A lithium ion battery supplemented with lithium and a lithium ion battery lithium supplementing method

Abstract

The present application belongs to the field of lithium ion battery lithium supplement, and particularly relates to a lithium supplement lithium ion battery and a lithium supplement method for lithium ion battery. The lithium supplement lithium ion battery comprises a battery shell, an electric core, a positive pole and a negative pole. The battery shell comprises a detachable lithium supplement part for supplementing lithium to the battery. The detachable lithium supplement part is sealedly assembled with the corresponding part of the battery shell. The detachable lithium supplement part comprises a lithium source arranged towards the electric core and spaced from the electric core, and a current leading part for connecting with an external power source. The current leading part is electrically connected with the lithium source. The lithium supplement lithium ion battery provided by the present application takes the detachable lithium supplement part as a part of the lithium supplement lithium ion battery shell. When the external power source is connected, the lithium supplement lithium ion battery plays a lithium supplement role. After lithium supplement, the lithium supplement part is removed, and then the lithium ion battery is manufactured through sealing. Since the lithium source is removed in time after lithium supplement, there is no lithium source residue left in the battery, which greatly improves the safety of the battery.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery lithium replenishment, specifically relating to a lithium-ion battery for lithium replenishment and a method for lithium-ion battery lithium replenishment. Background Technology

[0002] Lithium-ion batteries, with their unique advantages, are widely used in consumer electronics, power, and energy storage. With the continuous development of new energy application technologies, the requirements for lithium-ion batteries (especially cycle life and energy density) are becoming increasingly stringent. During the first charge of a battery, some lithium is consumed due to the formation of the solid electrolyte membrane (SEI membrane), resulting in lithium loss in the positive electrode material and thus reducing battery capacity and initial efficiency. Furthermore, during lithium-ion battery cycling, the consumption and repair of the SEI membrane and the increase of dead lithium within the positive and negative electrodes lead to a continuous decrease in battery capacity, resulting in a reduced cycle life. To reduce the capacity reduction caused by irreversible capacity loss during the first charge / discharge and cycling processes, researchers have studied pre-lithiation technology. Pre-lithiation replenishes lithium in the electrode material, compensating for irreversible lithium loss.

[0003] Current lithium replenishment methods typically involve attaching lithium strips or lithium powder to the surface of the negative electrode, allowing direct contact between the metallic lithium and the electrode material. This requires high precision in lithium sheet thickness and lithium powder spraying uniformity, and involves stringent operating conditions, resulting in high process costs and operational difficulties. Furthermore, the rapid reaction rate of lithium metal in contact with the electrolyte after replenishment using this method leads to poor controllability of the replenishment speed, resulting in an unstable SEI film and poor replenishment performance. Moreover, lithium source residues after replenishment generally remain permanently inside the battery, wasting resources. Additionally, some lithium metal particles remaining on the electrode surface pose a risk of puncturing the separator, creating a safety hazard.

[0004] Chinese invention patent application CN109728365A discloses a lithium-ion battery and its lithium replenishment method. The lithium-ion battery includes a battery casing that houses an electrolyte, a positive electrode, a negative electrode, and a lithium source. The positive and negative electrodes are connected to a positive terminal and a negative terminal, respectively. The lithium source is connected to the inner wall of the casing. When the casing and either the positive or negative electrode are simultaneously connected to an external power source, the lithium source releases lithium ions into the electrolyte. However, when replenishing lithium using this built-in lithium source, there is a risk of the lithium source puncturing the separator due to its long-term presence inside the battery. Furthermore, the long-term presence of residual lithium source may dissolve, leading to uncontrollable lithium replenishment. Summary of the Invention

[0005] The purpose of this invention is to provide a lithium-ion battery that can be replenished with lithium to solve the problem of residual lithium source in existing lithium-ion batteries.

[0006] The second objective of this invention is to provide a lithium replenishment method for lithium-ion batteries, so as to improve the safety and controllability of lithium replenishment.

[0007] To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0008] A lithium-ion battery with lithium replenishment includes a battery casing, a battery cell, a positive electrode post, and a negative electrode post. The battery casing includes a removable lithium replenishment part for replenishing lithium in the battery. The removable lithium replenishment part is sealed and assembled with a corresponding part of the battery casing. The removable lithium replenishment part includes a lithium source facing the battery cell and spaced apart from the battery cell, and a draining part for connecting to an external power source. The draining part is electrically connected to the lithium source.

[0009] The lithium-ion battery provided by this invention uses a removable lithium-replenishing section as part of the battery casing. This section functions as a lithium replenisher when connected to an external power source, and is removed after replenishment. The battery is then repackaged to manufacture a lithium-ion battery. Because the lithium source is removed promptly after replenishment, no lithium source residue remains inside the battery, significantly improving battery safety.

[0010] Preferably, the detachable lithium replenishment section includes a substrate and a lithium source disposed on the cell side of the substrate, as well as a guide embedding part connected to the cell side of the substrate and protruding towards the cell, wherein the height of the lithium source is lower than the height of the guide embedding part. The detachable and sealed assembly of the lithium replenishment (casing) section can be achieved through a conventional fitting structure combined with a rubber sealing ring. Furthermore, the height design of the lithium source ensures isolation between the lithium source and the cell, thereby improving the safety of the lithium replenishment process.

[0011] Preferably, the battery casing includes an annular side plate and a cover plate connected to both sides of the annular side plate, with the base plate being one of the cover plates. Since hard-shell batteries generally have a cover plate, manufacturing a removable cover plate based on this cover plate simplifies the manufacturing process. Using a terminal post as the current-guiding terminal simplifies wiring and provides good current conduction.

[0012] Preferably, the drain portion includes an electrode post extending from the substrate; both the positive and negative electrode posts are mounted on a cover plate on the opposite side of the substrate. The cover plate mounting the positive and negative electrode posts is arranged opposite to the substrate, ensuring that the manufacturing and lithium replenishment processes of the lithium-ion battery do not interfere with each other, thus facilitating battery production.

[0013] Preferably, the lithium source is metallic lithium or an alloy of metallic lithium. The lithium source only needs to meet the requirements of routine lithium replenishment; metallic lithium or its alloys are readily available and provide good lithium replenishment. Lithium alloys include alloys of metallic lithium with metals such as magnesium and aluminum.

[0014] More preferably, the lithium source is in the form of a strip, a mesh, or a foam. Using lithium sources with these shapes simplifies the manufacturing process, and using mesh or foam lithium sources further increases the contact area between the lithium source and the electrolyte, thereby improving lithium replenishment efficiency.

[0015] A lithium-ion battery replenishment method includes the following steps: designing a detachable battery casing, setting a lithium source on the inner side and a current-draining part on the outer side of the detachable part of the battery casing to form a detachable replenishment part, and then fabricating it with a battery cell to form a replenished lithium-ion battery; during replenishment, connecting the positive terminal of an external power supply to the lithium source and the negative terminal of the external power supply to the negative terminal of the battery; after replenishment, removing the detachable replenishment part and assembling the complete battery casing with the corresponding battery casing parts.

[0016] The lithium-ion battery replenishment method provided by this invention removes residual lithium sources after replenishing the battery cell, preventing lithium sources from remaining inside the battery, reducing the risk of the separator being punctured due to residual lithium sources, and improving battery safety. The lithium replenishment process is only performed when the external power supply is on, improving the controllability of the lithium replenishment process, optimizing the formation of the SEI film, and improving the charge and discharge stability of the lithium-ion battery.

[0017] Preferably, the battery casing includes a cover plate, and the detachable portion of the battery casing is the cover plate. Using a cover plate facilitates the installation and recycling of various materials.

[0018] Preferably, the lithium source is metallic lithium or an alloy of metallic lithium. The lithium source only needs to meet the requirements of routine lithium replenishment; metallic lithium or its alloys are readily available and provide good lithium replenishment. Lithium alloys include alloys of metallic lithium with metals such as magnesium and aluminum.

[0019] More preferably, the lithium source is in the form of a strip, a mesh, or a foam. Using lithium sources with these shapes simplifies the manufacturing process, and using mesh or foam lithium sources further increases the contact area between the lithium source and the electrolyte, thereby improving lithium replenishment efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the lithium-ion battery according to Embodiment 1 of the present invention;

[0021] Figure 2 This is a schematic diagram of the lithium replenishment cover plate in Embodiment 1 of the present invention;

[0022] Figure 3 This is a schematic diagram of a lithium source shape according to the present invention;

[0023] Figure 4 This is a schematic diagram of another lithium source shape in this invention;

[0024] Among them, 1-shell; 2-top cover plate; 2.1-positive electrode post; 2.2-negative electrode post; 3-cell; 3.1-positive electrode sheet; 3.2-negative electrode sheet; 4-lithium replenishment cover plate; 4.1-current leading terminal; 4.2-guide embedding ring edge; 5-lithium source. Detailed Implementation

[0025] The implementation process of the present invention will be described in detail below with reference to specific embodiments.

[0026] Example 1

[0027] The structural schematic diagram of the lithium-ion battery in this embodiment is shown below. Figure 1 As shown, the casing of a lithium-ion battery for lithium replenishment is made using a removable lithium replenishment cover. After lithium replenishment, the lithium replenishment cover is removed and replaced with a normal cover to complete the replenishment. The removable lithium replenishment cover does not change the original battery structure of the lithium-ion battery, thus simplifying the manufacturing process. Furthermore, the lithium replenishment cover can be recycled and reused, thereby reducing the cost of lithium replenishment.

[0028] Specifically, the lithium-ion battery includes a lithium-ion battery casing 1, and the battery cell 3, electrolyte, etc. are disposed inside the lithium-ion battery casing.

[0029] The lithium-ion battery casing provides a sealed environment that meets the requirements for battery manufacturing or operation. The casing includes a top cover 2, a bottom cover 2, and an annular side plate. The bottom cover 4 is a lithium-ion battery cover plate, with a lithium source 5 installed on its inner side, spaced apart from the battery cell 3. A current-guiding terminal 4.1, electrically connected to the lithium source, is installed on its outer side. The current-guiding terminal is in direct contact with the lithium source. It should be noted that lithium replenishment requires the lithium source to be connected to an external power source. Therefore, if the casing itself is made of conductive material, it can also be directly connected to the external power source. However, using a current-guiding terminal provides a more reliable connection and avoids damaging the casing.

[0030] The lithium replenishment cover 4 is detachably and sealed to the corresponding part of the housing 1, such as... Figure 2 As shown, the lithium replenishment cover plate 4 includes a base plate and a guide insert ring edge 4.2 connected to the base plate and protruding towards the battery cell side. The guide insert ring edge 4.2 is inserted into the corresponding part of the battery casing. The annular cavity of the guide insert ring edge 4.2 is used to install the lithium source 5. The outer surface of the lithium source 5 is lower than the end face of the guide insert ring edge 4.2 facing the battery cell to achieve isolation from the battery cell. To facilitate the installation and removal of the lithium source 5, the guide insert ring edge 4.2 includes a high side and a low side connecting the high side. The base plate is also provided with an annular abutment area for the corresponding part of the battery casing to abut against the guide insert ring edge 4.2 after insertion. The annular abutment area is connected to the outside of the guide insert ring edge.

[0031] Specifically, the lithium-ion battery is a square battery. The substrate of the lithium-filling cover 4 and the projection of the guide embedding ring 4.2 in the insertion direction are rectangular. The pair of short sides of the guide embedding ring 4.2 are the high sides, and the pair of long sides are the low sides. The corresponding positions of the substrate and the guide embedding ring 4.2 extend outward to form an annular abutment area for the corresponding parts of the battery casing to abut after insertion. The corresponding parts of the battery casing are the (square) annular side plates, which are square or rectangular on the four sides.

[0032] The lithium source material only needs to meet the lithium replenishment requirements; it can be lithium metal sheets, lithium-containing alloys, or lithium alloys such as those with magnesium or aluminum. The lithium source can be further attached to other non-lithium carriers, such as copper or aluminum foils, or metal mesh.

[0033] The lithium source can be in the shape of a strip (e.g., Figure 3 (As shown), mesh-like, and foam-porous. Strip-like lithium sources can be made using conventional lithium foil. During the fabrication of mesh-like lithium sources, metallic lithium is arranged on a copper mesh substrate in an inert gas atmosphere (such as argon), and then rolled to ensure the metallic lithium strips are evenly embedded between the mesh openings, thus obtaining the finished lithium source. For example... Figure 4 As shown, the porous lithium source can be processed into a porous structure in an inert gas atmosphere (such as argon) during fabrication, which is beneficial for the rapid precipitation of lithium ions.

[0034] The lithium source can be fixed to the inner side of the guide embedding ring by means of embedding, snapping, welding, etc.

[0035] The top cover plate 2 corresponds to the lithium replenishment cover plate 4 and is installed at the other end of the annular side plate. The top cover plate 2 is equipped with a positive electrode post 2.1 and a negative electrode post 2.2, which are connected to the positive electrode plate 3.1 and the negative electrode plate 3.2, respectively.

[0036] The lithium-ion battery in this embodiment can be manufactured as follows:

[0037] 1) The battery cell is manufactured using existing common technologies, typically a wound structure or a laminated structure. Using existing common technologies, the positive terminal 2.1 is welded to the positive electrode tab of the bare battery cell 3, and the negative terminal 2.2 is welded to the negative electrode tab of the bare battery cell 3. The welding area is shaped, dust-removed, and protected with insulating tape. The exposed parts of the electrode tabs are also protected with insulating tape.

[0038] 2) After welding the positive and negative terminals, the bare battery cell 3 is wrapped with insulating Mylar film and placed in the corresponding position in the housing 1. The assembled battery cell is then laser-welded together with the top cover plate and the annular side plate. The assembled battery cell is then placed in an oven to bake and remove moisture from the battery cell.

[0039] 3) In an inert gas atmosphere, the lithium source is installed and fixed inside the guide ring to form a lithium replenishment cover. A sealing rubber ring is set on the guide ring, and the lithium replenishment cover is installed at the bottom of the baked cell. The sealing rubber ring achieves a shell seal to prevent electrolyte leakage.

[0040] 4) Add electrolyte through the injection hole of the top cover plate 2, and perform conventional operations such as soaking, formation, and aging on the semi-finished battery to finally obtain the lithium-ion battery with lithium replenishment cover plate structure of the present invention.

[0041] In other embodiments of the lithium-ion battery described in this example, the detachable lithium replenishment structure can be a cover plate or part of an annular side plate, which is detachably and sealed onto the battery casing to achieve the lithium-ion battery replenishment process. After lithium replenishment, the detachable lithium replenishment structure is removed, and the corresponding casing portion is used for encapsulation.

[0042] Example 2

[0043] The lithium-ion battery replenishment method of this embodiment utilizes a detachable battery casing to carry the lithium source. During replenishment, the lithium source is connected to the positive terminal of an external power supply, and the negative terminal of the lithium-ion battery is connected to the negative terminal of the external power supply. Then, the power is turned on, and the lithium ions from the lithium source move through the electrolyte to the negative electrode to be replenished through an electrochemical reaction between the positive and negative electrodes. There, they gain electrons and are reduced to metallic lithium, thus achieving lithium replenishment. After replenishment, the detachable casing carrying the lithium source is removed, and the battery is repackaged using a suitable battery casing to obtain the replenished lithium-ion battery.

[0044] Specifically, taking the lithium-ion battery of Example 1 as an example, the lithium-ion battery uses both the lithium-replenishing cover and the lithium source as the third electrode. When the lithium-replenishing cover and the negative electrode post of the top cover are simultaneously connected to an external power source, the lithium ions from the lithium source move through the electrolyte to the negative electrode to be replenished through the electrochemical reaction between the positive and negative electrodes, gain electrons on the negative electrode, and are reduced to generate metallic lithium, thereby achieving lithium replenishment. The lithium replenishment speed and amount can be controlled by adjusting the current and voltage of the external power source as needed. By accurately controlling the charging current and charging time, the amount of lithium replenishment can be precisely controlled. This lithium replenishment structure has a reliable connection, which is conducive to accurately controlling the charging current, thereby achieving precise and controllable pre-lithiation. After lithium replenishment is completed, the lithium-replenishing cover is removed, and the shell is sealed and welded using a bottom cover plate, ensuring that any remaining lithium source residue is left inside the battery after lithium replenishment, greatly improving battery safety.

[0045] After the lithium-ion battery undergoes the above-mentioned lithium replenishment process, the energy density of the lithium-ion battery can be improved, and the cycle life of the lithium-ion battery can also be improved.

Claims

1. A lithium-ion battery, comprising a battery casing, a cell, a positive electrode post, and a negative electrode post, characterized in that, The battery casing includes a detachable lithium replenishment section for replenishing lithium in the battery. The detachable lithium replenishment section is sealed and assembled with a corresponding part of the battery casing. The detachable lithium replenishment section includes a lithium source facing the battery cell and spaced apart from the battery cell, and a drain section for connecting to an external power source. The drain section is electrically connected to the lithium source. The detachable lithium replenishment section includes a substrate and the lithium source disposed on the battery cell side of the substrate, and a guide embedding section connected to the battery cell side of the substrate and protruding towards the battery cell. The height of the lithium source is lower than the height of the guide embedding section to achieve isolation between the lithium source and the battery cell. The battery casing includes an annular side plate and a cover plate connected to both sides of the annular side plate. The substrate is one of the cover plates. After replenishing lithium, the detachable lithium replenishment section is removed and the complete battery casing is assembled with the corresponding battery casing parts.

2. The lithium-ion battery as described in claim 1, characterized in that, The lithium-ion battery is a square battery, and the projection of the substrate in the embedding direction is rectangular.

3. The lithium-ion battery as described in claim 1, characterized in that, The substrate forms a lithium replenishment cover plate, and the cover plate on the other side corresponding to the lithium replenishment cover plate is a top cover plate. The top cover plate is equipped with a positive electrode post and a negative electrode post, which are connected to the positive electrode plate and the negative electrode plate, respectively.

4. The lithium-ion battery as described in claim 3, characterized in that, The drain portion includes an electrode post extending out of the substrate; the positive electrode post and the negative electrode post are both mounted on a cover plate on the opposite side of the substrate.

5. The lithium-ion battery as described in claim 1 or 2, characterized in that, The lithium source is metallic lithium or an alloy of metallic lithium.

6. The lithium-ion battery as described in claim 5, characterized in that, The lithium source is in the form of a strip, a mesh, or a foam.

7. A method for replenishing lithium in a lithium-ion battery as described in claim 1, characterized in that, The process includes the following steps: designing a detachable battery casing, setting a lithium source on the inner side of the detachable part of the battery casing and setting a current-draining part on the outer side to form a detachable lithium replenishment part, and then making it into a lithium-ion battery with the battery cell; during lithium replenishment, connecting the positive terminal of an external power source to the lithium source and the negative terminal of the external power source to the negative terminal of the battery; after lithium replenishment, removing the detachable lithium replenishment part and assembling the complete battery casing with the corresponding battery casing parts.

8. The lithium-ion battery replenishment method as described in claim 7, characterized in that, The battery housing includes a cover plate, and the removable portion of the battery housing is the cover plate.

9. The lithium-ion battery replenishment method as described in claim 7, characterized in that, The lithium source is metallic lithium or an alloy of metallic lithium.

10. The lithium-ion battery replenishment method as described in claim 9, characterized in that, The lithium source is in the form of a strip, a mesh, or a foam.

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