Battery structure and lithium ion battery
By using a porous elastic material as a buffer body in lithium-ion batteries, the problem of battery swelling caused by the expansion of graphite negative electrodes is solved, maintaining battery structural stability and improving battery performance and lifespan.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HEFEI GUOXUAN HIGH TECH POWER ENERGY
- Filing Date
- 2025-06-24
- Publication Date
- 2026-06-05
Smart Images
Figure CN224328733U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, and in particular to a battery structure and a lithium-ion battery. Background Technology
[0002] Lithium-ion batteries typically use graphite as the negative electrode material. During the lithium intercalation process during charging, the interlayer spacing of the graphite changes as lithium is inserted, causing the graphite to expand in volume, increasing the thickness of the battery electrode, and consequently leading to cell expansion. Conversely, during the lithium removal and discharge process, the interlayer spacing of the graphite decreases as lithium is removed, and the electrode thickness also decreases.
[0003] When a battery is subjected to repeated charge and discharge cycles, the overall thickness of the cell gradually increases, eventually leading to battery bulging. After bulging, gaps appear between the electrodes, obstructing lithium-ion transport channels and causing lithium plating. This chain reaction inevitably alters battery performance, significantly impacting battery lifespan and reliability. Furthermore, the change in battery thickness also restricts battery pack design, becoming a pressing technical challenge. Utility Model Content
[0004] The main purpose of this invention is to provide a battery structure and a lithium-ion battery, aiming to optimize the battery structure and reduce the thickness change trend of the battery under repeated charge and discharge conditions.
[0005] To achieve the above objectives, this utility model proposes a battery structure, comprising:
[0006] Core with tabs;
[0007] The electrode buffer section is connected to the winding core and is located on the same side as the electrode; and
[0008] A buffer body having an open side, the buffer body being wrapped around the outer wall of the core, the tab buffer portion and the tab being placed on the open side of the buffer body; the buffer body being made of a porous elastic material.
[0009] In the above scheme, the buffer body is preferably made of a porous elastic material. Porous elastic materials have high porosity and elastic properties, and they can adsorb a certain amount of electrolyte. After adsorbing electrolyte, the buffer body can adjust the electrolyte distribution in the core to a certain extent, improve the wettability of the electrolyte, and promote the transport of lithium ions between the electrodes. During the charging and discharging process of the battery, the thickness of the buffer electrode changes. When the thickness of the electrode inside the core increases, the buffer body is compressed. The increase in the thickness of the electrode inside the core keeps the overall thickness of the battery constant and the stability of the force. At the same time, when the buffer body is compressed, it can release the adsorbed electrolyte to replenish the electrolyte loss caused by the increase in electrode thickness and avoid the obstruction of the transport channel caused by the gap between the battery electrodes.
[0010] Furthermore, the tabs include a first tab and a second tab connected to one side wall of the core. The tab buffer includes a first shoulder buffer layer and a second shoulder buffer layer, which are respectively positioned on the sides of the first tab and the second tab that are far apart from each other. When the core expands, the first shoulder buffer layer and the second shoulder buffer layer can fill the tiny gaps between the tab and the electrode sheet, keeping them in close contact. This ensures that the current can be stably transferred from the tab to the electrode sheet of the core. They also provide some fixation and support for the tab, limiting its displacement and maintaining the stability of the battery's internal structure.
[0011] Furthermore, the tab buffer section includes a middle buffer layer, which is connected to the core and located between the first tab and the second tab. The middle buffer layer separates the first tab and the second tab to avoid the risk of short circuits, and also buffers and fills the space between the first tab and the second tab.
[0012] Furthermore, the cross-sections of the first and second electrodes are trapezoidal, and the first shoulder buffer layer, the second shoulder buffer layer, and the middle buffer layer are inclined on the side closest to the first and second electrodes, and are arranged parallel to the waistlines of the first and second electrodes. This strengthens the limiting effect on the first and second electrodes, while also reducing the direct impact on the electrodes and the core structure, protecting the electrode sheets and diaphragms and other components inside the core.
[0013] Furthermore, the buffer body includes a bottom buffer section, a side buffer section, and a front buffer section. The bottom buffer section is disposed on the side wall opposite to the tab buffer section of the winding core, and the side buffer section and the front buffer section are disposed on the periphery of the winding core. The bottom buffer section, the side buffer section, and the front buffer section are individually sealed using methods such as sealant, sealing strips, or direct mechanical compression to prevent leakage.
[0014] Furthermore, the positive buffer section includes a positive buffer layer one and a positive buffer layer two, both of which are connected to the large surfaces of the core that are opposite to each other.
[0015] Furthermore, the side buffer section includes a first side buffer layer and a second side buffer layer, which sequentially cover the periphery of the core.
[0016] Furthermore, the thickness of the buffer body is 0.1 mm to 10 mm.
[0017] Furthermore, the porous elastic material is polyethylene or polypropylene. Its porosity is required to be no less than 20%, so that the buffer body has electrolyte resistance and does not dissolve or swell in the electrolyte.
[0018] This application also discloses a lithium-ion battery, which is used in the battery structure described above.
[0019] The above technical solution has the following advantages:
[0020] The buffer body of this application is made of a porous elastic material with high porosity, which can absorb electrolyte after the battery is filled with electrolyte. During the charging and discharging process of the battery, the buffer body can buffer the changes in the thickness of the electrode sheets inside the core, maintaining the overall thickness of the battery and the stability of the stress. When the electrode sheet thickness increases, the buffer body is compressed, releasing electrolyte and replenishing the electrolyte loss caused by electrode sheet expansion. This effectively prevents lithium deposition during battery cycling, reduces the tendency of battery thickness change under repeated charging and discharging conditions, and thus maintains the stability of the lithium battery electrode assembly under stress during charging and discharging. It has significant technical effects, helps to improve the electrical and safety performance of lithium batteries, and meets the requirements of the Patent Law for beneficial effects. Attached Figure Description
[0021] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings, wherein:
[0022] Figure 1 This is a front cross-sectional view of the present invention;
[0023] Figure 2 This is a side cross-sectional view of the present invention;
[0024] Figure 3 This is a top-view cross-sectional view of the present invention;
[0025] Figure 4 This is a fast charging cycle curve diagram of this utility model.
[0026] In the diagram: 1. Core; 2. Electrode tab; 21. First electrode tab; 22. Second electrode tab; 3. Electrode tab buffer section; 31. Shoulder buffer layer one; 32. Middle buffer layer; 33. Shoulder buffer layer two; 4. Side buffer section; 41. Side buffer layer one; 42. Side buffer layer two; 5. Bottom buffer section; 6. Positive buffer section; 61. Positive buffer layer one; 62. Positive buffer layer two. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain this utility model and do not constitute a limitation on this utility model.
[0028] like Figure 1 and Figure 2 As shown, a battery structure includes a winding core 1 with tabs 2, a tab buffer portion 3, and a buffer body. The tab buffer portion 3 is connected to the winding core 1 and is located on the same side as the tabs 2. The buffer body has an open side and is wrapped around the outer wall of the winding core 1. The tab buffer portion 3 and the tabs 2 are located on the open side of the buffer body. The buffer body is made of a porous elastic material. The tabs 2 are welded to one end of the winding core 1, and the tab buffer portion 3 is installed at the tabs 2 to buffer them. It fills the tiny gaps between the tabs 2 and the inner electrode sheets of the winding core 1, ensuring close contact and stable current transfer from the tabs 2 to the electrode sheets. The buffer body wraps around the entire winding core 1, protecting its periphery. The buffer body and the tab buffer portion 3 work together to buffer the winding core 1 and the electrode sheets from different positions.
[0029] The buffer body is preferably made of a porous elastic material, which has high porosity and elastic properties, enabling it to adsorb a certain amount of electrolyte. After adsorbing the electrolyte, the buffer body can regulate the electrolyte distribution in the core 1 to a certain extent, improve the wettability of the electrolyte, and promote the transport of lithium ions between the electrodes. During the charging and discharging process of the battery, the thickness of the buffer electrode changes. When the thickness of the electrode inside the core 1 increases, the buffer body is compressed. The increase in the thickness of the electrode inside the buffer core 1 maintains the overall thickness of the battery and the stability of the force. At the same time, when the buffer body is compressed, it can release the adsorbed electrolyte to replenish the electrolyte loss caused by the increase in electrode thickness, and avoid the obstruction of the transport channels caused by the gaps between the battery electrodes.
[0030] like Figure 2As shown, the tab 2 includes a first tab 21 and a second tab 22 connected to one side wall of the core 1. The tab buffer 3 includes a first buffer layer 31 and a second buffer layer 33, which are respectively located on the side away from the first tab 21 and the second tab 22. The first tab 21 and the second tab 22 are welded to one end of the core 1. The first buffer layer 31 and the second buffer layer 33 are respectively installed on the periphery of the end of the core 1 and rely on the first tab 21 and the second tab 22. When the core 1 expands, the first buffer layer 31 and the second buffer layer 33 can fill the tiny gap between the tab 2 and the electrode sheet, keeping them in close contact. This ensures that the current can be stably transmitted from the tab 2 to the electrode sheet of the core 1. They can also fix and support the tab 2 to a certain extent, restrict the displacement of the tab 2, and maintain the stability of the internal structure of the battery.
[0031] like Figure 1 and Figure 2 As shown, the tab buffer section 3 further includes a middle buffer layer 32, which is connected to the core 1 and located between the first tab 21 and the second tab 22. The middle buffer layer 32 is used to separate the first tab 21 and the second tab 22 to avoid the risk of short circuit. At the same time, the middle buffer layer 32 can also buffer and fill the portion between the first tab 21 and the second tab 22.
[0032] In one embodiment of this application, the first electrode tab 21 and the second electrode tab 22 have trapezoidal cross-sections. The first shoulder buffer layer 31, the second shoulder buffer layer 33, and the middle buffer layer 32 are inclined on the side closest to the first electrode tab 21 and the second electrode tab 22, and are arranged parallel to the waistline of the first electrode tab 21 and the second electrode tab 22. By altering the cross-sections of the first electrode tab 21 and the second electrode tab 22, the first electrode tab 21 is embedded between the first shoulder buffer layer 31 and the middle buffer layer 32, and the second electrode tab 22 is embedded between the second shoulder buffer layer 33 and the middle buffer layer 32. This strengthens the limiting effect on the first electrode tab 21 and the second electrode tab 22, and also reduces the direct impact on the electrode tab 2 and the core 1 structure, protecting the electrode sheets and diaphragms and other components inside the core 1.
[0033] like Figures 1-3 As shown, the buffer body can be a single piece. Preferably, the buffer body includes a bottom buffer part 5, a side buffer part 4, and a front buffer part 6. The bottom buffer part 5 is located on the side wall opposite to the tab buffer part 3 of the core 1, and the side buffer parts 4 and the front buffer part 6 are located on the periphery of the core 1. The bottom buffer part 5, the side buffer part 4, and the front buffer part 6 are individually sealed using methods such as sealant, sealing strips, or direct mechanical compression to prevent leakage.
[0034] like Figure 2 and Figure 3As shown, the positive buffer section 6 includes a first positive buffer layer 61 and a second positive buffer layer 62, both of which are connected to the large surfaces of the core 1 that are opposite to each other. The side buffer section 4 includes a first side buffer layer 41 and a second side buffer layer 42, which sequentially cover the periphery of the core 1. In this application, the core 1 has a waist-shaped cross-section. The first positive buffer layer 61 and the second positive buffer layer 62 are square blocks that are attached to the large surface of the core 1. The first side buffer layer 41 and the second side buffer layer 42 are also square blocks, but they have an arc-shaped groove on one side for attaching to the arc-shaped end of the core 1. By dividing the buffer body into the first side buffer layer 41, the first positive buffer layer 61, the second side buffer layer 42 and the positive buffer layer, when the core 1 expands to one side, only one buffer layer is affected. This ensures that each side of the buffer body is compensated individually, so as to avoid interference between the first side buffer layer 41, the first positive buffer layer 61, the second side buffer layer 42 and the positive buffer layer when the whole body is compensated.
[0035] In this application, the thickness of the buffer body is 0.1 mm to 10 mm. Because a thicker buffer body can absorb more impact energy, it can effectively reduce the impact force transmitted to the core 1 itself and reduce the risk of damage to the core 1 due to impact. At the same time, in order to ensure the heat dissipation effect of the core 1, the thickness of the buffer body needs to be reduced as much as possible. Therefore, in this application, the bottom buffer part 5, the first side buffer layer 41, the first positive buffer layer 61, the second side buffer layer 42 and the positive buffer layer are preferably 5 mm thick.
[0036] In this application, the porous elastic material is polyethylene or polypropylene, and its porosity is required to be not less than 20%, so that the buffer body has electrolyte resistance and does not dissolve or swell in the electrolyte.
[0037] A lithium-ion battery, characterized in that it uses the battery structure described above.
[0038] like Figure 4 As shown, in one embodiment of this application, a high-reliability lithium battery structure is specifically designed, comprising a 39Ah capacity core 1 with dimensions of 23cm*10cm and a thickness of 8mm. A 23cm*10cm positive buffer portion 6 is placed on one side of the core 1 and fixed with tape. The positive buffer portion 6 is made of polyethylene fiber with a porosity of 40%. The thickness of the positive buffer layer 1 61 and positive buffer layer 2 62 on its large surface is 1.5mm, and the thickness of the side buffer layer 1 41 and side buffer layer 2 42 is 0.5-3mm. Subsequently, the core 1 is welded with tabs 2, inserted into the casing, the top cover is welded, dried, injected with electrolyte, formed, and capacity tested. The finished cell is clamped using an aluminum plate clamp, and its cycle performance is tested. Based on the above parameters, but without the buffer body and tab buffer portion 3, only a rigid material lithium battery structure is used as a comparison sample.
[0039] project Embodiments of the present invention Comparison sample capacity 39Ah 39Ah First effect 89％ 89％ Cycle (90% capacity retention) 900 weeks 300 weeks
[0040] The comparison shows that the battery provided by the present invention has a significant advantage in accelerating cycling, with a 200% increase in cycle life.
[0041] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.
Claims
1. A battery structure, characterized in that, include: Core (1) with tabs (2); The tab buffer section (3) is connected to the winding core (1) and is on the same side as the tab (2); and The buffer body has an open side and is wrapped around the outer wall of the core (1). The tab buffer part (3) and the tab (2) are placed on the open side of the buffer body. The buffer body is made of a porous elastic material.
2. The battery structure as described in claim 1, characterized in that, The tab (2) includes a first tab (21) and a second tab (22) connected to one side wall of the core (1). The tab buffer part (3) includes a first shoulder buffer layer (31) and a second shoulder buffer layer (33). The first shoulder buffer layer (31) and the second shoulder buffer layer (33) are respectively located on the side away from each other of the first tab (21) and the second tab (22).
3. The battery structure as described in claim 2, characterized in that, The tab buffer section (3) includes a middle buffer layer (32), which is connected to the core (1) and is located between the first tab (21) and the second tab (22).
4. The battery structure as described in claim 3, characterized in that, The cross-section of the first electrode (21) and the second electrode (22) is trapezoidal. The first shoulder buffer layer (31), the second shoulder buffer layer (33) and the middle buffer layer (32) are inclined on the side close to the first electrode (21) and the second electrode (22), and are arranged parallel to the waistline of the first electrode (21) and the second electrode (22).
5. The battery structure as described in claim 1, characterized in that, The buffer body includes a bottom buffer part (5), a side buffer part (4) and a front buffer part (6). The bottom buffer part (5) is disposed on the side wall of the core (1) opposite to the tab buffer part (3). The side buffer part (4) and the front buffer part (6) are disposed on the periphery of the core (1).
6. The battery structure as described in claim 5, characterized in that, The positive buffer section (6) includes a positive buffer layer one (61) and a positive buffer layer two (62), both of which are connected to the large surfaces of the core (1) that are opposite to each other.
7. The battery structure as described in claim 6, characterized in that, The side buffer section (4) includes a side buffer layer one (41) and a side buffer layer two (42), which are sequentially wrapped around the periphery of the core (1).
8. The battery structure as described in claim 1, characterized in that, The thickness of the buffer body is 0.1 mm to 10 mm.
9. The battery structure as described in claim 1, characterized in that, The porous elastic material is polyethylene or polypropylene.
10. A lithium-ion battery, characterized in that, Its application is in the battery structure as described in any one of claims 1 to 9.