Online repairing method of high-capacity battery

Abstract

The invention discloses an on-line repairing method of a high-capacity battery, and the repairing process of the method is divided into two stages: in the first stage, the content of active lithium ions in the high-capacity battery is increased by supplementing lithium, and the first-stage on-line repairing of the high-capacity battery is completed; in the second stage, the thickness of the SE I film is reduced through overdischarge, dead lithium in the high-capacity battery is activated, the ion impedance is reduced, a functional interface of the high-capacity battery is used for supplementing and replacing liquid for the high-capacity battery, electrolyte consumption in the high-capacity battery is made up, the conductivity of lithium ions is improved, meanwhile, the high-capacity battery is exhausted, and the service life of the high-capacity battery is prolonged. Not only is the influence on the performance of the high-capacity battery caused by overlarge air pressure reduced, but also the liquid supplementing process can be smoother; in this way, the second-stage online repair of the high-capacity battery is completed.

Description

Technical Field

[0001] This invention belongs to the field of batteries, specifically an online repair method for large-capacity batteries. Background Technology

[0002] Lithium-ion batteries are rechargeable batteries that primarily function by the movement of lithium ions between the positive and negative electrodes. During charging and discharging, Li... + During charging, Li intercalates and deintercalates back and forth between the two electrodes, and during charging... + The lithium is extracted from the positive electrode and inserted into the negative electrode through the electrolyte, putting the negative electrode in a lithium-rich state; the opposite occurs during discharge.

[0003] With the widespread application of lithium-ion batteries, increasing their capacity has become a key focus in the battery industry.

[0004] Existing technology discloses a high-capacity battery comprising multiple battery cells connected by an electrolyte chamber to ensure consistent electrolyte content within each cell. Simultaneously, the battery cells are connected by a gas chamber to ensure consistent gas pressure within each cell. Due to the consistent electrolyte and gas pressure, the cycle life of the high-capacity battery can be greatly improved.

[0005] However, after prolonged use, the performance of large-capacity batteries will decline due to factors such as electrolyte decomposition and consumption of active lithium ions. How to suppress the performance decline of large-capacity batteries and restore their capacity is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] The purpose of this invention is to provide an online repair method for large-capacity batteries, which can repair large-capacity batteries online to extend their charge-discharge cycle performance.

[0007] The method includes the following steps:

[0008] Step 1: Real-time monitoring of the large-capacity battery. If the battery capacity is detected to have decreased to X1 or after Y1 charge-discharge cycles, Step 2 shall be executed at least once; wherein, 85% ≤ X1 ≤ 98%; Y1 ≥ 200 cycles.

[0009] Step 2: First Stage Online Repair

[0010] Step a: Replenish lithium in the large-capacity battery using a lithium replenishment device;

[0011] Step 3: Real-time detection of the capacity of the large-capacity battery. If the large-capacity battery reaches the second repair condition, execute Step 4 at least once.

[0012] Step 4: Second Stage Online Repair

[0013] Step b: Perform over-discharge on the high-capacity battery;

[0014] Step c: Perform electrolyte replenishment or electrolyte replacement on the large-capacity battery through the function interface, and vent the large-capacity battery using the function interface;

[0015] The second repair condition is one of the following two situations:

[0016] Scenario 1: After the first stage of online repair, there is no significant improvement in the capacity and capacity retention rate of the large-capacity battery;

[0017] Case 2: When the capacity of a large-capacity battery decreases to X2 or has undergone Y2 charge-discharge cycles; where 70% ≤ X2 ≤ 95% and Y2 > Y1.

[0018] Since the degradation of large-capacity batteries is caused by different factors at each stage, this invention divides the repair process of large-capacity batteries into two stages: the first stage is to replenish lithium to increase the content of active lithium ions in the large-capacity battery, thus completing the first stage of online repair of the large-capacity battery.

[0019] After prolonged operation, the SEI film of the high-capacity battery gradually thickens, leading to a continuous increase in ionic impedance and a continuous decrease in active lithium ions. Therefore, to solve this problem, the second stage reduces the thickness of the SEI film through over-discharge, activates dead lithium in the high-capacity battery, reduces ionic impedance, and replenishes electrolyte in the high-capacity battery using the battery's functional interface to compensate for electrolyte consumption and improve lithium-ion conductivity. At the same time, the high-capacity battery is vented, which not only reduces the impact of excessive gas pressure on the performance of the high-capacity battery, but also makes the electrolyte replenishment process smoother.

[0020] Alternatively, this stage utilizes the functional interface of the large-capacity battery to replace the electrolyte, compensating for the electrolyte consumption within the large-capacity battery, improving the conductivity of lithium ions, and venting the large-capacity battery, reducing the impact of excessive gas pressure on the battery's performance, making the electrolyte replacement process smoother. At the same time, the electrolyte replacement process removes impurities from the old electrolyte, achieving electrolyte purification, and thus completing the second stage of online repair of the large-capacity battery.

[0021] Furthermore, to improve the repair effect of large-capacity batteries after over-discharge, the above method also includes step d: performing a heating treatment on the large-capacity battery through a heat transfer pipe on the polarity terminal of the large-capacity battery. This invention transfers heat to each individual cell within the large-capacity battery through the heat transfer pipe. After the positive and negative electrode materials in each individual cell are heated, their crystal structure changes, thereby restoring their original structure. This allows active lithium ions to smoothly insert into or extract from the positive and negative electrodes during the charging and discharging process, thereby further improving the cycle performance of the large-capacity battery.

[0022] Furthermore, step 4 above also includes step e: secondary lithium replenishment of the large-capacity battery using a lithium replenishment device.

[0023] Furthermore, step 2 above also includes step f: performing electrolyte replenishment on the large-capacity battery through the functional interface, and simultaneously venting the large-capacity battery using the functional interface.

[0024] Furthermore, the aforementioned functional interface is a cylindrical body, which contains a gas channel connecting the gas sharing chamber of the large-capacity battery and the external gas pipe, as well as an electrolyte channel connecting the electrolyte sharing chamber of the large-capacity battery and the external liquid pipe, and the gas channel and the electrolyte channel are isolated from each other.

[0025] Furthermore, the aforementioned lithium replenishment device includes a lithium source, a lithium replenishment wire, a rheostat, and a switch;

[0026] The lithium source is placed inside the high-capacity battery and immersed in the electrolyte;

[0027] One end of the lithium replenishment wire is connected to the lithium source, and the other end is used to connect to the polarity terminal of the high-capacity battery. The lithium replenishment wire is equipped with a switch and a rheostat.

[0028] The switch is used to turn the lithium-ion charging wire on or off.

[0029] Furthermore, the lithium source includes two copper mesh layers and a metallic lithium layer disposed between the two copper mesh layers.

[0030] Furthermore, the cutoff voltage for the aforementioned over-discharge is between 0.01V and 2.4V.

[0031] Furthermore, the heating temperature range is 45 to 60°C.

[0032] The beneficial effects of this invention are:

[0033] This invention utilizes the structural characteristics of large-capacity batteries to complete the first stage of online repair of large-capacity batteries through methods such as lithium replenishment. Then, the second stage of online repair of large-capacity batteries is completed through methods such as over-discharge, electrolyte replenishment, and venting. Compared with the existing method of repairing batteries after removing them from the rack, this invention saves the battery disassembly and assembly steps and improves repair efficiency. Attached Figure Description

[0034] Figure 1 This is a structural diagram of the first type of high-capacity battery;

[0035] Figure 2 This is a structural diagram of the second type of high-capacity battery;

[0036] Figure 3 A cross-sectional view of a large-capacity battery;

[0037] Figure 4A structural diagram showing that a functional interface is provided on the endplate of a large-capacity battery.

[0038] Figure 5 This is a schematic diagram of a lithium replenishment device;

[0039] The attached figures are labeled as follows:

[0040] 100-Large capacity battery, 1-Single cell, 2-First hollow tube, 3-Second hollow tube, 4-Box, 5-Electrolyte shared chamber, 6-Gas shared chamber, 7-Functional interface, 8-Gas channel, 9-Electrolyte channel, 10-Lithium replenishment device, 11-Lithium source, 12-Lithium replenishment wire, 13-Rheostat, 14-Switch. Detailed Implementation

[0041] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0042] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0043] The main reasons for the decline in lithium-ion battery capacity are as follows:

[0044] 1. Thickening of the SE I film on the negative electrode will bring a series of negative effects.

[0045] First, a thicker SEI film leads to increased battery impedance. Impedance is an indicator of the internal resistance of a battery. Increased impedance means increased internal resistance, which affects the movement speed of lithium ions, thereby reducing battery performance and efficiency.

[0046] Secondly, the thickening of the SEI film also leads to irreversible lithium loss. During battery aging, the SEI film thickens due to the deposition of electrolyte reaction products. This process is accompanied by the consumption of lithium ions, resulting in irreversible lithium loss. Lithium is a crucial element in batteries, and its loss directly reduces battery capacity.

[0047] Furthermore, the thickening of the SE I film not only affects the negative electrode of the battery, but also blocks the active particles of the positive electrode, increasing impedance and leading to a reduction in available active material and capacity. This means that the energy and power that the battery can provide will gradually decrease during storage and use.

[0048] SEI film thickening is an important phenomenon in the aging process of lithium-ion batteries. It directly affects the performance and lifespan of the battery by increasing impedance, causing lithium loss, and reducing usable capacity.

[0049] 2. Electrolyte decomposition and consumption

[0050] The decomposition and consumption of electrolyte will reduce its conductivity, thereby leading to a decrease in the battery's cycle performance.

[0051] 3. Decrease in active lithium

[0052] There are two main structural forms for high-capacity batteries:

[0053] The first structure: such as Figure 1 As shown, the high-capacity battery 100 includes multiple individual cells 1, a first hollow tube 2, and a second hollow tube 3;

[0054] Multiple individual cells 1 are placed side by side, with the positive terminals of all individual cells connected as the overall positive terminal and the negative terminals of all individual cells connected as the overall negative terminal;

[0055] At least one heat transfer tube is mounted on both the positive and negative electrodes.

[0056] The first hollow tube 2 connects the gas zones of multiple individual cells, thereby ensuring that the gas pressure inside each individual cell remains consistent.

[0057] The second hollow tube 3 connects the electrolyte zones of multiple individual cells, thereby ensuring that the electrolyte in each individual cell remains consistent.

[0058] In the first type of high-capacity battery, the functional interface 7 includes valves respectively connected to the first hollow tube and the second hollow tube.

[0059] The second structure: such as Figures 2 to 4 As shown, the high-capacity battery 100 includes a housing 4 and multiple individual battery cells 1;

[0060] Multiple individual cells 1 are arranged in the same direction inside the housing 4, and the electrolyte area of ​​each individual cell 1 is connected through the electrolyte sharing chamber 5 located at the bottom of the housing 4, and the gas area of ​​each individual cell is connected through the gas sharing chamber 6 located at the top of the housing 4.

[0061] The top plate of the housing 4 has clearance holes for the polarity terminals of each individual battery 1; the polarity terminals of each individual battery 1 extend out of the clearance holes, and the area of ​​the top plate of the housing corresponding to the clearance holes is fixedly sealed with the individual battery casing.

[0062] The positive terminals of all individual cells 1 are connected as the total positive terminal, and the negative terminals of all individual cells are connected as the total negative terminal.

[0063] At least one heat transfer tube is mounted on both the positive and negative electrodes.

[0064] In the second type of large-capacity battery, the functional interface 7 is a columnar body set on the housing 4. The columnar body is provided with a gas channel 8 that connects the large-capacity battery gas sharing chamber 6 and the external gas pipe, and an electrolyte channel 9 that connects the large-capacity battery electrolyte sharing chamber 5 and the external liquid pipe. The gas channel 8 and the electrolyte channel 9 are isolated from each other.

[0065] like Figure 5 As shown, the specific structure of the lithium replenishment device 10 includes a lithium source 11, a lithium replenishment wire 12, a rheostat 13, and a switch 14.

[0066] The lithium source 11 is placed inside the large-capacity battery and immersed in the electrolyte;

[0067] One end of the lithium replenishment wire 12 is electrically connected to the lithium source 11, and the other end is used to connect to the negative terminal of the high-capacity battery. A switch 14 and a rheostat 13 are sequentially arranged on the lithium replenishment wire 12 from the connection end with the negative terminal of the high-capacity battery to the connection end with the lithium source 11. The switch 14 is used to turn the lithium replenishment wire 12 on or off.

[0068] The lithium source 11 includes two copper mesh layers and a metallic lithium layer disposed between the two copper mesh layers.

[0069] In the first type of high-capacity battery structure, the lithium source 11 of the lithium replenishment device is installed inside the second hollow tube 3. In the second type of high-capacity battery structure, the lithium source 11 of the lithium replenishment device is installed inside the electrolyte sharing chamber 5.

[0070] Based on the above introduction to the causes of lithium-ion battery capacity reduction and the structure of large-capacity batteries, this invention utilizes the structural characteristics of large-capacity batteries to perform online repair of large-capacity batteries in the first stage by replenishing lithium, and to achieve online repair of large-capacity batteries in the second stage by means of over-discharge, electrolyte replenishment and other methods.

[0071] This embodiment uses the second type of large-capacity battery structure as an example to describe the body repair process in detail:

[0072] Step 1: Real-time monitoring of the large-capacity battery. If the battery capacity is detected to have decreased to X1 or after Y1 charge-discharge cycles, Step 2 shall be executed at least once; wherein, 85% ≤ X1 ≤ 98%; Y1 ≥ 200 cycles.

[0073] Step 2: First stage online repair; During the formation of a large-capacity battery cell and after long-term charge-discharge cycles, some active lithium ions will be consumed, which will cause the capacity of the large-capacity battery to decay.

[0074] The repair method at this stage is as follows: Step a: Replenish lithium in the large-capacity battery using a lithium replenishment device;

[0075] The specific process of step a is as follows: turn on the switch, adjust the resistance value of the variable resistor, control the lithium replenishment current within a suitable range, and then realize the lithium replenishment of the large-capacity battery.

[0076] Step 3: Real-time monitoring of the large-capacity battery. If the capacity and capacity retention rate of the large-capacity battery do not improve significantly after the first stage of online repair, or if the capacity of the large-capacity battery is detected to have decreased to X2, or if the large-capacity battery has undergone Y2 charge-discharge cycles, the SE I film will thicken after the large-capacity battery has been running for a long time again. An excessively thick SE I film will lead to an increase in ion resistance and a decrease in active lithium ions. Therefore, Step 4 should be performed at least once. Among these conditions, 70% ≤ X2 ≤ 95%; Y2 > Y1.

[0077] Step 4: Second stage online repair;

[0078] Step b: Perform over-discharge on the high-capacity battery;

[0079] Over-discharge is performed on large-capacity batteries; by over-discharging large-capacity batteries, the thickness of the SE I film can be reduced, dead lithium in large-capacity batteries can be activated, and ionic resistance can be reduced.

[0080] When performing over-discharge treatment on large-capacity batteries, the over-discharge cutoff voltage needs to be controlled between 0.01V and 2.4V. Specifically, the over-discharge cutoff voltage can be selected from the high voltage range, such as between 1.0V and 2.4V, the medium voltage range, such as between 0.1V and 0.9V, or the low voltage range, such as between 0.01V and 0.09V.

[0081] Step c: Perform electrolyte replacement on the large-capacity battery through the function interface, and at the same time, vent the large-capacity battery using the function interface.

[0082] The specific process of step c is as follows: First, open the gas channels of the external gas pipe and functional interface, as well as the valves on the electrolyte channels of the external liquid pipe and functional interface. Inert gas is injected into the large-capacity battery sequentially through the external gas pipe and gas channels, and the old electrolyte in the large-capacity battery is discharged through the electrolyte channels and external liquid pipes. Then, new electrolyte is introduced into the large-capacity battery sequentially through the external liquid pipe and electrolyte channels, and the gas in the large-capacity battery is discharged from the large-capacity battery sequentially through the gas channels and external gas pipes, thereby completing the replacement of electrolyte in the large-capacity battery.

[0083] In this embodiment, step 4 is specifically performed in the order of step b followed by step c. The main reason is that the electrolyte consumption and gas production are large after over-discharge. Also, the electrolyte may contain impurities due to the thinning of the SE I film during over-discharge. Therefore, performing electrolyte replacement after over-discharge can remove impurities from the old electrolyte, improve the performance of the electrolyte in the large-capacity battery, and discharge the gas generated during the over-discharge process. At the same time, the conductivity of the newly injected electrolyte in the large-capacity battery is greatly improved.

[0084] In some other embodiments, the fluid replacement in step c can also be fluid replenishment;

[0085] In some other embodiments, the electrolyte can be replenished before over-discharge; the purpose of this repair process is that, after the large-capacity battery is repaired in the first stage, the electrolyte is decomposed and consumed after a long period of charging and discharging, and the gas pressure inside the large-capacity battery is also relatively high. In order to improve the subsequent over-discharge effect, it is necessary to replenish the electrolyte and vent the gas before over-discharge.

[0086] Example 2

[0087] This embodiment adds step d to embodiment 2: heating the large-capacity battery through the heat transfer tube on the polarity terminal of the large-capacity battery. Step d can be performed after step b, or during the execution of step b (i.e., the heating step is performed after or during the over-discharge step).

[0088] Of course, it is also possible to perform step d after performing step c (that is, to perform the heating step after the lithium replenishment step or during the lithium replenishment process);

[0089] Specifically, heat is transferred from the polar terminals of the large-capacity battery to the electrode components in each individual cell using heat transfer pipes. This causes a change in the lattice structure of the positive and negative electrode materials in each individual cell's electrode components, restoring them to their original structure. This allows active lithium ions to be smoothly inserted into or extracted from the positive and negative electrodes during the charging and discharging process, thereby improving the repair effect of the large-capacity battery.

[0090] Preferably, the heating temperature needs to be controlled between 45°C and 60°C.

[0091] Example 3

[0092] This embodiment is based on embodiment 1 or 2, specifically adding step e to step 4: performing secondary lithium replenishment on the large-capacity battery through a lithium replenishment device; the specific process of step e is: turning on the switch, adjusting the resistance value of the variable resistor, controlling the lithium replenishment current to 1mA, and realizing lithium replenishment on the large-capacity battery.

[0093] Example 4

[0094] This embodiment is based on embodiment 1, embodiment 2, or embodiment 3. Specifically, step f is added to step 2: liquid replenishment is performed on the large-capacity battery through the functional interface, and the large-capacity battery is vented using the functional interface.

[0095] The process is as follows: the valves on the gas channels of the external air pipe and the functional interface, as well as the valves on the electrolyte channels of the external liquid pipe and the functional interface, are opened. The electrolyte enters the large-capacity battery in sequence through the external liquid pipe and the electrolyte channel, and the gas in the large-capacity battery is discharged from the large-capacity battery in sequence through the gas channel and the external air pipe.

Claims

1. An on-line repair method of a large capacity battery, characterized by, The method comprises the following steps: Step 1: Real-time detection of the large capacity battery, if the capacity of the large capacity battery is detected to be attenuated to X1 or the number of charge-discharge cycles is detected to be more than Y1, at least one step 2 is performed; wherein 85%≤X1≤98% and Y1≥200 times; Step 2: First stage online repair Step a: supplementing lithium to the large capacity battery through a lithium supplementing device; Step 3: Real-time detection of the capacity of the large capacity battery, if the second repair condition of the large capacity battery is detected, at least one step 4 is performed; Step 4: Second stage online repair Step b: performing over-discharge on the large capacity battery; Step c: performing liquid supplementing or liquid replacing on the large capacity battery through a functional interface, and performing exhaust on the large capacity battery through the functional interface; The second repair condition is the following two cases: Case 1: the capacity and capacity retention rate of the large capacity battery are not obviously improved after the first stage online repair; Case 2: the capacity of the large capacity battery is attenuated to X2 or the number of charge-discharge cycles is more than Y2; wherein 70%≤X2≤95% and Y2>Y1.

2. The method of claim 1, wherein the method is performed on-line. The step 4 further comprises a step d: performing heating treatment on the large capacity battery through a heat transfer pipe on the polarity terminal of the large capacity battery.

3. The on-line repair method of a large capacity battery according to claim 1 or 2, characterized by, The step 4 further comprises a step e: performing secondary lithium supplementing on the large capacity battery through the lithium supplementing device.

4. The method of claim 1, wherein the method is performed on-line. The step 2 further comprises a step f: performing liquid supplementing on the large capacity battery through the functional interface, and performing exhaust on the large capacity battery through the functional interface.

5. The method of claim 1, wherein the method is performed on-line. The functional interface is a columnar body, a gas passage connecting a gas chamber of the large capacity battery and an external gas pipe, and an electrolyte passage connecting an electrolyte chamber of the large capacity battery and an external liquid pipe are arranged in the columnar body, and the gas passage and the electrolyte passage are isolated from each other.

6. The method of claim 1, wherein the method is performed on-line. The lithium supplementing device comprises a lithium source, a lithium supplementing wire, a variable resistor and a switch; The lithium source is arranged in the large capacity battery and is soaked in the electrolyte; One end of the lithium supplementing wire is electrically connected with the lithium source, and the other end is used for connecting with the polarity terminal of the large capacity battery, and the lithium supplementing wire is provided with the switch and the variable resistor; The switch is used for turning on or turning off the lithium supplementing wire.

7. The method of claim 6, wherein the method comprises: The lithium source comprises two copper mesh layers and a metal lithium layer arranged between the two copper mesh layers.

8. The method of claim 1, wherein: The cut-off voltage of the over-discharge is 0.01V to 2.4V.

9. The method of claim 2, wherein: The heating temperature range is 45 to 60℃.

Images