Battery cell structure and secondary battery
By setting an elastic buffer layer on the surface of the bare cell, the problems of uneven electrode wetting and detachment during transportation of secondary batteries are solved, achieving full wetting of the electrode and electrolyte, and improving the life and safety of the cell.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-24
- Publication Date
- 2026-03-03
AI Technical Summary
Existing secondary batteries suffer from uneven expansion of bare cells during charging and discharging, which makes it difficult for the electrodes to wet the electrolyte, resulting in black spots, lithium plating, and other phenomena. This affects the performance and lifespan of the cells, and the bottom of the bare cells is prone to detachment during transportation, leading to abnormalities.
An elastic buffer layer is covered on the surface of the bare cell, including a first buffer layer, a second buffer layer and a third buffer layer, which are respectively attached to the front and back two large surfaces, the left and right sides and the bottom surface of the bare cell. The buffer layer abuts against the inner wall of the encapsulation shell to ensure that the electrode and electrolyte are fully wetted and to prevent the active material from falling off.
The elastic buffer layer ensures that the electrode is fully wetted by the electrolyte, preventing the active material from falling off, improving the life and safety of the battery cell, and solving the performance degradation problem caused by uneven expansion of bare battery cells.
Smart Images
Figure CN223967265U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, specifically to a cell structure and a secondary battery. Background Technology
[0002] Secondary batteries have advantages such as stable voltage, safety and reliability, low price and abundant raw materials. They mainly include lithium-ion batteries, sodium-ion batteries and lithium-sulfur batteries, and are widely used in consumer electronics, energy storage and power fields.
[0003] Currently used square battery cells with aluminum or other metal casings, or soft-pack battery cells with aluminum-plastic film casings, generally consist of bare cells, electrolyte, and an outer aluminum casing or aluminum-plastic film. A bare cell typically comprises one or more wound or stacked bare cells, which are combined with an empty aluminum casing or a pre-punched aluminum-plastic film. The electrolyte is then injected into the casing through a cover plate or an injection hole on the aluminum-plastic film, ultimately forming the finished battery cell. During charging and discharging, due to anode expansion and internal gas generation, the large surface and sides of the bare cell expand. The degree of expansion gradually decreases from the center along the height of the cell. With prolonged charging and discharging use, the internal core expansion becomes increasingly pronounced, the gaps between the electrodes increase, and electrolyte wetting within the bare cell becomes difficult, leading to black spots, lithium plating, and other phenomena, thus causing a decline in the cell's cycle life, charge / discharge rate, and other performance characteristics. Meanwhile, due to the uneven expansion of bare cells along their height, the electrolyte wetting of the electrodes varies. Furthermore, the outer casing of the bare cell affects the middle section, causing the active material on the electrodes to be compressed, leading to active material shedding or lithium plating. To address the difficulty in electrode wetting caused by bare cell expansion during cycling, clamps with a certain pre-tightening force are typically used to bind the cells before charging and discharging. In modules, steel strips, sheet metal plates, or insulating supports are usually used to bind the cells on both sides. However, whether in a single cell or a module, the external clamps or steel strips lack elasticity, and the binding dimensions are fixed. With prolonged use, the inherent dimensional constraints gradually increase the restraining force on the cells. During internal expansion, the positive and negative electrodes are compressed, affecting electrolyte wetting and causing black spots, which adversely impacts performance and may even render the cells unusable. Utility Model Content
[0004] In view of this, the present invention provides a secondary battery structure to solve the problem that in the prior art, during the transportation or handling of batteries, the bottom of the bare cell inside the cell inevitably comes into contact with the cell casing due to shaking. Over time, this can cause the bottom electrode of the bare cell to fall off, resulting in abnormalities such as lithium plating and insufficient capacity, which further affects the cell's lifespan and safety.
[0005] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:
[0006] In a first aspect, this utility model provides a battery cell structure, comprising: a packaging shell, a bare battery cell, and an elastic buffer layer; the bare battery cell is disposed within the packaging shell and is adaptable for connection to positive and negative terminals; the elastic buffer layer is fitted onto the front and rear surfaces of the bare battery cell, extending from the front and rear surfaces to the left and right sides and bottom surface of the bare battery cell, respectively, with the side of the elastic buffer layer facing away from the bare battery cell abutting against the inner wall of the packaging shell. It has the following advantages:
[0007] By covering the surface of the bare cell with an elastic buffer layer, the bare cell is placed inside a package. Electrolyte is injected into the package. During the discharge process, when the bare cell expands, it is restrained by the elastic buffer layer and the package, thus ensuring that the electrode is fully wetted by the electrolyte. Because the elastic buffer layer is elastic, the electrode is restrained while preventing the active material from falling off due to restraint, thereby ensuring the life and safety of the cell.
[0008] According to a first aspect of the present invention, the elastic buffer layer includes a first buffer layer, a second buffer layer and a third buffer layer. The first buffer layer and the second buffer layer are both attached to the front and rear surfaces of the bare battery cell. The second buffer layer is located on both sides of the first buffer layer. The third buffer layer extends from the side of the second buffer layer away from the first buffer layer to the left and right sides of the bare battery cell and covers at least a portion of the bottom surface of the bare battery cell.
[0009] According to a first aspect of the present invention, the thickness of the first buffer layer is greater than the thickness of the second buffer layer, and the thickness of the second buffer layer is greater than the thickness of the third buffer layer.
[0010] According to a first aspect of the present invention, along the height direction of the bare cell, the thickness of the second buffer layer gradually decreases from the side closest to the first buffer layer to the side furthest from the first buffer layer.
[0011] According to a first aspect of the present invention, the thicknesses of the first buffer layer and the third buffer layer are uniformly distributed.
[0012] According to a first aspect of the present invention, the third buffer layer has a first gap between the side of the third buffer layer facing away from the bare battery cell and the inner wall of the encapsulation housing. According to a first aspect of the present invention, the length of the elastic buffer layer is greater than or equal to 2 / 3 times the height of the bare battery cell and less than or equal to the height of the bare battery cell; the width of the first buffer layer is equal to the width of the bare battery cell, and the width of the third buffer layer is equal to the side width of the bare battery cell and equal to the thickness of the bare battery cell; the length of the first buffer layer is greater than or equal to 1 / 3 times the height of the bare battery cell and less than or equal to the length of the elastic buffer layer; the third buffer layer includes a connected side section and a bottom section, the length of the side section is equal to the length of the first buffer layer; the length of the bottom section is greater than or equal to 1 / 4 times the width of the bare battery cell and less than or equal to 1 / 2 times the width of the bare battery cell. According to a first aspect of the present invention, the elastic buffer layer is made of an insulating porous material.
[0013] According to a first aspect of the present invention, the first buffer layer, the second buffer layer and the third buffer layer are provided with adhesive on the side near the bare battery cell, and the side of the first buffer layer, the second buffer layer and the third buffer layer near the bare battery cell is a flat surface.
[0014] Secondly, this utility model also provides a secondary battery, including the aforementioned cell structure. Attached Figure Description
[0015] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0016] Figure 1 This is a front view of an embodiment of the present invention showing the elastic buffer layer attached to a bare battery cell in a battery cell structure.
[0017] Figure 2 This is a side view of an embodiment of the present invention showing an elastic buffer layer attached to a bare battery cell in a battery cell structure.
[0018] Figure 3 A cross-sectional schematic diagram of an elastic buffer layer attached to a bare battery cell in a battery cell structure according to an embodiment of this utility model;
[0019] Figure 4 This is a cross-sectional schematic diagram of the first buffer layer according to an embodiment of the present invention;
[0020] Figure 5This is another cross-sectional view of the first buffer layer in an embodiment of the present invention.
[0021] Explanation of reference numerals in the attached figures:
[0022] 1. Encapsulation shell; 2. Bare battery cell; 3. First buffer layer; 4. Second buffer layer; 5. Third buffer layer; 51. Side section; 52. Bottom section. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0024] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model 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, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0025] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0026] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.
[0027] Reference Figure 1 and Figure 2As shown, in a first aspect, this utility model provides a battery cell structure, including: a package housing 1, a bare battery cell 2, and an elastic buffer layer; the bare battery cell 2 is disposed inside the package housing 1 and is suitable for connection with positive and negative terminals; the elastic buffer layer is attached to the front and rear surfaces of the bare battery cell 2, extending from the front and rear surfaces of the bare battery cell 2 to the left and right sides and the bottom surface of the bare battery cell 2, respectively, with the side of the elastic buffer layer facing away from the bare battery cell 2 abutting against the inner wall of the package housing 1. Specifically, by covering the surface of the bare battery cell 2 with an elastic buffer layer, and placing the bare battery cell 2 inside the package housing 1, by injecting electrolyte into the package housing 1, during the discharge process of the bare battery cell 2, when it expands, it will be restrained by the elastic buffer layer and the package housing 1, thereby ensuring that the electrode is fully wetted by the electrolyte. Because the elastic buffer layer is elastic, while the electrode is restrained, the active material can be prevented from falling off due to restraint, thus ensuring the life and safety of the battery cell. The elastic buffer layer extends from the front and rear surfaces of the bare cell 2 to the left and right sides and the bottom surface of the bare cell 2, so as to fully cover and wrap the bare cell 2 and improve the restraint performance.
[0028] Reference Figure 3 As shown, in the first aspect embodiment of the present invention, the elastic buffer layer includes a first buffer layer 3, a second buffer layer 4 and a third buffer layer 5. The first buffer layer 3 and the second buffer layer 4 are both attached to the front and rear two large surfaces of the bare battery cell 2. The second buffer layer 4 is located on both sides of the first buffer layer 3. The third buffer layer 5 extends from the side of the second buffer layer 4 away from the first buffer layer 3 to the left and right sides of the bare battery cell 2 and covers at least part of the bottom surface of the bare battery cell 2.
[0029] Specifically, by setting the elastic buffer layer into a first buffer layer 3, a second buffer layer 4, and a third buffer layer 5, the expansion degree of the bare cell 2 at different parts can be adapted to achieve different degrees of restraint on the expansion of different parts of the bare cell 2, ensuring that each part of the bare cell 2 can be fully wetted with electrolyte, and avoiding performance degradation caused by uneven electrolyte wetting.
[0030] It should be noted that the first buffer layer 3, the second buffer layer 4 and the third buffer layer 5 are connected in sequence to fully cover the surface of the bare cell 2, thereby achieving full confinement of the bare cell 2 and ensuring that the bare cell 2 is completely immersed in the electrolyte.
[0031] It is understandable that the encapsulation housing 1 is an aluminum shell or an aluminum-plastic film.
[0032] In a first aspect embodiment of the present invention, the thickness of the first buffer layer 3 is greater than the thickness of the second buffer layer 4, and the thickness of the second buffer layer 4 is greater than the thickness of the third buffer layer 5. (Refer to...) Figure 4 and Figure 5As shown, in the first aspect embodiment of the present invention, along the height direction of the bare cell 2, the thickness of the second buffer layer 4 gradually decreases from the side closer to the first buffer layer 3 to the side farther away from the first buffer layer 3.
[0033] Specifically, because the bare cell 2 expands significantly on both the front and rear sides, the thickness of the first buffer layer 3 is greater than that of the second buffer layer 4. Furthermore, the thickness of the second buffer layer 4 gradually decreases from the side closest to the first buffer layer 3 to the side furthest from the first buffer layer 3. This increases the binding force on the middle of the two large surfaces of the bare cell 2, ensuring that the electrode in the middle of the bare cell 2 can be fully wetted with the electrolyte under the binding and squeezing of the first buffer layer 3 and the encapsulation shell 1. This solves the problem of performance loss caused by expansion or uneven expansion position during the charging and discharging process of the bare cell 2, as well as electrode detachment caused by impacts to the bottom of the cell.
[0034] In a first aspect embodiment of the present invention, the thicknesses of the first buffer layer 3 and the third buffer layer 5 are uniformly distributed.
[0035] Specifically, since the bare cell 2 expands relatively little on its sides during charging and discharging, and the expansion in the height direction of the cell is relatively uniform, the thickness of the third buffer layer 5 is uniformly set to achieve balanced restraint on the bare cell 2. The first buffer layer 3 is located in the middle of the front and rear surfaces, and its overall expansion is relatively uniform, so the thickness of the first buffer layer 3 is uniformly set.
[0036] In a first aspect of this utility model, the third buffer layer 5 has a first gap between the side of the bare battery cell 2 facing away from the inner wall of the package housing 1.
[0037] Specifically, the first gap provides space for the flow of electrolyte, the elastic force of the third buffer layer 5 can meet the expansion of the side of the bare cell 2, and the first gap ensures that the electrode is fully wetted by the electrolyte.
[0038] In a first aspect of this invention, the elastic buffer layer is made of an insulating porous material.
[0039] Specifically, the elastic buffer layer is made of insulating material and has a porous design, which ensures that the electrolyte can enter the bare cell 2 and fully wet the electrode.
[0040] In a first aspect embodiment of the present invention, the length of the elastic buffer layer is greater than or equal to 2 / 3 times the height of the bare battery cell 2 and less than or equal to the height of the bare battery cell 2; the width of the first buffer layer 3 is equal to the width of the bare battery cell 2, and the width of the third buffer layer 5 is equal to the side width of the bare battery cell 2 and equal to the thickness of the bare battery cell 2; the length of the first buffer layer 3 is greater than or equal to 1 / 3 times the height of the bare battery cell 2 and less than or equal to the length of the elastic buffer layer; the third buffer layer 5 includes a side section 51 and a bottom section 52 connected to each other, the length of the side section 51 is equal to the length of the first buffer layer 3; the length of the bottom section 52 is greater than or equal to 1 / 4 times the width of the bare battery cell 2 and less than or equal to 1 / 2 times the width of the bare battery cell 2.
[0041] Specifically, to ensure the elastic buffer layer effectively restrains the bare cell 2, the length of the elastic buffer layer must be greater than or equal to 2 / 3 times the height of the bare cell 2, and less than or equal to the height of the bare cell 2, in order to avoid material waste and improve space utilization.
[0042] In a first aspect embodiment of the present invention, adhesive is provided on the side of the first buffer layer 3, the second buffer layer 4 and the third buffer layer 5 near the bare battery cell 2, and the side of the first buffer layer 3, the second buffer layer 4 and the third buffer layer 5 near the bare battery cell 2 is a flat surface.
[0043] Specifically, adhesive is provided on the side of the first buffer layer 3, the second buffer layer 4, and the third buffer layer 5 near the bare battery cell 2 to achieve adhesion and fixation with the bare battery cell 2. The side of the first buffer layer 3, the second buffer layer 4, and the third buffer layer 5 away from the bare battery cell 2 is a smooth surface. When the bare battery cell 2 is in an expanded state, the side of the first buffer layer 3, the second buffer layer 4, and the third buffer layer 5 away from the bare battery cell 2 can abut against the inner wall of the encapsulation shell 1. When the bare battery cell 2 is not expanded, the side of the first buffer layer 3, the second buffer layer 4, and the third buffer layer 5 away from the bare battery cell 2 can be separated from the encapsulation shell 1. The smooth surface avoids the first buffer layer 3, the second buffer layer 4, and the third buffer layer 5 from sticking to the encapsulation shell 1, ensuring that the first buffer layer 3, the second buffer layer 4, and the third buffer layer 5 restrain the bare battery cell 2.
[0044] In a first aspect embodiment of the present invention, the side of the first buffer layer 3, the second buffer layer 4 and the third buffer layer 5 closest to the bare battery cell 2 is a flat surface.
[0045] Secondly, this utility model also provides a secondary battery, including a cell structure.
[0046] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.
Claims
1. A battery cell structure, characterized in that, include: Encapsulation housing (1); Bare battery cell (2), the bare battery cell (2) is disposed inside the package housing (1), and the bare battery cell (2) can be adapted to be connected to the positive and negative terminals; An elastic buffer layer is attached to the front and rear surfaces of the bare battery cell (2). The elastic buffer layer extends from the front and rear surfaces of the bare battery cell (2) to the left and right sides and the bottom surface of the bare battery cell (2), respectively. The side of the elastic buffer layer away from the bare battery cell (2) abuts against the inner wall of the packaging shell (1).
2. The cell structure according to claim 1, characterized in that, The elastic buffer layer includes a first buffer layer (3), a second buffer layer (4) and a third buffer layer (5). The first buffer layer (3) and the second buffer layer (4) are both attached to the front and rear surfaces of the bare cell (2). The second buffer layer (4) is located on both sides of the first buffer layer (3). The third buffer layer (5) extends from the side of the second buffer layer (4) away from the first buffer layer (3) to the left and right sides of the bare cell (2) and covers at least part of the bottom surface of the bare cell (2).
3. The cell structure according to claim 2, characterized in that, The thickness of the first buffer layer (3) is greater than the thickness of the second buffer layer (4), and the thickness of the second buffer layer (4) is greater than the thickness of the third buffer layer (5).
4. The cell structure according to claim 3, characterized in that, Along the height direction of the bare cell (2), the thickness of the second buffer layer (4) gradually decreases from the side close to the first buffer layer (3) to the side away from the first buffer layer (3).
5. The cell structure according to claim 3, characterized in that, The thicknesses of the first buffer layer (3) and the third buffer layer (5) are uniformly set.
6. The cell structure according to claim 5, characterized in that, The third buffer layer (5) has a first gap between the side of the bare cell (2) facing away from the outer wall and the inner wall of the encapsulation housing (1).
7. The cell structure according to claim 2, characterized in that, The length of the elastic buffer layer is greater than or equal to 2 / 3 times the height of the bare cell (2) and less than or equal to the height of the bare cell (2); the width of the first buffer layer (3) is equal to the width of the bare cell (2), and the width of the third buffer layer (5) is equal to the side width of the bare cell (2) and equal to the thickness of the bare cell (2); the length of the first buffer layer (3) is greater than or equal to 1 / 3 times the height of the bare cell (2) and less than or equal to the length of the elastic buffer layer; the third buffer layer (5) includes a side section (51) and a bottom section (52) connected to each other, the length of the side section (51) is equal to the length of the first buffer layer (3); the length of the bottom section (52) is greater than or equal to 1 / 4 times the width of the bare cell (2) and less than or equal to 1 / 2 times the width of the bare cell (2).
8. The cell structure according to claim 1, characterized in that, The elastic buffer layer is made of an insulating porous material.
9. The cell structure according to claim 2, characterized in that, The first buffer layer (3), the second buffer layer (4) and the third buffer layer (5) are provided with adhesive on the side near the bare cell (2), and the side of the first buffer layer (3), the second buffer layer (4) and the third buffer layer (5) near the bare cell (2) is a flat surface.
10. A secondary battery, characterized in that, Includes the cell structure described in any one of claims 1-9.