Winding cell and lithium battery
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-16
- Publication Date
- 2026-08-11
AI Technical Summary
[0004]而在实际卷绕过程中，由于收尾处的隔膜难以受力，只能自然卷过拐角处
[0016]本申请技术方案的卷绕电芯包括依次层叠的正极片、第一隔膜、负极片以及第二隔膜，在卷绕形成多个卷绕圈，任意一个卷绕圈包括平直部和弯曲部，第一隔膜在最外圈的第一弯曲部设置有加强件，形成复合结构，提升机械强度和刚性，在卷绕收尾时，能够避免因第一隔膜自身的柔性和无法受力而产生褶皱，进而确保第一隔膜有效隔离正极片和负极片，避免正极片和负极片短接而导致卷绕电芯发生短路，提升卷绕电芯的安全性和稳定性，且加强件贴设在第一隔膜朝向正极片的一面上，该面位卷绕过程的外侧面，便于人工或设备粘接加强件，提升粘贴精准性和效率，能够避免粘贴失误导致的产品报废，进而提升卷绕电芯的成品良率。
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Figure CN224625609U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of lithium-ion batteries, and in particular to a wound cell and a lithium battery. Background Technology
[0002] With the development of new energy technologies, lithium-ion batteries are being used more and more widely, for example in mobile phones, laptops, electric vehicles, electric cars, and electric aircraft. Winded cells are one type of cell, mostly used in prismatic and cylindrical batteries.
[0003] In the winding process, the positive electrode, separator, and negative electrode are sequentially stacked and wound to form a wound battery cell. Typically, the lengths of the cut positive and negative electrode sheets are shorter than the length of the separator. At the final end of the winding, the separator covers the negative electrode sheet at a corner.
[0004] During the actual winding process, the diaphragm at the end is difficult to bear the force and can only roll naturally over the corner. Therefore, the diaphragm is prone to wrinkling during the winding process, and the diaphragm cannot properly isolate the positive and negative electrodes, resulting in a short circuit between the positive and negative electrodes. This leads to a short circuit inside the wound cell, affecting the product yield. Utility Model Content
[0005] The main purpose of this application is to propose a wound cell and lithium battery, which aims to reduce the wrinkle rate of the separator at the end of the winding process, thereby improving the yield of the wound cell.
[0006] To achieve the above objectives, this application proposes a wound battery cell, which includes a positive electrode sheet, a first separator, a negative electrode sheet, and a second separator stacked sequentially. The positive electrode sheet is provided with a positive electrode tab, and the negative electrode sheet is provided with a negative electrode tab. In each winding, the positive electrode, the first separator, the negative electrode, and the second separator have a straight portion and a curved portion. The outermost curved portion is defined as the first curved portion. The first separator located in the first curved portion is provided with a reinforcing member, which is attached to the side of the first separator facing the positive electrode.
[0007] In some embodiments, along the length direction of the first separator, the length of the first separator is greater than the length of the negative electrode sheet, and at the winding end of the first separator, the reinforcing member is disposed on the surface of the first separator that extends beyond the negative electrode sheet.
[0008] In some embodiments, the length of the reinforcing member is defined as L1 along the length direction of the first diaphragm, and the length of the first diaphragm greater than that of the negative electrode is defined as L2; Where 1mm<L1≤L2.
[0009] In some embodiments, L2 satisfies: 5mm≤L2≤8mm.
[0010] In some embodiments, along the width direction of the first separator, the width of the negative electrode sheet is defined as W0, the width of the reinforcing member is defined as W1, and the width of the first separator is defined as W2. Where W0≤W1≤W2.
[0011] In some embodiments, W0 satisfies: 55mm≤W0≤94mm.
[0012] In some embodiments, W2 satisfies: 58mm≤W2≤96mm.
[0013] In some embodiments, a fixing member is attached to the winding end of the positive electrode sheet, and the other end of the fixing member is attached to the straight portion of the previous winding loop via the first curved portion.
[0014] In some embodiments, a previous bend on the same side as the first bend is defined as a second bend, and an insulating element is bonded to the positive electrode sheet at the second bend.
[0015] This application further proposes a lithium battery, which includes a casing, an electrolyte, and a wound cell as described above, wherein the wound cell is disposed inside the casing and the electrolyte is filled inside the casing.
[0016] The wound battery cell of this application includes a positive electrode sheet, a first separator, a negative electrode sheet, and a second separator stacked sequentially. Multiple winding loops are formed, each loop including a straight portion and a curved portion. The first separator has a reinforcing member at the first curved portion of its outermost loop, forming a composite structure that enhances mechanical strength and rigidity. During the winding process, wrinkles are prevented due to the first separator's flexibility and inability to withstand force, thus ensuring effective isolation between the positive and negative electrode sheets. This prevents short circuits in the wound battery cell caused by short circuits between the positive and negative electrode sheets, improving the safety and stability of the wound battery cell. Furthermore, the reinforcing member is attached to the side of the first separator facing the positive electrode sheet, which is the outer side during the winding process. This facilitates manual or equipment bonding of the reinforcing member, improving bonding accuracy and efficiency, preventing product scrap due to bonding errors, and ultimately increasing the yield of the wound battery cell. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the structure of an embodiment of the wound battery cell of this application; Figure 2 This is a schematic diagram of the unfolded structure of an embodiment of the wound battery cell of this application; Figure 3 This is a schematic diagram of another embodiment of the wound battery cell of this application.
[0018] Explanation of icon numbers: 100. Winded battery cells; 200. Positive electrode plate; 210. Positive electrode tab; 300. First diaphragm; 400, negative electrode plate; 410, negative electrode tab; 500, Second diaphragm; 610. Straight section; 620. Bending portion; 621. First bending portion; 622. Second bending portion; 700. Reinforcing components; 800. Fasteners; 900. Insulating components. Detailed Implementation
[0019] The solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments in this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0020] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application 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.
[0021] 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.
[0022] Furthermore, the use of terms such as "first" and "second" in this application 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 in this application.
[0023] This application discloses a wound battery cell 100. Please refer to [reference needed]. Figures 1 to 3The wound battery cell 100 includes a positive electrode 200, a first separator 300, a negative electrode 400 and a second separator 500 stacked in sequence. The positive electrode 200 is provided with a positive electrode tab 210 and the negative electrode 400 is provided with a negative electrode tab 410. In each winding, the positive electrode 200, the first separator 300, the negative electrode 400, and the second separator 500 have a straight portion 610 and a curved portion 620. The outermost curved portion 620 is defined as the first curved portion 621. The first separator 300 located in the first curved portion 621 is provided with a reinforcing member 700, which is attached to the side of the first separator 300 facing the positive electrode 200.
[0024] In this application embodiment, the design of the positive electrode 200 can be varied. In a preferred embodiment, the positive electrode 200 may include a positive current collector and positive active material and a positive ceramic coating disposed on both sides of the positive current collector.
[0025] The primary function of the separator is to separate the positive electrode 200 and the negative electrode 400 and provide a pathway for lithium-ion migration. The use of the separator is not limited in any way, as long as it is a commonly used separator in lithium-ion secondary batteries. In particular, a separator with low resistance to electrolyte ion movement and excellent electrolyte permeability is preferred. Specifically, porous polymer membranes can be used, such as porous polymer membranes formed from polyolefin-based polymers (e.g., ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, etc.) or laminated structures with two or more layers. Alternatively, nonwoven fabrics formed from conventional porous nonwoven fabrics (e.g., high-melting-point glass fibers, polyethylene terephthalate fibers, etc.) can be used. Furthermore, coated separators containing ceramic components or polymer materials to ensure heat resistance or mechanical strength can be used, and can optionally be used as single-layer or multi-layer structures.
[0026] In this application, the number of diaphragms can be selected in various ways. In a preferred embodiment, please refer to... Figure 1 The number of separators is set to 2. The separators may include a first separator 300 and a second separator 500. The first separator 300 is located between the positive electrode 200 and the negative electrode 400, and the second separator 500 is located on the side of the negative electrode 400 opposite to the positive electrode 200. When the positive electrode 200 and the negative electrode 400 are wound, the second separator 500 can prevent the positive electrode 200 and the negative electrode 400 from coming into contact and short-circuiting, thereby improving the safety of the wound cell 100.
[0027] In this application embodiment, the design of the negative electrode 400 can be varied. In a preferred embodiment, the negative electrode 400 may include a negative electrode current collector and negative electrode active material and negative electrode ceramic coating disposed on both sides of the negative electrode current collector.
[0028] In this application embodiment, the design of the positive electrode tab 210 can be varied. In a preferred embodiment, the positive electrode tab 210 is strip-shaped, with one end electrically connected to the positive electrode plate 200 and the other end extending out of the top seal of the outer casing.
[0029] In this application embodiment, the negative electrode tab 410 can be designed in several ways. In a preferred embodiment, the negative electrode tab 410 is strip-shaped, with one end electrically connected to the negative electrode plate 400 and the other end extending out of the top sealing portion of the outer casing.
[0030] Please refer to Figure 1 In this embodiment of the application, the wound cell 100 includes a plurality of winding coils, each winding coil including a straight portion 610 and a curved portion 620. In a preferred embodiment, the outermost curved portion 620 is defined as a first curved portion 621, and a reinforcing member 700 is provided on the first diaphragm 300 located at the first curved portion 621.
[0031] In this embodiment, the type of reinforcing member 700 can be varied, for example, it can be a material with insulating properties. In a preferred embodiment, the reinforcing member 700 is anti-wrinkle adhesive paper, which has an insulating function and can prevent wrinkles at the winding end of the first separator 300. It can also effectively isolate the reaction between the positive electrode 200 and the negative electrode 400, improving the safety of the wound cell 100. Furthermore, the substrate of the reinforcing member 700 can be polyethylene terephthalate (PET), biaxially oriented polypropylene (BOPP), etc., which have certain mechanical strength and rigidity, and form a "composite structure" after being pasted with the first separator 300. After the positive electrode 200 and negative electrode 400 are finished and cut, the first separator 300 is wound for the last time. This "composite structure" can resist the bending stress and shear force during winding, and reduce the wrinkles caused by the flexibility and inability of the first separator 300 to bear force. This avoids the danger of short circuit caused by the first separator 300 ineffectively isolating the positive electrode 200 and negative electrode 400, thereby improving the safety and stability of the wound cell 100.
[0032] In this embodiment, the reinforcement 700 can be configured in several ways. Please refer to the following references. Figure 1 In a preferred embodiment, the reinforcing member 700 is attached to the side of the first separator 300 facing the positive electrode 200. When the positive electrode 200, the first separator 300, the negative electrode 400, and the second separator 500 are sequentially stacked and wound, the side of the first separator 300 facing the positive electrode 200 is the outer side, which facilitates manual or equipment attachment of the reinforcing member 700, improves the efficiency and accuracy of adhesive application, avoids product scrap due to adhesive application errors, and improves product yield.
[0033] In this embodiment of the wound battery cell 100, the positive electrode 200, the first separator 300, the negative electrode 400, and the second separator 500, stacked sequentially, are wound to form multiple winding loops. Each winding loop includes a straight portion 610 and a curved portion 620. The first separator 300 has a reinforcing member 700 at the outermost curved portion 621, forming a composite structure that improves mechanical strength and rigidity. During the winding process, wrinkles can be avoided due to the flexibility and inability to withstand force of the first separator 300, thereby ensuring the stability of the first separator. The membrane 300 effectively isolates the positive electrode 200 and the negative electrode 400, preventing short circuits in the wound cell 100 caused by short circuits between the positive electrode 200 and the negative electrode 400, thus improving the safety and stability of the wound cell 100. The reinforcing member 700 is attached to the side of the first membrane 300 facing the positive electrode 200. This side is the outer side during the winding process, which facilitates manual or equipment bonding of the reinforcing member 700, improving bonding accuracy and efficiency, avoiding product scrap due to bonding errors, and thus improving the yield of the wound cell 100.
[0034] In this application embodiment, the length of the first diaphragm 300 can be selected in various ways. In a preferred embodiment, please refer to... Figure 2 Along the length of the first separator 300, the length of the first separator 300 is greater than the length of the negative electrode 400. At the winding tail end of the first separator 300, a reinforcing member 700 is disposed on the surface of the first separator 300 that extends beyond the negative electrode 400. During winding tail end, the positive electrode 200 and the negative electrode 400 are first cut. At this time, the tail ends of the positive electrode 200 and the negative electrode 400 are located in the straight portion 610. Furthermore, the length of the negative electrode 400 is greater than the length of the positive electrode 200. The first separator 300 and the second separator 500 continue to be wound to form the first curved portion 621 and are attached to the straight portion 610 of the previous winding turn, specifically, attached to the positive electrode ceramic coating of the positive electrode 200. Since the negative electrode 400 is cut, the first separator 300 is not easily stressed during winding. Therefore, a reinforcing member 700 is attached to the part of the first separator 300 that extends beyond the negative electrode 400, which can improve rigidity and mechanical strength, and prevent wrinkles from forming during winding. This ensures that the first separator 300 effectively isolates the positive electrode 200 and the negative electrode 400, preventing the positive electrode 200 and the negative electrode 400 from short-circuiting and causing a short circuit in the wound cell 100, thereby improving the safety and stability of the wound cell 100.
[0035] In the embodiments of this application, please refer to Figure 2Along the length of the first diaphragm 300, the length of the reinforcing member 700 is defined as L1, and the length of the first diaphragm 300 exceeding that of the negative electrode 400 is defined as L2. The design of L1 and L2 can have various options. In a preferred embodiment, 1mm < L1 ≤ L2. That is, in some embodiments, the length of the reinforcing member 700 can be approximately 1mm, attached to the tail of the first diaphragm 300. The deformation of the unattached area of the first diaphragm 300 is "held back" by the rigidity of the adhesive tape, reducing wrinkles caused by local relaxation or shrinkage, and keeping the first diaphragm 300 in a straight shape as it is wound around the first curved portion 621.
[0036] In other embodiments, the length of the reinforcing member 700 may also be equal to the length of the portion of the first separator 300 extending beyond the negative electrode 400. In this case, the reinforcing member 700 is attached to the portion of the first separator 300 extending beyond the negative electrode 400, further optimizing stress distribution and uniformly transferring stress to a larger area of the separator.
[0037] In some embodiments, 5mm ≤ L2 ≤ 8mm. For example, the value of L2 can be 5mm, 6mm, 7mm, or 8mm, etc. In this case, the value of L1 can be 1.2mm, 2mm, 2.5mm, 3mm, 5mm, 7mm, or 8mm, etc. By setting a reasonable length, it is ensured that the first diaphragm 300 can be completely rolled around the first curved portion 621.
[0038] In this application, the length of the second diaphragm 500 can be selected in several ways. In a preferred embodiment, the length of the second diaphragm 500 is equal to the length of the first diaphragm 300.
[0039] In this embodiment, along the width direction of the first separator 300, the width of the negative electrode 400 is defined as W0, the width of the reinforcing member 700 is defined as W1, and the width of the first separator 300 is defined as W2. The design of W0, W1, and W2 can be varied. In a preferred embodiment, W0 ≤ W1 ≤ W2, ensuring that the reinforcing member 700 completely covers the area where the first separator 300 contacts the negative electrode 400, preventing wrinkles in the first separator 300 at the edges of the negative electrode 400.
[0040] In some embodiments, 55mm ≤ W0 ≤ 94mm. For example, the value of W0 can be 55mm, 74.5mm, or 94mm, etc. By setting the negative electrode sheet 400 with an appropriate width, sufficient negative electrode active material on the negative electrode sheet 400 can be ensured, thereby improving the performance of the wound cell 100.
[0041] In some embodiments, 58mm ≤ W2 ≤ 96mm. For example, the value of W2 can be 58mm, 77mm, or 96mm, etc. In this case, the value of W1 can be 55mm, 58mm, 74.5mm, 77mm, 94mm, or 96mm, etc. By setting a first separator 300 and a reinforcing member 700 of appropriate width, it can be ensured that the negative electrode 400 and the positive electrode 200 are completely isolated by the first separator 300, preventing short circuits between the positive electrode 200 and the negative electrode 400. Simultaneously, it can be ensured that the reinforcing member 700 completely covers the area where the first separator 300 contacts the negative electrode 400, preventing wrinkles in the first separator 300 at the edge of the negative electrode 400.
[0042] After winding is complete, the first diaphragm 300, the reinforcing member 700, and the second diaphragm 500 need to be fixed to the flat section 610 to maintain the wound cell 100 in its wound shape. Therefore, please refer to... Figure 1 and Figure 2 In a preferred embodiment, a fixing member 800 is bonded to the winding end of the positive electrode 200, and the other end of the fixing member 800 is bonded to the straight portion 610 of the previous winding coil via a first bending portion 621. That is, the starting end of the fixing member 800 is bonded to the cut end of the positive electrode 200, and the end is bonded to the positive electrode ceramic coating of the positive electrode 200 on the straight portion 610 of the previous winding coil, ensuring that the first separator 300, the reinforcing member 700, etc. are completely fixed.
[0043] In this application embodiment, the type of fastener 800 can be selected in several ways. In a preferred embodiment, the fastener 800 can be adhesive tape, which has an insulating function and can isolate the reaction between the positive electrode 200 and the negative electrode 400, thereby improving the safety of the wound cell 100.
[0044] In this embodiment, the preceding curved portion 620 on the same side as the first curved portion 621 is defined as the second curved portion 622. Please refer to... Figure 1 An insulating element 900 is bonded to the positive electrode 200 at the second bend 622 to prevent the positive electrode ceramic coating from reacting with the negative electrode 400.
[0045] In this application embodiment, the type of insulating element 900 can be selected from several options. In a preferred embodiment, the insulating element 900 can be adhesive tape.
[0046] This application further proposes a lithium battery, which includes a casing, an electrolyte, and a wound cell 100 as described above. The wound cell 100 is disposed inside the casing, and the electrolyte is filled inside the casing. The specific structure of the wound cell 100 is as described in the above embodiments. Since this lithium battery adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.
[0047] The above description is only a part or preferred embodiment of this application. Neither the text nor the drawings should limit the scope of protection of this application. All equivalent structural transformations made using the content of this application's specification and drawings under the overall concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.
Claims
1. A wound battery cell, characterized in that, It includes a positive electrode plate, a first separator, a negative electrode plate and a second separator stacked in sequence, wherein the positive electrode plate is provided with a positive electrode tab and the negative electrode plate is provided with a negative electrode tab; In each winding, the positive electrode, the first separator, the negative electrode, and the second separator have a straight portion and a curved portion. The outermost curved portion is defined as the first curved portion. The first separator located in the first curved portion is provided with a reinforcing member, which is attached to the side of the first separator facing the positive electrode.
2. The wound battery cell according to claim 1, characterized in that, Along the length of the first separator, the length of the first separator is greater than the length of the negative electrode sheet. At the winding end of the first separator, the reinforcing member is disposed on the surface of the first separator that extends beyond the negative electrode sheet.
3. The wound battery cell according to claim 2, characterized in that, Along the length direction of the first diaphragm, the length of the reinforcing member is defined as L1, and the length of the first diaphragm greater than that of the negative electrode is defined as L2; Where 1mm<L1≤L2.
4. The wound battery cell according to claim 3, characterized in that, The L2 satisfies: 5mm≤L2≤8mm.
5. The wound battery cell according to claim 1, characterized in that, Along the width direction of the first diaphragm, the width of the negative electrode sheet is defined as W0, the width of the reinforcing member is defined as W1, and the width of the first diaphragm is defined as W2; Where W0≤W1≤W2.
6. The wound battery cell according to claim 5, characterized in that, The W0 satisfies: 55mm≤W0≤94mm.
7. The wound battery cell according to claim 6, characterized in that, The W2 satisfies: 58mm≤W2≤96mm.
8. The wound battery cell according to claim 1, characterized in that, The positive electrode sheet is attached to a fixing member at the winding end, and the other end of the fixing member is attached to the straight part of the previous winding loop through the first bending part.
9. The wound battery cell according to claim 1, characterized in that, The first bend on the same side as the first bend is defined as the second bend, and the positive electrode sheet is bonded with an insulating component on the second bend.
10. A lithium battery, characterized in that, It includes a housing, an electrolyte, and a wound battery cell as described in any one of claims 1 to 9, wherein the wound battery cell is disposed within the housing, and the electrolyte fills the housing.