Lithium ion cell and battery

Abstract

The utility model belongs to the technical field of lithium ion batteries, and particularly relates to a lithium ion battery cell which comprises a first isolating membrane, an anode plate, a second isolating membrane and a cathode plate which are sequentially stacked, and two or more sections of uniformly spaced glue solutions are arranged between the first isolating membrane and the second isolating membrane. And the length L1 of each section of glue solution is 10-25% of the longitudinal length of the first isolating membrane. According to the lithium ion battery cell provided by the utility model, a plurality of sections of glue solutions are arranged between the first isolating membrane and the second isolating membrane for bonding and fixing, so that thermal shrinkage generated by the isolating membranes at high temperature is effectively inhibited, and the phenomenon of short circuit of a battery caused by unnecessary contact between a cathode piece and an anode piece is avoided; and by adopting proper glue solution coating length and interval length, a firm and stable bonding effect can be realized, and meanwhile, the electrolyte can flow from the glue solution interval and gas generated by the pole piece can be discharged.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery core and a battery. Background Art

[0002] Lithium-ion battery is a common type of rechargeable battery that stores and releases electrical energy by the migration of lithium ions between the positive and negative electrodes. It is highly favored due to its unique advantages such as high specific energy, high operating voltage, wide application temperature range, low self-discharge rate, long cycle life, no pollution, and good safety performance. It is widely used in mobile devices, electric vehicles, energy storage systems and other fields.

[0003] Lithium-ion batteries are mainly composed of five parts: positive electrode material, negative electrode material, separator, electrolyte and packaging material. The separator of lithium-ion batteries is a porous film with evenly distributed micropores. It is located between the positive electrode material and the negative electrode material of lithium batteries. It prevents direct contact between the positive and negative electrodes, prevents battery short circuits, and transmits ions. It is a key material to ensure battery safety and affect battery performance. Although the separator does not directly participate in the electrochemical reaction of the battery, its performance affects the interface structure, internal resistance and other properties of the battery, and thus affects the battery's energy density, cycle life and rate performance; the thermal stability of the separator also determines the battery's operating temperature tolerance range and battery safety.

[0004] As the application scenarios of lithium-ion batteries become more and more abundant, how to build batteries with higher safety performance becomes particularly important. The diaphragm of lithium-ion batteries can act as a fuse. The diaphragm plays a key role in blocking the current and preventing the battery from having safety hazards. The diaphragm is a protective belt in the case of a short circuit, that is, the resistance of the diaphragm will suddenly increase at about 130 degrees, thereby preventing lithium ions from being transmitted between the cathode and cathode. When the diaphragm is above 130 degrees, its protective effect is safer. However, when lithium-ion batteries are used in high temperature environments, the diaphragm often shrinks, causing the anode and cathode to directly contact and short-circuit, which can cause the battery to catch fire or even explode; therefore, an effective way is needed to improve the performance of the diaphragm to solve the problem of battery short circuit. Utility Model Content

[0005] One of the purposes of the utility model is to provide a lithium ion battery cell to address the deficiencies of the prior art, so as to solve the problem of a short circuit caused by direct contact between the anode and cathode due to shrinkage of the diaphragm in a high temperature environment, thereby improving safety performance.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A lithium-ion battery cell comprises a first separator, an anode sheet, a second separator and a cathode sheet stacked in sequence, wherein two or more sections of glue at even intervals are arranged between the first separator and the second separator, and the length L of each section of the glue is1 The length of the first isolating film is 10%-25%. The first isolating film and the second isolating film are bonded by multiple adhesives, which can effectively suppress the thermal shrinkage of the isolating film at high temperature, thereby avoiding the problem of short circuit failure caused by direct contact between the positive and negative electrodes.

[0008] Preferably, the glue is coated on both sides of the first isolation film along the longitudinal direction close to the edge, and the coating width W is 0.1-10 mm from the edge. An appropriate coating width is set to achieve a bonding effect between isolation films.

[0009] Preferably, the distance L between the first section and the last section of the glue and the lateral edge of the first isolation film is 2 The minimum distance L between the edges of two adjacent sections of the adhesive is 1%-10% of the longitudinal length of the first isolation film. 3 The length of the first isolating film is 5% to 15%. By reserving a certain length of spacing, the flow of electrolyte and the discharge of gas are facilitated.

[0010] Preferably, the coating method of the glue solution includes extrusion spot coating, extrusion line coating, spray spot coating and spray line coating. Various coating methods can meet different production needs.

[0011] Preferably, the total coating amount of the glue solution is 0.01-5 ml, so that a strong bonding effect can be achieved with a lower coating amount, effectively saving production costs.

[0012] Preferably, the material of the adhesive includes at least one of CPP, OPP, BOPP, MOPP, PE, PET and PVC. Adhesives of different materials can be used for bonding according to different production requirements.

[0013] Preferably, the first isolation film and the second isolation film each include a base film and a coating layer, the coating layer is arranged on both sides of the base film, the glue is arranged on the coating layer of the first isolation film, the base film thickness is 2-10 μm, and the coating layer thickness is 1-6 μm. The coating layer can be a water-based coating layer or an oil-based coating layer. The anode sheet and the cathode sheet are arranged between the coating layers.

[0014] Preferably, the porosity of the base film is 20%-60%, the air permeability of the base film is ≥50s / 100ml, and the thermal shrinkage values ​​of the first and second isolation films are 1.1%-3.3% (MD) and 1.0%-2.3% (TD) at 130°C and 1h. The lower thermal shrinkage value can protect the isolation film from shrinkage deformation under high temperature conditions and maintain the stability of the overall shape structure of the battery cell.

[0015] Preferably, at least one electrode tab is provided on each of the anode sheet and the cathode sheet.

[0016] The second purpose of the utility model is to provide a battery with high safety performance and long service life, including the above-mentioned lithium ion battery cell.

[0017] Compared with the prior art, the beneficial effects of the utility model are as follows: a lithium-ion battery cell provided by the utility model is bonded and fixed by arranging multiple sections of glue between the first isolation membrane and the second isolation membrane, which effectively suppresses the thermal shrinkage of the isolation membrane at high temperature and avoids unnecessary contact between the positive and negative electrodes to cause a short circuit in the battery; by adopting appropriate glue coating length and interval length, a firm and stable bonding effect can be achieved, which is also beneficial to the flow of electrolyte from the glue interval and the discharge of gas generated by the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the battery core structure of the utility model.

[0019] Figure 2 It is a structural schematic diagram of embodiment 1 of the utility model.

[0020] Figure 3 It is a structural schematic diagram of embodiment 2 of the present utility model.

[0021] Figure 4 It is a structural schematic diagram of embodiment 3 of the present utility model.

[0022] Figure 5 It is a structural schematic diagram of embodiment 4 of the present utility model.

[0023] Figure 6 It is a structural schematic diagram of embodiment 5 of the present utility model.

[0024] Figure 7 It is a schematic diagram of the rolling process of the utility model.

[0025] Reference numerals:

[0026] 1. first isolation film, 11. base film, 12. coating layer,

[0027] 2. Anode sheet,

[0028] 3. The second isolation film,

[0029] 4. Cathode sheet,

[0030] 5. Glue.

[0031] L1: glue length.

[0032] L2: The distance between the first and last sections of the glue and the lateral edge of the isolation membrane.

[0033] L3: The shortest distance between the edges of two adjacent sections of glue.

[0034] W: coating width. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] like Figure 1-7 As shown, a lithium-ion battery cell includes a first separator 1, an anode sheet 2, a second separator 3 and a cathode sheet 4 stacked in sequence, and two or more sections of glue 5 are arranged between the first separator 1 and the second separator 3, and the length L of each section of glue 5 is 1 The glue 5 is arranged on both sides of the longitudinal length of the first isolation film 1, and each side is provided with a row of several sections of glue 5 of equal length evenly spaced, specifically, the number of sections can be 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.; and the length L of each section of glue 5 is 1 It is 10%-25% of the longitudinal length of the first isolation film 1 of the single-layer battery cell. Specifically, the value can be 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 25%, etc. The anode sheet 2 is placed between two columns of glue 5 and covered by the second isolation film 3 to encapsulate the anode sheet 2 therein. The second isolation film 3 is provided with the same arrangement of glue 5, and the cathode sheet 4 is placed between the glue 5 of the second isolation film 3. When the battery cell stacking method is winding or lamination, the first isolation film 1 of another layer of the battery cell can be covered on the second isolation film 3 of the original battery cell to achieve the coating of the cathode sheet 4, which is also bonded and fixed by the glue 5.

[0037] Furthermore, the glue 5 is coated on both sides close to the edge along the longitudinal direction of the first isolation membrane 1, and the coating width W is 0.1-10 mm from the edge. Preferably, the coating width is 0.1-2 mm. More specifically, the coating width can be 0.1 mm, 0.2 mm, 0.4 mm, 0.5 mm, 0.8 mm, 1 mm, 1.5 mm, 1.7 mm, 2 mm, 2.5 mm, 3 mm, 4 mm and 5 mm, etc.

[0038] Furthermore, the distance L between the first and last sections of the glue 5 and the lateral edge of the first isolation film 1 is 2 The minimum distance L between the edges of two adjacent sections of glue 5 is 1%-10% of the longitudinal length of the first isolation film 1. 3 It is 5%-15% of the longitudinal length of the first isolation film 1 .

[0039] By reserving an opening distance L between the two lateral edges of the first isolation film 1 and the glue 5 2 , it can be avoided that when the lithium-ion battery cell is wound or stacked, the thickness of the outermost lateral edge of the battery cell is too large due to the addition of the glue 5, which may cause the battery cell to be damaged. 2 The value of can be 1%, 1.5%, 2%, 2.5%, 3%, 4%, 5%, 6%, 7%, 8%, 9% and 10%, etc.

[0040] Between two adjacent sections of the glue 5, there are evenly spaced blank gaps L. 3 , through this gap, the electrolyte can flow to the anode sheet 2 or cathode sheet 4 between the first isolation membrane 1 and the second isolation membrane 3, thereby increasing the reaction rate and improving the electrochemical performance. At the same time, the amount of glue 5 can be reduced while ensuring the bonding strength, so as to save production costs. Similarly, the gap can also be used as a gas discharge channel during gas production, effectively improving the exhaust effect. Specifically, L 3 The value of can be 5%, 5.5%, 6%, 6.5%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% and 15%, etc.

[0041] Furthermore, the coating method of the glue liquid 5 includes extrusion spot coating, extrusion line coating, spray spot coating and spray line coating. The above methods can all achieve segmented glue liquid 5 coating, and an adaptive coating method can be adopted according to production requirements.

[0042] Further, the total coating amount of the glue 5 is 0.01-5 ml. Preferably, the coating amount is 0.1-2 ml. A smaller amount of the glue 5 can be used to complete the bonding and fixing of the battery core, while reducing the production cost. Specifically, the coating amount of the glue 5 can be 0.05 ml, 0.1 ml, 0.2 ml, 0.4 ml, 0.5 ml, 0.8 ml, 1 ml, 1.2 ml, 1.5 ml, 2 ml, 3 ml, 4 ml and 5 ml, etc.

[0043] Furthermore, the material of the adhesive 5 includes at least one of CPP, OPP, BOPP, MOPP, PE, PET and PVC. The type that matches the material of the isolation film can be selected as the adhesive 5 so as to better bond and fix the two isolation films.

[0044] Further, the first isolation film 1 and the second isolation film 3 both include a base film 11 and a coating layer 12, the coating layer 12 is arranged on both sides of the base film 11, the glue 5 is arranged on the coating layer 12 of the first isolation film 1, the base film 11 has a thickness of 2-10 μm, specifically, the base film 11 can have a thickness of 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm and 10 μm, etc. The coating layer 12 has a thickness of 1-6 μm, specifically, the coating layer 12 can have a thickness of 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 5 μm and 6 μm, etc. The coating layer 12 is arranged on opposite sides of the base film 11, and the coating layer 12 can be arranged on both the upper and lower surfaces of the base film 11. The anode sheet 2 and the cathode sheet 4 are both disposed in the coating layer 12, and the thickness of the coating layer 12 can be set according to the thickness of the anode sheet 2 and the cathode sheet 4. The coating layer 12 of the first isolation film 1 and the coating layer 12 of the second isolation film 3 are bonded by the glue 5.

[0045] Furthermore, the porosity of the base film 11 is 20%-60%, the air permeability of the base film 11 is ≥50s / 100ml, and the thermal shrinkage values ​​of the first isolation film 1 and the second isolation film 3 are 1.1%-3.3% (MD) and 1.0%-2.3% (TD) at 130°C and 1h.

[0046] Furthermore, at least one electrode tab is disposed on each of the anode sheet 2 and the cathode sheet 4 .

[0047] The present application also provides a battery, which is made by stacking the above-mentioned lithium-ion battery cells. The battery has high safety performance and long service life.

[0048] Embodiment 1:

[0049] like Figure 2 As shown, a lithium-ion battery cell comprises a first separator 1, an anode sheet 2, a second separator 3 and a cathode sheet 4 stacked in sequence, and four sections of glue 5 are arranged evenly spaced along the longitudinal edges of the first separator 1 and the second separator 3, and the length of each section of glue 5 is L 1 is the longitudinal length L of the first isolation film 1 of the single-layer battery cell 0 15%, the equidistant gap L between two adjacent sections of glue 5 3 is the longitudinal length L 0 10%, and the opening distance L between the first and last sections of the glue 5 and the transverse length edge of the first isolation film 1 2 is the longitudinal length L 0 The coating method used in this embodiment is extrusion line coating, the material of the glue 5 is CPP, the total coating amount of the glue 5 is 2 ml, and the coating width of the glue 5 is 1 mm.

[0050] The thickness of the base film 11 of the first isolation film 1 and the second isolation film 3 is 5 μm, and the thickness of the coating layer 12 on the base film 11 is 2 μm. The coating layer 12 is provided on both sides of the base film 11 in the thickness direction, and specifically, a coating layer 12 is provided on each of the two side edges along the longitudinal direction of the base film 11, and the glue 5 is coated on the coating layer 12 by extrusion line coating so as to be pressed and bonded later.

[0051] like Figure 7 As shown, each layer of bare cells includes a first separator 1, an anode sheet 2, a second separator 3 and a cathode sheet 4. Before winding the core, a separator edge pressing roller mechanism is provided in front of the laminating machine. After coating the first separator 1 with multiple sections of glue 5, the layered bare cells enter the separator edge pressing roller mechanism. After rolling, the first separator 1 and the second separator 3 are firmly adhered together, the anode sheet 2 is wrapped therein, and the cathode sheet 4 is placed above the second separator 3. After rolling, the bare cells are subjected to lamination process. Before another layer of bare cells is stacked on the original bare cells, glue 5 is coated on the second separator 3 of the original bare cells. The coating operation is the same as that of the glue 5 on the first separator 1, and then the cathode sheet 4 is coated with the first separator 1 of another layer of bare cells. Repeating this operation can complete a complete lithium-ion cell. When the Z-shaped lamination process is adopted, the glue 5 can also be coated on both lateral edges of the isolation film by the above method to suppress the deformation of the laminated core due to heat.

[0052] Embodiment 2:

[0053] like Figure 3 As shown, the manufacturing process of the battery cell is basically the same as that of Example 1, except that, in this embodiment, six sections of glue 5 are arranged evenly spaced along the longitudinal edges of both sides of the first isolation membrane 1 and the second isolation membrane 3, and the length of each section of glue 5 is L 1 is the longitudinal length L of the first isolation film 1 0 10%, equidistant gap L 3 is the longitudinal length L 0 6%, opening distance L 2 is the longitudinal length L 0 5%.

[0054] Embodiment 3:

[0055] like Figure 4 As shown, the manufacturing process of the battery cell is basically the same as that of Example 1, except that in this embodiment, five sections of glue 5 are arranged evenly spaced along the longitudinal edges of the two sides of the first isolation membrane 1 and the second isolation membrane 3, and the length of each section of glue 5 is L 1 is the longitudinal length L of the first isolation film 1 0 14%, equidistant gap L 3 is the longitudinal length L0 5%, opening distance L 2 is the longitudinal length L 0 5%.

[0056] Embodiment 4:

[0057] like Figure 5 As shown, the manufacturing process of the battery cell is basically the same as that of Example 1, except that in this embodiment, three sections of glue 5 are arranged evenly spaced along the longitudinal edges of the two sides of the first isolation membrane 1 and the second isolation membrane 3, and the length of each section of glue 5 is L 1 is the longitudinal length L of the first isolation film 1 0 20%, equidistant gap L 3 is the longitudinal length L 0 12% of the opening distance L 2 is the longitudinal length L 0 8%.

[0058] Embodiment 5:

[0059] like Figure 6 As shown, the manufacturing process of the battery cell is basically the same as that of Example 1, except that, in this embodiment, 7 sections of glue 5 are evenly spaced along the longitudinal edges of the two sides of the first isolation membrane 1 and the second isolation membrane 3, and the length of each section of glue 5 is L 1 is the longitudinal length L of the first isolation film 1 0 8%, equidistant gap L 3 is the longitudinal length L 0 6%, opening distance L 2 is the longitudinal length L 0 4%.

[0060] Embodiment 6-10:

[0061] like Figure 2-6 As shown, the production process of the battery cell is the same as that of the coating size of the glue 5 in Examples 1-5, except that the spraying method adopted in Examples 6-10 is spray line coating, the total coating amount of the glue 5 is 2 ml, and the coating width of the glue 5 is 1 mm.

[0062] Embodiment 11-15:

[0063] like Figure 2-6 As shown, the production process of the battery cell is the same as the coating size of the glue 5 in Examples 1-5, except that the thickness of the base film 11 in Examples 11-15 is modified to 3μm, 4μm, 5.5μm, 6μm and 7μm, respectively, and the thickness of the coating layer 12 is modified to 1μm, 1.5μm, 2.5μm, 3μm and 3.5μm, respectively.

[0064] Embodiment 16-21:

[0065] like Figure 2 As shown, the production process of the battery cell is basically the same as that of Example 1, except that the material of the glue 5 used in Examples 16-21 is replaced by OPP, BOPP, MOPP, PE, PET and PVC.

[0066] The battery cells prepared by the above embodiments can effectively suppress the thermal shrinkage of the diaphragm at high temperatures, thereby protecting the anode and cathode plates from contacting each other and causing a short circuit, and have excellent safety performance.

[0067] According to the disclosure and teaching of the above description, the technicians in the field of the utility model can also change and modify the above implementation. Therefore, the utility model is not limited to the above specific implementation, and any obvious improvement, replacement or modification made by the technicians in this field on the basis of the utility model belongs to the protection scope of the utility model. In addition, although some specific terms are used in this specification, these terms are only for the convenience of explanation and do not constitute any limitation to the utility model.

Claims

1. A lithium-ion battery cell, characterized in that: It includes a first isolation membrane, an anode sheet, a second isolation membrane and a cathode sheet stacked in sequence, and two or more sections of glue evenly spaced apart are arranged between the first isolation membrane and the second isolation membrane, and the length L1 of each section of the glue is 10%-25% of the longitudinal length of the first isolation membrane.

2. The lithium-ion battery cell according to claim 1, characterized in that: The glue is coated on both sides of the first isolation film along the longitudinal direction close to the edge, and the coating width W is 0.1-10 mm from the edge.

3. The lithium-ion battery cell according to claim 1, characterized in that: The distance L2 between the first and last sections of the glue and the transverse edge of the first isolation membrane is 1%-10% of the longitudinal length of the first isolation membrane, and the shortest distance L3 between the edges of two adjacent sections of the glue is 5%-15% of the longitudinal length of the first isolation membrane.

4. The lithium-ion battery cell according to claim 1, characterized in that: The coating methods of the glue solution include extrusion spot coating, extrusion line coating, spray spot coating and spray line coating.

5. The lithium-ion battery cell according to claim 1, characterized in that: The total coating amount of the glue solution is 0.01-5 ml.

6. The lithium-ion battery cell according to claim 1, characterized in that: The material of the glue is one of CPP, OPP, BOPP, MOPP, PE, PET and PVC.

7. The lithium-ion battery cell according to claim 1, characterized in that: The first isolation film and the second isolation film both include a base film and a coating layer, the coating layer is arranged on both sides of the base film, the glue is arranged on the coating layer of the first isolation film, the base film thickness is 2-10μm, and the coating layer thickness is 1-6μm.

8. The lithium-ion battery cell according to claim 7, characterized in that: The porosity of the base film is 20%-60%, the air permeability of the base film is ≥50s / 100ml, and the heat shrinkage values ​​of the first isolation film and the second isolation film are 1.1%-3.3% MD and 1.0%-2.3% TD under the conditions of 130°C and 1h.

9. The lithium-ion battery cell according to claim 1, characterized in that: The anode sheet and the cathode sheet are each provided with at least one electrode lug.

10. A battery, characterized in that: A lithium-ion battery cell comprising any one of claims 1 to 9.

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