative to the second side 212 has less impact on the welding between the first electrode tab 22 and the first fixing part 32. The position of the main body 31 relative to the second side 212 also has less pulling effect on the first electrode tab 22 when the first battery cell 2 is flipped. Therefore, it is only necessary to control the distance between the first fixing part 32 and the second side 212.

[0076] Optionally, refer to Figures 1 to 3 The battery cell also includes a second cell 4 disposed inside the casing 1. The thickness direction X of the first cell body 21 is parallel to the thickness direction of the second cell body 41. The second cell 4 includes a second cell body 41 and a plurality of second tabs 42. The plurality of second tabs 42 have different lengths. Along the thickness direction X of the first cell body 21, the second cell body 41 has a third side 411 and a fourth side 412 disposed opposite to each other. The third side 411 is closer to the body portion 31 than the fourth side 412.

[0077] The adapter plate 3 also includes a second fixing part 33. Along the thickness direction X of the first cell body 21, the second fixing part 33 and the first fixing part 32 are respectively disposed at both ends of the body part 31. The distance between the second fixing part 33 and the fourth side surface 412 is d2mm, and the size of the second cell body 41 is D2mm, satisfying: 0.6≤d2 / D2≤0.9.

[0078] Among the multiple second electrodes 42 of different lengths, the length of the second electrode 42 closer to the welding position with the adapter piece 3 is shorter than the length of the second electrode 42 farther away from the welding position with the adapter piece 3. By controlling the length of the multiple second electrodes 42, the misalignment between the multiple second electrodes 42 can be reduced when the multiple second electrodes 42 are closed and welded to the adapter piece 3. This can reduce the probability of weak welding of some second electrodes 42 and reduce the cold solder joint caused by some second electrodes 42 being inserted between the electrode terminal 12 and the adapter piece 3.

[0079] The phrase "before the second cell 4 is joined" refers to the state of the second cell 4 when multiple second tabs 42 are welded to the adapter piece 3. "After the second cell 4 is joined" refers to the state of the second cell 4 after it has been rotated 90° from its previous state and is now installed inside the outer casing 1. Before the second cell 4 is rotated and joined, when the joined second tabs 42 are welded to the adapter piece 3, the adapter piece 3 is placed on one side of the second cell 4. That is, the first cell 2, the adapter piece 3, and the second cell 4 are arranged flat. At this time, the thickness direction of the second cell body 41 is parallel to the thickness direction X of the first cell body 21, the thickness direction of the adapter piece 3, and the thickness direction of the first wall 11. At this time, the third side 411 of the second cell body 41 is closer to the adapter piece 3 than the fourth side 412. Because the second tabs 42 are joined and welded to the adapter piece 3... When the second battery cell 4 is in a taut state, it is easy to pull on the second tab 42 when the second battery cell 4 is flipped and reassembled, causing the second tab 42 to tear. Therefore, it is necessary to control the distance between the adapter plate 3 and the third side 411 and the fourth side 412 when the second tab 42 is welded to the adapter plate 3. Before the second battery cell 4 is flipped and reassembled, the welding position of the second fixing part 33 of the adapter plate 3 and the second tab 42 is close to the third side 411 and far away from the fourth side 412, so that when the second battery cell 4 is flipped and reassembled, the pulling on the second tab 42 can be reduced, thereby reducing the tearing of the second tab 42. After the second battery cell 4 is flipped and reassembled, the thickness direction of the second battery cell body 41 is parallel to the thickness direction X of the first battery cell body 21, and the thickness direction of the second battery cell body 41 is perpendicular to the thickness direction of the adapter plate 3 and the thickness direction of the first wall 11.

[0080] Before the second cell 4 is flipped and reassembled, if the value of d2 / D2 is too small, it means that the distance between the second fixing part 33 and the fourth side 412 along the thickness direction X of the first cell body 21 is too small, and the second electrode 42 is easily torn when the second cell 4 is flipped and reassembled. If the value of d2 / D2 is too large, it means that the distance between the second fixing part 33 and the fourth side 412 is too large or even exceeds the thickness of the second cell body 41, which means that the length of the second electrode 42 is too long. After the second cell 4 is flipped and reassembled, it may cause redundancy of the second electrode 42, or even the second electrode 42 may come into contact with the outer casing 1 and cause a short circuit. In addition, the pulling force received by the second electrode 22 is large, and it is easy to tear.

[0081] The value of d2 / D2 can be 0.6, 0.63, 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.81, 0.83, 0.86, 0.87, 0.88 or 0.9, etc.

[0082] Optionally, the first electrode lug 22 has multiple reinforcing portions 5 for enhancing its structural strength. The reinforcing portions 5 can improve the structural strength of the first electrode lug 22, thereby reducing tearing. The reinforcing portions 5 can be constructed as raised or recessed structures, and their shapes can be elongated, circular, or elliptical. The raised and recessed structures can be embossed structures formed on the first electrode lug 22 by stamping or other methods. They can be elongated reinforcing ribs, or circular or elliptical embossed structures. Of course, the reinforcing portions 5 can also be other uneven textures formed on the first electrode lug 22 by stamping or other methods; the structural form of the reinforcing portions 5 can be selected according to the actual situation. Of course, the above-mentioned reinforcing portions 5 can also be provided on the second electrode lug 42, which will not be elaborated here.

[0083] Secondly, embodiments of this application also provide a battery pack, including the battery cells described in any of the above embodiments.

[0084] The battery pack of this application has the beneficial effects of the battery cells described in any of the above embodiments.

[0085] A battery pack comprises a battery array consisting of multiple individual battery cells connected in series and / or parallel to form a battery pack, a battery management system (BMS), a thermal management system, an electrical connection system (high-voltage / low-voltage connectors, wiring harnesses, etc.), structural components (casing, brackets, etc.), and protective parts. These components are housed within a casing and sealed with a cover, forming a complete functional unit capable of directly outputting electrical energy. The battery pack, as a rechargeable battery, is the power source for new energy vehicles. A battery pack typically includes cell modules, a battery management system (BMS) control module, and a casing that houses the cell modules and the BMS module.

[0086] For example, the battery pack includes a housing and a plurality of individual batteries housed within the housing. The housing is divided into upper and lower parts, which are sealed together.

[0087] For example, the battery pack includes at least two battery cells, a BMS control assembly, and a housing.

[0088] For example, a battery pack generally includes a battery box and a battery module, with the battery box including a lower box and a top cover.

[0089] For example, a battery pack generally includes a housing, battery cells, and a separator. Both the battery cells and the separator are located in the housing. The separator is located on the side of the battery cell away from the bottom wall of the housing, separating the battery cell from other devices located above the battery cell, thus serving as an isolation device.

[0090] Thirdly, embodiments of this application provide an electrical device including a battery cell or a battery pack as described in any of the above embodiments. The electrical device in this application includes both the battery cell and the battery pack as described in any of the above embodiments, and therefore possesses the beneficial effects of the battery cell and battery pack described in any of the above embodiments.

[0091] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0092] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0093] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

[0094] Although embodiments of this application 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 this application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, include: The outer casing has a first wall, and electrode terminals are provided on the first wall; A first battery cell is disposed inside the housing. The first battery cell includes a first battery cell body and a plurality of first tabs, at least two of which have different lengths. The adapter includes a connecting body portion and a first fixing portion, wherein the body portion is welded to the electrode terminal, and the first fixing portion is welded to a plurality of first electrode tabs after being closed. Along the thickness direction of the first cell body, the first cell body has a first side and a second side disposed opposite to each other. The first side is closer to the body portion than the second side. Before the first cell is assembled, the distance between the first fixing portion and the second side is d1 mm, and the thickness of the first cell body is D1 mm, satisfying: 0.6≤d1 / D1≤0.

9.

2. The battery cell according to claim 1, characterized in that, The length difference between the smallest and largest of the multiple first electrode tabs is L mm, satisfying: 0.5 mm ≤ L mm ≤ 4 mm.

3. The battery cell according to claim 1, characterized in that, The thickness of the multiple first electrode tabs after being joined together is e mm, which satisfies: 0.11≤e / D1≤1.

4. The battery cell according to claim 1, characterized in that, The width of the first electrode tab is w mm, which satisfies: 30mm≤w mm≤80mm.

5. The battery cell according to claim 1, characterized in that, Along the thickness direction of the first wall, the first fixing part has a first surface and a second surface disposed opposite to each other. Along the thickness direction of the first cell body, the first fixing part also has a third surface away from the body part. The third surface connects the first surface and the second surface. The third surface and the first surface are rounded to transition. The third surface and the second surface are rounded to transition.

6. The battery cell according to claim 1, characterized in that, The adapter plate also includes a connecting portion that connects the main body portion and the first fixing portion, and the main body portion and the first fixing portion are spaced apart along the thickness direction of the first wall.

7. The battery cell according to claim 1, characterized in that, It also includes a second battery cell disposed within the housing. The thickness direction of the first battery cell body is parallel to the thickness direction of the second battery cell body. The second battery cell includes a second battery cell body and a plurality of second tabs with different lengths. Along the thickness direction of the first battery cell body, the second battery cell body has a third side and a fourth side disposed opposite to each other. The third side is closer to the body portion than the fourth side.

8. The battery cell according to claim 7, characterized in that, The adapter also includes a second fixing part, which is disposed at both ends of the body part along the thickness direction of the first cell body. The distance between the second fixing part and the fourth side is d2 mm, and the size of the second cell body is D2 mm, satisfying: 0.6≤d2 / D2≤0.

85.

9. The battery cell according to claim 1, characterized in that, The first cell is constructed as a wound cell, and when the first cell leads out one first tab every half turn, the following condition is met: 0.65≤d1 / D1≤0.

9.

10. The battery cell according to claim 1, characterized in that, The first cell is constructed as a wound cell, and when one first tab is led out from each turn of the first cell, the following condition is met: 0.6≤d1 / D1≤0.

85.

11. The battery cell according to claim 1, characterized in that, When the first electrode is led out from the first cell body through the full electrode method, the following condition is met: 0.65≤d1 / D1≤0.

9.

12. The battery cell according to claim 1, characterized in that, The distance d1mm between the first fixing part and the second side meets the following requirements: 18mm≤d1mm≤72mm; the thickness D1mm of the first cell body meets the following requirements: 30mm≤D1mm≤80mm.

13. The battery cell according to claim 1, characterized in that, The first electrode has multiple reinforcing parts for improving the structural strength of the first electrode.

14. A battery pack, characterized in that, Includes the battery cell according to any one of claims 1-13.

15. An electrical appliance, characterized in that, Includes the battery cell of any one of claims 1-13 or the battery pack of claim 14.

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