Soft package lithium ion battery
By setting an isolation pre-sealing line or bending it 180° to fit the second airbag of the soft-pack battery with the cell packaging area, and using clips to hold the second airbag, the problem of uneven distribution of electrolyte and gas inside the cell is solved, and the uniformity of cell hardness and electrochemical performance are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-11
- Publication Date
- 2026-04-07
AI Technical Summary
The existing double-sealing method for soft-pack batteries results in uneven distribution of electrolyte and gas inside the cell. The side closest to the airbag is easy to remove, while the side farther away from the airbag is difficult to remove, leading to inconsistent cell hardness and affecting the internal consistency of the battery.
An airbag is used to set an isolation pre-sealing line or bend it 180° to fit the battery cell packaging area, and is fixed with a thermally conductive silicone sheet. The airbag is then clamped with a clip to ensure that the electrolyte and gas are drawn out evenly. The distribution of electrolyte is controlled by adjusting the area and shape of the sealing area.
This achieves similar levels of electrolyte and gas extraction on both sides of the cell, consistent cell hardness, improved internal consistency of the battery, and avoids electrolyte waste and impact on electrochemical performance.
Smart Images
Figure CN224096715U_ABST
Abstract
Description
Technical Field
[0001] This technology belongs to the field of new energy batteries, specifically involving a soft-pack battery. Background Technology
[0002] The manufacturing process of pouch batteries involves several steps, including electrolyte injection, sealing, formation, and secondary sealing. During formation, the electrolyte reacts and decomposes with the positive and negative electrode materials, generating gas. Therefore, to ensure sufficient electrolyte quantity, the mass of electrolyte injected into a pouch battery is slightly higher than that used during normal charging and discharging. The secondary sealing process, performed after formation, involves vacuum-sealing the pouch battery to remove gas and excess electrolyte.
[0003] Currently, the double-sealing method used in pouch batteries is as follows: Figure 1 As shown: The pouch cell 2' is placed parallel to the horizontal plane 1. During the second sealing process, the pouch cell 2' is clamped by two clamps. Then, the pouch cell airbag 5 is cut open to perform vacuum extraction, achieving the purpose of removing gas and excess electrolyte from the battery. The drawback of this second sealing method is that the airbag 5' is located on one side of the pouch cell 2'. During the vacuum extraction process, the electrolyte and gas on the side 6 close to the airbag are easily extracted, while the electrolyte and gas on the side 7 far from the airbag are not easily extracted. This results in uneven distribution of residual electrolyte and residual gas inside the pouch cell 2. The positive and negative electrode plates on the side 6 close to the airbag are in close contact with the separator, while the side 7 of the pouch cell far from the airbag is prone to the problem of the cell being too soft. Summary of the Invention
[0004] The purpose of this invention is to overcome the above-mentioned shortcomings of the prior art and provide a soft-pack lithium-ion battery that allows the amount of electrolyte and gas extracted from both sides of the soft-pack cell to be roughly the same during the double sealing process, so that the hardness of both sides of the cell is consistent and the internal consistency of the cell is better.
[0005] The technical solution of this utility model is: a soft-pack lithium-ion battery, comprising an outer bag formed by folding a soft packaging film, the outer bag comprising a cell packaging area in the middle for accommodating the soft-pack cell, an airbag bag one located on the left side of the cell packaging area, and an airbag bag two located on the right side of the cell packaging area, the top of the soft-pack cell, airbag bag one, and airbag bag two placed in the cell packaging area are heat-sealed by a top sealing area, the left side of airbag bag one is heat-sealed by a first side sealing area, and the right side of airbag bag two is heat-sealed by a second side sealing area, an isolation pre-sealing line parallel to the second side sealing area is provided on the left side of airbag bag two near the cell packaging area, the isolation pre-sealing line is formed by gap heat sealing, the isolation pre-sealing line comprises a sealing area composed of multiple sealing points arranged in sequence at intervals, and an unsealed area is formed between two adjacent sealing points.
[0006] Before the first side sealing area is heat-sealed, it serves as an electrolyte filling port.
[0007] The sealing points can be rectangles, squares, parallelograms, or triangles.
[0008] The distance between the isolation pre-sealing line and the cell housing area is ≥5mm.
[0009] The pouch cell is a bare cell formed by winding or stacking.
[0010] When ternary lithium-ion batteries are used in pouch cells, the area of the sealed edge area of the isolation pre-sealing line is smaller than the area of the unsealed edge area; when lithium iron phosphate batteries are used in pouch cells, the area of the sealed edge area of the isolation pre-sealing line is greater than or equal to the area of the unsealed edge area.
[0011] A soft-pack lithium-ion battery includes an outer bag formed by folding a soft packaging film. The outer bag includes a cell packaging area in the middle for accommodating the soft-pack cell, an airbag bag one located on the left side of the cell packaging area, and an airbag bag two located on the right side of the cell packaging area. The top of the soft-pack cell, airbag bag one, and airbag bag two, which are placed in the cell packaging area, are heat-sealed by a top sealing area. The left side of airbag bag one is heat-sealed by a first side sealing area, and the right side of airbag bag two is heat-sealed by a second side sealing area. An isolation pre-sealing line parallel to the second side sealing area is provided on the left side of airbag bag two near the cell packaging area. The isolation pre-sealing line clip is clamped to airbag bag two.
[0012] A soft-pack lithium-ion battery includes an outer bag formed by folding a soft packaging film. The outer bag includes a cell encapsulation area in the middle for accommodating the soft-pack battery cell, an airbag bag one located on the left side of the cell encapsulation area, and an airbag bag two located on the right side of the cell encapsulation area. The top of the soft-pack battery cell, airbag bag one, and airbag bag two, which are placed in the cell encapsulation area, are heat-sealed by a top sealing area. The left side of airbag bag one is heat-sealed by a first side sealing area, and the right side of airbag bag two is heat-sealed by a second side sealing area. An isolation pre-sealing line parallel to the second side sealing area is provided on the left side of airbag bag two near the cell encapsulation area. The isolation pre-sealing line is formed by bending airbag bag two 180° toward the cell encapsulation area. Airbag bag two is attached to the large surface of the cell encapsulation area and fixed to the cell encapsulation area by a thermally conductive silicone sheet or double-sided adhesive.
[0013] When a pouch cell has two air bladders on the left and right sides, one air bladder can be sealed using a gap-sealing method. This means the second air bladder is not completely sealed, leaving a sealed area and an unsealed area. This ensures that during subsequent electrolyte injection and formation processes, the electrolyte is not wasted because the cell is placed vertically with the second air bladder below the horizontal plane (1) and excessive electrolyte flows into the bottom air bladder under gravity. It also ensures that when the cell is laid flat and sealed, residual electrolyte and gas inside the cell can be discharged from both sides, resulting in consistent electrolyte levels on both sides and improved internal consistency. Attached Figure Description
[0014] Figure 1 This is a structural diagram of existing technology;
[0015] Figure 2 This is a structural diagram of airbag bag two without an isolation pre-sealing line;
[0016] Figure 3 This is one of the structural schematic diagrams of this utility model (the second airbag is clamped by clip 10).
[0017] Figure 4 This is the second structural schematic diagram of this utility model;
[0018] Figure 5 This is the third structural schematic diagram of this utility model (the airbag is bent in the 9th direction of the battery cell encapsulation area 13).
[0019] In the diagram, 1 is the horizontal plane, 2 is the soft-pack battery cell, 3 is the first tab, 4 is the second tab, 5 is the first airbag, 9 is the second airbag, 10 is the clip, 11 is the sealing area, 12 is the unsealed area, 13 is the battery cell packaging area, 14 is the top sealing area, 15 is the first side sealing area, and 16 is the second side sealing area. Detailed Implementation
[0020] like Figure 2 As shown, the soft-pack battery cell 2 has two air bags on the left and right sides, namely air bag 5 and air bag 9. When sealed, the soft-pack battery cell 2 can be placed parallel to the horizontal plane 1. The residual free electrolyte and gas inside the battery cell can be discharged from the left and right sides of the battery cell. The liquid retention on the left and right sides of the battery cell is consistent, and the internal consistency of the battery cell is better.
[0021] like Figure 3 As shown, when the soft-pack battery cell 2 has two air bags on the left and right sides, namely air bag 5 and air bag 9, during liquid injection and subsequent formation processes, one side of air bag 9 can be clamped with clip 10 to prevent the air bag 9 from being lower than the horizontal plane 1 when the soft-pack battery cell 2 is placed vertically. Under the action of gravity, the electrolyte inside will flow into the air bag 9 located at the bottom, causing electrolyte waste.
[0022] like Figure 4As shown, when the pouch cell (hereinafter referred to as cell) 2 has two air bladders on the left and right sides, one side of the air bladder 9 can be sealed using a gap sealing method. That is, the air bladder 9 is not completely sealed, with a sealed area 11 and an unsealed area 12. This ensures that during subsequent processes such as electrolyte injection and formation, the cell 2 is not placed vertically with the air bladder 9 below the horizontal plane 1, preventing excessive electrolyte from flowing into the bottom air bladder 9 under gravity, thus avoiding electrolyte waste. It also ensures that when the cell is laid flat and sealed, residual electrolyte and gas inside the cell can be discharged from both sides of the cell, resulting in consistent electrolyte retention on both sides of the cell and improved internal consistency.
[0023] The areas of the sealed area 11 and the unsealed area 12 can be equal, or the area of the sealed area 11 can be larger or smaller than the area of the unsealed area 12. When the battery cell 2 uses raw materials that produce a lot of gas, such as ternary lithium, the area of the sealed area 11 can be smaller than the area of the unsealed area 12 to facilitate the discharge of gases generated inside the battery cell 2 during its formation. When the battery cell 2 uses raw materials that produce less gas, such as lithium iron phosphate, the area of the sealed area 11 can be larger than or equal to the area of the unsealed area 12 to allow the discharge of any remaining small amount of gas inside the battery cell 2.
[0024] The edge sealing point of the edge sealing area 11 can be a rectangle, a square, a parallelogram, a triangle, or other shapes.
[0025] The number of both the sealed area 11 and the unsealed area 12 is at least 1. This ensures that the residual gas inside the battery cell 2 can flow out from the side of the air bag 9 where the unsealed area 12 is located, and also prevents excessive electrolyte from flowing into the air bag 9 where the unsealed area 12 is located during the production process, which would result in a low electrolyte retention of the battery cell 2 and affect its electrochemical performance.
[0026] The distance between the sealing area 11 and the battery cell 2 should be ≥5mm. This ensures that when the battery cell 2 is fully sealed, the gap between the sealing area 11 and the battery cell 2 is large enough to accommodate the heat-sealing head, without affecting the sealing effect of the airbag 9 containing the sealing area 11 during the second sealing process. If the distance between the sealing area 11 and the battery cell 2 is too small, the second sealing area may overlap with the area containing the sealing area 11 and the unsealed area 12, causing wrinkles in the second sealing area and affecting the sealing effect of the battery cell 2. In severe cases, this may lead to leakage from the battery cell 2.
[0027] like Figure 5As shown, when the pouch cell 2 has two air bags 5 and 9 on the left and right sides, the air bag 9 can be bent 180° towards the cell packaging area 13, so that the air bag 9 is in close contact with the large surface of the cell packaging area 13, and is fixed to the cell packaging area 13 with thermally conductive silicone sheet, double-sided tape, or other tape. After the cell 2 is formed, the air bag 9 is separated from the cell packaging area 13. This ensures that during subsequent liquid injection and formation processes, the pouch cell 2 is not placed vertically with the air bag 9 below the horizontal plane 1, and the electrolyte does not flow excessively into the bottom air bag 9 under gravity, causing electrolyte waste. It also ensures that when the cell 2 is laid flat for secondary sealing, the residual electrolyte and gas inside the cell 2 can be discharged from the air bags 5 and 9 on the left and right sides of the cell, so that the liquid retention on the left and right sides of the cell 2 is consistent, and the internal consistency of the cell 2 is improved.
[0028] The specific implementation process of this utility model is as follows: Example 1
[0029] 1. Place the bare battery cell that has been wound or stacked into the battery cell packaging area 13, and use a heat sealer to heat seal the top sealing area 14 and the second side sealing area 16.
[0030] 2. Use clip 10 to clamp the connection between airbag 29 and battery cell 2.
[0031] 3. Inject the electrolyte into the unsealed airbag bag 5.
[0032] 4. Use a heat sealing machine to heat seal the first side sealing area 15.
[0033] 5. Allow the battery cell to stand still, so that the electrolyte can fully immerse the battery cell body (when standing still, if the battery cell is placed vertically, the airbag 29 should be lower than the horizontal plane, and the corresponding airbag 15 on the other side should be higher than the horizontal plane).
[0034] 6. Form the battery cell. During the formation process, if the battery cell is placed vertically, the airbag 29 should be below the horizontal plane, while the corresponding airbag 15 on the other side should be above the horizontal plane.
[0035] 7. After formation, allow the battery cell to cool down by standing (when standing, if the battery cell is placed vertically, place airbag 29 below the horizontal plane, and the corresponding airbag 15 on the other side above the horizontal plane).
[0036] Remove clamp 10, cut open airbag 1 5 and airbag 2 9, and place the battery cell in the secondary sealing machine for secondary sealing.
[0037] 9. Cut off airbag 1 (5) and airbag 2 (9) from the second seal.
[0038] The length of clamp 10 is greater than or equal to the width of cell 2, and clamp 10 can completely clamp the connection between airbag 2 9 and cell 2. The clamping force of clamp 10 is greater than or equal to 50N. If the clamping force is too low, the gas pressure generated inside cell 2 during formation will be too high, causing clamp 10 to open, resulting in some free electrolyte inside cell 2 leaking into airbag 2 9, causing the electrolyte retention of cell 2 to be too low, thus affecting the electrochemical performance of cell 2. Example 2
[0039] 1. Place the bare battery cell that has been wound or stacked into the battery cell packaging area 13, and use a heat sealer to heat seal the top sealing area 14 and the second side sealing area 16.
[0040] 2. Heat seal the gap between the airbag 2 9 and the battery cell 2, that is, there are both sealed area 11 and unsealed area 12 at the same time.
[0041] 3. Inject the electrolyte into the unsealed airbag bag 5.
[0042] 4. Use a heat sealing machine to heat seal the first side sealing area 15.
[0043] 5. Allow the battery cell to stand still, so that the electrolyte can fully immerse the battery cell body (when standing still, if the battery cell is placed vertically, the airbag 29 should be lower than the horizontal plane, and the corresponding airbag 15 on the other side should be higher than the horizontal plane).
[0044] 6. Form the battery cell. During the formation process, if the battery cell is placed vertically, the airbag 29 should be below the horizontal plane, while the corresponding airbag 15 on the other side should be above the horizontal plane.
[0045] 7. After formation, allow the battery cell to cool down by standing (when standing, if the battery cell is placed vertically, place airbag 29 below the horizontal plane, and the corresponding airbag 15 on the other side above the horizontal plane).
[0046] 8. Cut open airbag 1 (5) and airbag 2 (9), and place the battery cell in the secondary sealing machine for secondary sealing.
[0047] 9. Cut off airbag 1 (5) and airbag 2 (9) from the second seal. Example 3
[0048] 1. Place the bare battery cell that has been wound or stacked into the battery cell packaging area 13, and use a heat sealer to heat seal the top sealing area 14 and the second side sealing area 16.
[0049] 2. Bend the airbag 29 towards the cell encapsulation area 13 by 180° and fix it to the cell encapsulation area 13 with thermally conductive silicone sheet, double-sided tape or other tape.
[0050] 3. Inject the electrolyte into the unsealed airbag bag 5.
[0051] 4. Use a heat sealing machine to heat seal the first side sealing area 15.
[0052] 5. Allow the battery cell to stand to allow the electrolyte to fully penetrate the battery cell body.
[0053] 6. Form the battery cells.
[0054] 7. After formation, the battery cells are left to cool down by standing.
[0055] 8. Tear off the tape securing the airbag 2 9 to the cell packaging area 13, and unfold the airbag 2 9 from the cell packaging area 13.
[0056] 9. Cut open airbag 5 and airbag 9, and place the battery cell in the secondary sealing machine for secondary sealing.
[0057] 10. Cut off airbag 1 (5) and airbag 2 (9) from the second seal.
Claims
1. A soft-pack lithium-ion battery, characterized in that: The outer bag is formed by folding a soft packaging film. The outer bag includes a cell packaging area (13) in the middle for accommodating the soft-pack cell (2), an airbag bag 1 (5) on the left side of the cell packaging area (13), and an airbag bag 2 (9) on the right side of the cell accommodating area. The top of the soft-pack cell (2), airbag bag 1 (5), and airbag bag 2 (9) placed in the cell packaging area (13) is heat-sealed by a top sealing area (14). The left side of airbag bag 1 (5) is heat-sealed by a first side sealing area (15), and the right side of airbag bag 2 (9) is heat-sealed by a second side sealing area (16). An isolation pre-sealing line parallel to the second side sealing area (16) is provided on the left side of airbag bag 2 (9) near the cell accommodating area. The isolation pre-sealing line is formed by gap heat sealing. The isolation pre-sealing line includes a sealing area (11) composed of multiple sealing points arranged in sequence at intervals. An unsealed area (12) is formed between two adjacent sealing points.
2. The soft-pack lithium-ion battery according to claim 1, characterized in that: Before the first side sealing area (15) is heat-sealed, it is an electrolyte filling port.
3. The soft-pack lithium-ion battery according to claim 1, characterized in that: The sealing area (11) can be a rectangle, a square, a parallelogram, or a triangle.
4. The soft-pack lithium-ion battery according to claim 1, characterized in that: The distance between the isolation pre-sealing line and the cell housing area is ≥5mm.
5. The soft-pack lithium-ion battery according to claim 1, characterized in that: The soft-pack battery cell (2) is a bare battery cell formed by winding or stacking.
6. The soft-pack lithium-ion battery according to claim 1, characterized in that: When the soft-pack battery cell (2) uses ternary raw materials, the area of the sealing area (11) of the isolation pre-sealing line is smaller than the area of the unsealed area (12); when the soft-pack battery cell (2) uses lithium iron phosphate raw materials, the area of the sealing area (11) of the isolation pre-sealing line is greater than or equal to the area of the unsealed area (12).
7. A soft-pack lithium-ion battery, characterized in that: The outer bag is formed by folding a soft packaging film. The outer bag includes a cell packaging area (13) in the middle for accommodating the soft-pack cell (2), an airbag bag one (5) on the left side of the cell packaging area (13), and an airbag bag two (9) on the right side of the cell accommodating area. The top of the soft-pack cell (2), airbag bag one (5), and airbag bag two (9) placed in the cell packaging area (13) are heat-sealed by a top sealing area (14). The left side of airbag bag one (5) is heat-sealed by a first side sealing area (15), and the right side of airbag bag two (9) is heat-sealed by a second side sealing area (16). An isolation pre-sealing line parallel to the second side sealing area (16) is provided on the left side of airbag bag two (9) near the cell accommodating area. The isolation pre-sealing line clip (10) is clamped in airbag bag two (9) to form the isolation pre-sealing line.
8. A soft-pack lithium-ion battery, characterized in that: The outer bag is formed by folding a flexible packaging film. The outer bag includes a cell packaging area (13) in the middle for accommodating the flexible battery cell (2), an airbag bag one (5) on the left side of the cell packaging area (13), and an airbag bag two (9) on the right side of the cell housing area. The top of the flexible battery cell (2), airbag bag one (5), and airbag bag two (9) placed in the cell packaging area (13) are heat-sealed by a top sealing area (14). The left side of airbag bag one (5) is sealed by a first sealing area. The side sealing area (15) is heat-sealed, and the right side of the second airbag (9) is heat-sealed by the second side sealing area (16). The left side of the second airbag (9) near the cell housing area is provided with an isolation pre-sealing line parallel to the second side sealing area (16). The isolation pre-sealing line is formed by bending the second airbag (9) 180° towards the cell packaging area (13). The second airbag (9) and the cell packaging area (13) are attached to the large surface and fixed to the cell packaging area (13) by thermally conductive silicone sheet or double-sided tape.