Square-shell battery cell
By providing a porous material layer inside the battery cell shell, the problem of insufficient electrolyte storage is solved, and the uniform distribution of the electrolyte and the extension of the battery life are achieved.
Patent Information
- Application Number
- CN202422704393.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-06
- Publication Date
- 2025-10-03
- Estimated Expiration
- 2034-11-06
AI Technical Summary
The electrolyte storage capacity in existing secondary batteries is insufficient, causing the battery cells to fail in the later stages of their lifespan.
A porous material layer is set in the battery cell shell to absorb the electrolyte and release the electrolyte when the pole core expands to replenish the free electrolyte inside the battery cell and enhance the uniform distribution of the electrolyte.
The design of the porous material layer extends the battery life, improves the reliability and stability of the battery cell, and avoids battery cell failure caused by insufficient electrolyte.
Smart Images
Figure CN223414118U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of secondary batteries, in particular to a square shell battery core. Background Art
[0002] A rechargeable battery, also known as a rechargeable battery or storage battery, is a battery that can be recharged after discharge to reactivate its active materials and allow continued use. A secondary battery typically contains one or more cells, each consisting of a housing and a core within the housing. The cell housing also contains an electrolyte, which bathes the core.
[0003] To increase battery life and boost the energy density of battery cells, current designs minimize redundant space within the battery cells and the porosity between the electrodes, increasing internal cell space utilization. This results in less free space within the cell walls, reducing the amount of free electrolyte stored. Insufficient electrolyte storage can lead to cell failure later in a battery's lifespan. Utility Model Content
[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a square shell battery cell to solve the problem of uneven electrolyte storage capacity in the prior art.
[0005] To achieve the above-mentioned and other related purposes, the present invention provides a square shell battery cell, comprising:
[0006] a housing having two housing walls arranged opposite to each other along a first direction;
[0007] A pole core, the pole core being disposed in the shell, the pole core having two flat surfaces disposed along a first direction, the flat surfaces being disposed opposite to the inwardly facing side surfaces of the shell wall;
[0008] A porous material layer is disposed in the shell and between the inwardly facing side of the shell wall and the flat surface of the pole core.
[0009] Optionally, the porous material layer abuts against the flat surface of the pole core.
[0010] Optionally, the electrode core is a laminated structure, comprising a positive electrode sheet, a negative electrode sheet and a separator, and the positive electrode sheet, the negative electrode sheet and the separator are stacked along the first direction.
[0011] Optionally, the electrode core is a wound structure, including a positive electrode sheet, a negative electrode sheet and a separator, and the winding axes of the positive electrode sheet, the negative electrode sheet and the separator are all perpendicular to the first direction.
[0012] Optionally, an insulating film is provided between the inner wall of the shell and the pole core.
[0013] Optionally, the porous material layer is provided on a surface of the insulating film close to the pole core.
[0014] Optionally, the porosity of the porous material layer is 50% to 70%.
[0015] Optionally, a dimension of the porous material layer in the first direction is T, a dimension of the battery core in the first direction is H, and T=0.04H-0.07H.
[0016] Optionally, T≥0.2mm.
[0017] Optionally, the side surface of the shell wall opposite to the flat surface of the pole core is a main wall surface, the area of the main wall surface is D, and along the first direction, the area of the projection of the porous material layer on the main wall surface is A, and A≥0.9D.
[0018] As described above, the square shell battery cell of the present invention has the following beneficial effects: the pole core has two flat surfaces arranged along a first direction, the shell has two shell walls arranged opposite to each other along the first direction, the pole core is arranged in the shell, and the flat surfaces are arranged opposite to the inward-facing side surfaces of the shell walls. Since a porous material layer is provided between the inward-facing side surfaces of the shell walls and the flat surfaces of the opposite pole core, and the porous material layer adopts a porous structural material that can adsorb electrolyte, after the pole core expands in the later stage of the battery life, the pole core can compress the porous material layer, so that the porous material layer releases the electrolyte adsorbed therein, thereby replenishing the free electrolyte inside the battery cell shell, which is beneficial to improving the reliability of the battery cell in the later stage of use. In the process of the porous material layer releasing the electrolyte, the parts of the pole core that are in contact with the porous material layer can all receive the replenished electrolyte, which is beneficial to the uniform distribution of the electrolyte, and further beneficial to extending the service life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 This is a schematic cross-sectional view of a square shell battery cell before the porous material layer is compressed in an embodiment of the present invention;
[0020] Figure 2 This is a cross-sectional view of the square shell battery cell after the porous material layer is compressed in the embodiment of the present utility model;
[0021] Figure 3 This is a schematic diagram of the explosion structure of the shell, insulating film and porous material layer in the embodiment of the present utility model;
[0022] Figure 4 This is a schematic diagram of the structure of the pole core in the embodiment of the present utility model;
[0023] Figure 5This is the second structural diagram of the pole core in the embodiment of the present utility model.
[0024] Explanation of the reference numerals: shell 1, pole core 2, porous material layer 3, insulating film 4, diaphragm 5, pole piece 6, flat surface 7, length direction X, width direction Y, thickness direction Z. DETAILED DESCRIPTION
[0025] The following describes the implementation of the present invention through specific embodiments. People familiar with this technology can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.
[0026] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for understanding and reading by those familiar with this technology, and are not used to limit the conditions for implementation of the present invention. Therefore, they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose of the present invention. At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments in their relative relationships should also be considered as the scope of implementation of the present invention without substantially changing the technical content.
[0027] See also Figures 1 to 5 This embodiment provides a prismatic battery cell comprising a housing 1 and a core 2. The housing 1 has two walls disposed opposite each other along a first direction. The core 2 is disposed within the housing 1 and has two flat surfaces 7 disposed along the first direction. The flat surfaces 7 oppose the inwardly facing sides of the housing 1 walls. After the core 2 is encapsulated and placed within the housing 1, electrolyte needs to be added to the housing 1. After the electrolyte is added, the core 2 can be immersed in the electrolyte.
[0028] In this embodiment, a porous material layer 3 is further provided between the inwardly facing side of the shell wall and the flat surface 7 of the pole core 2. The porous material layer 3 is a porous material that can absorb electrolyte. After the pole core 2 expands in the later stage of the battery life, the pole core 2 compresses the porous material layer 3, causing the porous material layer 3 to release the electrolyte adsorbed therein, thereby replenishing the free electrolyte inside the battery cell, which helps to avoid the battery cell from failing due to lack of free electrolyte in the later stage of use and improves the reliability of the battery cell. During the process of the porous material layer 3 releasing the electrolyte, the parts of the pole core 2 that contact the porous material layer 3 can all receive the replenished electrolyte, so that the electrolyte can be evenly distributed, which helps to extend the service life of the battery. The porous material layer 3 can be arranged parallel to or nearly parallel to the flat surface 7 of the pole core 2 and the side of the shell wall of the shell 1 opposite to the flat surface 7, which is conducive to arranging more porous material layers 3 in a limited space, thereby increasing the electrolyte that can be adsorbed by the porous material layer 3. During the expansion of the pole core 2, the porous material layer 3 can also exert a reaction force on the pole core 2, which is beneficial to reducing the expansion of the pole core 2, and further beneficial to maintaining the stability of the internal layer structure of the pole core 2 and improving the service life of the battery cell.
[0029] Specifically, in this embodiment, the side surface of one side of the porous material layer 3 abuts against the flat surface 7 of the pole core 2 along the first direction. The porous material layer 3 can provide support for the flat surface 7 of the pole core 2, which is beneficial to maintaining the stability of the layered structures inside the pole core 2 such as the pole piece 6, the diaphragm 5, etc.
[0030] In this embodiment, the porous material layer 3 is made of an insulating material, and its insulation performance needs to be greater than 300MΩ at a DC voltage of 500V to improve the insulation effect between the pole core 2 and the shell 1. At the same time, the material of the porous material layer 3 also needs to have good chemical stability to avoid reaction with components such as HF (hydrogen fluoride) in the electrolyte. In this embodiment, the material of the porous material layer 3 is sponge ceramic, which has good insulation and chemical stability and is elastic. When the porous material layer 3 abuts the pole core 2, the porous material layer 3 can provide support for the pole core 2. When the pole core 2 expands, the porous material layer 3 can also be compressed to release the electrolyte adsorbed therein.
[0031] Specifically, in this embodiment, the porosity of the porous material layer 3 is 50% to 70%, and while having sufficient strength, it can absorb enough electrolyte to meet the demand for electrolyte reserve.
[0032] like Figure 1 and Figure 2 and Figure 3As shown, in this embodiment, an insulating film 4 is provided between the inner wall of the housing 1 and the pole core 2. This insulating film 4 provides insulation and protects the pole core 2, minimizing external damage to the pole core 2. In this embodiment, the insulating film 4 is made of mylar polyester, a soft, tough polyester film with excellent insulation, heat resistance, and chemical resistance. The mylar film covers the pole core 2, providing excellent protection.
[0033] like Figure 3 As shown, in this embodiment, among the inner side surfaces of the battery cell shell wall, except for the inner side surface corresponding to the end cover, the remaining inner side surfaces are correspondingly provided with an insulating film to protect the pole core 2 in multiple aspects.
[0034] The porous material layer 3 can be sprayed or other processes and placed separately in the battery cell housing 1. The porous material layer 3 can also be first composited on the insulating film 4 and then assembled into the battery cell together with the insulating film 4 to simplify the battery cell assembly process. Of course, the porous material layer 3 can also be sprayed on the surface of the insulating film 4 after the insulating film 4 is assembled in the housing 1.
[0035] In this embodiment, the porous material layer 3 is provided on the surface of the insulating film 4 close to the pole core 2. Specifically, Figure 3 As shown, in this embodiment, the porous material layer 3 is disposed on the inner surface of the insulating film 4 corresponding to the flat surface of the pole core 2 (i.e., the surface of the insulating film 4 close to the pole core 2). The insulating film 4 positions and supports the porous material layer 3, thereby preventing the porous material layer 3 from moving or displacing and facilitating the installation of the porous material layer 3.
[0036] At the same time, since the porous material layer 3 is located on the surface of the insulating film 4 close to the pole core 2, when the pole core 2 expands and compresses the porous material layer 3, the porous material layer 3 releases the electrolyte, and the released electrolyte can be directly replenished to the pole core 2, reducing the electrolyte transfer process and making the electrolyte replenishment fast and effective.
[0037] Specifically, such as Figure 4 and Figure 5 As shown in the figure, the electrode core is a multi-layer structure, including a positive electrode sheet, a negative electrode sheet and a separator. Figure 4As shown, in some embodiments, the pole core is a wound structure, and the winding axes of the positive electrode sheet, the negative electrode sheet and the separator are all perpendicular to the first direction, that is, the positive electrode sheet, the negative electrode sheet and the separator adopt a winding process to form a pole core. For a pole core adapted for a square shell battery cell and adopting a winding process, its flat surface 7 is usually the two sides with the largest area and facing each other among the sides of the pole core, and the side of the pole core between the two flat surfaces 7 is usually a curved surface. When the pole core expands and compresses the porous material layer, the porous material layer can provide a reaction force, acting on the pole core along the normal direction of the flat surface 7 (that is, the first direction). After the pole core is subjected to the force of the porous material layer, it is also beneficial to reduce the wrinkles of the pole core layers and maintain the stability of the pole core structure. In some embodiments, the thickness of the pole core in the normal direction of the flat surface 7 is the smallest. Therefore, when the pole core is subjected to a force along the normal direction of the flat surface 7 (that is, the first direction), the stability between the layers of the pole core is good, and it is not easy to cause problems such as dislocation and separation.
[0038] like Figure 5 As shown, in other embodiments, the electrode core has a laminated structure, with the positive electrode sheet, the negative electrode sheet, and the separator stacked along a first direction. The side of the electrode core in the first direction is a flat surface 7, and the first direction is also the normal direction of the flat surface 7. When the electrode core expands and compresses the porous material layer, the porous material layer can provide a reaction force and act on the electrode core along the first direction, which is also the normal direction of the flat surface 7. The reaction force provided by the porous material layer can compact the layers of the electrode core, which helps reduce gaps and wrinkles between the layers of the electrode core, thereby helping to maintain the stability of the electrode core structure.
[0039] In this embodiment, the dimension of the porous material layer 3 in the first direction is T, and the dimension of the square shell battery cell in the first direction is H, and T=0.04H~0.07H. In this embodiment, the porous material layer 3 is parallel or approximately parallel to the flat surface of the pole core. The first direction is the thickness direction of the porous material layer 3, and T is the thickness of the porous material layer 3. The greater the proportion of the thickness of the porous material layer 3 in the overall size of the battery cell, the more electrolyte the porous material layer 3 can store, which is beneficial to increasing the cycle life of the battery cell. Conversely, the smaller the proportion of the thickness of the porous material layer 3 in the overall size of the battery cell, the larger the available space of the pole core 2, which is beneficial to improving the energy density of the battery cell. In this embodiment, T is between 0.04H and 0.07H, which can achieve a better balance between the energy density of the battery cell and the cycle life of the battery cell, thereby improving the overall performance of the battery cell.
[0040] like Figure 3As shown, a prismatic battery cell typically has a length direction X, a width direction Y, and a thickness direction Z. In this embodiment, the thickness direction Z of the battery cell is the first direction, which is also the normal direction of the flat surface of the electrode core 2 and the thickness direction of the porous material layer 3. In this embodiment, the porous material layer 3 is arranged corresponding to the side surface with the largest area among the side surfaces of the prismatic battery cell. When the thickness of the porous material layer 3 remains unchanged, the area of the porous material layer 3 has a larger installation space, which is conducive to increasing the total amount of electrolyte that can be adsorbed by the porous material layer 3.
[0041] At the same time, if the porous material layer 3 is too thin, its ability to store electrolyte is too small. Therefore, in this embodiment, T≥0.2mm is required, that is, the thickness of the porous material layer 3 is at least 0.2mm, to meet the minimum requirement of the battery cell for the porous material layer 3 to store electrolyte.
[0042] The side of the battery cell shell wall opposite the flat surface of the pole core is the main wall surface, and the area of the main wall surface is D. Along the thickness direction of the porous material layer 3, the area of the projection of the porous material layer 3 on the main wall surface is A, and A ≥ 0.9D. The greater the proportion of the projected area of the porous material layer 3 on the main wall surface to the main wall surface area, the more conducive it is to improving the utilization rate of the limited space inside the battery cell shell 1. When the thickness of the porous material layer 3 remains unchanged, it is also more conducive to increasing the electrolyte that can be stored in the porous material layer 3, thereby improving the cycle life of the battery cell. At the same time, the greater the proportion of the projected area of the porous material layer 3 on the main wall surface to the main wall surface area, the greater the contact area between the porous material layer 3 and the pole core 2 when the battery cell expands and the pole core 2 compresses the porous material layer 3. The electrolyte released by the porous material layer 3 can more evenly contact all parts of the pole core 2, which is conducive to further improving the service life of the battery cell.
[0043] In this embodiment, among the inner side surfaces of the shell wall of the housing 1, the inner side surface parallel to the length direction X and the width direction Y of the housing 1 is the main wall surface, making the main wall surface the surface with the largest area among the inner side surfaces of the battery cell housing 1. In this embodiment, the porous material layer 3 is disposed between the main wall surface and the electrode core 2, which helps to increase the layout space of the porous material layer 3 and increase the electrolyte storage capacity of the porous material layer 3.
[0044] In summary, the battery cell provided by this embodiment can release the electrolyte adsorbed therein after the pole core expands in the later stage of the battery life, thereby replenishing the free electrolyte inside the battery cell, which is beneficial to avoid the battery cell from failing due to lack of free electrolyte in the later stage of use and improving the reliability of the battery cell. During the process of the porous material layer releasing the electrolyte, the parts of the pole core that are in contact with the porous material layer can all receive the replenished electrolyte, so that the electrolyte can be evenly distributed, which is beneficial to extending the service life of the battery.
[0045] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed in the present invention are intended to be covered by the claims of the present invention.
Claims
1. A square shell battery cell, characterized in that: include: a housing having two housing walls arranged opposite to each other along a first direction; A pole core, the pole core being disposed in the shell, the pole core having two flat surfaces disposed along a first direction, the flat surfaces being disposed opposite to the inwardly facing side surfaces of the shell wall; A porous material layer is disposed in the shell and between the inwardly facing side of the shell wall and the flat surface of the pole core.
2. The square shell battery cell according to claim 1, characterized in that: The porous material layer abuts against the flat surface of the pole core.
3. The square shell battery cell according to claim 1, characterized in that: The electrode core is a laminated structure, comprising a positive electrode sheet, a negative electrode sheet and a separator, and the positive electrode sheet, the negative electrode sheet and the separator are stacked along the first direction.
4. The square shell battery cell according to claim 1, characterized in that: The electrode core is a wound structure, including a positive electrode sheet, a negative electrode sheet and a separator, and the winding axes of the positive electrode sheet, the negative electrode sheet and the separator are all perpendicular to the first direction.
5. The square shell battery cell according to claim 1, characterized in that: An insulating film is provided between the inner wall of the shell and the pole core.
6. The square shell battery cell according to claim 5, characterized in that: The porous material layer is provided on a surface of the insulating film close to the pole core.
7. The square shell battery cell according to claim 1, characterized in that: The porosity of the porous material layer is 50% to 70%.
8. The square shell battery cell according to any one of claims 1 to 7, characterized in that: The dimension of the porous material layer in the first direction is T, the dimension of the battery core in the first direction is H, and T=0.04H-0.07H.
9. The square shell battery cell according to claim 8, characterized in that: T≥0.2mm.
10. The square-shell battery cell according to any one of claims 1 to 7, characterized in that: The side surface of the shell wall opposite to the flat surface of the pole core is a main wall surface, and the area of the main wall surface is D. Along the first direction, the area of the projection of the porous material layer on the main wall surface is A, and A≥0.9D.