Lithium supplement electrode of lithium ion battery, preparation method and lithium ion battery

Abstract

The invention belongs to the field of batteries, and particularly relates to a lithium supplement electrode of a lithium ion battery, a preparation method and the lithium ion battery. The problem that the cycle life of an existing lithium ion battery is shortened due to lithium ion consumption is solved. Comprising an electrode main body, and the electrode main body comprises a graphite substrate and active lithium embedded on the surface and / or inside the graphite substrate. The active lithium is embedded into the surface and / or the interior of the graphite substrate to form the lithium supplement electrode of the lithium ion battery, and compared with the scheme that metal lithium is directly used as a third electrode for lithium supplement in the prior art, the lithium supplement electrode has lower requirements on environment and equipment. In the lithium supplementing stage, the active lithium distributed on the surface of the graphite substrate and the active lithium embedded into the graphite substrate can participate in the lithium supplementing process, and the charge-discharge cycle performance of the lithium ion battery can be remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the field of batteries, and specifically relates to a lithium-ion battery lithium-supplementing electrode, a preparation method and a lithium-ion battery. Background Art

[0002] Lithium-ion batteries are lithium-ion batteries that rely primarily on the movement of lithium ions between the positive and negative electrodes. During the charge and discharge process, lithium ions are intercalated and deintercalated between the two electrodes. During charging, lithium ions are deintercalated from the positive electrode and then intercalated into the negative electrode through the electrolyte, leaving the negative electrode in a lithium-rich state. The reverse occurs during discharge.

[0003] During the charge and discharge cycle of lithium-ion batteries, lithium ions are consumed, causing the capacity of the lithium-ion battery to gradually decay during the cycle, thereby reducing the charge and discharge cycle life of the lithium-ion battery. Summary of the Invention

[0004] The purpose of the present invention is to provide a lithium-ion battery lithium-supplementing electrode, a preparation method and a lithium-ion battery, so as to overcome the problem that the cycle life of existing lithium-ion batteries is reduced due to lithium ion consumption.

[0005] The technical solution of the present invention is to provide a lithium-ion battery lithium supplement electrode, which is special in that it includes an electrode body, which includes a graphite substrate and active lithium embedded in the surface and / or inside of the graphite substrate.

[0006] The present invention forms a lithium-ion battery lithium-replenishing electrode by embedding active lithium on the surface and / or within a graphite substrate. Compared to existing solutions that use metallic lithium directly as a third electrode for lithium replenishment, the present invention's lithium-replenishing electrode has lower environmental and equipment requirements. During the lithium replenishment phase, both the active lithium distributed on the graphite substrate surface and the active lithium embedded within the graphite substrate participate in the lithium replenishment process, significantly improving the charge-discharge cycle performance of the lithium-ion battery.

[0007] Furthermore, the graphite substrate is a graphite sheet or a graphite column. Because the present invention is a lithium replenishment electrode, the electrode only participates in the lithium replenishment process and does not affect the internal resistance of the normal charge and discharge cycle of the battery. Therefore, commercially available graphite sheets or graphite columns can be directly selected as the substrate, and the thickness of the graphite sheet or graphite column is generally not limited.

[0008] In order to further improve the stability of the electrode body and protect the active lithium from oxidation, the present invention can also coat the electrode body with a protective film. The protective film can adopt an existing lithium-ion battery separator with high ionic conductivity and good permeability to lithium ions.

[0009] The present invention also provides a method for preparing the lithium-ion battery lithium-supplementing electrode, which is special in that it comprises the following steps:

[0010] The lithium-rich material and graphite substrate are placed in an electrolyte solution, and a lithium-ion-permeable separator is placed between the lithium-rich material and the graphite substrate. The separator described here is a conventional separator used in lithium-ion batteries. If the electrode body is already coated with a protective film, the separator can be omitted in this step.

[0011] An external power source causes the lithium-rich material to undergo an oxidation reaction, and lithium ions are released from the lithium-rich material and embedded in the graphite substrate, forming a graphite substrate containing active lithium, which serves as a lithium-replenishing electrode for lithium-ion batteries.

[0012] Furthermore, the lithium-rich material may be metallic lithium, or may be a common cathode material for lithium-ion batteries, such as at least one of lithium iron phosphate, lithium cobalt oxide, and lithium manganese oxide.

[0013] Furthermore, the electrolyte is an electrolyte containing lithium ions.

[0014] The present invention also provides a lithium-ion battery, comprising a shell having an open end, an electrode assembly located in the shell, and an upper cover assembly for closing the open end of the shell;

[0015] Its special features are:

[0016] The upper cover assembly is provided with a first polarity terminal and a second polarity terminal.

[0017] The positive and negative tabs of the electrode assembly are electrically connected to the first polarity terminal and the second polarity terminal respectively;

[0018] Also included is the lithium-ion battery lithium-replenishing electrode;

[0019] The lithium-ion battery lithium-replenishing electrode is arranged in the shell and is used to be electrically connected to the first polarity terminal so that the lithium-ion battery lithium-replenishing electrode replenishes lithium to the electrode assembly.

[0020] The present invention can controllably replenish lithium for a lithium-ion battery by controlling the connection between the lithium-ion battery replenishing electrode and the first polarity terminal. For example, lithium replenishment can be performed during the formation stage, or after a set time of charge and discharge cycles of the lithium-ion battery.

[0021] Furthermore, the shell includes a bottom plate and a side plate, and the lithium-ion battery lithium replenishing electrode is arranged between the electrode assembly and the bottom plate. The lithium replenishing electrode is parallel to the end face of the electrode assembly, so that the distance between each circle of electrode plates in the electrode assembly and the lithium replenishing electrode is the same. When the lithium replenishing power supply replenishes the electrode assembly, lithium can be quickly and evenly embedded in each circle of electrode plates.

[0022] Furthermore, the lithium-ion battery's lithium-ion battery replenishment electrode is electrically connected to the first polarity terminal via a varistor and a diode. By adjusting the resistance of the varistor, the discharge current is regulated, enabling precise and controllable lithium replenishment and preventing lithium deposition at the negative electrode due to excessive lithiation. The diode ensures unidirectional conduction of the lithium replenishment current, preventing lithium insertion into the replenishment electrode during charge and discharge.

[0023] Furthermore, the upper cover assembly is also provided with a third polarity terminal; the lithium-ion battery lithium replenishment electrode is electrically connected to the third polarity terminal. When lithium replenishment is needed, it is only necessary to electrically connect the third polarity terminal to the first polarity terminal.

[0024] The beneficial effects of the present invention are:

[0025] The present invention embeds active lithium into a graphite substrate to form a lithium-ion battery recharge electrode. Compared to existing solutions that use metallic lithium directly as a third electrode for recharge, the present invention's recharge electrode has lower environmental and equipment requirements. During the recharge phase, both the active lithium distributed on the surface of the graphite substrate and the active lithium embedded within the graphite substrate participate in the recharge process, significantly improving the charge and discharge cycle performance of the lithium-ion battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic structural diagram of the lithium-ion battery lithium-replenishing electrode in Example 1;

[0027] Figure 2 Schematic diagram of the structure of a single cell in Example 2;

[0028] Figure 3 Schematic diagram of the explosion structure of a single cell in Example 2;

[0029] Figure 4 Schematic diagram of the external electrical connection structure of a single cell in Example 2;

[0030] The accompanying drawings are denoted as follows:

[0031] 1. Graphite substrate; 2. Lead-out terminal; 3. Shell; 31. Bottom plate; 32. Side plate; 4. Upper cover assembly; 41. First polarity terminal; 42. Second polarity terminal; 5. Insulating lining; 6. Lithium replenishing electrode; 7. Varistor; 8. Diode. DETAILED DESCRIPTION

[0032] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It is obvious that the described embodiments are only 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 persons in this field without creative work should fall within the scope of protection of the present invention.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0034] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "top", "bottom", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0035] During the charge and discharge process of lithium-ion batteries, lithium ions are embedded and released back and forth between the positive and negative electrodes. Due to changes in the structure of the positive and negative active materials, decomposition of the electrolyte, and the formation and destruction of the solid electrolyte (SEI) film on the surface of the negative active material, lithium ions are inevitably consumed, resulting in the continuous attenuation of the lithium-ion battery capacity and difficulty in having a longer cycle life.

[0036] In order to overcome such problems, the prior art generally adopts the optimization of positive or negative electrode materials to increase the active lithium in lithium-ion batteries. However, such solutions require adjustment of the preparation process of the positive and negative electrodes, which makes the production cost of the entire battery higher. There are also solutions in the prior art that use metallic lithium as the third electrode for lithium replenishment. However, the chemical properties of metallic lithium are very active and easily react with moisture in the air. Therefore, the requirements for the environment (air humidity, oxygen content, etc.) and equipment during the replenishment process are relatively high, which increases the difficulty of the process. At the same time, lithium powder is easy to float in the air, resulting in a higher safety risk during the replenishment process. In addition, direct lithium replenishment based on metallic lithium is prone to problems such as excessive replenishment leading to decomposition at the negative electrode interface and even short circuit in the battery.

[0037] The present invention forms a lithium-ion battery lithium-replenishing electrode by embedding active lithium on a graphite substrate. Compared to the existing solutions that use optimized positive or negative electrode materials, the present invention does not require adjustments to the preparation processes of the positive and negative electrodes. Compared to the existing solutions that use metallic lithium directly as a third electrode for lithium replenishment, the lithium-replenishing electrode of the present invention has lower requirements for the environment and equipment (especially when the electrode body is coated with a protective film, which can protect the active lithium in the lithium-replenishing electrode from oxidation, and has better stability), and there is no lithium powder floating, which is safer. In addition, the present invention can also achieve precise and controllable lithium replenishment by controlling the lithium replenishment current, preventing lithium precipitation from occurring at the negative electrode due to excessive lithiation.

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0039] Example 1

[0040] This embodiment is a lithium-ion battery lithium-replenishing electrode 6 . The main body of the lithium-replenishing electrode 6 is a graphite substrate 1 , which is prepared by embedding active lithium on the surface and / or inside of the graphite substrate 1 .

[0041] like Figure 1 As shown, the shape of the graphite substrate 1 can be set as needed. Generally, its shape should be compatible with the shape of the corresponding installation space in the lithium-ion battery. Generally, a sheet (also called a plate) or a column (also called a strip or ribbon) is selected. It can have a lead end 2, which can be electrically connected to the corresponding polarity terminal through the lead end 2. Specifically, the lead end 2 can be a copper sheet or copper wire provided on the graphite substrate 1.

[0042] The graphite substrate 1 can be made of natural graphite or artificial graphite.

[0043] In this embodiment, active lithium can be embedded into the graphite substrate 1 through the following process:

[0044] The lithium-rich material and the graphite substrate 1 are placed in an electrolyte tank containing electrolyte, and a diaphragm is provided between the lithium-rich material and the graphite substrate 1. The diaphragm here is a diaphragm commonly used in lithium-ion batteries to allow lithium ions to pass through;

[0045] An external power source is used to electrically connect the lithium-rich material to the graphite substrate 1. The lithium-rich material undergoes an oxidation reaction, and lithium ions are released from the lithium-rich material, pass through the electrolyte, reach the graphite substrate 1, and are embedded in the graphite substrate 1, forming a graphite substrate 1 containing active lithium, which serves as a lithium-ion battery lithium supplement electrode 6.

[0046] It should be noted that the active lithium mentioned here is metallic lithium with electrochemical activity.

[0047] The lithium-rich material in this embodiment is metallic lithium or a lithium alloy, and may also be a positive electrode material for a lithium-ion battery, such as at least one of lithium iron phosphate, lithium cobalt oxide, and lithium manganese oxide.

[0048] The electrolyte of this embodiment is a lithium-ion battery electrolyte, comprising an electrolyte salt and a solvent. The type of electrolyte salt is not specifically limited and can be selected according to actual needs. As an example, the electrolyte salt can be selected from one or more of lithium hexafluorophosphate LiPF6, lithium tetrafluoroborate LiBF4, and lithium perchlorate LiClO4. The type of solvent is not specifically limited and can be selected according to actual needs. As an example, the solvent can be selected from ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), etc.

[0049] It should be noted that the lithium content of the lithium replenishing electrode 6 should be moderate, neither too much to cause lithium deposition nor too little to fail to meet the lithium replenishing requirement. At the same time, the lithium replenishing demand during the cycle should also be considered.

[0050] It can be specifically determined based on the lithium replenishment demand of the target lithium battery to be replenished and the effective lithium replenishment amount.

[0051] This embodiment avoids the use of a lithium metal third electrode by providing a lithium replenishing electrode 6, making the preparation conditions safer and milder; and as a lithium replenishing electrode 6, active lithium is replenished as needed during the cycle, thereby improving the charge and discharge cycle performance of the battery.

[0052] In order to further improve the stability of the electrode body, this embodiment can also coat the above-mentioned lithium-supplementing electrode (the above-mentioned lithium-supplementing electrode without a diaphragm can be defined as the electrode body) with a protective film. The protective film can adopt an existing lithium-ion battery diaphragm, which has high ionic conductivity and good permeability to lithium ions.

[0053] Example 2

[0054] like Figure 2 and Figure 3 As shown, this embodiment is a lithium-ion battery, comprising a shell 3, an upper cover assembly 4 and an electrode assembly; wherein one end of the shell 3 is open, the upper cover assembly 4 covers the open end of the shell 3 and is sealed with the shell 3, thereby closing the open end of the shell 3, and a first polarity terminal 41 and a second polarity terminal 42 are provided on the upper cover assembly 4; the electrode assembly is mainly composed of a positive electrode sheet, a diaphragm and a negative electrode sheet, the electrode assembly is encapsulated in the shell 3 and the positive and negative tabs are electrically connected to the first polarity terminal 41 and the second polarity terminal 42, respectively. The lithium-ion battery of this embodiment also includes the lithium supplement electrode 6 in Example 1. The lithium supplement electrode 6 is placed in the shell 3, and the lead-out terminal 2 extends out of the shell (it should be noted that the lead-out terminal 2 and the shell need to be sealed). The number of lithium supplement electrodes 6 can be one or more, and can be set according to specific lithium supplement needs.

[0055] When lithium replenishment is needed, the lead end 2 of the lithium replenishment electrode 6 is electrically connected to the first polarity terminal 41. Because the potential of the lithium replenishment electrode 6 is lower than that of the positive electrode, the active lithium in the lithium replenishment electrode 6 is deintercalated into the positive electrode sheet, and electrons travel through the external circuit to the positive electrode sheet, replenishing the positive electrode sheet. After lithium replenishment is complete, the lead end 2 of the lithium replenishment electrode 6 and the first polarity terminal 41 are disconnected.

[0056] like Figure 4 As shown, this embodiment can also connect a resistor 7 in the electrical connection path between the lead end 2 of the lithium replenishing electrode 6 and the first polarity terminal 41, and adjust the resistance value of the resistor 7 to adjust the discharge current and accurately control the amount of lithium replenishment.

[0057] A diode 8 may also be connected to the electrical connection path between the lead end 2 of the lithium replenishing electrode 6 and the first polarity terminal 41 to achieve unidirectional conduction of the lithium replenishing current and block the lithium insertion process of the lithium replenishing electrode during charging and discharging.

[0058] In some other embodiments, a third polarity terminal may be provided on the upper cover assembly 4. Inside the housing, the lead end 2 of the lithium replenishment electrode 6 is electrically connected to the portion of the third polarity terminal located inside the housing. When lithium replenishment is required, the portion of the third polarity terminal located outside the housing is electrically connected to the first polarity terminal 41. The active lithium in the lithium replenishment electrode 6 is deintercalated into the positive electrode sheet, and electrons travel through the external circuit to the positive electrode sheet, thereby replenishing the positive electrode sheet. After lithium replenishment is complete, the third polarity terminal and the first polarity terminal 41 are disconnected.

[0059] By inserting a varistor 7 in the electrical connection path between the third polarity terminal and the first polarity terminal 41, the discharge current can be adjusted by adjusting the resistance of the varistor 7, thereby precisely controlling the amount of lithium replenishment. A diode 8 is inserted in the electrical connection path between the third polarity terminal and the first polarity terminal 41 to ensure unidirectional conduction of the lithium replenishment current, thereby preventing lithium insertion into the lithium replenishment electrode during charge and discharge.

[0060] In this embodiment, the timing of lithium replenishment for the lithium-ion battery is not restricted and can be selected according to actual needs. For example, the lead end 2 of the lithium replenishment electrode 6 can be electrically connected to the first polarity terminal 41 during the battery preparation process (for example, before the formation process or after the formation process) to compensate for the loss of lithium ions caused by the formation of the SEI film on the surface of the negative electrode active material. The electrode assembly can also be replenished with lithium according to actual needs during the charging and discharging process, storage process, and repair process of the lithium-ion battery. For example, during the charging and discharging process, storage process, and repair process of the lithium-ion battery, according to the attenuation of the discharge capacity of the lithium-ion battery, the third electrode terminal is electrically connected to the first electrode terminal so that the lithium replenishment electrode 6 replenishes lithium to the positive electrode of the electrode assembly, increasing the number of lithium ions that can migrate between the positive and negative electrodes, thereby effectively reducing the capacity loss of the lithium-ion battery and improving the cycle performance and storage performance of the lithium-ion battery.

[0061] The number of times the lithium-ion battery of this embodiment is replenished is not specifically limited and can be selected based on actual needs. For example, lithium replenishment can be performed once or multiple times as needed during the lithium-ion battery manufacturing process, as well as during the lithium-ion battery charging and discharging process, storage process, and repair process. The amount of lithium replenished during each replenishment can be adjusted based on actual needs, for example, by precisely controlling parameters such as the discharge current. Lithium replenishment can also be performed continuously during the lithium-ion battery charging and discharging process.

[0062] The lithium-ion battery housing 3 of this embodiment includes a bottom plate 31 and a side plate 32. The graphite substrate 1 of the lithium supplement electrode 6 is a graphite sheet and is placed between the bottom plate 31 and the electrode assembly in the housing 3. Figure 3 As shown, in this embodiment, an insulating liner 5 is further provided between the bottom plate 31 and the lithium replenishing electrode 6 to separate the lithium replenishing electrode 6 from the bottom plate 31 and the outer shell.

[0063] In some other embodiments, the lithium-replenishing electrode 6 can be placed between the side plate 32 and the electrode assembly. However, compared with this embodiment, the surface of the lithium-replenishing electrode 6 is parallel to the large surface of the electrode assembly, and in this case, uneven lithium insertion may easily occur at the winding tail of the electrode assembly. When the lithium-replenishing electrode 6 is placed between the bottom plate 31 and the electrode assembly, the surface of the lithium-replenishing electrode 6 is parallel to the end face of the electrode assembly, so that the distance between the surface of the lithium-replenishing electrode 6 and each circle of electrode plates of the electrode assembly is the same. When the lithium-replenishing electrode 6 is used to replenish lithium to the electrode assembly through an external power supply, lithium can be quickly and evenly inserted into each circle of electrode plates.

[0064] In some other embodiments, the graphite substrate 1 of the lithium supplementing electrode 6 may be a graphite shell 3 adapted to the shell 3, and may be sleeved in the shell 3, and placed between the electrode assembly and the shell 3. However, the structure thereof is more complicated than that of this embodiment.

[0065] Example 3

[0066] In this example, four waste 24Ah prismatic lithium iron phosphate batteries produced by the same manufacturer and the same batch were taken, two of which were used as comparison samples, and the other two were treated as lithium-replenishing samples as follows:

[0067] The lithium supplement electrode 6 in Example 1 is additionally provided between the bottom plate 31 of the housing 3 and the electrode assembly;

[0068] The graphite substrate 1 of the lithium supplement electrode 6 in this embodiment is a graphite plate with a thickness of 2 mm, a length of 50 mm, and a width of 24 mm;

[0069] The lithium-rich material used to prepare the lithium-supplementing electrode 6 is lithium iron phosphate;

[0070] The electrolyte used to prepare the lithium supplement electrode 6 is the electrolyte of a 24Ah square shell lithium iron phosphate battery;

[0071] The surface of the finally formed lithium-supplementing electrode 6 is golden yellow.

[0072] After the preparation of the lithium-replenished samples was completed, the initial capacities of the two lithium-replenished samples and two comparison samples were directly tested on a charge-discharge tester at 0.5-1C. Specific data can be found in Table 1.

[0073] Afterwards, the two lithium-replenished samples were recharged with the following process:

[0074] The first polarity terminal 41 is connected to the lead-out terminal 2 of the lithium replenishing electrode 6 , and the variable resistor 7 is adjusted to make the discharge current 1 mA to continuously replenish lithium to the electrode assembly.

[0075] After completing lithium replenishment, perform charge and discharge tests:

[0076] At 25℃±5℃, use a 5V-20A charge and discharge tester to charge at constant current (0.75C) to a voltage of 3.65V, then charge at constant voltage to a current of 1 / 20C, leave for 10 minutes, and then discharge at constant current to a cut-off voltage of 2.5V. This is one cycle. The capacity of the battery after the 100th and 200th cycle discharge is tested. Combined with the initial cycle capacity of the battery, the capacity retention rate at the 100th and 200th charge and discharge cycles is calculated. Specific data can be found in Table 1.

[0077] Table 1

[0078]

[0079] As can be seen from Table 1, after 100 and 200 charge and discharge cycles, the capacity and capacity retention rate of the lithium-supplemented sample are higher than those of the control sample.

[0080] When the repaired lithium-ion battery has been charged and discharged for a period of time, the capacity decays again. The first polarity terminal and the lithium replenishment electrode lead-out terminal can be connected to perform multiple lithium replenishment.

Claims

1. A lithium-ion battery lithium-supplementing electrode, characterized in that: The electrode body comprises an electrode main body, which includes a graphite substrate and active lithium embedded in the surface and / or inside of the graphite substrate.

2. The lithium-ion battery lithium-supplementing electrode according to claim 1, characterized in that: The graphite substrate is a graphite sheet or a graphite column.

3. The lithium-ion battery lithium-supplementing electrode according to claim 1 or 2, characterized in that: Also included is a protective film wrapped around the electrode body.

4. A method for preparing a lithium-ion battery lithium-supplementing electrode according to any one of claims 1 to 3, characterized in that: The following steps are involved: Placing the lithium-rich material and the graphite substrate in an electrolyte, and providing a diaphragm between the lithium-rich material and the graphite substrate to allow lithium ions to pass through; An external power source causes the lithium-rich material to undergo an oxidation reaction, and lithium ions are released from the lithium-rich material and embedded in the graphite substrate, forming a graphite substrate containing active lithium, which serves as a lithium-replenishing electrode for lithium-ion batteries.

5. The preparation method according to claim 4, characterized in that: The lithium-rich material is one of metallic lithium, lithium alloy, lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, etc.

6. The preparation method according to claim 5, characterized in that: The electrolyte contains lithium ions.

7. A lithium-ion battery comprising a housing having an open end, an electrode assembly located within the housing, and an upper cover assembly for sealing the open end of the housing; Its characteristics are: The upper cover assembly is provided with a first polarity terminal and a second polarity terminal. The positive and negative tabs of the electrode assembly are electrically connected to the first polarity terminal and the second polarity terminal respectively; Also includes the lithium-ion battery lithium supplement electrode according to any one of claims 1 to 3; The lithium-ion battery lithium-replenishing electrode is arranged in the shell and is used to be electrically connected to the first polarity terminal so that the lithium-ion battery lithium-replenishing electrode replenishes lithium to the electrode assembly.

8. The lithium-ion battery according to claim 7, wherein: The shell includes a bottom plate and a side plate, and the lithium-ion battery lithium replenishing electrode is arranged between the electrode assembly and the bottom plate.

9. The lithium-ion battery according to claim 7 or 8, characterized in that: The lithium replenishing electrode of the lithium ion battery is electrically connected to the first polarity terminal through a varistor and a diode.

10. The lithium-ion battery according to claim 6, wherein: The upper cover assembly is also provided with a third polarity terminal; The lithium-ion battery lithium supplement electrode is electrically connected to the third polarity terminal.

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