Roll core and square shell battery

Abstract

The utility model provides a roll core and a square shell battery, and relates to the technical field of batteries. The roll core comprises a pole piece body and a tab structure. Wherein the pole piece body comprises at least two straight sections and bent sections connected with the two adjacent straight sections, and in the first direction, each straight section is provided with a first end and a second end which are opposite to each other. The tab structure is connected to at least one straight section, and the tab structure on one straight section extends to the second end of the straight section along the first end of the straight section. The pole piece body and the tab structure are wound around the winding center to form a winding core, the at least two straight sections are located on the two opposite sides of the winding core in the second direction, and the first direction intersects with the second direction. Therefore, when the tabs carry out current transmission, current paths can be more, and the current transmission capability of the square shell battery can be improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a wound core and prismatic battery. Background Technology

[0002] With the development of new energy technologies, energy storage batteries have developed rapidly. Among them, prismatic batteries are widely used due to their advantages such as large capacity, reliable packaging, and high space utilization.

[0003] However, the current transmission path of the square-shell battery is not set up properly in the existing technology, resulting in a longer current transmission path and lower energy efficiency. Utility Model Content

[0004] This application provides a wound core and a prismatic battery, which can reduce the current transmission path in the prismatic battery and improve energy efficiency.

[0005] In a first aspect, this application provides a winding core, including an electrode body and an electrode tab structure. The electrode body includes at least two straight sections and a bent section connected to two adjacent straight sections. In a first direction, the straight sections have opposing first and second ends. The electrode tab structure is connected to at least one straight section, and the electrode tab structure on one straight section extends from the first end of the straight section to the second end of the straight section.

[0006] The electrode body and the tab structure are wound around the winding center to form a core, and at least two adjacent straight segments are located on opposite sides of the core in the second direction, wherein the first direction intersects the second direction.

[0007] In this embodiment, the tab structure on a straight segment extends from the first end to the second end of the straight segment, allowing for a wider distribution of the tab structure. This provides more current paths during current transmission through the tabs, improving the current transmission capability of the prismatic battery.

[0008] Furthermore, in the straight section, the tab structure can transmit charge along the width of the electrode body, reduce the current transmission distance, reduce the internal resistance of the prismatic battery, and thus increase the rate performance of the prismatic battery, making the energy conversion efficiency of the prismatic battery higher during the storage and release of electrical energy, that is, improving the energy efficiency of the prismatic battery.

[0009] Optionally, the electrode structure includes sub-electrodes, with a straight section connected to a plurality of sub-electrodes connected sequentially along a first direction.

[0010] With the above configuration, multiple sequentially connected sub-tabs are distributed from the first end to the second end of a straight section. In this way, multiple sub-tabs can transmit current, improving the current transmission capability of the prismatic battery.

[0011] Optionally, the electrode structure includes a long electrode, with a straight section connected to a long electrode.

[0012] With the above configuration, a long tab is provided between the first and second ends of a straight section. This allows current to be transmitted through the long tab, thus improving the current transmission capability of the prismatic battery.

[0013] Optionally, the electrode structure may also include side electrodes connected to at least a portion of the bent section.

[0014] In this way, the side tabs can transmit current to at least part of the bent section, reducing the current transmission distance at the bent section. The side tabs and the tab structure of the straight section can work together to transmit current, improving the energy efficiency of the prismatic battery.

[0015] Optionally, the distance between two adjacent straight segments gradually increases along the direction from the starting end to the ending end of the winding of the electrode body.

[0016] This allows for a more reasonable arrangement of the straight and bent sections, reducing the possibility of the straight section being bent during the winding process of the electrode body.

[0017] Optionally, the core also has a third direction intersecting both the first and second directions. The tab structure is configured as multiple tab units, each connected to a corresponding straight segment. Along the direction from the starting end to the ending end of the winding of the electrode body, the height of the multiple tab units gradually increases. The height of each tab unit is defined as the dimension between its two ends in the third direction.

[0018] The above configuration allows for a larger height in the outer portion of the tab unit located on the core. During the flattening process of the tab structure, the outer tab unit can overlap with the inner tab unit.

[0019] Optionally, the core also has a third direction intersecting both the first and second directions. In the third direction, the core has an end face, and the tab structure is folded inward toward the core until it is parallel to the end face.

[0020] Thus, multiple tab structures are arranged in a planar manner on the end face of the core. When connecting the tab structure to the adapter plate later, the connection between the tab structure and the adapter plate is a surface-to-surface connection, which can improve the reliability of the connection between the tab structure and the adapter plate, optimize the welding process route, and improve the current carrying capacity of the prismatic battery.

[0021] Secondly, this application provides a prismatic battery, including any of the winding cores described in the first aspect above. The winding core includes a positive electrode sheet and a negative electrode sheet, wherein the electrode sheet body made of positive electrode material forms the positive electrode sheet, and the electrode sheet body made of negative electrode material forms the negative electrode sheet. Both the positive and negative electrode sheets are connected to tab structures, wherein the tab structure on the positive electrode sheet forms the positive tab, and the tab structure on the negative electrode sheet forms the negative tab.

[0022] Optionally, the positive and negative electrode sheets are stacked, and the positive electrode sheet, positive electrode tab, negative electrode sheet, and negative electrode tab are wound around the winding center to form a core. In the extension direction of the winding center, the positive electrode tab and the negative electrode tab are located on opposite sides.

[0023] Optionally, the prismatic battery also includes an adapter piece, which includes a first connecting part, a bending part, and a second connecting part connected in sequence. The first connecting part and the second connecting part can be bent relative to the bending part. The adapter piece is used to connect the positive electrode to the terminal, or to connect the negative electrode to the terminal.

[0024] When the adapter connects the positive electrode to the terminal, the first connecting part is connected to the positive tab, and the second connecting part is used for terminal connection. When the adapter connects the negative electrode to the terminal, the first connecting part is connected to the negative tab, and the second connecting part is used for terminal connection.

[0025] The beneficial effects of the prismatic battery provided in the second aspect and the various possible designs of the second aspect can be found in the first aspect and the various possible implementations of the first aspect, and will not be repeated here. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a prismatic battery according to an embodiment of this application.

[0027] Figure 2 This is an exploded view of a prismatic battery according to an embodiment of this application.

[0028] Figure 3 This is a schematic diagram of a winding core according to an embodiment of this application.

[0029] Figure 4 This is a schematic diagram of a positive electrode sheet according to an embodiment of this application.

[0030] Figure 5 This is a schematic diagram of a negative electrode sheet according to an embodiment of this application.

[0031] Figure 6 This is a schematic diagram of an adapter piece according to an embodiment of this application.

[0032] Figure 7 This is a schematic diagram illustrating the connection between a core and an adapter sheet according to an embodiment of this application.

[0033] Figure 8 This is a schematic diagram illustrating another embodiment of the connection between the core and the adapter plate in this application.

[0034] Figure 9 This is a schematic diagram of another positive electrode sheet according to an embodiment of this application.

[0035] Figure 10 This is a schematic diagram of a processed electrode structure according to an embodiment of this application.

[0036] Figure 11 for Figure 10 A magnified view of a portion of point A in the middle.

[0037] Explanation of reference numerals in the attached figures:

[0038] 100: Core; 101: End face; 10: Electrode body; 11: Straight section; 12: Bending section; 20: Electrode structure; 21: Sub-electrode; 22: Long electrode; 201: Electrode unit; 200: Square battery; 210: Positive electrode; 220: Negative electrode; 230: Adapter piece; 231: First connecting part; 232: Bending part; 233: Second connecting part; 240: Shell; 250: Cover plate; 260: Explosion-proof valve; X: First direction; Y: Second direction; Z: Third direction. Detailed Implementation

[0039] 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.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the 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 specification, claims and drawings of this application are intended to cover non-exclusive inclusion.

[0041] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0042] In this article, 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 mean: A exists, A and B exist simultaneously, or B exists. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0043] The directional terms appearing in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the current limiting module of this application. For example, in the description of this application, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0044] Furthermore, the terms "first," "second," etc., in the specification and claims of this application or in the aforementioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0045] In the description of this application, unless otherwise stated, "multiple" means two or more (including two), and similarly, "multiple groups" means two or more (including two groups).

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, "connection" or "joining" in mechanical structures can refer to a physical connection. A physical connection can be a fixed connection, such as a connection fixed by spacers, such as a connection fixed by screws, bolts, or other spacers; a physical connection can also be a detachable connection, such as a snap-fit ​​or interlocking connection; a physical connection can also be an integral connection, such as a connection formed by welding, bonding, or integral molding. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0047] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0048] For example, such as Figures 1 to 2 As shown in the figure, this application provides a prismatic battery 200. The prismatic battery 200 includes as follows: Figure 3 The core in the middle is 100.

[0049] Combination Figure 4 as well as Figure 5 The core 100 includes a positive electrode 210 and a negative electrode 220. The electrode body 10, made of positive electrode material, can form the positive electrode 210, and the electrode body 10, made of negative electrode material, can form the negative electrode 220. Both the positive electrode 210 and the negative electrode 220 are connected to tab structures 20; the tab structure 20 on the positive electrode 210 forms the positive tab, and the tab structure 20 on the negative electrode 220 forms the negative tab.

[0050] In the embodiments of this application, the electrode body 10 can be made of different materials so that it has different functions in the core 100.

[0051] Among them, the electrode body 10 made of positive electrode material can form a positive electrode 210. The positive electrode 210 is the electrode with a higher potential in the square battery 200. It undergoes a reduction reaction during discharge, that is, cations can be extracted from the positive electrode 210 and migrate to the negative electrode 220.

[0052] The electrode body 10 made of negative electrode material can form a negative electrode 220. The negative electrode 220 is the electrode with a lower potential in the prismatic battery 200. It undergoes an oxidation reaction during discharge, and cations can be embedded in the negative electrode 220 and stored.

[0053] In this way, the positive electrode 210 and the negative electrode 220 can work together to convert chemical energy into electrical energy, thus maintaining the normal operation of the prismatic battery 200.

[0054] The positive and negative tabs work together to transfer the current inside the winding core 100 to the outside of the prismatic battery 200.

[0055] It should be noted that the electrode body 10 generally includes a current collector and an active material. The active material can be mixed with binders, conductive agents, etc. to form a slurry, which is then coated on the current collector to form the electrode body 10.

[0056] Both the positive electrode 210 and the negative electrode 220 include a current collector and an active material. The positive electrode material includes the material of the current collector in the positive electrode 210 and the material of the active material, and the negative electrode material includes the material of the current collector in the negative electrode 220 and the material of the active material.

[0057] For lithium-ion batteries, in the positive electrode 210, the current collector material is usually aluminum, and the active material is usually lithium cobalt oxide, lithium iron phosphate, ternary lithium (lithium nickel cobalt manganese oxide) or lithium manganese oxide, etc.

[0058] In negative electrode materials, the current collector is usually copper, and the active material is usually natural graphite or artificial graphite.

[0059] Of course, the positive electrode 210 and the negative electrode 220 can also be made of other materials to form other types of prismatic batteries 200. For example, in sodium-ion batteries, the active material of the positive electrode 210 can also be transition metal oxides, phosphates, etc.

[0060] The specific composition of the positive and negative electrode materials is not specifically limited in the embodiments of this application.

[0061] It should also be noted that the prismatic battery 200 may have one core 100 or multiple cores 100. Multiple cores 100 can be connected in series or in parallel, which can effectively utilize the internal space of the prismatic battery 200 and increase the capacity and energy density of the prismatic battery 200.

[0062] In some embodiments, the positive electrode 210 and the negative electrode 220 are stacked, and the positive electrode 210, the positive electrode tab, the negative electrode 220, and the negative electrode tab are wound around a winding center to form a core 100. In the extending direction of the winding center, the positive electrode tab and the negative electrode tab are located on opposite sides.

[0063] With the above configuration, the positive and negative tabs can be located on opposite sides of the square battery 200, which facilitates the subsequent welding of the positive and negative tabs and reduces the possibility of mutual interference or even direct contact between the positive and negative tabs during the subsequent welding process, leading to a short circuit.

[0064] It should be noted that a separator can also be provided between the positive electrode 210 and the negative electrode 220. The separator can be wound together with the positive electrode 210 to separate the positive electrode 210 and the negative electrode 220 in the formed core 100, thereby reducing the direct contact between the positive electrode 210 and the negative electrode 220, which may lead to excessive current and damage to the prismatic battery 200.

[0065] In some embodiments, such as Figure 2 and Figure 6 As shown, the square battery 200 also includes an adapter piece 230. The adapter piece 230 includes a first connecting part 231, a bending part 232 and a second connecting part 233 connected in sequence. The first connecting part 231 and the second connecting part 233 can be bent relative to the bending part 232. The adapter piece 230 is used to connect the positive electrode 210 to the terminal or to connect the negative electrode 220 to the terminal.

[0066] When the adapter 230 connects the positive electrode 210 to the terminal, the first connecting portion 231 is connected to the positive electrode tab, and the second connecting portion 233 is used for terminal connection. When the adapter 230 connects the negative electrode 220 to the terminal, the first connecting portion 231 is connected to the negative electrode tab, and the second connecting portion 233 is used for terminal connection.

[0067] That is, in the square battery 200, the core 100 can be connected to the terminal through the adapter piece 230.

[0068] In this embodiment of the application, the adapter 230 can be connected to the positive or negative tab via the first connecting part 231 and to the terminal via the second connecting part 233, so as to realize the connection between the positive tab and the terminal, and the connection between the negative tab and the terminal.

[0069] Since the first connecting portion 231 and the second connecting portion 233 can be bent relative to the bending portion 232, after the first connecting portion 231 is connected to the positive or negative tab, the second connecting portion 233 can be bent in front of the connecting terminal to position the second connecting portion 233 in a convenient position for connecting the terminal. Alternatively, the second connecting portion 233 can be bent behind the connecting terminal to connect the terminal to the prismatic battery 200.

[0070] It should be noted that the terminals may include a positive terminal and a negative terminal. The positive terminal can be connected to the positive terminal through the adapter 230, and the negative terminal can be connected to the negative terminal through the adapter 230.

[0071] The adapter piece 230 can be connected to the positive or negative electrode tab by means of welding, screwing, or other methods. Similarly, the adapter piece 230 can be connected to the terminal by means of welding, screwing, or other methods.

[0072] The specific connection method between the adapter piece 230 and the positive tab, negative tab and terminal is not specifically limited in this embodiment.

[0073] It should also be noted that, such as Figure 2 As shown, the square battery 200 may also include a housing 240 and a cover plate 250. The housing 240 may have a receiving cavity inside, and the core 100 may be disposed in the receiving cavity, so that the positive and negative tabs extend out of the receiving cavity for connection of terminals.

[0074] The cover plate 250 is also connected to the terminal, and can be used to seal the internal cavity of the square battery 200 to ensure the safety, sealing and insulation performance of the square battery 200.

[0075] In addition, such as Figure 1 and Figure 2 As shown, an explosion-proof valve 260 may also be provided on the housing 240 to provide safety protection for the housing battery 200.

[0076] In the case where multiple winding cores 100 are provided in a square-shell battery 200, the positive tabs of the multiple winding cores 100 can be connected to the same adapter piece 230, such as... Figure 7 As shown.

[0077] Alternatively, each core 100 can be equipped with an adapter 230 connected to its positive terminal, and then multiple adapters 230 connected to the positive terminals can be connected together, such as... Figure 8 As shown.

[0078] Similarly, when multiple winding cores 100 are provided in a square battery 200, the negative tabs of the multiple winding cores 100 can be connected to the same adapter plate 230 or to different adapter plates 230.

[0079] The core 100 provided in the embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0080] Reference Figures 3 to 5As shown, this application provides a winding core 100, including an electrode body 10 and an electrode tab structure 20. The electrode body 10 includes at least two straight sections 11 and bent sections 12 connected to adjacent straight sections 11. In a first direction X, the straight sections 11 have opposing first and second ends. The electrode tab structure 20 is connected to at least one straight section 11, and the electrode tab structure 20 on one straight section 11 extends from the first end of the straight section 11 to the second end of the straight section 11.

[0081] The electrode body 10 and the tab structure 20 are wound around the winding center to form a core 100. At least two adjacent straight segments 11 are located on opposite sides of the core 100 in the second direction Y, wherein the first direction X intersects the second direction Y.

[0082] In this application, the electrode body 10 and the tab structure 20 connected thereto can be wound to form a core 100. By winding, the space occupied by the electrode body 10 in the prismatic battery 200 can be reduced, the effective area of ​​the electrode body 10 can be increased, and the prismatic battery 200 with the aforementioned core 100 can store more electrical energy.

[0083] In this embodiment, the electrode body 10 includes at least two straight segments 11 and a bent segment 12 connecting two adjacent straight segments 11. That is, the straight segments 11 and the bent segments 12 are sequentially adjacent and continuously distributed.

[0084] During the winding of the electrode body 10, adjacent straight sections 11 can be located on both sides of the core 100 in the second direction Y, and maintain their original straight shape. The bent section 12 is located between two adjacent straight sections 11 and is the part that is bent during the winding of the electrode body 10.

[0085] In other words, when the electrode body 10 is wound, the bending section 12 is located at the curved corner of the winding of the electrode body 10, while the straight section 11 is located at the relatively large long straight surface of the winding of the electrode body 10. This facilitates the orderly and stable winding process.

[0086] The tab structure 20 is connected to the straight section 11 to facilitate current transfer during the charging and discharging of the prismatic battery 200.

[0087] The tab structure 20 is connected to at least one straight segment 11. Since the tab structure 20 on a straight segment 11 extends from the first end of the straight segment 11 to the second end of the straight segment 11, the tab structure 20 is connected at every position on the straight segment 11 where the tab structure 20 is connected, so that the tab structure 20 is widely distributed.

[0088] Thus, when current is transmitted through the tabs, there can be more current paths, which can improve the current transmission capability of the prismatic battery 200. For details, please refer to... Figure 4 and Figure 9 , Figure 4 and Figure 9 The arrows on the intermediate electrode body 10 indicate the path of the current.

[0089] In the existing technology, the tabs of the prismatic battery are only connected at a certain position in the middle of the straight section, which means that the tabs need to transmit charge along the length of the electrode body. This results in a long current transmission distance, which in turn leads to a large internal resistance of the prismatic battery.

[0090] In this application, tab structures 20 are connected to various positions on the straight section 11, so that the tab structures 20 can transmit charge along the width direction of the electrode body 10 at the straight section 11.

[0091] In this way, the current transmission distance can be reduced, the internal resistance of the prismatic battery 200 can be lowered, and the rate performance of the prismatic battery 200 can be increased, so that the energy conversion efficiency of the prismatic battery 200 in the process of storing and releasing electrical energy is higher, that is, the energy efficiency of the prismatic battery 200 can be improved.

[0092] The length and width directions of the electrode body 10 mentioned above refer to the unfolded state of the electrode body 10. The length direction of the electrode body 10 is the distribution direction of the multiple tabs, and the width direction of the electrode body 10 is the direction from one end of the electrode body 10 where the tab structure 20 is provided to the opposite end.

[0093] It should be noted that, in the embodiments of this application, the specific number of straight sections 11 and bent sections 12 can be set according to the size and performance requirements of the square battery 200, and this embodiment of the application does not make specific limitations here.

[0094] In the case where there are at least three straight sections 11, there are at least two bent sections 12, and any two adjacent bent sections 12 are located on both sides of the core 100 in the first direction X.

[0095] It should also be noted that the first direction X can be perpendicular to the second direction Y, or the angle between the first direction X and the second direction Y can be 65°, 78°, 82°, 96° or 99.1°, etc. The specific positional relationship between the first direction X and the second direction Y is not specifically limited in this embodiment of the application.

[0096] In the embodiments of this application, the tab structure 20 has different configuration methods, and the following two methods are used as examples for illustration.

[0097] Method 1, such as Figure 4 and Figure 5 As shown, the electrode structure 20 includes a sub-electrode 21, and a straight section 11 is connected to a plurality of sub-electrodes 21 connected sequentially along the first direction X.

[0098] With the above arrangement, multiple sequentially connected sub-tabs 21 are distributed from the first end to the second end of a straight section 11. In this way, multiple sub-tabs 21 can transmit current, improving the current transmission capability of the prismatic battery 200.

[0099] Furthermore, the arrangement of multiple sub-tabs 21 can effectively disperse the current during current transmission, reducing the situation of excessive local current, thereby reducing the internal resistance of the prismatic battery 200 and improving its performance and lifespan.

[0100] Method 2, such as Figure 9 As shown, combined with Figure 4 The electrode structure 20 includes a long electrode 22, and a straight section 11 is connected to a long electrode 22.

[0101] With the above configuration, a long tab 22 is provided from the first end to the second end of a straight section 11. In this way, current can be transmitted through the long tab 22, which can also improve the current transmission capability of the prismatic battery 200.

[0102] Furthermore, the inclusion of a single long tab 21 reduces the manufacturing cost of the tab structure 20. For each straight segment 11, the tab structure 20 can be formed in a single die-cutting operation. This increases the die-cutting rate of the tab structure 20 on the electrode body 10 and reduces the possibility of burrs forming at the tab structure 20.

[0103] It should be noted that the above-mentioned method one and method two can also be used in combination. For example, at multiple straight sections 11, some of the electrode structures 20 on the straight sections 11 are set in the manner of method one, while the electrode structures 20 on other straight sections 11 are set in the manner of method two.

[0104] It should also be noted that, in the embodiments of this application, all of the multiple straight segments 11 may be connected to the tab structure 20, or some of the straight segments 11 may be provided with the tab structure 20. The embodiments of this application do not specifically limit this.

[0105] In some embodiments, such as Figure 2 , Figure 3 , Figure 10 and Figure 11As shown, the core 100 also has a third direction Z that intersects both the first direction X and the second direction Y. In the third direction Z, the core 100 has an end face 101, and the tab structure 20 is folded toward the inside of the core 100 until it is parallel to the end face 101.

[0106] That is, the tab structure 20 can be shaped by flattening so that the tab structure 20 is folded to be parallel to the end face 101.

[0107] Thus, on the end face 101 of the core 100, multiple tab structures 20 are arranged in a planar manner. When connecting the tab structure 20 to the adapter piece 230, the connection between the tab structure 20 and the adapter piece 230 is a surface-to-surface connection, which can improve the reliability of the connection between the tab structure 20 and the adapter piece 230, optimize the welding process route, and improve the current carrying capacity of the prismatic battery 200.

[0108] In addition, in the second direction Y, the tab structures 20 are distributed on both sides of the core 100. Both sides of the tab structures 20 can be folded toward the winding center, so that the tab structures 20 are located inside the end face 101. In this way, the end face 101 can support the tab structures 20, which facilitates the welding of the tab structures 20.

[0109] In addition, the above solution can reduce the space occupied by the tab structure 20 in the prismatic battery 200, which is conducive to reducing the volume of the prismatic battery 200 and can optimize the internal structure of the prismatic battery 200.

[0110] Especially when the electrode structure 20 adopts the scheme provided in Method 1, it can also reduce the possibility of the problem that the sub-electrode 21 and the adapter piece 230 are not easy to connect when there are a large number of sub-electrode 21.

[0111] Of course, after the core 100 is wound into shape, the tab structure 20 can also be shaped in other ways, such as by bending and gathering the tab structure 20 in the prior art.

[0112] In some embodiments, the tab structure 20 further includes a side tab connected to at least a portion of the bent section 12.

[0113] In this way, the side tabs can transmit current to at least a portion of the bent section 12, reducing the current transmission distance at the bent section 12. The side tabs and the tab structure 20 of the straight section 11 can cooperate to transmit current, improving the energy efficiency of the prismatic battery 200.

[0114] That is, by setting the side tabs, the distribution range of the tab structure 20 on the electrode body 10 can be further increased, which has a better effect on improving the performance of the square battery 200.

[0115] It should be noted that the side electrode can be connected to the entire bending section 12, that is, it can extend from one straight section 11 adjacent to the bending section 12 to another straight section 11 adjacent to the bending section 12.

[0116] Alternatively, the side tab can be connected to a portion of the bent section 12. For example, the bent section 12 can be connected between two straight sections 11, with a larger curvature in the middle, or it can be positioned close to the straight section 11, etc. In this way, the possibility of the side tab deforming too much after being wound with the bent section 12, which could easily puncture the electrode body 10 during the subsequent flattening process, can be reduced.

[0117] Of course, the side electrode can be connected at a position with a larger curvature in the middle. The specific connection method of the side electrode is not specifically limited in this embodiment.

[0118] Of course, in this embodiment, the side tabs may not be provided. This reduces the possibility that the side tabs may obstruct the flow of electrolyte, thereby reducing the flow resistance of the electrolyte in the area where the bending section 12 is located, which is beneficial to the penetration of the electrolyte.

[0119] Furthermore, when flattening the tab structure 20 in the subsequent process, it can also reduce the possibility that the side tabs may easily puncture the electrode body 10, thereby affecting the performance and safety of the prismatic battery 200.

[0120] In some embodiments, the distance between two adjacent straight segments 11 gradually increases in the direction from the starting end to the ending end of the winding along the electrode body 10.

[0121] During the winding process of the electrode body 10, the electrode body 10 gradually accumulates along the winding process, which causes the outer dimension of the core 100 to gradually increase. Based on this, the length of the straight end and the bent section 12 near the end of the winding is larger than that near the beginning of the winding.

[0122] To accommodate the winding process, the distance between two adjacent straight sections 11 can gradually increase along the direction from the starting end to the ending end of the winding of the electrode body 10. This allows for a more reasonable arrangement of the straight sections 11 and the bent sections 12, reducing the possibility of the straight sections 11 being bent during the winding process of the electrode body 10.

[0123] When the tab structure 20 is provided only on the straight section 11 of the electrode body 10, the possibility of the tab structure 20 being located at the curved straight section 11 and easily puncturing the electrode body 10 during the subsequent flattening process can be reduced.

[0124] In the embodiments of this application, the specific changes in the distance between two adjacent straight segments 11 can be referred to the following description.

[0125] Between any three consecutive straight segments 11, the distance between the two straight segments 11 closest to the beginning of the winding is L1, and the distance between the two straight segments 11 closest to the end of the winding is L2.

[0126] Among them, L1 and L2 satisfy: L1×1.0≤L2≤L1×1.2.

[0127] Specifically, the design of the winding parameters of the prismatic battery 200 and its dimensions also need to be considered.

[0128] In some embodiments, such as Figure 3 , Figure 4 and Figure 9 As shown, the core 100 also has a third direction Z that intersects both the first direction X and the second direction Y. The tab structure 20 is configured as a plurality of tab units 201, and the plurality of tab units 201 are connected one-to-one to a plurality of straight segments 11.

[0129] That is, in the embodiments of this application, a tab structure 20 connected to a straight segment 11 can form a tab unit 201. In this application, a plurality of tab units 201 are connected to the electrode body 10.

[0130] During the winding process of the electrode body 10, the electrode body 10 gradually accumulates along the winding process, which will also gradually increase the distance between the outer side of the core 100 and the winding center.

[0131] In this embodiment, the height of the plurality of tab units 201 gradually increases along the direction from the starting end to the ending end of the winding of the electrode body 10. The height of the tab unit 201 is the dimension between its two ends in the third direction Z.

[0132] With the above configuration, the portion of the tab unit 201 located on the outer side of the core 100 can have a larger height. When flattening the tab structure 20, the outer tab unit 201 can overlap with the inner tab unit 201.

[0133] This improves the reliability of the connection between the prismatic battery 200 and the external circuit, and makes the current distribution inside the prismatic battery 200 more uniform, reducing the internal resistance.

[0134] In addition, the gradually increasing height of the tab unit 201 can result in a larger overlap area between different tab units 201, thereby improving the reliability of current transmission in the tab structure 20.

[0135] In the embodiments of this application, the height variation between two adjacent tab units 201 can be specifically described below.

[0136] Between any two adjacent tab units 201, the height of the tab unit 201 closer to the winding center is H1, and the height of the tab unit 201 farther from the winding center is H2.

[0137] Among them, H1 and H2 satisfy: 0.1mm≤H2-H1≤15mm.

[0138] Specifically, the settings need to be combined with parameters such as the size, capacity, and overcurrent capability of the 200 square battery.

[0139] It should be noted that the plane formed by the first direction X and the second direction Y can intersect with the third direction Z. As a preferred approach, the first direction X, the second direction Y, and the third direction Z can be perpendicular to each other to form a Cartesian coordinate system.

[0140] In this embodiment, the tab structure 20 on a straight segment 11 extends from the first end to the second end of the straight segment 11, which allows for a wider distribution of the tab structure 20. Thus, when current is transmitted through the tabs, there can be more current paths, improving the current transmission capability of the prismatic battery 200.

[0141] Furthermore, in the straight section 11, the tab structure 20 can transmit charge along the width direction of the electrode body 10, reduce the current transmission distance, reduce the internal resistance of the prismatic battery 200, and thus increase the rate performance of the prismatic battery 200, making the energy conversion efficiency of the prismatic battery 200 higher during the storage and release of electrical energy, that is, improving the energy efficiency of the prismatic battery 200.

[0142] Finally, it should be noted that the above embodiments are merely specific implementations of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A type of winding core, characterized in that, include: The electrode body includes at least two straight sections and a bent section connected to two adjacent straight sections, wherein, in a first direction, the straight sections have opposing first ends and second ends; A tab structure is connected to at least one of the straight segments, and the tab structure on one of the straight segments extends from a first end of the straight segment to a second end of the straight segment. The electrode body and the electrode tab structure are wound around the winding center to form the core, and any two adjacent straight segments of at least two straight segments are located on opposite sides of the core in the second direction. Wherein, the first direction intersects with the second direction.

2. The winding core according to claim 1, characterized in that, The electrode structure includes sub-electrodes, and a straight segment is connected to a plurality of sub-electrodes connected sequentially along the first direction.

3. The winding core according to claim 1, characterized in that, The electrode structure includes a long electrode, and a straight section is connected to one of the long electrodes.

4. The winding core according to claim 1, characterized in that, The electrode structure also includes a side electrode, which is connected to at least a portion of the bent section.

5. The winding core according to claim 1, characterized in that, Along the direction from the starting end to the ending end of the winding of the electrode body, the distance between two adjacent straight segments gradually increases.

6. The winding core according to claim 1, characterized in that, The core also has a third direction that intersects both the first direction and the second direction, and the tab structure is configured as multiple tab units, with each tab unit connected to a multiple straight segment in a one-to-one correspondence. Along the direction from the starting end to the ending end of the winding of the electrode body, the height of the plurality of electrode units gradually increases; The height of the tab unit is the dimension between the two ends of the tab unit in the third direction.

7. The winding core according to claim 1, characterized in that, The core also has a third direction that intersects both the first direction and the second direction; In the third direction, the core has an end face, and the tab structure is folded inward toward the core until it is parallel to the end face.

8. A prismatic battery, characterized in that, Includes the core as described in any one of claims 1-7; The core includes a positive electrode sheet and a negative electrode sheet. The positive electrode sheet is formed by the electrode sheet body made of the positive electrode material, and the negative electrode sheet is formed by the electrode sheet body made of the negative electrode material. Both the positive electrode and the negative electrode are connected to the tab structure, with the tab structure on the positive electrode forming a positive tab and the tab structure on the negative electrode forming a negative tab.

9. The prismatic battery according to claim 8, characterized in that, The positive electrode sheet and the negative electrode sheet are stacked together, and the positive electrode sheet, the positive electrode tab, the negative electrode sheet and the negative electrode tab are wound around the winding center to form the core; In the extending direction of the winding center, the positive electrode tab and the negative electrode tab are located on opposite sides.

10. The prismatic battery according to claim 8, characterized in that, The square-shell battery also includes an adapter piece, which includes a first connecting part, a bending part, and a second connecting part connected in sequence. The first connecting part and the second connecting part can be bent relative to the bending part. The adapter piece is used to connect the positive electrode plate to the terminal, or to connect the negative electrode plate to the terminal. When the adapter plate connects the positive electrode plate and the terminal, the first connecting part is connected to the positive electrode tab, and the second connecting part is used for the terminal connection; When the adapter connects the negative electrode plate and the terminal, the first connecting part is connected to the negative electrode tab, and the second connecting part is used for the terminal connection.

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