Formation device and formation process of lithium battery

Abstract

The invention belongs to the technical field of lithium batteries, and discloses a lithium battery formation device and a lithium battery formation process. The device comprises an electric control box and a rotating assembly arranged in the electric control box, and a first driving part and a second driving part are oppositely arranged at the two ends of the rotating assembly; a first connecting shaft and a second connecting shaft are arranged on the inner side of the electric control box, the first connecting shaft is arranged above the rotating assembly, and the second connecting shaft is arranged below the rotating assembly; a first connecting piece is arranged between the first driving piece and the first connecting shaft, and a second connecting piece is arranged between the second driving piece and the second connecting shaft; a tray used for placing a battery cell is arranged in the rotating assembly, and the electric control box controls the first driving part and the second driving part to rotate so as to drive the battery cell on the tray to rotate by 360 degrees in the rotating assembly. According to the formation device of the lithium battery provided by the invention, the solid electrolyte interface film can be formed more stably, and the electrode capacity utilization rate of the lithium battery is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium batteries, and in particular relates to a formation device and a formation process of a lithium battery. Background Art

[0002] With the rise of new energy in today's society, lithium batteries are widely used in fields such as electric vehicles, household energy storage, portable batteries, digital batteries, etc. However, due to the high compaction density of the existing lithium batteries, the electrolyte infiltration time is long and uneven during the formation process of the lithium battery, which leads to uneven current density distribution of the lithium battery and unstable formation of the solid electrolyte interface film, which further leads to low electrode capacity utilization, shortened cycle performance and service life of the lithium battery.

[0003] Therefore, how to improve the stability of solid electrolyte interface film formation during the lithium battery formation process and further improve the electrode capacity utilization of lithium batteries is a technical problem that needs to be solved urgently. Summary of the invention

[0004] In order to solve the technical problem of unstable solid electrolyte boundary film formation during the above-mentioned lithium battery formation process, the present invention provides a lithium battery formation device and a formation process thereof.

[0005] In a first aspect, the present invention provides a lithium battery formation device, comprising an electric control box and a rotating assembly arranged in the electric control box, wherein two ends of the rotating assembly are oppositely provided with a first driving member and a second driving member;

[0006] A first connecting shaft and a second connecting shaft are arranged inside the electric control box, and the first connecting shaft is arranged above the rotating assembly, and the second connecting shaft is arranged below the rotating assembly;

[0007] A first connecting member is provided between the first driving member and the first connecting shaft, and a second connecting member is provided between the second driving member and the second connecting shaft;

[0008] A tray for placing battery cells is arranged in the rotating assembly, and the electric control box controls the first driving member and the second driving member to rotate so as to drive the battery cells on the tray to rotate 360 ​​degrees in the rotating assembly.

[0009] Preferably, the first driving member and the second driving member include at least two bearings respectively.

[0010] Preferably, the bearing is a universal joint bearing.

[0011] Preferably, a plurality of grooves are provided inside the tray, the grooves are arranged at equal intervals, and a battery cell structure is embedded in each groove.

[0012] Preferably, the rotating assembly is a cubic barrel.

[0013] Preferably, the formation device further comprises a mounting base, and the electric control box is fixedly mounted on the mounting base.

[0014] In a second aspect, the present invention further provides a lithium battery formation process, using the lithium battery formation device described in any one of the first aspects above, the process comprising:

[0015] Step S1, embedding the battery cell structure after the electrolyte is injected into the groove on the tray, and installing the tray with the battery cell structure embedded in the rotating assembly;

[0016] Step S2, installing the rotating assembly after the installation tray in the electric control box, and adjusting the temperature in the electric control box to a preset temperature;

[0017] Step S3, controlling the first driving member and the second driving member at both ends of the rotating assembly to rotate at a preset rotation rate through the electric control box, so that the battery core structure in the tray rotates 360 degrees in the rotating assembly;

[0018] Step S4, presetting the step current value and the cut-off voltage value of the battery cell structure in the tray during charging, and performing step charging on the battery cell structure after 360-degree rotation to the cut-off voltage value through the electric control box;

[0019] Step S5, taking out the battery cell structure after step charging in the tray.

[0020] Preferably, the step current value and cut-off voltage value of the battery cell structure in the preset tray during charging include:

[0021] The first step current value of the battery cell structure in the preset tray when charging is 1800mA, the second step current value is 3600mA, the third step current value is 7200mA, and the cut-off voltage value of the battery cell structure in the preset tray when charging is 3950mV.

[0022] Preferably, adjusting the temperature in the electric control box to a preset temperature comprises:

[0023] The temperature in the electric control box was adjusted to 35°C.

[0024] Preferably, the step of controlling the first driving member and the second driving member at both ends of the rotating assembly to rotate at a preset rotation rate by the electric control box includes:

[0025] The electric control box controls the first driving member and the second driving member at both ends of the rotating assembly to rotate 360 ​​degrees at a rotation speed of 20r / min-40r / min.

[0026] Compared with the prior art, the lithium battery formation device provided by the present invention controls the rotation of the first driving member and the second driving member at both ends of the rotating assembly through an electric control box to drive the battery cells on the tray to rotate 360 ​​degrees in the rotating assembly, effectively shortening the electrolyte infiltration time, making the electrolyte infiltration more uniform, and the solid electrolyte interface film formation more stable, further improving the electrode capacity utilization rate of the lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only part of the embodiments of the present invention, rather than all of the embodiments. For ordinary technicians in this field, without paying creative work, other drawings obtained based on these drawings all fall within the scope of protection of the present invention.

[0028] Figure 1 A schematic diagram of the structure of a lithium battery formation device provided in an embodiment of the present invention;

[0029] Figure 2 A cross-sectional view of a lithium battery formation device provided by an embodiment of the present invention;

[0030] Figure 3 A schematic diagram of a formation process flow of a lithium battery provided in an embodiment of the present invention.

[0031] Among them, 10 is an electric control box, 20 is a rotating assembly, 31 is a first driving member, 32 is a second driving member, 33 is a bearing, 41 is a first connecting shaft, 42 is a second connecting shaft, 51 is a first connecting member, 52 is a second connecting member, 60 is a tray, 61 is a groove, and 70 is a mounting base. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] In order to make the description of the content of the present invention more detailed and complete, the following is an illustrative description of the implementation method and specific examples of the present invention; however, this is not the only form of implementing or applying the specific embodiments of the present invention. The implementation method covers the features of multiple specific embodiments and the method steps and their sequence for constructing and operating these specific embodiments. However, other specific embodiments can also be used to achieve the same or equal functions and step sequences. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein.

[0035] In the description of the embodiments of the present invention, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present invention, “multiple” means two or more than two, and other quantifiers are similar. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention, and the embodiments of the present invention and the features in the embodiments may be combined with each other without conflict.

[0036] In order to solve the technical problem of unstable solid electrolyte boundary film formation during the above-mentioned lithium battery formation process, the present invention provides a lithium battery formation device, please refer to Figure 1-2 , Figure 1 A schematic diagram of the structure of a lithium battery formation device provided in an embodiment of the present invention, Figure 2A cross-sectional view of a lithium battery formation device provided in an embodiment of the present invention, the lithium battery formation device comprises an electric control box 10 and a rotating assembly 20 arranged in the electric control box, a first driving member 31 and a second driving member 32 are arranged at two ends of the rotating assembly 20 opposite to each other; a first connecting shaft 41 and a second connecting shaft 42 are arranged on the inner side of the electric control box 10, and the first connecting shaft 41 is arranged above the rotating assembly 20, and the second connecting shaft 42 is arranged below the rotating assembly 20; a first connecting member 51 is arranged between the first driving member 31 and the first connecting shaft 41, and a second connecting member 52 is arranged between the second driving member 32 and the second connecting shaft 42; a tray 60 for placing battery cells is arranged in the rotating assembly 20, and the electric control box 10 controls the rotation of the first driving member 31 and the second driving member 32 to drive the battery cells on the tray 60 to rotate 360 ​​degrees in the rotating assembly 20. Specifically, in the embodiment of the present invention, the first driving member 31 and the second driving member 32 can rotate 360 ​​degrees, and the first driving member 31 and the second driving member 32 at both ends of the rotating assembly 20 can be controlled to rotate by the electric control box 10. The first driving member 31 and the second driving member 32 can drive the rotating assembly 20 to rotate 360 ​​degrees. The tray 60 is fixedly installed in the rotating assembly 20, further driving the battery cells on the tray to rotate 360 ​​degrees in the rotating assembly. Under the action of multi-directional centrifugal force and gravity, the infiltration of the electrolyte is more uniform and the formation of the solid electrolyte interface film is more stable, thereby further improving the electrode capacity utilization rate of the lithium battery.

[0037] As an embodiment, the first driving member 31 and the second driving member 32 respectively include at least two bearings 33. Specifically, in the embodiment of the present invention, the first driving member 31 and the second driving member 32 are respectively provided at both ends of the rotating assembly 20, and the first driving member may include two bearings 33, and the two bearings 33 are combined to support the rotation of the rotating assembly 20, and the two bearings 33 assemblies can reduce the friction coefficient of the rotating assembly 20 during the rotation process to ensure its precise rotation.

[0038] As an implementation mode, the bearing device 33 is a universal joint bearing device. Specifically, in the embodiment of the present invention, a universal joint bearing device can be used, which is a combination of a universal joint and a transmission shaft, and can use a ball connection to realize power transmission of different shafts, and has the advantages of large transmission angle, stable transmission, small gap impact, and large transmission torque.

[0039] As an implementation mode, a plurality of grooves 61 are provided inside the tray 60, and the grooves 61 are arranged at equal intervals, and a battery cell structure is embedded in each groove 61. Specifically, in the embodiment of the present invention, a battery cell structure is embedded in each groove 61 in the tray, and the rotating assembly 20 can be controlled by the electric control box 10 to rotate 360 ​​degrees, and the battery cell structure in the tray 60 can further rotate 360 ​​degrees in three dimensions in the rotating assembly 20.

[0040] As an implementation mode, the rotating assembly 20 is a cubic barrel. Specifically, in the embodiment of the present invention, the rotating assembly 20 can be a cubic barrel, which can make the electrolyte infiltration more uniform under the action of multi-directional centrifugal force and gravity.

[0041] As an embodiment, the formation device further includes a mounting base 70, and the electric control box 10 is fixedly mounted on the mounting base 70. Specifically, in the embodiment of the present invention, the electric control box 10 can be fixedly mounted on the mounting base 70, and the specific mounting method can be set according to actual needs, and the embodiment of the present invention does not impose further restrictions.

[0042] Based on the above-mentioned lithium battery formation device, the present invention also proposes a lithium battery formation process, please refer to Figure 3 , Figure 3A schematic diagram of a formation process flow of a lithium battery provided in an embodiment of the present invention, the process comprising: step S1, embedding a cell structure after injecting an electrolyte into a groove 61 on a tray, and installing the tray 60 with the embedded cell structure in a rotating assembly 20; step S2, installing the rotating assembly 20 after the tray 60 is installed in an electric control box 10, and adjusting the temperature in the electric control box 10 to a preset temperature; step S3, controlling the first driving member 31 and the second driving member 32 at both ends of the rotating assembly 20 to rotate at a preset rotation rate through the electric control box 10, so that the cell structure in the tray rotates 360 degrees in the rotating assembly 20; step S4, presetting a step current value and a cut-off voltage value when charging the cell structure in the tray, and performing step charging on the cell structure after 360 degrees rotation to the cut-off voltage value through the electric control box 10; step S5, taking out the cell structure in the tray 60 after step charging. Specifically, in the embodiment of the present invention, the first driving member 31 and the second driving member 32 at both ends of the rotating component 20 can be controlled by the electrical control box 10 to rotate at a preset rotation rate, and the first driving member 31 and the second driving member 32 can drive the rotating component 20 to rotate 360 ​​degrees. The tray 60 is fixedly installed in the rotating component 20, and further drives the battery cells on the tray to rotate 360 ​​degrees in the rotating component. During the formation process, the battery cells on the tray can be more evenly infiltrated with the electrolyte and the solid electrolyte interface film can be formed more stably under the action of multi-directional centrifugal force and gravity, thereby further improving the electrode capacity utilization rate, cycle life and service life of the lithium battery.

[0043] As an implementation mode, the step current value and the cut-off voltage value when charging the battery cell structure in the preset tray include: the first step current value when charging the battery cell structure in the preset tray is 1800mA, the second step current value is 3600mA, and the third step current value is 7200mA, and the cut-off voltage value when charging the battery cell structure in the preset tray is 3950mV. Specifically, in the embodiment of the present invention, the battery cell after 360-degree three-dimensional rotation is firstly kept at rest for 5 minutes, and then the battery cell structure in the tray is step-charged, and finally, the battery cell structure in the tray after step charging is taken out from the groove 61 of the tray after being left at rest for 5 minutes. Among them, the parameters for step-charging the battery cell structure in the tray are shown in Table 1 below. In an embodiment of the present invention, the charging of the battery cell structure in the tray is divided into three stages. In the first stage, a constant current of 1800 mA is used for charging until the voltage value of the lithium battery reaches 3950 mV, and the charging time is up to 150 min, that is, when the charging voltage of the lithium battery reaches 3950 mV, or the charging time reaches 150 min, the charging of the battery cell structure in the tray enters the second stage; in the second stage, a constant current of 3600 mA is used for charging until the voltage value of the lithium battery reaches 3950 mV, and the charging time is up to 180 min, that is, when the charging voltage of the lithium battery reaches 3950 mV, or the charging time reaches 180 min, the charging of the battery cell structure in the tray enters the third stage; in the third stage, a constant current of 7200 mA is used for charging until the voltage value of the lithium battery reaches 3950 mV, and the charging time is up to 60 min, that is, when the charging voltage of the lithium battery reaches 3950 mV, or the charging time reaches 60 min, the charging of the battery cell structure in the tray is stopped.

[0044] Table 1

[0045] step Working Mode Main parameters Time Limit Voltage Limitation 1 Stand —— 5min —— 2 Constant current charging 1800mA 150min 3950mV 3 Constant current charging 3600mA 180min 3950mV 4 Constant current charging 7200mA 60min 3950mV 5 Stand —— 5min ——

[0046] As an implementation mode, adjusting the temperature in the electric control box to a preset temperature includes: adjusting the temperature in the electric control box to 35° C. Specifically, in the embodiment of the present invention, adjusting the temperature in the electric control box to 35° C. can ensure the best electrolyte infiltration effect during the lithium battery formation process.

[0047] As an embodiment, the first driving member and the second driving member at both ends of the rotating assembly are controlled by the electric control box to rotate at a preset rotation speed, including: controlling the first driving member and the second driving member at both ends of the rotating assembly to rotate 360 ​​degrees at a rotation speed of 20r / min-40r / min by the electric control box. Specifically, in an embodiment of the present invention, in order to verify the optimal rotation speed of the battery cell structure in the rotating assembly, the first driving member and the second driving member at both ends of the rotating assembly can be controlled by the electric control box to rotate 360 ​​degrees at different rotation speeds. In an embodiment of the present invention, the first driving member and the second driving member at both ends of the rotating assembly are controlled by the electric control box to rotate 360 ​​degrees at a rotation speed of 20r / min, a rotation speed of 40r / min, and a rotation speed of 60r / min, respectively, and then the battery cell structure after the electrolyte solution of the same batch is injected is placed in a formation cabinet for static formation. After the formation of the lithium battery cell structure is completed, the step current can be set through the electric control box to charge to the preset cut-off voltage program. After the lithium battery is charged, the cell structure is taken out to test the liquid retention rate and first efficiency at different rotation rates to evaluate the electrolyte infiltration effect and formation effect during the lithium battery formation process. The specific formation effect is shown in Table 2 below.

[0048] Table 2

[0049] Formation method Fluid retention Charging efficiency 20r / min rotation speed 96.20％ 92％ Rotation speed of 40r / min 97％ 93.40％ 60r / min rotation speed 94.20％ 91％ Stand 96％ 92％

[0050] As can be seen from Table 2 above, when the electric control box controls the first and second driving members at both ends of the rotating assembly to rotate 360 ​​degrees at a rotation speed of 40r / min respectively, the liquid retention and charging efficiency of the lithium battery are optimal, indicating that its electrolyte wettability is the best and the formation effect is the best. In addition, when the electric control box controls the first and second driving members at both ends of the rotating assembly to rotate 360 ​​degrees at a rotation speed of 20r / min respectively, the liquid retention and charging efficiency of the lithium battery are better than the effect of directly placing it in the formation cabinet and static formation. In addition, when the first and second driving members at both ends of the rotating assembly are controlled by the electric control box to rotate 360 ​​degrees at a rotation speed of 20r / min-40r / min, its electrolyte infiltration effect is better than the traditional static formation effect.

[0051] In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0052] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of software functional units. The above is only an implementation mode of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present invention.

[0053] The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Although the present invention has been disclosed as above in the form of preferred embodiments, it is not intended to limit the present invention. Any technical personnel in the field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A lithium battery formation device, characterized in that: It comprises an electric control box and a rotating assembly arranged in the electric control box, wherein two ends of the rotating assembly are oppositely provided with a first driving member and a second driving member; A first connecting shaft and a second connecting shaft are arranged inside the electric control box, and the first connecting shaft is arranged above the rotating assembly, and the second connecting shaft is arranged below the rotating assembly; A first connecting member is provided between the first driving member and the first connecting shaft, and a second connecting member is provided between the second driving member and the second connecting shaft; A tray for placing battery cells is arranged in the rotating assembly, and the electric control box controls the first driving member and the second driving member to rotate so as to drive the battery cells on the tray to rotate 360 ​​degrees in the rotating assembly.

2. The lithium battery formation device according to claim 1, characterized in that: The first driving member and the second driving member each include at least two bearings.

3. The lithium battery formation device according to claim 2, characterized in that: The bearing is a universal joint bearing.

4. The lithium battery formation device according to claim 3, characterized in that: A plurality of grooves are provided inside the tray, the grooves are arranged at equal intervals, and a battery cell structure is embedded in each groove.

5. The lithium battery formation device according to claim 4, characterized in that: The rotating component is a cubic barrel.

6. The lithium battery formation device according to claim 1, characterized in that: The formation device also includes a mounting base, and the electric control box is fixedly mounted on the mounting base.

7. A lithium battery formation process, characterized in that: The lithium battery formation device according to any one of claims 1 to 6 is used, wherein the process comprises: Step S1, embedding the battery cell structure after the electrolyte is injected into the groove on the tray, and installing the tray with the battery cell structure embedded in the rotating assembly; Step S2, installing the rotating assembly after the installation tray in the electric control box, and adjusting the temperature in the electric control box to a preset temperature; Step S3, controlling the first driving member and the second driving member at both ends of the rotating assembly to rotate at a preset rotation rate through the electric control box, so that the battery core structure in the tray rotates 360 degrees in the rotating assembly; Step S4, presetting the step current value and the cut-off voltage value of the battery cell structure in the tray during charging, and performing step charging on the battery cell structure after 360-degree rotation to the cut-off voltage value through the electric control box; Step S5, taking out the battery cell structure after step charging in the tray.

8. The lithium battery formation process according to claim 7, characterized in that: The step current value and cut-off voltage value of the battery cell structure in the preset tray during charging include: The first step current value of the battery cell structure in the preset tray when charging is 1800mA, the second step current value is 3600mA, the third step current value is 7200mA, and the cut-off voltage value of the battery cell structure in the preset tray when charging is 3950mV.

9. The lithium battery formation process according to claim 8, characterized in that: The step of adjusting the temperature in the electric control box to a preset temperature comprises: The temperature in the electric control box was adjusted to 35°C.

10. The lithium battery formation process according to claim 9, characterized in that: The method of controlling the first driving member and the second driving member at both ends of the rotating assembly to rotate at a preset rotation rate by the electric control box includes: The electric control box controls the first driving member and the second driving member at both ends of the rotating assembly to rotate 360 ​​degrees at a rotation speed of 20r / min-40r / min.

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