Pre-lithiation structure for roll core and pre-lithiated roll core
By pre-lithiation at the lithium-ion battery core level and using a windable current collector to connect to the lithium source, the problems of low initial efficiency and low cycle performance of the lithium-ion battery negative electrode are solved, achieving high coulombic efficiency and safety improvement.
Patent Information
- Application Number
- CN202422369152.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-09-16
- Estimated Expiration
- 2034-09-26
AI Technical Summary
Lithium-ion batteries in the prior art have problems such as low initial efficiency of the negative electrode, low initial coulombic efficiency, and low cycle performance, and pre-lithiation of the negative electrode poses safety risks and the risk of reduced pre-lithiation effect.
A pre-lithiation structure for the core is adopted. By setting a windable current collector connected to the lithium source, the current collector is wound on the core and electrically connected to the negative electrode tab of the core to achieve pre-lithiation at the core level, avoiding the need to compound lithium foil and replenish lithium before processing such as die-cutting, reducing safety risks, and controlling the amount of pre-lithiation by controlling the number and distance of lithium strips.
High first coulombic efficiency and cycle performance are achieved, the safety risks caused by the active nature of lithium are reduced, and the reduction of pre-lithiation effect caused by long-term processing after pre-lithiation is avoided.
Smart Images
Figure CN223347823U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of lithium battery production, and in particular to a pre-lithiation structure for a winding core and a pre-lithiation winding core. Background Art
[0002] Lithium-ion batteries often suffer from low initial negative electrode efficiency, especially for new silicon negative electrode materials, which have lower initial efficiency than graphite. During the initial charge and discharge process, lithium-ion batteries generally experience irreversible capacity loss and consume some of the lithium in the positive electrode, resulting in low initial coulombic efficiency and poor cycle performance. Pre-lithiation of the negative electrode can compensate for the irreversible loss of lithium in the negative electrode, thereby improving the initial coulombic efficiency and cycle performance of lithium-ion batteries.
[0003] In existing technologies, pre-lithiation of negative electrodes typically involves pre-lithiating the negative electrode material before preparing the negative electrode sheet, which is then assembled with the positive electrode sheet, separator, and electrolyte to form a battery cell. However, pre-lithiating the negative electrode material carries the risk of reduced pre-lithiation effectiveness over time and, due to the reactive nature of lithium, poses significant safety risks during manufacturing. Utility Model Content
[0004] The main purpose of the utility model is to provide a pre-lithiation structure for a winding core and a pre-lithiation winding core, so as to solve the problems of reduced pre-lithiation effect and safety risks in the prior art of battery pre-lithiation.
[0005] In order to achieve the above-mentioned purpose, the utility model provides a pre-lithium structure for a roll core, including: a lithium source; a current collector, which can be arranged in a winding manner, and the current collector includes a main body and a connector connected to the main body, the connector is configured to be electrically connected to the negative electrode tab of the roll core, and the main body is connected to the lithium source.
[0006] Through the above-mentioned arrangement, by arranging a current collector that can be wound and connected to a lithium source, the current collector can be wound on a core, and the current collector can be electrically connected to the negative electrode tab of the core. In this way, the core can be directly pre-lithiated, so that the battery can be replenished with lithium at the core level, thereby achieving a higher first coulombic efficiency and cycle performance; compared with the prior art of pre-lithiating the negative electrode material, the utility model replenishes lithium at the core level, which not only avoids compounding lithium foil and replenishing lithium before processing such as die-cutting, so as to reduce the safety risks caused by the active nature of lithium, but also avoids the risk of reduced pre-lithiation effect due to long-term processing after pre-lithiation.
[0007] Furthermore, the lithium source includes a plurality of lithium strips, which are spaced apart along the length direction of the current collector, each lithium strip extending along the width direction of the current collector, and the connector and the main body are arranged along the width direction.
[0008] Through the above settings, according to actual conditions, the amount of pre-lithium can be controlled by controlling the number of lithium strips, so that appropriate lithium can be supplemented, thereby ensuring the effect of lithium supplementation.
[0009] Furthermore, the thickness of the lithium ribbon is greater than or equal to 5 μm and less than or equal to 10 μm.
[0010] The above arrangement can avoid the problem of uneven surface of the pre-lithiation core due to the lithium ribbon being too thick, and the problem of difficult processing due to the lithium ribbon being too thin.
[0011] Furthermore, the distance between two adjacent lithium ribbons is greater than or equal to 15 mm and less than or equal to 40 mm.
[0012] The above arrangement can avoid the problem that the current collector can carry a small number of lithium strips due to the distance between the two lithium strips being too large, and can also avoid the problem that the local lithium ion content is too high due to the distance between the two lithium strips being too small.
[0013] Furthermore, the pre-lithium structure for the core also includes a diaphragm. Along the thickness direction of the current collector, the main body has a first side and a second side that are relatively arranged. The lithium source is connected to the first side, the diaphragm is connected to the second side, and the connector protrudes from the diaphragm.
[0014] Through the above arrangement, it is convenient to electrically connect the connector to the negative electrode tab of the winding core, wrap the first side on the winding core, and the separator can wrap the second side of the current collector to avoid short circuit problems.
[0015] Furthermore, the pre-lithium structure for the winding core further includes a fixing tape, a portion of which is connected to the separator, and the remaining portion of the fixing tape is configured to be bonded to the winding core.
[0016] With the above arrangement, the composite lithium replenishing component formed by the separator, the current collector and the lithium source can be fixed on the winding core by using the fixing tape.
[0017] Furthermore, the fixing tape is located on the side of the diaphragm away from the current collector, and an adhesive layer is provided on the side of the fixing tape facing the diaphragm. Along the length direction of the current collector, both ends of the fixing tape protrude from the diaphragm.
[0018] Through the above-mentioned arrangement, the composite lithium replenishment component can be fixed on the fixing belt, and then the core can be wound on the core with the pre-lithium structure, and the fixed ends at both ends in the length direction can be bonded to the core, so as to facilitate the electrical connection of the current collector with the negative electrode tab of the core to achieve pre-lithiation. In this way, a higher first coulombic efficiency and cycle performance can be achieved, and lithium replenishment is performed at the core level, which can not only avoid the composite lithium foil and lithium replenishment before processing such as die-cutting, so as to reduce the safety risks caused by the active nature of lithium, but also avoid the risk of reduced pre-lithiation effect due to long-term processing after pre-lithiation.
[0019] Furthermore, along the width direction of the current collector, one end of the fixing tape away from the connector protrudes from the separator.
[0020] Through the above arrangement, the pre-lithium structure for the winding core can be more stably fixed on the winding core, thereby reducing the probability of the pre-lithium structure for the winding core detaching from the winding core.
[0021] Furthermore, the pre-lithium structure for the core further includes a protective layer, which is bonded to the side of the lithium source facing away from the current collector.
[0022] Through the above arrangement, before the winding core is installed on the winding core with the pre-lithium structure, the protective layer can protect the lithium source to avoid the problem of lithium source failure due to the active nature of lithium.
[0023] According to another aspect of the present invention, the present invention provides a pre-lithiation winding core, comprising a winding core and the above-mentioned pre-lithiation structure for the winding core wound around the outer periphery of the winding core.
[0024] By applying the technical solution of the present invention, a current collector that can be wound up and connected to a lithium source is provided, the current collector can be wound on a core, and the current collector can be electrically connected to the negative electrode tab of the core. In this way, the core can be directly pre-lithiated, so that the battery can be replenished with lithium at the core level, thereby achieving a higher first coulombic efficiency and cycle performance. Compared with the prior art of pre-lithiating the negative electrode material, the present invention replenishes lithium at the core level, which not only avoids the need to compound lithium foil and replenish lithium before processing such as die-cutting, so as to reduce safety risks caused by the active nature of lithium, but also avoids the risk of reduced pre-lithiation effect due to long-term processing after pre-lithiation. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The drawings constituting part of this application are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:
[0026] Figure 1 A schematic structural diagram of an embodiment of a pre-lithiation winding core of the present invention is shown;
[0027] Figure 2 Shown Figure 1 A structural diagram of a pre-lithiation structure for a pre-lithiation core;
[0028] Figure 3 Shown Figure 2 A cross-sectional view of a pre-lithium structure for a winding core;
[0029] Figure 4 Shown Figure 1Another structural schematic diagram of the pre-lithiation core of the pre-lithiation core;
[0030] Figure 5 Shown Figure 4 Cross-sectional view of the pre-lithiation structure for the winding core.
[0031] The above drawings include the following reference numerals:
[0032] 1. Pre-lithium structure for core; 101. Current collector; 1011. Main body; 1012. Connector; 102. Separator; 103. Lithium source; 104. Protective layer; 2. Fixing tape; 3. Core; 301. Negative electrode tab; 302. Positive electrode tab; 303. Core separator. DETAILED DESCRIPTION
[0033] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.
[0034] like Figures 1 to 5 As shown, an embodiment of the present invention provides a pre-lithium structure for a roll core. The pre-lithium structure for a roll core includes a lithium source 103 and a current collector 101. The current collector 101 can be wound and includes a main body 1011 and a connector 1012 connected to the main body 1011. The connector 1012 is configured to be electrically connected to the negative electrode tab 301 of the roll core 3, and the main body 1011 is connected to the lithium source 103.
[0035] In the above technical solution, by providing a windable current collector 101, and the current collector 101 is connected to the lithium source 103, the current collector 101 can be wound on the core 3, and the current collector 101 is electrically connected to the negative electrode tab of the core 3. In this way, the core 3 can be directly pre-lithiated, so that the battery can be replenished with lithium at the core level, thereby achieving a higher first coulombic efficiency and cycle performance; compared with the prior art of pre-lithiating the negative electrode material, the utility model replenishes lithium at the core level, which not only avoids the composite lithium foil and replenishment of lithium before processing such as die-cutting, so as to reduce the safety risks caused by the active nature of lithium, but also avoids the risk of reduced pre-lithiation effect due to long-term processing after pre-lithiation.
[0036] Preferably, in the embodiment of the present invention, the current collector 101 is made of negative electrode copper foil.
[0037] Preferably, in an embodiment of the present invention, the length of the current collector 101 is 80 mm to 100 mm, and the width is 40 mm to 60 mm. One end of the negative electrode copper foil forms a connector 1012. The shape of the connector 1012 can be changed according to the shape of the pole ear of the winding core. For example, it can be laser cut into a trapezoid, a parallelogram, or a rectangle.
[0038] Preferably, in the embodiment of the present invention, the connector 1012 overlaps with the negative electrode tab 301 .
[0039] like Figure 2 As shown, in an embodiment of the present invention, the lithium source 103 includes a plurality of lithium ribbons, which are spaced apart along the length direction of the current collector 101, each lithium ribbon extends along the width direction of the current collector 101, and the connector 1012 and the main body 1011 are arranged along the width direction.
[0040] Through the above settings, according to actual conditions, the amount of pre-lithium can be controlled by controlling the number of lithium strips, so that appropriate lithium can be supplemented, thereby ensuring the effect of lithium supplementation.
[0041] Preferably, in an embodiment of the present invention, the lithium strip is a metal lithium foil.
[0042] Preferably, in an embodiment of the present invention, the plurality of lithium ribbons are arranged in parallel, and the ends of the plurality of lithium ribbons are arranged flush.
[0043] Preferably, the thickness of the lithium ribbon is greater than or equal to 5 μm and less than or equal to 10 μm. This can avoid the problem of uneven surface of the pre-lithiation core caused by too thick lithium ribbon, and can also avoid the problem of difficult processing caused by too thin lithium ribbon.
[0044] Preferably, in the embodiment of the present invention, the distance between two adjacent lithium ribbons is greater than or equal to 15 mm and less than or equal to 40 mm. This can avoid the problem of the current collector 101 being able to carry a small number of lithium ribbons due to a large distance between the two lithium ribbons, and can also avoid the problem of the local lithium ion content being too high due to a small distance between the two lithium ribbons.
[0045] like Figure 3 As shown, in an embodiment of the present invention, the pre-lithium structure for the core roll also includes a diaphragm 102. Along the thickness direction of the current collector 101, the main body 1011 has a first side and a second side that are relatively arranged. The lithium source 103 is connected to the first side, the diaphragm 102 is connected to the second side, and the connector 1012 protrudes from the diaphragm 102.
[0046] Through the above arrangement, it is convenient to electrically connect the connector 1012 to the negative electrode tab 301 of the winding core 3, wrap the first side on the winding core 3, and the separator 102 can wrap the second side of the current collector 101 to avoid short circuit problems.
[0047] Preferably, in the embodiment of the present invention, the diaphragm 102 is a composite diaphragm, which is a polymer diaphragm with a glue layer.
[0048] like Figure 4As shown, in an embodiment of the present invention, the pre-lithium structure for the winding core further includes a fixing tape 2, a portion of which is connected to the separator 102, and the remaining portion of the fixing tape 2 is configured to adhere to the winding core 3. In this way, the fixing tape 2 can be used to fix the composite lithium supplement component formed by the separator 102, the current collector 101, and the lithium source 103 to the winding core 3.
[0049] like Figure 5 As shown, in the embodiment of the present invention, the fixing tape 2 is located on the side of the diaphragm 102 away from the current collector 101, and an adhesive layer is provided on the side of the fixing tape 2 facing the diaphragm 102. Along the length direction of the current collector 101, both ends of the fixing tape 2 protrude from the diaphragm 102.
[0050] Through the above-mentioned arrangement, the composite lithium replenishment component can be fixed on the fixing belt 2, and then the core can be wound on the core 3 with the pre-lithium structure, and the two ends of the fixing belt 2 in the length direction can be bonded to the core 3, so as to facilitate the electrical connection of the current collector 101 with the negative electrode tab 301 of the core 3 to achieve pre-lithiation. In this way, a higher first coulombic efficiency and cycle performance can be achieved, and lithium replenishment is performed at the core level, which can not only avoid the composite lithium foil and lithium replenishment before processing such as die-cutting to reduce the safety risks caused by the active nature of lithium, but also avoid the risk of reduced pre-lithiation effect due to long-term processing after pre-lithiation.
[0051] like Figure 5 As shown, in the embodiment of the present invention, the end of the fixing tape 2 away from the connector 1012 protrudes from the separator 102 along the width direction of the current collector 101. This allows the pre-lithium structure for the core to be more stably fixed to the core 3, thereby reducing the probability of the pre-lithium structure for the core detaching from the core 3.
[0052] Preferably, in the embodiment of the present invention, the fixing tape 2 is a termination tape, the length of the termination tape is 100mm to 120mm, the width of the termination tape is 80 to 100mm, and the positions of the composite lithium supplement component on the termination tape are A, B, and C, respectively, wherein the sum of A and B is less than 50% of the circumference of the winding core 3, and C is less than the height of the winding core 3. In this way, sufficient installation space can be provided for the lithium source 103, and the connector 1012 can be ensured to overlap with the negative electrode tab 301 to ensure the operation of the subsequent process. Wherein, A refers to Figure 4 The distance between the left end of the middle diaphragm and the left end of the fixing belt 2, B is Figure 4 The distance between the right end of the middle diaphragm and the right end of the fixing belt 2, C is Figure 4 The distance between the bottom end of the middle diaphragm and the bottom end of the fixing belt 2.
[0053] like Figure 4 and Figure 5As shown, in an embodiment of the present invention, the pre-lithium structure for the winding core further includes a protective layer 104, which is bonded to the side of the lithium source 103 facing away from the current collector 101. Thus, before the pre-lithium structure for the winding core is installed on the winding core 3, the protective layer 104 can protect the lithium source 103 to prevent failure of the lithium source 103 due to the active nature of lithium.
[0054] Preferably, in an embodiment of the present invention, a PET (polyethylene terephthalate) protective film with metal lithium foil can be directly used. In this way, on the one hand, the procurement cost can be reduced, and on the other hand, the risk of composite manufacturing of metal lithium foil materials can be reduced; wherein the PET protective film forms the protective layer 104, and the metal lithium foil forms the lithium strip.
[0055] like Figure 1 As shown, an embodiment of the present invention provides a pre-lithiation core, comprising a core 3 and the pre-lithiation structure 1 for the core wound around the outer periphery of the core 3 .
[0056] Preferably, in an embodiment of the present invention, the winding core is a full-tab or multi-tab cylindrical battery cell.
[0057] It should be noted that, in the embodiment of the present invention, in the pre-lithiation core, the length of the current collector 101 is arranged around the cylindrical core, and the width direction of the current collector 101 extends along the axis of the cylindrical core.
[0058] Specifically, in an embodiment of the present invention, the core 3 includes a core body, a positive electrode tab 302, a negative electrode tab 301 and a core separator 303, wherein along the axis of the core body, the positive electrode tab 302 and the negative electrode tab 301 are respectively connected to the two ends of the core body, and a core separator 303 is provided on the outer periphery of the core body.
[0059] The above-mentioned pre-lithiation core has all the advantages of the above-mentioned pre-lithiation structure 1 for the core, which will not be described in detail here.
[0060] An embodiment of the present utility model provides a pre-lithiation method for a roll core, which is used to prepare the above-mentioned pre-lithiation roll core. The pre-lithiation method for the roll core includes: compounding a lithium source 103 on one side of a main body 1011 of a current collector 101, and compounding a separator 102 on the other side of the main body 1011 to form a composite lithium replenishing component; using a fixing tape 2 to bond the composite lithium replenishing component to the outer periphery of the roll core 3; and electrically connecting the connector 1012 of the current collector 101 to the negative electrode tab 301 of the roll core 3.
[0061] Through the above-mentioned arrangement, the core 3 can be directly pre-lithiated, so that the battery can be replenished with lithium at the core level, thereby achieving a higher first coulombic efficiency and cycle performance; compared with the prior art of pre-lithiating the negative electrode material, the utility model replenishes lithium at the core level, which not only avoids the need to compound lithium foil and replenish lithium before processing such as die-cutting to reduce the safety risks caused by the active nature of lithium, but also avoids the risk of reduced pre-lithiation effect due to long-term processing after pre-lithiation.
[0062] Preferably, in an embodiment of the present invention, a lithium source 103 is laminated onto one side of the main body 1011 of the current collector 101 to form a lithium-replenishing electrode sheet. The lithium-replenishing electrode sheet and the separator are then laminated together using a roller press to form a composite lithium-replenishing component. The separator and the lithium-replenishing electrode sheet are then laminated using a hot roller at a temperature of 70°C-100°C. The composite lithium-replenishing component is then attached to the adhesive layer of a termination tape. While the cylindrical core is in the winding needle unloading station, a finishing tape, formed by combining the finishing tape and the composite lithium-replenishing component, is applied to the surface of the cylindrical core around the winding needle unloading station. The PET protective film is removed before the finishing tape is bonded to the core. This pre-lithiation method is simple, environmentally friendly, and easy to operate.
[0063] Preferably, in the embodiment of the present invention, the lithium source 103 and the current collector 101 are laminated by rolling.
[0064] The above-mentioned core pre-lithiation method has all the advantages of the above-mentioned pre-lithiation core, which will not be described in detail here.
[0065] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: by providing a current collector that can be wound and the current collector is connected to a lithium source, the current collector can be wound on a core, and the current collector can be electrically connected to the negative electrode tab of the core. In this way, the core can be directly pre-lithiated, so that the battery can be replenished with lithium at the core level, thereby achieving a higher first coulombic efficiency and cycle performance; compared with the prior art of pre-lithiating the negative electrode material, the present invention replenishes lithium at the core level, which not only avoids the composite lithium foil and replenishing lithium before processing such as die-cutting, so as to reduce the safety risks caused by the active nature of lithium, but also avoids the risk of reduced pre-lithiation effect due to long-term processing after pre-lithiation.
[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.
Claims
1. A pre-lithium structure for a winding core, characterized in that: include: lithium source (103); A current collector (101) is provided, wherein the current collector (101) can be wound, and the current collector (101) comprises a main body (1011) and a connector (1012) connected to the main body (1011), wherein the connector (1012) is configured to be electrically connected to the negative electrode tab (301) of the winding core (3), and the main body (1011) is connected to the lithium source (103).
2. The pre-lithium structure for a winding core according to claim 1, characterized in that The lithium source (103) includes a plurality of lithium ribbons, which are spaced apart along the length direction of the current collector (101), each of the lithium ribbons extending along the width direction of the current collector (101), and the connector (1012) and the main body (1011) are arranged along the width direction.
3. The pre-lithium structure for a winding core according to claim 2, characterized in that: The thickness of the lithium ribbon is greater than or equal to 5 μm and less than or equal to 10 μm.
4. The pre-lithium structure for a winding core according to claim 2, characterized in that: The distance between two adjacent lithium ribbons is greater than or equal to 15 mm and less than or equal to 40 mm.
5. The pre-lithium structure for a winding core according to any one of claims 1 to 4, characterized in that: The pre-lithium structure for the core also includes a diaphragm (102). Along the thickness direction of the current collector (101), the main body (1011) has a first side and a second side that are arranged opposite to each other. The lithium source (103) is connected to the first side, the diaphragm (102) is connected to the second side, and the connector (1012) protrudes from the diaphragm (102).
6. The pre-lithium structure for a winding core according to claim 5, characterized in that: The pre-lithium structure for the winding core further includes a fixing tape (2), a portion of which is connected to the diaphragm (102), and the remaining portion of the fixing tape (2) is configured to be bonded to the winding core (3).
7. The pre-lithium structure for a winding core according to claim 6, characterized in that: The fixing tape (2) is located on the side of the diaphragm (102) facing away from the current collector (101), and an adhesive layer is provided on the side of the fixing tape (2) facing the diaphragm (102). Along the length direction of the current collector (101), both ends of the fixing tape (2) protrude from the diaphragm (102).
8. The pre-lithium structure for a winding core according to claim 7, characterized in that: Along the width direction of the current collector (101), one end of the fixing belt (2) away from the connector (1012) protrudes from the diaphragm (102).
9. The pre-lithium structure for a winding core according to any one of claims 1 to 4, characterized in that: The pre-lithium structure for the winding core further includes a protective layer (104), and the protective layer (104) is bonded to the side of the lithium source (103) away from the current collector (101).
10. A pre-lithiation core, characterized in that: A pre-lithium structure (1) for a winding core according to any one of claims 1 to 9, comprising a winding core (3) and a winding core disposed around the outer periphery of the winding core (3).