Device and method for pre-lithiation of battery

Abstract

The invention discloses a battery pre-lithiation device and a method thereof. The battery pre-lithiation device comprises at least one placement assembly arranged in the vertical direction; the top cover assembly is arranged at the top of the placing assembly, the top cover assembly comprises a first air connecting pipe and a second air connecting pipe, and the first air connecting pipe and the second air connecting pipe are arranged at the two ends of the upper surface of the top cover assembly side by side; the at least two negative pressure liquid injection assemblies are respectively arranged on the inner sides of the placing assembly and the top cover assembly; a battery; by arranging the placing assembly, the top cover assembly, the negative pressure liquid injection assembly, the first gas connecting pipe and the second gas connecting pipe, pre-lithiation can be conveniently carried out through negative pressure infiltration, the mottled influence of bubbles on a negative plate during pre-lithiation is reduced, and the device is simple in structure, high in pre-lithiation speed, capable of reducing lithium residues and capable of effectively improving mottles.

Description

Technical Field

[0001] The present invention specifically relates to a battery pre-lithiation device and method. Background Art

[0002] During the first charge of a lithium-ion battery, the surface of the negative electrode reacts with the electrolyte to form a solid electrolyte membrane. Although this electrolyte membrane is beneficial to the cycle stability of the lithium-ion battery, it will consume the lithium ions of the positive electrode, and this reaction is irreversible, resulting in a decrease in the initial coulombic efficiency (ICE) of the battery and a reduction in the battery capacity. In order to solve the problem of low initial coulombic efficiency of the negative electrode material, chemical reduction, artificial SEI membrane and electrochemical pre-lithiation are usually used. Among them, electrochemical pre-lithiation is the most direct method to solve the low ICE of lithium-ion negative electrode materials.

[0003] The existing automatic pre-lithiation method, in which a lithium-copper composite sheet is built into the battery and connected to the negative electrode of the battery during pre-lithiation, can achieve the purpose of pre-lithiation, but the pre-lithiation rate is slow, resulting in a large amount of residual lithium, affecting battery safety. In addition, from the disassembly interface, there are also a large number of spots on the negative electrode sheet. The spots are mainly caused by uneven electrolyte infiltration due to gas production during the pre-lithiation process. The spots will not only affect the performance of the battery, but also the consistency of the battery cell. For this reason, we propose a battery pre-lithiation device and method. Summary of the invention

[0004] The object of the present invention is to provide a battery pre-lithiation device and method thereof to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a battery pre-lithiation device, comprising:

[0006] At least one placement component arranged in a vertical direction;

[0007] A top cover assembly is arranged on the top of the placement assembly, and the top cover assembly includes a first air connection pipe and a second air connection pipe, wherein the first air connection pipe and the second air connection pipe are arranged side by side at two ends of the upper surface of the top cover assembly;

[0008] At least two negative pressure liquid injection components are respectively arranged on the inner sides of the placement component and the top cover component;

[0009] The battery is arranged at the upper end of the inner side of the placement component, and the battery is provided with a liquid injection port which is connected with the negative pressure liquid injection component for liquid injection.

[0010] It is convenient to connect with an external negative pressure system to control the negative pressure value during injection, so as to achieve rapid flow of electrolyte, while reducing the influence of bubbles in the electrolyte on the negative electrode of the battery to form spots, thereby improving the effect of injection.

[0011] Preferably, the placement assembly includes a stacking trough body, a connecting tube and a battery trough body, the battery trough body is slidably mounted inside the stacking trough body, and the battery trough body is provided with positioning holes for placing the battery, and the two ends of the inner side of the stacking trough body have connecting tubes connected to the negative pressure injection assembly.

[0012] It is convenient to position and place multiple batteries, and then fill the electrolyte into the battery through negative pressure.

[0013] Preferably, avoidance grooves are provided on both end surfaces of the battery container body, and the avoidance grooves correspond to the connecting pipes.

[0014] It is convenient to accurately place the battery tank body inside the stacking tank body, reducing the interference effect between the two ends of the battery tank body and the connecting pipe.

[0015] Preferably, the negative pressure injection component includes a main injection tube, an auxiliary injection tube, a buffer tank, an injection hole and a connecting hole. The main injection tube is arranged at the lower end of the inner side of the placement component, and the side of the main injection tube is connected to the buffer tank through the auxiliary injection tube. The lower surface of the buffer tank is provided with an injection hole corresponding to the injection port, and one end face of the buffer tank has a connecting hole connected to the inside of the auxiliary injection tube.

[0016] It is convenient to cache the electrolyte through the buffer tank, and then use negative pressure to make the electrolyte flow from the inside of multiple buffer tanks to the inside of the corresponding battery.

[0017] Preferably, an ear plate is fixed to the side wall of the cache slot, and a spring is arranged on the ear plate.

[0018] The buffer slot is conveniently attached to the liquid filling port of the battery through the elastic force of the spring.

[0019] Preferably, a plurality of the cache slots are evenly distributed along the axial direction of the main injection tube, and every two of the cache slots are symmetrically distributed along the main injection tube.

[0020] It is convenient to divert the electrolyte from the main injection pipe to the inner sides of multiple buffer tanks.

[0021] Preferably, the top cover assembly comprises a frame body and a top plate, the inner side of the frame body is provided with a slot body for placing the negative pressure injection assembly, and the top plate is fixed to the top end of the inner side of the slot body.

[0022] It is convenient to seal the topmost component of the stack through the top cover component.

[0023] Preferably, there are 2-10 placement components.

[0024] Easy to handle filling of multiple batteries.

[0025] A method for pre-lithiation of a battery comprises the following steps:

[0026] Step A: Install the battery tank body inside the stacking tank body, connect the connecting pipe with the main injection pipe, and provide electrolyte inside the buffer tank;

[0027] Step B: Then place multiple batteries inside the positioning holes to assemble into a placement component, and then stack multiple placement components so that the injection holes correspond to the injection ports;

[0028] Step C: placing the top cover assembly onto the topmost placement assembly, and the second air connection pipe and the first air connection pipe correspond to the connecting pipes at both ends of the inner side of the stacking tank body respectively;

[0029] Step D: Connect the second air pipe to an external vacuum pipe and the first air pipe to an external pressure pipe, thereby adjusting the negative pressure value inside the buffer tank so that the electrolyte flows from the injection hole below the buffer tank into the injection port of the battery for injection.

[0030] It is convenient to inject electrolyte into the inner side of the battery through negative pressure, so as to reduce the mottling of the negative electrode caused by the generation of bubbles and improve the effect of adding electrolyte.

[0031] Preferably, in the step B, a sealing ring is provided on the liquid injection port corresponding to the liquid injection hole.

[0032] This facilitates better flow of the electrolyte inside the buffer tank to the inside of the liquid injection port, so as to achieve the addition of electrolyte for pre-lithiation.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention is provided with a placement component, a top cover component, a negative pressure liquid injection component, a first air connection pipe and a second air connection pipe, so as to facilitate pre-lithiation by negative pressure infiltration, reduce the mottled effect of bubbles on the negative electrode sheet during pre-lithiation, the device has a simple structure, a fast pre-lithiation speed, reduces lithium residue, and can effectively improve the mottled effect, thereby improving the effect of pre-lithiation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of the present invention;

[0036] Figure 2 It is a schematic diagram of the connecting pipe structure of the present invention;

[0037] Figure 3 It is a schematic diagram of the structure of the negative pressure injection component of the present invention;

[0038] Figure 4 It is a schematic diagram of the exploded structure of the placement assembly of the present invention;

[0039] Figure 5 It is a schematic diagram of the structure of the negative pressure injection component of the present invention;

[0040] Figure 6 It is a schematic diagram of the cross-sectional structure of the cache slot of the present invention;

[0041] Figure 7 It is a schematic diagram of the principle of the present invention;

[0042] Figure 8 Schematic diagram of positive and negative electrode voltage curves of different voltage transformation processes of the present invention.

[0043] In the figure: 1. placement assembly; 101. stacking trough body; 102. connecting pipe; 103. battery trough body; 1031. positioning hole; 1032. avoidance groove; 2. top cover assembly; 201. frame body; 202. top plate; 203. first air connecting pipe; 204. second air connecting pipe; 3. battery; 4. liquid injection port; 5. negative pressure liquid injection assembly; 501. main liquid injection pipe; 502. auxiliary liquid injection pipe; 503. cache slot; 504. ear plate; 505. spring; 506. liquid injection hole; 507. connecting hole. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example

[0046] See also Figure 1-Figure 7 The present invention provides a technical solution: a battery pre-lithiation device, comprising:

[0047] At least one placement component 1 arranged in a vertical direction;

[0048] The top cover assembly 2 is arranged on the top of the placement assembly 1, and the top cover assembly 2 includes a first air receiving pipe 203 and a second air receiving pipe 204, and the first air receiving pipe 203 and the second air receiving pipe 204 are arranged side by side at two ends of the upper surface of the top cover assembly 2;

[0049] At least two negative pressure injection components 5 are respectively arranged inside the placement component 1 and the top cover component 2;

[0050] The battery 3 is arranged at the upper end of the inner side of the placement component 1, and a liquid injection port 4 connected to the negative pressure liquid injection component 5 for liquid injection is opened on the battery 3.

[0051] It is convenient to connect with an external negative pressure system and control the negative pressure value during injection through gas to achieve rapid flow of electrolyte, while reducing the generation of bubbles in the electrolyte to avoid affecting the negative electrode of the battery 3 to form spots, thereby improving the effect of injection.

[0052] Preferably, the placement component 1 includes a stacking trough body 101, a connecting tube 102 and a battery trough body 103. The battery trough body 103 is slidably installed on the inner side of the stacking trough body 101, and a positioning hole 1031 is provided on the battery trough body 103 for placing the battery 3. The two ends of the inner side of the stacking trough body 101 have connecting tubes 102 connected to the negative pressure injection component 5.

[0053] It is convenient to position and place multiple batteries 3, ensure that the batteries 3 correspond to the injection port 4 after being placed, and then inject electrolyte into the inside of the battery 3 through negative pressure.

[0054] Preferably, avoidance grooves 1032 are formed on both end surfaces of the battery container body 103 , and the avoidance grooves 1032 correspond to the connecting pipe 102 .

[0055] It is convenient to accurately place the battery container 103 inside the stacking container 101 , and reduce the interference between the two ends of the battery container 103 and the connecting pipe 102 , so as to facilitate the stacking of multiple groups of batteries 3 later.

[0056] Preferably, the negative pressure injection component 5 includes a main injection tube 501, an auxiliary injection tube 502, a buffer groove 503, an injection hole 506 and a connecting hole 507. The main injection tube 501 is arranged at the lower end of the inner side of the placement component 1, and the side of the main injection tube 501 is connected to the buffer groove 503 through the auxiliary injection tube 502. The lower surface of the buffer groove 503 is provided with an injection hole 506 corresponding to the injection port 4, and one end face of the buffer groove 503 has a connecting hole 507 connected to the inside of the auxiliary injection tube 502.

[0057] It is convenient to cache the electrolyte through the cache slots 503, and then use negative pressure to make the electrolyte flow from the inside of the multiple cache slots 503 to the inside of the corresponding battery 3 to add the electrolyte.

[0058] Preferably, an ear plate 504 is fixed to the side wall of the cache slot 503 , and a spring 505 is provided on the ear plate 504 .

[0059] The elastic force of the spring 505 is convenient to make the buffer slot 503 and the battery's liquid injection port 4 fit tightly together, so as to reduce the accidental outflow of electrolyte from the gap between the two.

[0060] Preferably, a plurality of cache slots 503 are evenly distributed along the axial direction of the main injection tube 501 , and every two cache slots 503 are symmetrically distributed along the main injection tube 501 .

[0061] This facilitates the electrolyte to flow from the main injection pipe 501 to the inner sides of multiple buffer slots 503 , thereby realizing the filling of electrolyte into multiple batteries 3 .

[0062] Preferably, the top cover assembly 2 includes a frame 201 and a top plate 202 . A slot for placing the negative pressure injection assembly 5 is provided inside the frame 201 , and the top plate 202 is fixed to the top of the inner side of the slot.

[0063] It is convenient to seal the topmost stacked component 1 through the top cover component 2.

[0064] Preferably, 2 to 10 placement components 1 are provided.

[0065] It is convenient to handle the injection of multiple batteries 3.

[0066] A method for pre-lithiation of a battery comprises the following steps:

[0067] Step A: Install the battery tank 103 inside the stacking tank 101, connect the connecting pipe 102 with the main injection pipe 501, and provide electrolyte inside the buffer tank 503;

[0068] Step B: Then, multiple batteries 3 are placed inside the positioning holes 1031 to assemble a placement assembly 1, and then multiple placement assemblies 1 are stacked so that the injection hole 506 corresponds to the injection port 4;

[0069] Step C: Place the top cover assembly 2 on the topmost placement assembly 1, and the second air receiving pipe 204 and the first air receiving pipe 203 correspond to the connecting pipes 102 at both ends of the inner side of the stacking tank body 101 respectively;

[0070] Step D: Connect the second air connection pipe 204 to an external vacuum pipe, and connect the first air connection pipe 203 to an external pressure pipe, so as to adjust the negative pressure value inside the buffer tank 503 so that the electrolyte flows from the injection hole 506 below the buffer tank 503 into the injection port 4 of the battery 3 for injection.

[0071] The specific steps for adjusting the negative pressure value are as follows:

[0072] Step 1: Set the initial negative pressure: the initial negative pressure value is -1 to -60KPa, and the control time is 30 to 60 minutes;

[0073] Step 2: Set and adjust the negative pressure: adjust the negative pressure value to -60~-100KPa, and control the time 0~10min;

[0074] Step 3: Alternate the negative pressure cycles of step 1 and step 2, with a total time of 48 to 120 hours.

[0075] During pre-lithium preparation, the ambient temperature is 45°C ± 5°C, the ambient dew point is below -40°C, and the dew point of the supplementary gas for regulating the air pressure is below -40°C.

[0076] It is convenient to inject electrolyte into the inner side of the battery 3 through negative pressure, so as to reduce the mottling of the negative electrode caused by the generation of bubbles and improve the effect of adding electrolyte.

[0077] Preferably, in step B, a sealing ring is provided on the liquid injection port 4 corresponding to the liquid injection hole 506 .

[0078] It is convenient to make the electrolyte inside the buffer tank 503 flow to the inside of the injection port 4 to realize the addition of electrolyte for pre-lithiation. After the pre-lithiation infiltration of the battery 3 is completed, the formation is carried out on the cabinet. Before the formation step starts, the voltage value of the battery cell is recorded, and the pre-lithiation degree of the battery cell is graded and marked according to the voltage range to screen out abnormal batteries.

[0079] Effect Example 1

[0080] The battery pre-lithiation device and method of the present invention are adopted, and the battery core adopts the LFP / C long cycle system. Except for the assembly and impregnation process, other processes are consistent with the production line battery;

[0081] 1. The moisture content of the electrode is 178ppm;

[0082] 2. The electrolyte adopts conventional LFP / C system electrolyte;

[0083] 3. During assembly, a layer of lithium-copper composite tape is coated on the outer layer of the battery cell according to the automatic pre-lithium process;

[0084] 4. Wetting environment: 25℃, dew point: -50℃;

[0085] 5. During infiltration, the negative pressure infiltration process and infiltration equipment of the present application example are used, and the process steps are as follows:

[0086] 1) Initial negative pressure value: -10Kpa, standing time 30min

[0087] 2) Adjust the negative pressure value: -80Kpa, stand for 5 minutes

[0088] 3) Steps 1 and 2 cycle: 124 cycles (about 72 hours)

[0089] 6. After the infiltration is completed, the chemical forming cabinet is put into operation, and the voltage value is automatically recorded before the chemical forming step is sent down;

[0090] 7. Follow up with the conventional battery manufacturing process for secondary injection, sealing and capacity division;

[0091] 8. Disassemble the fully charged battery and record the appearance, disassembly interface and residual lithium content;

[0092] 9. Carry out cycle test on the same batch of batteries with a cycle power of 500W.

[0093] Effect Example 2

[0094] This effect example 2 is the same as effect example 1, except that:

[0095] The infiltration process steps of step 5 are changed to:

[0096] 1) Initial negative pressure value: -10Kpa, standing time 15min

[0097] 2) Adjust the negative pressure value: -80Kpa, standstill time 2.5min

[0098] 3) Steps 1) to 2) cycle: 248 cycles (about 72 hours)

[0099] Effect Example 3

[0100] This effect example 3 is the same as effect example 1, except that:

[0101] The infiltration process steps of step 5 are changed to:

[0102] 1) Initial negative pressure value: -10Kpa, standing time 5min

[0103] 2) Adjust the negative pressure value: -80Kpa, stand for 30 minutes

[0104] 3) Steps 1) to 2) cycle: 124 cycles (about 72 hours)

[0105] Effect Example 4

[0106] This effect example 4 is the same as effect example 1, except that:

[0107] The infiltration pressure in step 5 is kept constant at -10 kPa and is left to stand for 72 hours.

[0108] Effect Example 5

[0109] This effect example 5 is the same as effect example 1, except that:

[0110] The infiltration pressure in step 5 is kept constant at -80 kPa and is left to stand for 72 hours.

[0111] Effect Example 6

[0112] This effect example 6 is the same as effect example 1, except that:

[0113] The infiltration process in step 5 is different. After the pre-lithium battery is filled with liquid, it is directly plugged with a rubber plug like the conventional battery in the production line and placed in an aging room for standing for 72 hours.

[0114] Effect Example 7 is a blank control group:

[0115] The conventional production line battery production process is used for battery production, and the general battery manufacturing process parameters are the same as those in Example 1.

[0116] Test analysis

[0117] Different transformer process parameters are as follows:

[0118]

[0119] The above effect examples were divided into components and cycled at room temperature, and the parameters were recorded under the same conditions and organized into a table as shown below:

[0120]

[0121]

[0122] The following conclusions can be drawn from the comprehensive chart results:

[0123] 1. The battery capacity and capacity retention rate after pre-lithiation of the present invention are significantly superior to those of mass-produced batteries on current production lines; the effect is better than that of conventional normal pressure infiltration within the same pre-lithiation time.

[0124] 2. The negative pressure infiltration adopted by the present invention can effectively improve the mottled condition of the pole piece of the pre-lithium battery, and the higher the negative pressure value, the more obvious the improvement effect.

[0125] 3. The variable pressure infiltration process adopted in the present invention can not only improve the mottling situation, but also promote the consumption of lithium belt and the diffusion of lithium ions.

[0126] 4. Contrast Figure 8 It can be seen from the three pre-lithium battery infiltration voltage curves that the voltage platform of transformer process 2 is higher, which also reflects from the side that its pre-lithium degree is the highest, indicating that within a certain range, increasing the frequency of negative pressure cycles can make the lithium ion migration rate faster.

[0127] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A battery pre-lithiation device, characterized in that: include: At least one placement component (1) arranged in a vertical direction; A top cover assembly (2) is arranged on the top of the placement assembly (1), and the top cover assembly (2) includes a first air receiving pipe (203) and a second air receiving pipe (204), wherein the first air receiving pipe (203) and the second air receiving pipe (204) are arranged side by side at two ends of the upper surface of the top cover assembly (2); At least two negative pressure liquid injection components (5), respectively arranged on the inner sides of the placement component (1) and the top cover component (2); The battery (3) is arranged at the upper end of the inner side of the placement component (1), and the battery (3) is provided with a liquid injection port (4) which is connected to the negative pressure liquid injection component (5) for liquid injection.

2. The battery pre-lithiation device according to claim 1, characterized in that: The placement assembly (1) comprises a stacking trough (101), a connecting pipe (102) and a battery trough (103); the battery trough (103) is slidably mounted inside the stacking trough (101), and a positioning hole (1031) for placing a battery (3) is provided on the battery trough (103); and connecting pipes (102) connected to a negative pressure injection assembly (5) are provided at both ends of the inner side of the stacking trough (101).

3. The battery pre-lithiation device according to claim 2, characterized in that: Avoidance grooves (1032) are provided on both end surfaces of the battery container body (103), and the avoidance grooves (1032) correspond to the connecting pipe (102).

4. The battery pre-lithiation device according to claim 1, characterized in that: The negative pressure liquid injection component (5) comprises a main liquid injection tube (501), an auxiliary liquid injection tube (502), a buffer tank (503), a liquid injection hole (506) and a connecting hole (507); the main liquid injection tube (501) is arranged at the lower end of the inner side of the placement component (1), and the side of the main liquid injection tube (501) is connected to the buffer tank (503) through the auxiliary liquid injection tube (502); the lower surface of the buffer tank (503) is provided with a liquid injection hole (506) corresponding to the liquid injection port (4); and one end surface of the buffer tank (503) has a connecting hole (507) connected to the inside of the auxiliary liquid injection tube (502).

5. The battery pre-lithiation device according to claim 4, characterized in that: An ear plate (504) is fixed to the side wall of the buffer slot (503), and a spring (505) is arranged on the ear plate (504).

6. The battery pre-lithiation device according to claim 4, characterized in that: A plurality of the buffer slots (503) are evenly distributed along the axial direction of the main liquid injection pipe (501), and every two of the buffer slots (503) are symmetrically distributed along the main liquid injection pipe (501).

7. The battery pre-lithiation device according to claim 1, characterized in that: The top cover assembly (2) comprises a frame (201) and a top plate (202); a slot for placing the negative pressure injection assembly (5) is provided on the inner side of the frame (201); and the top plate (202) is fixed to the top end of the inner side of the slot.

8. The battery pre-lithiation device according to claim 1, characterized in that: The number of the placement components (1) is 2 to 10.

9. A method for pre-lithiation of a battery, characterized in that: The steps include: Step A: installing the battery tank body (103) inside the stacking tank body (101), connecting the connecting pipe (102) to the main injection pipe (501), and providing electrolyte inside the buffer tank (503); Step B: Then, the plurality of batteries (3) are respectively placed inside the positioning holes (1031) to assemble into a placement assembly (1), and then the plurality of placement assemblies (1) are stacked so that the injection holes (506) correspond to the injection ports (4); Step C: placing the top cover assembly (2) on the topmost placement assembly (1), and then the second air receiving pipe (204) and the first air receiving pipe (203) respectively correspond to the connecting pipes (102) at both ends of the inner side of the stacking tank body (101); Step D: Connect the second air connection pipe (204) to an external vacuum pipe, and connect the first air connection pipe (203) to an external pressure pipe, thereby adjusting the negative pressure value inside the buffer tank (503) so that the electrolyte flows from the injection hole (506) below the buffer tank (503) into the injection port (4) of the battery (3) for injection.

10. A method for pre-lithiation of a battery according to claim 9, characterized in that: In the step B, a sealing ring is provided on the liquid injection port (4) corresponding to the liquid injection hole (506).

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