Battery cell assembly structure

Abstract

The utility model relates to the technical field of new energy batteries, in particular to a battery cell assembly structure, which comprises a hard shell, a sealing cover is hermetically mounted on the hard shell, a battery cell mounting cavity for mounting a battery cell is arranged in the hard shell, a first protection component is arranged in the hard shell, and a second protection component is arranged on the inner wall of the battery cell mounting cavity. According to the utility model, the second protection assembly is matched with the shape of the end part of the battery cell, so that the stress on the pole core is more uniform, and the phenomenon that the pole core is extruded by a hard shell to cause polarization difference after the battery cell is circulated due to the increase of the thickness of a pole piece, so that the performance degradation and the safety risk of the battery cell are further avoided; and the limitation of the number of layers of the winding pole cores on the capacity of the battery core is broken through, and a plurality of winding pole cores can be assembled in the technical scheme, so that the capacity of the battery core is ensured, and the problems and potential risks existing in a high-capacity winding pole core are avoided.

Description

Technical Field

[0001] This utility model relates to the field of new energy battery technology, specifically to a cell assembly structure. Background Technology

[0002] Lithium / sodium-ion batteries are rechargeable cells that can be repeatedly charged and discharged. They are mainly composed of anode and cathode plates, separators, electrolyte, hard shell, and top cover. Currently, the hard shell is mainly cylindrical or square. Square wound cells combine high volumetric energy density and high manufacturing efficiency.

[0003] However, the square-wound electrode core suffers from uneven stress distribution, especially at the radius (R-corners). As the cell cycles, the electrode expands, causing the cell to thicken. The outer casing presses against the apex of the radius (R-corners), leading to wrinkling of the electrode, particularly at the junction of the radius and the straight edge. Increased contact resistance at the wrinkled areas causes lithium plating, resulting in a rapid decrease in cell capacity and posing safety hazards. Existing hard-shell structures are mostly square, with the radius (R-corners) of the wound electrode core only connecting to the hard shell at the apex. When the cell cycles, the electrode expands, thickening the core. The outer casing presses against the apex of the radius (R-corners), causing wrinkling, especially at the junction of the radius and the straight edge. Increased contact resistance at the wrinkled areas causes lithium plating, leading to a rapid decrease in cell capacity and posing safety hazards. Furthermore, as cell capacity increases, the required number of winding layers per electrode core increases. This results in limited heating of the inner ring of the electrode core during hot pressing, leading to uneven hot pressing. Additionally, the increased thickness of the electrode after cycling increases the tension on the outer ring, making it prone to breakage. Utility Model Content

[0004] To address the aforementioned problems, a battery cell assembly structure is provided, which solves the current issues through a first protective component and a second protective component.

[0005] To address the problems in the prior art, this utility model provides a battery cell assembly structure, including a rigid shell, a sealing cover sealed on the rigid shell, a battery cell mounting cavity for mounting the battery cell inside the rigid shell, a first protective component inside the rigid shell, and a second protective component on the inner wall of the battery cell mounting cavity.

[0006] Preferably, the two ends of the battery cell are semi-circular arc-shaped, and the sidewalls of the two ends of the hard shell are in contact with the two ends of the battery cell.

[0007] Preferably, a plurality of battery cells are installed in the battery cell mounting cavity, the sum of the diameters of the plurality of arranged battery cells is equal to the length of the inner wall of the battery cell mounting cavity, and the width of the battery cell mounting cavity is equal to the length of the battery cells.

[0008] Preferably, the first protective component includes a first buffer pad and a second buffer pad. A plurality of first buffer pads are provided on the bottom wall of the cell mounting cavity, and a plurality of second buffer pads are provided on the inner wall of the cell mounting cavity on the side opposite to the sealing cover.

[0009] Preferably, the second protective component includes insulating arc-shaped pads symmetrically arranged on the inner wall of the cell mounting cavity and cooperating with the cell, and protective blocks are provided between the insulating arc-shaped pads.

[0010] The advantages of this utility model compared to the prior art are:

[0011] 1. By setting a second protective component that matches the shape of the end of the cell, this utility model can make the electrode core more uniformly stressed, thereby avoiding polarization differences caused by the hard shell squeezing the electrode core due to the increase in electrode thickness after the cell cycle, which in turn leads to cell performance degradation and safety risks.

[0012] 2. This utility model breaks through the limitation of cell capacity by the number of wound electrode core layers. This technical solution can assemble multiple wound electrode cores, which not only ensures the cell capacity, but also avoids the problems and potential risks of large-capacity wound electrode cores.

[0013] 3. By setting arc-shaped sides, this utility model can act as a reinforcing rib compared to straight sides, which is beneficial to fixing the shape of the battery cell and helps to alleviate the hard shell deformation caused by the expansion of the battery cell after cycling. Attached Figure Description

[0014] Figure 1 A three-dimensional structural diagram of a battery cell assembly structure Figure 1 .

[0015] Figure 2 A three-dimensional structural diagram of a battery cell assembly structure Figure 2 .

[0016] Figure 3 It is a cell assembly structure Figure 2 A magnified three-dimensional structural diagram of part A.

[0017] The numbers in the diagram are: 101, hard shell; 102, sealing cover; 103, cell mounting cavity; 104, cell; 105, insulating arc-shaped pad; 106, protective block; 200, first protective component; 201, first buffer pad; 202, second buffer pad. Detailed Implementation

[0018] To further understand the features, technical means, and specific objectives and functions achieved by this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and specific embodiments.

[0019] Reference Figures 1-3 A battery cell assembly structure includes a rigid shell 101, a sealing cover 102 sealed on the rigid shell 101, a battery cell mounting cavity 103 for mounting a battery cell 104 inside the rigid shell 101, a first protective component 200 inside the rigid shell 101, and a second protective component on the inner wall of the battery cell mounting cavity 103.

[0020] By setting a special shape for the hard shell 101, such as setting a first protective component 200 in the hard shell 101, the side wall of the hard shell 101 is made to be arc-shaped. With this special shape, it can make contact with the cell 104, so that the electrode core can be subjected to more uniform force. This avoids the polarization difference caused by the increased electrode thickness after the cell 104 is cycled, which would lead to the electrode core being squeezed by the hard shell 101, thus avoiding the performance degradation and safety risks of the cell 104. By setting the first protective component 200, the impact force on the cell 104 can be absorbed, thereby improving the stability of the cell 104.

[0021] Reference Figures 1-3 The battery cell 104 has semi-circular arc shapes at both ends, and the sidewalls of the hard shell 101 at both ends are in contact with the two ends of the battery cell 104.

[0022] By setting the sidewall of the hard shell 101 to be an arc-shaped side that matches the end of the battery cell 104, it can act as a reinforcing rib compared to a straight edge, which is beneficial to fixing the shape of the battery cell 104 and helps to alleviate the deformation of the hard shell 101 caused by the expansion of the battery cell 104 after cycling.

[0023] Reference Figures 1-2 The cell mounting cavity 103 contains a plurality of cells 104. The sum of the diameters of the plurality of cells 104 arranged in a row is equal to the length of the inner wall of the cell mounting cavity 103. The width of the cell mounting cavity 103 is equal to the length of the cells 104.

[0024] This installation method allows the size of the hard shell 101 to match the battery cell 104, improving the stability of the battery cell 104 installation.

[0025] Reference Figures 1-2 The first protective component 200 includes a first buffer pad 201 and a second buffer pad 202. A plurality of first buffer pads 201 are provided on the bottom wall of the cell mounting cavity 103, and a plurality of second buffer pads 202 are provided on the inner wall of the cell mounting cavity 103 on the side opposite to the sealing cover 102.

[0026] The first buffer pad 201 and the second buffer pad 202 are used to absorb the impact force on the battery cell 104 and improve the stability of the battery cell 104 installation.

[0027] Reference Figures 1-3The second protective component includes insulating arc-shaped pads 105 symmetrically arranged on the inner wall of the cell mounting cavity 103 and cooperating with the cell 104, and protective blocks 106 are provided between the insulating arc-shaped pads 105.

[0028] The insulating arc-shaped pad 105 is arc-shaped to adapt to the end shape of the battery cell 104, and the protective block 106 is used to prevent scratches on the main body of the battery cell 104.

[0029] Example 1: Assembly of 600Ah lithium iron phosphate hard-shell cells

[0030] Mechanical parts preparation: The thickness of the 300Ah hard shell on the market is increased by 1 times and processed and designed with rounded corners, while the width and height of the hard shell remain unchanged (the shape of the top cover must correspond to the hard shell, and its sides are also rounded).

[0031] Cell Assembly: 1. Prepare two sets of 300Ah system electrode cores from the market, i.e., four wound electrode cores, each with a capacity of 150Ah. Bundle the two wound electrode cores together with tape and weld the tabs together using ultrasonic welding; 2. Weld the bundled electrode core sets together with the adapter plates; 3. After baking, electrolyte injection, formation, sealing, capacity and internal resistance testing of the semi-finished cells, the finished cells are formed, with an average capacity of approximately 640Ah at 0.3C; 4. Randomly select cells for cycle testing. Currently, the capacity retention rate is around 97.5% after approximately 500 cycles, and no lithium plating is found at the R-corners of the electrode plates upon disassembly.

[0032] Comparative Example 1: Assembly of 600Ah Lithium Iron Phosphate Hard-Case Cells

[0033] Mechanical parts preparation: Double the width of the market 300Ah hard shell, while keeping other dimensions unchanged (the top cover length must correspond to the hard shell width, and its width must be doubled); customize larger coil needles; customize larger hot pressing plate; customize larger formation and cycle testing fixtures;

[0034] Cell Assembly: 1. Two 300Ah capacity electrode cores are obtained by winding with a custom-made enlarged winding needle; 2. The bundled electrode cores are then welded together with the adapter plate; 3. The semi-finished cells are baked, injected with electrolyte, formed, sealed, and tested for capacity and internal resistance in sequence to form finished cells, with an average capacity of about 640Ah at 0.3C; 4. Cells are randomly selected for cycle testing. Currently, the cycle life is about 500 cycles and the capacity retention rate is about 96%. The cell electrode plates are disassembled, the R-corners are wrinkled, and lithium plating is performed.

[0035] Comparative Example 2: Assembly of 600Ah Lithium Iron Phosphate Hard-Case Cells

[0036] Mechanical component preparation: Double the thickness of the 300Ah hard shell on the market, while keeping the width and height of the hard shell unchanged (the top cover shape must correspond to the hard shell, and its width must be doubled);

[0037] Cell Assembly: 1. Two 300Ah capacity electrode cores are obtained by winding with a custom-made enlarged winding needle; 2. The bundled electrode cores are then welded together with the adapter plate; 3. The semi-finished cells are sequentially baked, injected with electrolyte, formed, sealed, and tested for capacity and internal resistance to form finished cells, with an average capacity of about 640Ah at 0.3C; 4. Randomly selected cells are subjected to cycle tests. Currently, the cycle life is about 500 cycles and the capacity retention rate is about 93%. The disassembled cells show severe wrinkling of the electrode plates, severe lithium plating at the R-angle, and severe wrinkling of the inner ring of the electrode core.

[0038] Working Principle: By setting a special hard shell 101 shape, such as the hard shell 101 and the insulating arc-shaped pad 105 inside the hard shell 101 being in close contact with the end of the cell 104, the force on the electrode core can be more uniform. This avoids polarization differences caused by the increased electrode thickness after the cell 104 is cycled, which would lead to the electrode core being squeezed by the hard shell 101, thus preventing performance degradation and safety risks of the cell 104. This also overcomes the limitation of the cell 104 capacity on the number of wound electrode core layers. In the assembly of the cell 104, when the number of wound layers is large, the inner ring is not heated enough during hot pressing, resulting in insufficient hot pressing. In addition, the larger the number of wound layers, the greater the tension on the outer ring after the cell 104 is cycled, which poses a risk of electrode breakage. The above technical solution can assemble multiple wound electrode cores, which not only ensures the capacity of the cell 104, but also avoids the problems and potential risks of large-capacity wound electrode cores. Risk; It helps to mitigate the deformation of the hard shell 101 caused by the expansion of the battery cell 104 after cycling. The curved side of the insulating arc pad 105 can act as a reinforcing rib compared to the straight side, which is beneficial to the fixation of the shape of the battery cell 104. This also reduces the proportion of non-active components such as the hard shell 101 and the top cover in the battery cell 104, which is beneficial to improving the volumetric energy density and mass energy density of the battery cell 104 and the module. While ensuring that the volumetric energy density of the battery cell 101 module remains unchanged, this technology reduces the contact area between the battery cells 104. Compared with the ordinary square hard shell, the specially designed hard shell 101 with curved sides is more conducive to the heat dissipation of the battery cell 104 module. The first buffer pad 201 and the second buffer pad 202 are used to absorb the impact force on the battery cell 104 and improve the stability of the battery cell 104 installation.

[0039] The above embodiments only illustrate one or more implementations of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this utility model. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the appended claims.

Claims

1. A battery cell assembly structure, characterized in that, It includes a hard shell (101), a sealing cover (102) is sealed on the hard shell (101), a cell mounting cavity (103) for mounting a cell (104) is provided inside the hard shell (101), a first protective component (200) is provided inside the hard shell (101), and a second protective component is provided on the inner wall of the cell mounting cavity (103).

2. The cell assembly structure according to claim 1, characterized in that, The two ends of the battery cell (104) are semi-circular arc-shaped, and the sidewalls of the two ends of the hard shell (101) are in contact with the two ends of the battery cell (104).

3. The cell assembly structure according to claim 2, characterized in that, The battery cell mounting cavity (103) contains a plurality of battery cells (104), the sum of the diameters of the plurality of arranged battery cells (104) is equal to the length of the inner wall of the battery cell mounting cavity (103), and the width of the battery cell mounting cavity (103) is equal to the length of the battery cells (104).

4. The cell assembly structure according to claim 1, characterized in that, The first protective component (200) includes a first buffer pad (201) and a second buffer pad (202). A plurality of first buffer pads (201) are provided on the bottom wall of the cell mounting cavity (103), and a plurality of second buffer pads (202) are provided on the inner wall of the cell mounting cavity (103) opposite to the sealing cover (102).

5. The cell assembly structure according to claim 1, characterized in that, The second protective component includes insulating arc-shaped pads (105) symmetrically arranged on the inner wall of the cell mounting cavity (103) and cooperating with the cell (104), and protective blocks (106) are provided between the insulating arc-shaped pads (105).

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