Lithium ion battery and lithium supplement assembly

Abstract

The utility model discloses lithium ion battery and lithium supplement assembly, including electrode, first connecting piece, second connecting piece, elastic part and lithium sheet that connect gradually, first connecting piece and second connecting piece are detachably connected, elastic part adopts shape memory alloy material, elastic part has the state of curling and straight line state, elastic part keeps the state of curling under normal condition, when electrode is accessed external power supply, elastic part is heated and stretches into straight line state. Elastic part keeps the state of curling under normal condition, and lithium sheet is suspended above electrolyte, when electrode is accessed external power supply, elastic part is heated and stretches into straight line state, and drives lithium sheet to move down and contact electrolyte. The heat-induced deformation characteristics of shape memory alloy elastic part make lithium sheet isolate with electrolyte under normal condition, avoid self-discharge and lithium dendrite growth, when supplementing lithium, accurate elastic part stretching is triggered through external power supply, and lithium sheet contacts electrolyte and releases lithium ion, realizes controllable supplementing lithium on demand, improves cycle life and safety.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to lithium-ion batteries and lithium replenishment components. Background Technology

[0002] In the field of lithium-ion battery replenishment technology, traditional methods typically place the lithium source directly near the electrode or in continuous contact with the electrolyte. This leads to self-discharge reactions in the lithium source during non-replenishment phases, exacerbating the loss of active lithium. For example, Chinese patent CN109728365A discloses a lithium-ion battery in which the casing and lithium source are used simultaneously as the third electrode. When the casing and the positive or negative electrode are simultaneously connected to an external power source, the lithium source undergoes a discharge reaction under the influence of the external power source. The lithium metal in the lithium source loses electrons and precipitates lithium ions, which then migrate through the electrolyte to the positive or negative electrode to form lithium compounds. While this method achieves lithium replenishment, prolonged immersion of the lithium source in the electrolyte leads to a thickening of the interfacial passivation layer, reducing replenishment efficiency. Utility Model Content

[0003] To address the aforementioned technical problems, this utility model proposes a lithium-ion battery and a lithium replenishment component. By utilizing the thermal deformation characteristics of shape memory alloy elastic elements, the lithium sheet is isolated from the electrolyte under normal conditions, avoiding self-discharge and lithium dendrite growth, thereby achieving on-demand and controllable lithium replenishment and effectively delaying capacity decay.

[0004] The technical solution adopted by this utility model is as follows: a lithium replenishment component, comprising an electrode, a first connector, a second connector, an elastic element and a lithium sheet connected in sequence. The first connector and the second connector are detachably connected. The elastic element is made of shape memory alloy. The elastic element has a coiled state and a straight state. Under normal conditions, the elastic element remains in the coiled state. When the electrode is connected to an external power source, the elastic element is heated and stretches into a straight state.

[0005] Optionally, the first connector includes a first connecting frame and a latching protrusion disposed within the first connecting frame, the electrode extends into the first connecting frame and connects with the latching protrusion, the second connector includes a second connecting frame and a connecting block disposed within the second connecting frame, the connecting block has a latching groove that is interference-fitted with the latching protrusion, and the elastic element passes through the second connecting frame and connects with the connecting block.

[0006] Optionally, the inner wall of the second connecting frame is provided with a limiting protrusion, and the first connecting frame is provided with a limiting groove that cooperates with the limiting protrusion.

[0007] Optionally, the outer peripheral wall of the second connecting frame is provided with a buckle, the buckle including a first buckle plate, a second buckle plate and a connecting plate, the first buckle plate is connected to the second connecting frame, one end of the connecting plate is connected to both ends of the first buckle plate, and the other end of the connecting plate is connected to both ends of the second buckle plate. The second buckle plate, the connecting plate and the first buckle plate together form a first U-shaped groove for cooperating with the partition.

[0008] Optionally, the second card is an arc-shaped plate, and the radius of curvature of the second card gradually increases from the end far from the partition to the end far from the partition, so that the first U-shaped groove forms a tapered structure.

[0009] Optionally, the outer peripheral wall of the elastic element is provided with a guide cylinder at intervals, the guide cylinder is connected to the bottom of the second connecting frame, the first connecting frame, the second connecting frame and the guide cylinder are all made of non-conductive material, and the latch and the elastic element are made of conductive material.

[0010] Optionally, the lithium sheet is coated with a sealing membrane, which is a polymer membrane with nanopores.

[0011] This utility model also discloses a lithium-ion battery, including a cover, a shell, a separator, and the lithium replenishment component described above. The cover is provided with an electrode outlet. The first connector is provided on the inner side wall of the cover. One end of the electrode is provided at the electrode outlet, and the other end of the electrode extends to the first connector. The separator is provided inside the shell and divides the interior of the shell into a first area and a second area for installing the core. The separator is provided with a through hole connecting the first area and the second area. The cover is sealed to the shell. The shell contains an electrolyte. The lithium sheet is provided in the first area and is in active contact with the electrolyte.

[0012] Optionally, the partition is provided with a second U-shaped groove that engages with the first U-shaped groove, wherein the width of the first U-shaped groove is smaller than the width of the second U-shaped groove.

[0013] Optionally, the distance between the top of the partition and the top of the shell is 3~15mm, the distance between the bottom of the partition and the bottom of the shell is 1~3mm, the number of through holes is multiple, the multiple through holes are distributed in an array, and the area of ​​the through holes is 1 / 3~1 / 2 of the shell area.

[0014] The beneficial effects of this invention are as follows: Under normal conditions, the elastic element remains in a coiled state, with the lithium sheet suspended above the electrolyte. When the electrode is connected to an external power source, the elastic element is heated and extends into a straight state, driving the lithium sheet to move down to contact the electrolyte. Utilizing the thermal deformation characteristics of the shape memory alloy elastic element, the lithium sheet is isolated from the electrolyte under normal conditions, preventing self-discharge and lithium dendrite growth. During lithium replenishment, the elastic element is precisely triggered by an external power source to extend, driving the lithium sheet to contact the electrolyte and release lithium ions, achieving on-demand and controllable lithium replenishment, effectively delaying capacity decay, and improving cycle life and safety. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the lithium replenishment component proposed in an embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of the second connecting frame of the lithium replenishment component proposed in an embodiment of the present invention;

[0017] Figure 3 An exploded view of the lithium-ion battery proposed in this embodiment of the utility model;

[0018] Figure 4 This is a schematic diagram of the engagement between the clip and the separator of the lithium-ion battery according to an embodiment of the present invention.

[0019] The labels in the attached figures are as follows: 1. Cover; 2. Shell; 3. Partition; 4. Elastic element; 5. Lithium sheet; 6. First connecting frame; 7. Clip protrusion; 8. Second connecting frame; 9. Connecting block; 10. Slot; 11. Limiting protrusion; 12. Limiting groove; 13. First locking plate; 14. Second locking plate; 15. Connecting plate; 16. First U-shaped groove; 17. Second U-shaped groove; 18. Guide cylinder; 19. Sealing diaphragm; 20. Positive electrode post hole; 21. Liquid injection hole; 22. Explosion-proof valve; 23. Electrode outlet; 24. Negative electrode post hole; 25. Through hole; 26. Electrode. Detailed Implementation

[0020] The present application will now be described in further detail with reference to the accompanying drawings and embodiments.

[0021] like Figures 1 to 4As shown, this embodiment discloses a lithium replenishment component, including an electrode 26, a first connector, a second connector, an elastic element 4, and a lithium sheet 5 connected in sequence. The first and second connectors are detachably connected. The elastic element 4 is made of shape memory alloy and has a coiled state and a straight state. Under normal conditions, the elastic element 4 remains in the coiled state. When the electrode 26 is connected to an external power source, the elastic element 4 is heated and extends into a straight state. Under normal conditions, the elastic element 4 remains in the coiled state, and the lithium sheet 5 is suspended above the electrolyte. When the electrode is connected to an external power source, the elastic element 4 is heated and extends into a straight state, driving the lithium sheet 5 to move down to contact the electrolyte. By utilizing the thermal deformation characteristics of the shape memory alloy elastic element 4, the lithium sheet 5 is isolated from the electrolyte under normal conditions, avoiding self-discharge and lithium dendrite growth. During lithium replenishment, the elastic element 4 is precisely triggered by an external power source to extend, driving the lithium sheet 5 to contact the electrolyte and release lithium ions, achieving on-demand and controllable lithium replenishment, effectively delaying capacity decay, and improving cycle life and safety. The elastic element 4 is made of one of the following materials: Au-Cd, Ag-Cd, Cu-Zn, Cu-Zn-Al, Cu-Zn-Sn, Cu-Zn-Si, Cu-Sn, Cu-Zn-Ga, In-Ti, Au-Cu-Zn, NiAl, Fe-Pt, Ti-Ni, Ti-Ni-Pd, Ti-Nb, U-Nb, and Fe-Mn-Si.

[0022] like Figure 1 and 2 As shown, the first connector includes a first connecting frame 6 and a latching protrusion 7 disposed within the first connecting frame 6. The electrode extends into the first connecting frame 6 and connects to the latching protrusion 7. The second connector includes a second connecting frame 8 and a connecting block 9 disposed within the second connecting frame 8. The connecting block 9 has a latching groove 10 that is interference-fitted with the latching protrusion 7. The elastic member 4 passes through the second connecting frame 8 and connects to the connecting block 9. The inner wall of the second connecting frame 8 has a limiting protrusion 11, and the first connecting frame 6 has a limiting groove 12 that mates with the limiting protrusion 11. Both the first connecting frame 6 and the second connecting frame 8 are hollow frame structures. Through the interference fit of the latching protrusion 7 and the latching groove 10 of the first connecting frame 6 and the second connecting frame 8, and the synergistic effect of the limiting protrusion 11 and the limiting groove 12, the rapid assembly and disassembly of the lithium replenishment component and the electrode, as well as the stability of the conductive connection, are ensured.

[0023] like Figure 2As shown, the outer peripheral wall of the second connecting frame 8 is provided with a buckle. The buckle includes a first locking plate 13, a second locking plate 14, and a connecting plate 15. The first locking plate 13 is connected to the second connecting frame 8. One end of the connecting plate 15 is connected to both ends of the first locking plate 13, and the other end of the connecting plate 15 is connected to both ends of the second locking plate 14. The second locking plate 14, the connecting plate 15, and the first locking plate 13 together form a first U-shaped groove 16 for cooperating with the partition 3. The buckle can be made of elastic plastic material. Through the nesting and engagement of the first U-shaped groove 16 and the second U-shaped groove 17 on the partition 3, the lithium replenishment component and the partition 3 are mechanically self-locked, eliminating the need for adhesive or bolt connections and avoiding connection failure caused by corrosive electrolytes.

[0024] like Figure 2 As shown, the second clamping plate 14 is an arc-shaped plate, and the radius of curvature of the second clamping plate 14 gradually increases from the end far from the partition plate 3 to the end far from the partition plate 3, so that the first U-shaped groove 16 forms a tapered structure. The tapered first U-shaped groove 16 design, through the gradient change of the radius of curvature, makes the second clamping plate 14 generate an inward elastic clamping force when it is engaged, dynamically compensating for assembly gaps and differences in thermal expansion.

[0025] like Figure 1 As shown, the outer peripheral wall of the elastic element 4 is fitted with a guide cylinder 18 at intervals. The guide cylinder 18 is connected to the bottom of the second connecting frame 8. The first connecting frame 6, the second connecting frame 8, and the guide cylinder 18 are all made of non-conductive materials, while the latching protrusion 7 and the elastic element 4 are made of conductive materials. The non-conductive guide cylinder 18 covers the elastic element 4, blocking the electrical contact path between the elastic element 4 and the housing 2, and preventing the generation of parasitic current. The guide cylinder 18 restricts the deformation direction of the elastic element 4 along the axial direction, ensuring the accurate vertical downward trajectory of the lithium sheet 5 and avoiding the deviation of the lithium replenishment position caused by the distortion of the shape memory alloy. The non-conductive material can be plastic, silicone, rubber, etc., and the conductive material can be copper, tin, nickel, etc.

[0026] In this embodiment, as Figure 2 As shown, the lithium sheet 5 is covered with a sealing membrane 19, which is a polymer membrane with nanopores. The sealing membrane 19 can be a nanoporous polytetrafluoroethylene membrane or a polypropylene membrane, allowing the electrolyte to pass through. After the lithium sheet 5 is connected to the shape memory metal, it is completely sealed by the membrane to prevent the lithium sheet 5 from dissolving in contact with the shell 2 and forming dead lithium that enters the cell's functional system.

[0027] like Figure 3As shown, this utility model also discloses a lithium-ion battery, including a cover, a housing 2, a separator 3, and the lithium replenishment assembly described above. The cover 1 has an electrode outlet 23, the first connector is located on the inner sidewall of the cover, one end of the electrode is located at the electrode outlet 23, and the other end of the electrode extends to the first connector. The separator 3 is located inside the housing 2 and divides the interior of the housing 2 into a first area and a second area for mounting the core. The separator 3 has a through hole 25 connecting the first area and the second area. The cover 1 is sealed to the housing 2. The housing 2 contains an electrolyte, and the lithium sheet 5 is located in the first area and is in contact with the electrolyte. The separator 3 divides the housing 2 into a second area (core area) and a first area (lithium replenishment area), distinguishing the cell functional area from the lithium replenishment functional area, thus achieving functional zoning management. The first connecting frame 6 and the latching protrusion 7 are both connected to the inner sidewall of the cover, and the electrode extends along the inner wall of the housing 2. The cover 1 is provided with a positive electrode post hole 20, a liquid injection hole 21, an explosion-proof valve 22, an electrode outlet 23 and a negative electrode post hole 24 in sequence along the length direction. The positive electrode post hole 20 can be used to lead out the positive electrode post, and the negative electrode post hole 24 can be used to lead out the negative electrode post. The electrode outlet 23 connected to the electrode is located in the middle of the cover 1 to avoid the risk of limiting or slagging when the electrode outlet 23 is at the edge of the cover during welding.

[0028] In this embodiment, as Figure 3 and 4 As shown, the partition 3 is provided with a second U-shaped groove 17 that engages with the first U-shaped groove 16. The width of the first U-shaped groove 16 is smaller than the width of the second U-shaped groove 17. The design that the width of the first U-shaped groove 16 is smaller than that of the second U-shaped groove 17 allows the first U-shaped groove 16 and the second U-shaped groove 17 to engage with each other, forming a pre-tight contact, reducing the risk of loosening caused by vibration, evenly distributing contact stress, and avoiding structural damage caused by local stress concentration.

[0029] like Figure 3 As shown, the distance between the top of the partition 3 and the top of the shell 2 is 3-15mm, and the distance between the bottom of the partition 3 and the bottom of the shell 2 is 1-3mm. Multiple through holes 25 are arranged in an array, and the area of ​​each through hole 25 is 1 / 3 to 1 / 2 of the area of ​​the shell 2. Neither the top nor the bottom of the partition 3 protrudes from the shell 2, and the top of the partition 3 is not flush with the top of the shell 2, ensuring the plastic part of the cover sinks and facilitating smooth laser welding between the cover and the shell 2. The bottom of the partition 3 is not connected to the bottom of the shell 2, ensuring the electrolyte level in the cell functional area and the lithium replenishment functional area is consistent. The multiple rows of through holes 25 optimize the connection between the electrolyte in the first and second zones, enhance structural stability, and provide sufficient binding strength for the core.

[0030] It is understood that the specific embodiments described above are merely for explaining the relevant utility model and not for limiting the utility model. It should also be noted that, for ease of description, only the parts related to the utility model are shown in the accompanying drawings. Multiple technical solutions in the same embodiment, as well as multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions that do not contradict or conflict with each other. All equivalent structural transformations made based on the content of this utility model specification and drawings, directly or indirectly applied to other related technical fields, are similarly included within the protection scope of this utility model.

Claims

1. A lithium replenishment component, characterized in that, The device includes electrodes, a first connector, a second connector, an elastic element, and a lithium sheet connected in sequence. The first connector and the second connector are detachably connected. The elastic element is made of shape memory alloy and has a coiled state and a straight state. Under normal conditions, the elastic element remains in the coiled state. When the electrode is connected to an external power source, the elastic element is heated and stretches into a straight state.

2. The lithium replenishment component according to claim 1, characterized in that, The first connector includes a first connecting frame and a latching protrusion disposed within the first connecting frame. The electrode extends into the first connecting frame and connects with the latching protrusion. The second connector includes a second connecting frame and a connecting block disposed within the second connecting frame. The connecting block has a latching groove that is interference-fitted with the latching protrusion. The elastic element passes through the second connecting frame and connects with the connecting block.

3. The lithium replenishment component according to claim 2, characterized in that, The inner wall of the second connecting frame is provided with a limiting protrusion, and the first connecting frame is provided with a limiting groove that cooperates with the limiting protrusion.

4. The lithium replenishment component according to claim 2, characterized in that, The outer peripheral wall of the second connecting frame is provided with a buckle, the buckle includes a first buckle plate, a second buckle plate and a connecting plate. The first buckle plate is connected to the second connecting frame. One end of the connecting plate is connected to both ends of the first buckle plate, and the other end of the connecting plate is connected to both ends of the second buckle plate. The second buckle plate, the connecting plate and the first buckle plate together form a first U-shaped groove for cooperating with the partition.

5. The lithium replenishment component according to claim 4, characterized in that, The second card is an arc-shaped plate, and the radius of curvature of the second card gradually increases from the end far from the partition to the end far from the partition, so that the first U-shaped groove forms a tapered structure.

6. The lithium replenishment component according to claim 2, characterized in that, The elastic element is fitted with guide cylinders at intervals on its outer peripheral wall. The guide cylinders are connected to the bottom of the second connecting frame. The first connecting frame, the second connecting frame, and the guide cylinders are all made of non-conductive material, while the latch and the elastic element are made of conductive material.

7. The lithium replenishment component according to claim 1, characterized in that, The lithium sheet is coated with a sealing membrane, which is a polymer membrane with nanopores.

8. A lithium-ion battery, characterized in that, The device includes a cover, a housing, a partition, and a lithium replenishment assembly as described in any one of claims 4 to 7. The cover has an electrode outlet, a first connector is disposed on the inner side wall of the cover, one end of the electrode is disposed at the electrode outlet, and the other end of the electrode extends to the first connector. The partition is disposed inside the housing and divides the interior of the housing into a first area and a second area for mounting the core. The partition has a through hole connecting the first area and the second area. The cover is sealed to the housing. An electrolyte is disposed inside the housing. The lithium sheet is disposed in the first area and is in active contact with the electrolyte.

9. The lithium-ion battery according to claim 8, characterized in that, The partition is provided with a second U-shaped groove that engages with the first U-shaped groove, and the width of the first U-shaped groove is smaller than the width of the second U-shaped groove.

10. The lithium-ion battery according to claim 8, characterized in that, The distance between the top of the partition and the top of the shell is 3~15mm, the distance between the bottom of the partition and the bottom of the shell is 1~3mm, the number of through holes is multiple, the multiple through holes are distributed in an array, and the area of ​​the through holes is 1 / 3~1 / 2 of the shell area.

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