Battery cell and battery

Abstract

The utility model discloses a battery cell and a battery. The battery cell comprises at least one battery cell body, the battery cell body comprises a plurality of first pole pieces, and at least one of the plurality of first pole pieces is folded in a U shape; the diaphragm is folded in a folding fan manner and wraps the plurality of first pole pieces, a plurality of accommodating spaces which are sequentially spaced are formed in the diaphragm along the folding direction of the diaphragm, and openings of any two adjacent accommodating spaces face opposite directions; and the polarity of the second pole pieces is opposite to that of the first pole pieces, and each second pole piece is inserted into at least one accommodating space of the diaphragm. When the battery cell is manufactured and produced, only one type of pole piece insertion operation needs to be executed, and compared with the existing laminated battery cell production, the pole piece insertion step in the technological process is reduced, and the production efficiency can be improved.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery technology, and in particular to a battery cell and battery. Background Technology

[0002] Lithium-ion batteries, due to their high energy density and long cycle life, have been widely used in digital products and energy storage, among other fields. Throughout their development, various types have emerged to meet the diverse performance requirements of different applications. Currently, the mainstream types of lithium-ion batteries on the market include wound and stacked types.

[0003] Wound cells are made by winding cathode plates, separators, and anode plates into a specific shape in a certain order. Stacked cells are made by stacking electrodes and separators alternately. Compared with wound cells, stacked cells can better improve battery performance and have advantages in energy density and safety.

[0004] Despite the superior performance of laminated battery cells, the traditional manufacturing process has certain limitations. Traditional processes require repeatedly inserting individual anode and cathode electrodes into the separator, a process involving numerous steps that is cumbersome and complex, resulting in low production efficiency. Utility Model Content

[0005] The main purpose of this utility model is to propose a battery cell that aims to solve, to some extent, the technical problem of low production efficiency of current stacked battery cells.

[0006] To achieve the above objectives, this utility model proposes a battery cell, which includes at least one battery cell body;

[0007] The battery cell body includes:

[0008] A plurality of first electrodes, wherein at least one of the plurality of first electrodes is folded in a U-shape;

[0009] A diaphragm is folded in a fan shape and covers the plurality of first electrodes. The diaphragm has a plurality of sequentially spaced receiving spaces along its folding direction, and the openings of any two adjacent receiving spaces face opposite directions.

[0010] A plurality of second electrodes, the second electrodes having opposite polarity to the first electrodes, each second electrode being inserted into at least one receiving space of the diaphragm.

[0011] In some embodiments, all the first electrode sheets are configured to have a first straight portion, wherein the first electrode sheet folded in a U-shape is also configured to have a first corner portion, and the number of the first straight portions formed by the first electrode sheet folded in a U-shape is two, and the two first straight portions are connected by the first corner portion.

[0012] Each of the second electrode plates is folded in a U-shape to form a second corner portion and two second straight portions, with the two second straight portions connected by the second corner portion;

[0013] Each of the second electrode plates is inserted into the receiving space of the diaphragm through at least one of its two second straight portions, such that a plurality of the first straight portions and a plurality of the second straight portions are alternately stacked along the folding direction of the diaphragm, and a portion of the first corner portion is covered by the second corner portion.

[0014] In some embodiments, the first straight portion and the first corner portion both include a first current collector, and the first straight portion further includes a first active material layer disposed on its first current collector;

[0015] The first active material layer of each of the first straight sections is coated on the opposite two sides of the first current collector.

[0016] In some embodiments, both the second straight portion and the second corner portion include a second current collector, and the second straight portion further includes a second active material layer disposed on its second current collector;

[0017] Wherein, the second flat portion inserted in the accommodating space has its second active material layer coated on both opposite sides of the second current collector; the second flat portion not inserted in the accommodating space has its second active material layer coated on one side of the second current collector facing the first flat portion.

[0018] In some embodiments, the length of the first active material layer is greater than the length of the second active material layer; and / or,

[0019] The width of the first active material layer is greater than the width of the second active material layer.

[0020] In some embodiments, the cell body further includes:

[0021] Multiple first tabs, each of which is welded to the first straight portion of a first electrode sheet, and the multiple first tabs are stacked and connected along the folding direction of the diaphragm;

[0022] Multiple second tabs are provided, each of which is welded to the second straight portion of a second electrode sheet. The multiple second tabs are stacked and connected along the folding direction of the diaphragm and are spaced apart from the first tab along the width direction of the cell body.

[0023] In some embodiments, the ratio of negative to positive capacity between the first straight portion of the first electrode sheet with the first tab welded thereto and the adjacent second straight portion thereto is higher than the ratio of negative to positive capacity between the first straight portion without the first tab welded thereto and the adjacent second straight portion thereto.

[0024] In some embodiments, the number of the battery cell bodies is set to multiple, and the multiple battery cell bodies are stacked along the thickness direction of the battery cell.

[0025] In some embodiments, in a portion of the cell body, the plurality of first electrode plates are all U-shaped folds;

[0026] In another part of the cell body, a portion of the plurality of first electrode sheets are U-shaped folds, and another portion of the first electrode sheets are straight sheets.

[0027] This utility model also proposes a battery comprising a casing and a battery cell as described above, wherein the battery cell is disposed in the casing.

[0028] In this novel battery cell, at least one of the multiple first electrode sheets is folded in a U-shape. The diaphragm is designed as a continuous fan-shaped structure to cover the multiple first electrode sheets and form multiple accommodating spaces with openings facing opposite directions. Multiple second electrode sheets are inserted into different accommodating spaces of the diaphragm from opposite sides. When manufacturing this battery cell, only one type of electrode sheet insertion operation needs to be performed. Compared with the existing stacked battery cell production, the electrode sheet insertion steps in the process are reduced, which can improve production efficiency. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the battery cell structure in one embodiment of the present invention;

[0030] Figure 2 for Figure 1 Exploded view of the battery cell in the embodiment;

[0031] Figure 3 This is a schematic diagram of the battery cell structure in another embodiment of the present invention; Attached image description:

[0033] label name label name 100 Battery cell body 110 First Pole Film 120 diaphragm Z storage space 130 Second pole plate 111 First straight section 112 First corner 131 Second corner 132 Second straight section 10 First flow collector 20 First active substance layer 30 Second fluid 40 Second active substance layer

[0034] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0035] The solutions in 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 a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0036] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0037] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.

[0038] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0039] This utility model embodiment proposes a battery cell, referring to... Figure 1 and Figure 2 The battery cell includes at least one battery cell body 100;

[0040] The battery cell body 100 includes:

[0041] A plurality of first electrode plates 110, at least one of the plurality of first electrode plates 110 being folded in a U-shape;

[0042] The diaphragm 120 is folded in a fan shape and covers multiple first electrode plates 110. The diaphragm 120 has multiple sequentially spaced accommodating spaces Z along its folding direction, and the openings of any two adjacent accommodating spaces Z face opposite directions.

[0043] Multiple second electrodes 130, the polarities of which are opposite to those of the first electrode 110, are provided, and each second electrode 130 is inserted into at least one accommodating space Z of the diaphragm 120.

[0044] The battery cell involved in this embodiment includes a battery cell body 100. The number of battery cell bodies 100 is set to at least one, that is, there can be one or more, and the specific number is set according to actual needs. The battery cell body 100 includes a first electrode 110, a separator 120, and a second electrode 130. The second electrode 130 has the opposite polarity to the first electrode 110. One of the first electrode 110 and the second electrode 130 is a negative electrode (i.e., an anode electrode), and the other is a positive electrode (i.e., a cathode electrode). For example, the first electrode 110 is a negative electrode. In its preparation process, graphite can be used as the negative electrode active material and mixed evenly with a binder and a conductive agent in a certain proportion to form a negative electrode slurry. Then, the negative electrode slurry is coated on copper foil, and after drying, rolling, and other processes, the negative electrode is formed. The second electrode 130 is a positive electrode. In its preparation process, a ternary material can be used as the positive electrode active material and mixed with a binder and a conductive agent to form a positive electrode slurry. The positive electrode slurry is then coated onto aluminum foil, and after a similar drying and rolling process, the positive electrode sheet is produced.

[0045] The number of first electrode plates 110 can be multiple, that is, two or more, depending on actual needs. Among the multiple first electrode plates 110, at least one first electrode plate 110 is U-shaped folded, that is, one or more first electrode plates 110 can be U-shaped folded. For example, in three first electrode plates 110, two first electrode plates 110 are U-shaped folded, or all three first electrode plates 110 are U-shaped folded. The first electrode plate 110 adopts a U-shaped folded structure. This structural design gives the first electrode plate 110 a certain degree of flexibility and foldability, and also provides the basic framework for its subsequent combination with the diaphragm 120 and its cooperation with the second electrode plate 130.

[0046] The diaphragm 120 adopts a fan-shaped folded structure, which adapts to the shape of the multiple first electrode sheets 110 and covers the multiple first electrode sheets 110. For example, corresponding to the U-shaped folded structure adopted by the first electrode sheet 110, the fan-shaped folded diaphragm 120 can fit well into the first electrode sheet 110 and cover it. There can be two diaphragms 120, and the two diaphragms 120 are respectively attached to the opposite sides of each first electrode sheet 110.

[0047] The separator 120 is folded in a fan-like manner to form multiple accommodating spaces Z in its folding direction. The number of second electrode plates 130 can be multiple, i.e., two or more, depending on actual needs. Each second electrode plate 130 is inserted into at least one accommodating space Z of the separator 120. For example, when the second electrode plate 130 is a straight plate, it can be inserted into one accommodating space Z of the separator 120; when the second electrode plate 130 is a folded plate, it can be inserted into multiple accommodating spaces Z of the first electrode plate 110 simultaneously. The separator 120 can omnidirectionally separate the first electrode plate 110 and the second electrode plate 130, preventing direct contact between the positive and negative electrodes. Furthermore, it ensures a tight fit with the first electrode plate 110. During the charging and discharging process of the battery cell, even if the electrode plate undergoes slight deformation due to internal stress changes, the separator 120 can always maintain effective isolation, preventing displacement or damage, thereby ensuring the safety of the battery cell.

[0048] The manufacturing process for the battery cell body 100 can be as follows:

[0049] A diaphragm 120 is attached to the opposite sides of a plurality of first electrodes 110, and the diaphragm 120 and the plurality of first electrodes 110 are folded to form a fan-shaped folded structure, while at least one of the plurality of first electrodes 110 forms a U-shaped folded structure to achieve shaping. Then, a plurality of second electrodes 130 are inserted one by one into the accommodating space Z of the diaphragm 120 to achieve an overlapping arrangement with the diaphragm 120 and the first electrodes 110.

[0050] In this process, at least one of the multiple first electrode sheets 110 is folded in a U-shape. The diaphragm 120 is designed as a continuous fan-shaped structure to cover the multiple first electrode sheets 110 and form multiple accommodating spaces Z with openings facing opposite directions. Multiple second electrode sheets 130 are respectively inserted into different accommodating spaces Z of the diaphragm 120 from opposite sides. When manufacturing this cell, only one type of electrode insertion operation needs to be performed. Compared with the existing stacked cell production, the electrode insertion steps in the process are reduced, which can improve production efficiency.

[0051] Furthermore, when the first electrode 110 involved is folded in a U-shape, the structural strength of the side of the cell body 100 can be improved, thereby enhancing the overall structural strength of the cell.

[0052] In some embodiments, refer to Figure 1 and Figure 2All first electrode plates 110 are configured to have a first straight portion 111. The first electrode plate 110 that is folded in a U-shape is also configured to have a first corner portion 112. The number of the first straight portions 111 formed by the first electrode plate 110 that is folded in a U-shape is two, and the two first straight portions 111 are connected by the first corner portion 112.

[0053] Each second electrode 130 is folded in a U-shape to form a second corner portion 131 and two second straight portions 132, and the two second straight portions 132 are connected by the second corner portion 131.

[0054] Each second electrode 130 is inserted into the receiving space Z of the diaphragm 120 through at least one of its two second straight portions 132, such that a plurality of first straight portions 111 and a plurality of second straight portions 132 are alternately stacked along the folding direction of the diaphragm 120, and a portion of the first corner portion 112 is covered by the second corner portion 131.

[0055] Each first electrode 110 is configured with a first straight portion 111. The U-shaped folded first electrode 110, due to its U-shaped folding structure, has two first straight portions 111 and one first corner portion 112. In the U-shaped folded first electrode 110, the first corner portion 112 is located between the two first straight portions 111 and is connected to both first straight portions 111. Along the folding direction of the diaphragm 120, the first electrode 110s are arranged sequentially. Correspondingly, the multiple first straight portions 111 of the multiple first electrode 110s are arranged sequentially. Between any two adjacent first straight portions 111, an accommodating space Z is formed for the insertion of the second electrode 130.

[0056] The second electrode 130 adopts a U-shaped folded structure, correspondingly forming two second straight portions 132 and a second corner portion 131. The second corner portion 131 is located between the two second straight portions 132 to achieve the connection between them. Based on the U-shaped folded structure adopted by the second electrode 130, when it is inserted into the accommodating space Z of the diaphragm 120, depending on the different positions of the diaphragm 120, the second electrode 130 can have one second straight portion 132 inserted into the accommodating space Z of the diaphragm 120, or both second straight portions 132 can be inserted into the accommodating space Z of the diaphragm 120. For example, when the second electrode 130 is inserted at the end position of the folding direction of the diaphragm 120, one of the two second straight portions 132 of the second electrode 130 is inserted into the receiving space Z of the diaphragm 120; while when the second electrode 130 is inserted at a non-end position (such as the middle position) of the folding direction of the diaphragm 120, both of the second straight portions 132 of the second electrode 130 are inserted into the receiving space Z of the diaphragm 120, and when both of the second straight portions 132 of the second electrode 130 are inserted into the receiving space Z of the diaphragm 120, the two second straight portions 132 are respectively inserted into different receiving spaces Z of the diaphragm 120.

[0057] After the multiple second electrode plates 130 are inserted and fitted with the separator 120 and the first electrode plate 110, the multiple first straight portions 111 and the multiple second straight portions 132 are alternately stacked along the folding direction of the separator 120, and part of the first corner portion 112 of the first electrode plate 110 is wrapped by the second corner portion 131. This unique folding and insertion method of the first electrode plate 110, separator 120, and second electrode plate 130 makes the arrangement of the electrode plates more compact and orderly, allowing more electrode material to be accommodated in the same volume, thereby increasing the energy density of the battery and improving its overall performance. Furthermore, the wrapping of the first corner portion 112 by the second corner portion 131 enhances the connection stability between the second electrode plate 130 and the first electrode plate 110, reducing problems such as displacement and deformation of the electrode plates due to stress during battery charging and discharging, and improving the stability and reliability of the battery structure.

[0058] In addition, the second electrode 130 involved is U-shaped folded, which can improve the structural strength of the side of the cell body 100, thereby improving the overall structural strength of the cell.

[0059] In some embodiments, refer to Figure 2 Both the first straight portion 111 and the first corner portion 112 include a first current collector 10, and the first straight portion 111 also includes a first active material layer 20 disposed on its first current collector 10;

[0060] The first active material layer 20 of each first straight portion 111 is coated on the opposite two sides of the first current collector 10.

[0061] Depending on the type of the first electrode 110, the first current collector 10 and the first active material layer 20 can be made of appropriate materials. For example, when the first electrode 110 is a negative electrode, the first current collector 10 can be made of copper foil, which has good conductivity and ductility and can stably transport electrons. The first active material layer 20 can be made of a negative electrode active coating material, such as graphite, which has a high theoretical specific capacity and can effectively store and release lithium ions during battery charging and discharging, ensuring the normal operation of the battery.

[0062] Specifically, the first current collector 10 of the first straight portion 111 and the first current collector 10 of the first corner portion 112 are integrally formed. Furthermore, the first active material layer 20 of the first straight portion 111 is coated on both opposite sides of the first current collector 10. Since both sides of the first straight portion 111 need to participate in the electrochemical reaction inside the battery, by coating the first current collector 10 of the first straight portion 111 with the first active material layer 20 on both sides, space is fully utilized, the energy density of the battery is increased, and thus the charging and discharging efficiency of the battery is improved. In addition, due to the special structure of the first corner portion 112, it is more susceptible to external forces such as compression and bending than the first straight portion 111. If active material is coated on the first current collector 10 of the first corner portion 112, the active material may detach or shift when the battery cell is subjected to these external forces, thereby increasing the risk of short circuit. Therefore, this embodiment effectively reduces the risk of short circuit and ensures the safe and stable operation of the battery cell by using only the structure of the first current collector 10 for the first corner portion 112.

[0063] In some embodiments, refer to Figure 2 The second straight portion 132 and the second corner portion 131 both include a second current collector 30, and the second straight portion 132 also includes a second active material layer 40 disposed on its second current collector 30;

[0064] The second flat portion 132 inserted in the accommodating space Z has its second active material layer 40 coated on both opposite sides of the second current collector 30; the second flat portion 132 not inserted in the accommodating space Z has its second active material layer 40 coated on one side of the second current collector 30 facing the first flat portion 111.

[0065] Depending on the type of the second electrode 130, the second current collector 30 and the second active material layer 40 can be made of appropriate materials. For example, when the second electrode tab is a positive electrode, the second current collector 30 can be made of aluminum foil, which has good conductivity and light weight, and can reduce the overall weight of the battery while ensuring battery performance. The second active material layer 40 can be made of a positive electrode active coating material, such as lithium cobalt oxide.

[0066] Specifically, the second current collector 30 of the second straight portion 132 and the second current collector 30 of the second corner portion 131 are integrally formed. Furthermore, for the second straight portion 132 inserted into the accommodating space Z, a secondary active material layer is coated on both sides of the second current collector 30. Since both sides of the second straight portion 132 inserted into the accommodating space Z need to participate in the electrochemical reaction inside the battery, by coating the second current collector 30 of the second straight portion 132 inserted into the accommodating space ZR with the second active material layer 40 on both sides, space is fully utilized, the energy density of the battery is increased, and thus the charge and discharge efficiency of the battery is improved. For the second straight portion 132 not inserted into the accommodating space Z, its secondary active material layer is coated on the side of the second current collector 30 facing the first straight portion 111. Since the second straight portion 132, which is not inserted into the accommodating space Z, only one side needs to participate in the electrochemical reaction inside the battery, by coating the second straight portion 132, which is not inserted into the accommodating space Z, with the second active material layer 40, unnecessary material waste can be avoided while meeting functional requirements, and the overall structure and manufacturing process of the battery can be simplified. In addition, due to the special structure of the second corner portion 131, it is more susceptible to external forces such as compression and bending than the second straight portion 132. If the active material is coated on the second current collector 30 of the second corner portion 131, the active material may fall off or shift when the cell is subjected to these external forces, thereby increasing the risk of short circuit. Therefore, this embodiment effectively reduces the risk of short circuit and ensures the safe and stable operation of the cell by using the second current collector 30 only for the second corner portion 131.

[0067] In some embodiments, the length of the first active material layer 20 is greater than the length of the second active material layer 40; and / or,

[0068] The width of the first active material layer 20 is greater than the width of the second active material layer 40.

[0069] Specifically, the length of the first active material layer 20 can be greater than the length of the second active material layer 40 along the length direction of the electrode, or the width of the first active material layer 20 can be greater than the width of the second active material layer 40 along the width direction of the electrode, or the length of the first active material layer 20 can be greater than the length of the second active material layer 40, and simultaneously the width of the first active material layer 20 can be greater than the width of the second active material layer 40 along the width direction of the electrode. The length difference and / or width difference between the first active material layer 20 and the second active material layer 40 can be 1.5 mm to 2 mm. This allows the area of ​​the first active material layer 20 to be larger than the area of ​​the second active material layer 40.

[0070] Taking the first electrode 110 as the negative electrode and the second electrode 130 as the positive electrode as an example, by making the area of ​​the first active material layer 20 larger than the area of ​​the second active material layer 40, that is, increasing the area of ​​the negative electrode active material, it is ensured that the negative electrode has enough lithium insertion sites, thereby effectively avoiding the precipitation of lithium dendrites on the surface of the negative electrode and improving the safety and cycle life of the battery.

[0071] Optionally, at least one of the first current collector 10 and the second current collector 30 is a composite current collector. That is, the first current collector 10 can be a composite current collector, or the second current collector 30 can be a composite current collector, or both the first current collector 10 and the second current collector 30 can be composite current collectors, depending on actual needs. As a novel current collector material, the composite current collector has a structure similar to a "sandwich," composed of a polymer material and a metal layer. Specifically, the middle layer of the composite current collector is a base film, typically composed of polymer materials such as polyethylene terephthalate (PET), polypropylene (PP), or polyimide (PI), while the outer two layers are formed by depositing metal (copper or aluminum) using a coating technique to create a conductive layer. This structure allows the composite current collector to maintain high conductivity while also possessing the lightweight, flexibility, and insulation properties of polymer materials, thereby improving battery performance and safety.

[0072] In the cell body 100, the first electrode 110 and the second electrode 130 can be respectively welded with tabs to lead out the positive and negative terminals from the cell body 100 and achieve connection with an external circuit. In some embodiments, the cell body 100 further includes:

[0073] Multiple first tabs, each first tab is welded to the first straight portion 111 of a first electrode plate 110, and the multiple first tabs are stacked and connected along the folding direction of the diaphragm 120;

[0074] Multiple second tabs are provided, each of which is welded to the second straight portion 132 of a second electrode plate 130. The multiple second tabs are stacked and connected along the folding direction of the diaphragm 120, and are spaced apart from the first tabs along the width direction of the cell body 100.

[0075] Specifically, the first electrode 110 can be welded with first tabs. For multiple first electrode 110s, the same number of first tabs can be configured. Each first tab is welded to a first straight portion 111 of a first electrode 110. Alternatively, more first tabs than first electrode 110 can be configured. Both first straight portions 111 of the U-shaped folded first electrode 110 are welded with first tabs. Furthermore, the number of first tabs welded at each first straight portion 111 can be one or more, such as two, three, or four. This embodiment does not limit this.

[0076] The second electrode 130 can be welded with second tabs. For multiple second electrode 130s, the same number of second tabs can be configured, with each second tab welded to a second straight portion 132 of a second electrode 130; or, more second tabs than the number of second electrode 130s can be configured, with both second straight portions 132 of the second electrode 130 welded with second tabs. Furthermore, the number of second tabs welded to each second straight portion 132 can be one or more, such as two, three, or four, and this embodiment does not limit this.

[0077] When multiple first electrode plates 110 are combined with diaphragm 120, multiple first electrode tabs are stacked accordingly and can be fixed together by welding; and when multiple second electrode plates 130 are inserted into the accommodating space Z of diaphragm 120, multiple second electrode tabs are stacked accordingly and can be fixed together by welding.

[0078] In some embodiments, the ratio of negative to positive capacity between the first straight portion 111 with the first tab welded thereto and the adjacent second straight portion 132 in the first electrode 110 is higher than the ratio of negative to positive capacity between the first straight portion 111 without the first tab welded thereto and the adjacent second straight portion 132.

[0079] The so-called negative / positive electrode capacity ratio, also known as the N / P ratio, refers to the ratio of the specific capacity of the negative electrode active material to the specific capacity of the positive electrode active material. Its calculation formula can refer to commonly used formulas in the field, and will not be detailed in this embodiment. During the charging and discharging process of a lithium battery, lithium ions are released from the positive electrode, migrate through the electrolyte to the negative electrode, and embed themselves in the negative electrode material. If the negative electrode does not have enough space to accommodate these lithium ions, they will deposit on the surface of the negative electrode as metallic lithium, resulting in lithium plating.

[0080] Taking the first tab as the negative electrode tab as an example, since the current distribution and lithium ion flow rate are relatively large in the area near the negative electrode tab, if the N / P ratio is too low, the capacity of the negative electrode relative to the positive electrode is insufficient. During charging, not all lithium ions extracted from the positive electrode can be effectively received and embedded by the negative electrode, which easily leads to lithium plating. Based on this, this embodiment sets the negative-to-positive electrode capacity ratio between the first straight portion 111 with the first tab welded to it and the adjacent second straight portion 132 in the first electrode 110 to be higher than the negative-to-positive electrode capacity ratio between the first straight portion 111 without the first tab welded to it and the adjacent second straight portion 132. This increases the effective capacity of the negative electrode in the first tab area. For example, assuming the original N / P ratio is 1.04, it can be increased to 1.06 by replacing the second electrode 130. In this way, during charging, more lithium ions can find a place to be embedded in this negative electrode area with a high N / P ratio, which helps to reduce the risk of lithium plating and thus improves the safety and stability of the battery.

[0081] The ratio of negative to positive capacity between the first straight portion 111 without the first electrode tab and the adjacent second straight portion 132 can be 1.04. The N / P ratio between the first straight portion 111 with the first electrode tab and the adjacent second straight portion 132 in the first electrode 110 is greater than 1.04, for example, it can be 1.06.

[0082] In some embodiments, refer to Figures 1 to 3 Multiple cell bodies 100 are configured, stacked along the thickness direction of the cell. Specifically, by using multiple cell bodies 100, the overall capacity of the cell can be increased within a limited space, improving its energy density. This allows for the storage of more energy without significantly increasing the cell's volume, enabling the cell to provide longer-lasting power support to devices. Furthermore, the stacked arrangement of multiple cell bodies 100 along the cell's thickness provides mutual support and fixation, making the entire cell structure more stable. The rational design of electrode connections and circuit layout also allows for collaborative operation between the multiple cell bodies 100. Additionally, during production, automated production lines can be easily used for mass production of the cell bodies 100. This standardized and modular design gives the cell better versatility and scalability in different application scenarios, allowing for flexible combination and configuration of the number of cell bodies 100 according to actual needs, meeting the requirements of different devices for battery capacity, voltage, and other parameters. For example... Figure 1 and Figure 2 As shown, the separators in the multiple cell bodies 100 can be separated without any connection; or, as... Figure 3 As shown, the diaphragms in the multiple battery cell bodies 100 can be connected to each other or integrated.

[0083] In some embodiments, refer to Figure 1 and Figure 2 In a portion of the battery cell body 100, multiple first electrode plates 110 are U-shaped folds.

[0084] In another part of the cell body 100, some of the first electrode plates 110 are folded in a U-shape, while the other part of the first electrode plates 110 are straight.

[0085] The multiple cell bodies 100 can be divided into two parts based on the arrangement of the first electrode plates 110. One part of the cell bodies 100 includes multiple first electrode plates 110 that adopt a U-shaped folded structure. The other part of the cell bodies 100 includes multiple first electrode plates 110, some of which adopt a U-shaped folded structure, while others adopt a straight sheet structure. The positional arrangement of the two parts of the cell bodies 100 can be determined according to the arrangement of the positive and negative electrodes of the cell.

[0086] This utility model embodiment also proposes a battery, which includes a casing and a battery cell as described in the foregoing embodiments, with the battery cell disposed within the casing. The specific structure of the battery cell is as described in the foregoing embodiments. Since this battery adopts all the technical solutions of all the foregoing embodiments, it possesses at least all the technical effects brought about by the technical solutions of the foregoing embodiments, and will not be elaborated upon here. The battery may be a lithium battery, including but not limited to this.

[0087] The above description is only a part or preferred embodiment of this utility model. Neither the text nor the drawings should limit the scope of protection of this utility model. All equivalent structural transformations made using the content of this utility model specification and drawings under the overall concept of this utility model, or direct / indirect applications in other related technical fields, are included within the scope of protection of this utility model.

Claims

1. An electric cell, characterized by, The battery cell body comprises: The battery cell body comprises: a plurality of first pole pieces, at least one of the first pole pieces being U-shaped folded; a separator, the separator being fan-folded and covering the plurality of first pole pieces, the separator being formed with a plurality of sequentially spaced accommodation spaces along the folding direction of the separator, any two adjacent accommodation spaces having openings facing opposite directions; a plurality of second pole pieces, the second pole pieces being opposite in polarity to the first pole pieces, each of the second pole pieces being inserted into at least one accommodation space of the separator.

2. The electric cell of claim 1, wherein, All the first pole pieces are configured to form first flat portions, wherein the first pole pieces being U-shaped folded are further configured to form first corner portions, and the first flat portions configured by the first pole pieces being U-shaped folded are two in number, the two first flat portions being connected by the first corner portions. Each of the second pole pieces is U-shaped folded to be configured to form second corner portions and two second flat portions, the two second flat portions being connected by the second corner portions. Each of the second pole pieces is inserted into the accommodation space of the separator by at least one of the two second flat portions thereof, so that the plurality of first flat portions and the plurality of second flat portions are alternately stacked along the folding direction of the separator, and part of the first corner portions are covered by the second corner portions.

3. The electric cell of claim 2, wherein, The first flat portions and the first corner portions each comprise a first current collector, the first flat portions further comprising a first active material layer disposed on the first current collector. The first active material layer of each of the first flat portions is coated on opposite sides of the first current collector.

4. The cell of claim 3, wherein, The second flat portions and the second corner portions each comprise a second current collector, the second flat portions further comprising a second active material layer disposed on the second current collector. The second active material layer of the second flat portion inserted into the accommodation space is coated on opposite sides of the second current collector; the second active material layer of the second flat portion not inserted into the accommodation space is coated on one side of the second current collector facing the first flat portion.

5. The electric cell of claim 4, wherein, The length of the first active material layer is greater than the length of the second active material layer; and / or The width of the first active material layer is greater than the width of the second active material layer.

6. The electric cell of claim 2, wherein, The battery cell body further comprises: a plurality of first tabs, each of the first tabs being welded to the first flat portion of one of the first pole pieces, the plurality of first tabs being connected in stack along the folding direction of the separator; a plurality of second tabs, each of the second tabs being welded to the second flat portion of one of the second pole pieces, the plurality of second tabs being connected in stack along the folding direction of the separator and being spaced apart from the first tabs along the width direction of the battery cell body.

7. The electric cell of claim 6, wherein, The negative-positive capacity ratio between the first flat portion of the first pole piece to which the first tab is welded and the second flat portion adjacent thereto is higher than the negative-positive capacity ratio between the first flat portion of the first pole piece to which the first tab is not welded and the second flat portion adjacent thereto.

8. The battery cell of any one of claims 1 to 7, wherein, The number of the battery cell bodies is set to be multiple, and the multiple battery cell bodies are stacked along the thickness direction of the battery cell.

9. The electric cell of claim 8, wherein, In a part of the battery cell bodies, the multiple first electrode pieces are all U-shaped folded; In another part of the battery cell bodies, a part of the multiple first electrode pieces are U-shaped folded, and another part of the multiple first electrode pieces are straight pieces.

10. A battery, characterized by A battery cell as claimed in any one of claims 1 to 9 is included in a housing.

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