Battery electrolyte injection method and device

Abstract

The application belongs to the technical field of batteries, and discloses a battery electrolyte injection method and device. The battery electrolyte injection method comprises the following steps: S1, placing a battery to be injected into a sealed cavity, and keeping communication among a gas bag for injecting electrolyte into the battery, the battery and the sealed cavity. S2, performing vacuumization on the sealed cavity until the vacuum degree in the sealed cavity reaches K1, and then stopping. S3, injecting electrolyte into the gas bag, so that the electrolyte seals the battery. S4, injecting inert gas into the sealed cavity, so that the vacuum degree in the sealed cavity reaches K2, a pressure difference K0 is generated between the sealed cavity and the inside of the battery, and the electrolyte in the gas bag is sucked into the battery under the action of the pressure difference K0. The battery electrolyte injection method can improve the electrolyte injection speed without adding a high-aluminum plastic film or increasing the size of the gas bag.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a method and apparatus for injecting battery electrolyte. Background Technology

[0002] Lithium-ion batteries are widely used in various fields such as mobile phones, laptops, audio products, power tools, backup power supplies, and automotive power systems due to their advantages of energy saving, environmental protection, and high energy density. With the expansion of application areas, lithium-ion batteries will continue to enjoy strong market demand in the future.

[0003] A lithium-ion battery consists of an aluminum-plastic film, a bare cell, and an electrolyte. After the electrode plates are prepared and the bare cell is fabricated by stacking, winding, or other methods, the bare cell is placed inside the aluminum-plastic film. The electrolyte is then injected into the aluminum-plastic film to wet the bare cell. The electrolyte mainly plays the role of transporting lithium ions inside the lithium-ion battery.

[0004] For high-capacity batteries, due to their higher energy density, they need to withstand high-power charging and discharging. Therefore, more electrolyte needs to be injected to wet the cells, ensuring sufficient electrolyte supply during long-term use. This leads to a dilemma: if the electrolyte injection speed is too slow, relying on gravity for wetting results in excessively long processing times, hindering large-scale industrial production. If the injection speed is too fast, to prevent electrolyte overflow, it is often necessary to increase the height of the aluminum-plastic film and the size of the pre-installed air bladder. After formation and secondary electrolyte replenishment, a second heat sealing is performed, and the air bladder and excess aluminum-plastic film are removed. This results in waste and a significant increase in production costs.

[0005] Therefore, there is an urgent need for battery electrolyte injection methods and devices to solve the above problems. Summary of the Invention

[0006] One object of the present invention is to provide a battery electrolyte injection method that can increase the electrolyte injection speed without increasing the height of the aluminum-plastic film or increasing the size of the airbag.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] Battery electrolyte filling methods include:

[0009] The battery to be injected with liquid is placed in a sealed cavity, and the air bag for injecting liquid into the battery, the battery and the sealed cavity are kept in communication.

[0010] The sealed cavity is evacuated until the vacuum level inside the sealed cavity reaches K1, then the evacuation is stopped.

[0011] Electrolyte is injected into the airbag to seal the battery;

[0012] An inert gas is injected into the sealed cavity to create a vacuum of K2 within the sealed cavity, resulting in a pressure difference K0 between the sealed cavity and the inside of the battery. Under the action of this pressure difference K0, the electrolyte in the airbag is drawn into the battery.

[0013] As an optional solution, the ratio of the height of the electrolyte inside the airbag to the height of the airbag is h1. K2 is adjusted according to the size of h1 to keep the electrolyte inside the airbag sealing the battery.

[0014] As an optional option, h1 should not be less than 0.2.

[0015] As an alternative, h1 equals 0.45-0.55.

[0016] As an optional option, K0 equals 20 kPa - 55 kPa.

[0017] As an optional solution, the time for injecting the inert gas into the sealed cavity is set to T1, and the time for the battery to complete the liquid injection is set to T0, where T1 / T0 equals 0.3-0.6.

[0018] As an alternative, the injection rate of the inert gas is controlled so that the vacuum level K1 changes uniformly to the vacuum level K2.

[0019] Alternatively, the inert gas can be repeatedly injected into the sealed cavity to adjust the vacuum level K2 within the sealed cavity.

[0020] Another object of the present invention is to provide a battery electrolyte injection device for use in the battery electrolyte injection method described above, so as to improve the electrolyte injection speed.

[0021] To achieve this objective, the present invention adopts the following technical solution:

[0022] A battery electrolyte injection device, used in the battery electrolyte injection method described above, wherein the battery electrolyte injection device comprises:

[0023] A sealed cavity is provided inside the sealed cavity, and the battery to be injected with liquid is contained in the sealed cavity. An air bag is recessed on the upper side of the battery, and the air bag is connected to the inside of the battery.

[0024] An injection mechanism is provided on the sealed cavity, and the injection nozzle of the injection mechanism can seal through the sealed cavity to inject electrolyte into the airbag.

[0025] A vacuuming mechanism is disposed on the sealed cavity, and the vacuuming mechanism is configured to evacuate the sealed cavity.

[0026] An inert gas supply mechanism is disposed on the sealed cavity, and the inert gas supply mechanism is configured to introduce inert gas into the sealed cavity.

[0027] As an optional solution, the battery electrolyte injection device further includes:

[0028] A liquid level sensor is used to detect the liquid level of the electrolyte inside the airbag.

[0029] As an optional solution, the battery electrolyte injection device further includes:

[0030] A vacuum gauge is used to detect the vacuum level inside the sealed cavity.

[0031] As an optional solution, the sealed cavity includes a first cavity and a second cavity, the second cavity being used to install the battery, the first cavity being fastened to the second cavity and sealed to the second cavity, and the liquid injection mechanism, the vacuuming mechanism and the inert gas supply mechanism being disposed on the first cavity.

[0032] Beneficial effects:

[0033] The battery electrolyte injection method proposed in this invention utilizes the pressure difference between the sealed cavity and the inside of the battery to draw the electrolyte from the airbag into the battery, thereby increasing the battery injection speed. At the same time, it eliminates the need to increase the height of the aluminum-plastic film or the size of the airbag, thus reducing production costs.

[0034] The battery electrolyte injection device proposed in this invention involves placing the battery in a sealed cavity and evacuating the cavity to achieve the same vacuum level between the cavity, the airbag, and the battery interior. Electrolyte is then injected into the airbag, forming a barrier between the sealed cavity and the battery, effectively sealing the battery. Next, inert gas is injected into the sealed cavity to reduce the vacuum level. Due to the sealing effect of the electrolyte, the inert gas cannot enter the battery, maintaining a constant vacuum level and creating a pressure difference between the sealed cavity and the battery interior. The electrolyte in the airbag is then drawn into the battery under this pressure difference. By utilizing this pressure difference, the rate at which the electrolyte penetrates the battery is greatly accelerated. Furthermore, because the electrolyte is drawn into the battery by suction, it does not easily overflow. Therefore, there is no need to add extra height to the aluminum-plastic film or increase the size of the airbag, which helps reduce production costs. Attached Figure Description

[0035] Figure 1 This is a disassembly diagram of the battery electrolyte injection device provided in an embodiment of the present invention;

[0036] Figure 2This is a schematic diagram of the internal structure of the battery electrolyte injection device provided in an embodiment of the present invention;

[0037] Figure 3 This is a flowchart of the battery electrolyte injection method provided in the embodiments of the present invention.

[0038] In the picture:

[0039] 100. Battery; 110. Casing; 120. Battery cell; 200. Airbag; 300. Electrolyte;

[0040] 1. Sealed cavity; 11. Sealed cavity; 12. First cavity; 13. Second cavity;

[0041] 2. Injection nozzle;

[0042] 3. Vacuuming mechanism;

[0043] 4. Proportional valve;

[0044] 5. Fixed structure. Detailed Implementation

[0045] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0046] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0048] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0049] like Figure 1 and Figure 2 As shown, the battery 100 includes a casing 110 and a battery cell 120, with the battery cell 120 disposed within the casing 110. The casing 110 is generally made of aluminum-plastic film. The film is punched to create slots for placing the battery cell 120 and the airbag 200. After the battery cell 120 is placed inside, it is sealed. The side of the airbag 200 away from the battery cell 120 is left unsealed for injecting electrolyte 300. The airbag 200 is connected to the interior of the casing 110. When injecting electrolyte into the casing 110, the electrolyte 300 is first injected into the airbag 200, and then flows into the casing 110 through the airbag 200, wetting the battery cell 120.

[0050] To increase the electrolyte injection rate, such as Figure 1 and Figure 2 As shown, this embodiment provides a battery electrolyte injection device, including a sealed cavity 1, an injection mechanism, a vacuuming mechanism 3, and an inert gas supply mechanism. The sealed cavity 1 contains a sealed chamber 11, within which a battery 100 to be injected is housed. An airbag 200 is recessed on the upper side of the battery 100 and communicates with the interior of the battery 100. The injection mechanism, vacuuming mechanism 3, and inert gas supply mechanism are all mounted on the sealed cavity 1. The injection nozzle 2 of the injection mechanism can seal through the sealed cavity 1 to inject electrolyte 300 into the airbag 200. The vacuuming mechanism 3 is used to evacuate the sealed cavity 1, and the inert gas supply mechanism is used to introduce inert gas into the sealed cavity 1.

[0051] During electrolyte injection, the battery 100 is placed inside the sealed cavity 1, and the sealed cavity 1 is evacuated to achieve the same vacuum level as the sealed cavity 1, the airbag 200, and the battery 100. Then, electrolyte 300 is injected into the airbag 200, forming a barrier between the sealed cavity 1 and the housing 110, thus sealing the housing 110. Afterward, inert gas is injected into the sealed cavity 1 to reduce the vacuum level. Due to the sealing effect of the electrolyte 300, the inert gas cannot enter the housing 110, and the vacuum level inside the housing 110 remains unchanged. This creates a pressure difference between the sealed cavity 1 and the housing 110, causing the electrolyte 300 in the airbag 200 to be drawn into the housing 110 under the influence of this pressure difference. By utilizing the pressure difference, the speed at which the electrolyte 300 penetrates into the housing 110 is greatly accelerated. Moreover, because the electrolyte 300 is drawn into the housing 110 by suction, the electrolyte 300 will not easily overflow. Therefore, there is no need to add extra height to the aluminum-plastic film or increase the size of the airbag 200, which helps to reduce production costs.

[0052] Specifically, such as Figure 1 and Figure 2 As shown, the sealed cavity 1 includes a first cavity 12 and a second cavity 13. The second cavity 13 is used to install the battery 100. The first cavity 12 is fastened to the second cavity 13, and the first cavity 12 and the second cavity 13 are sealed together to form the aforementioned sealed cavity 11. The liquid injection mechanism, the vacuuming mechanism 3, and the inert gas supply mechanism are all disposed on the first cavity 12. The first cavity 12 and the second cavity 13 can be detachably connected by snap-fit ​​or screw connection.

[0053] In one embodiment, such as Figure 1 As shown, the second cavity 13 is flat to facilitate the installation of the battery 100. The lower end of the first cavity 12 is open. After the battery 100 is installed on the second cavity 13, the first cavity 12 is fastened onto the flat plate and then sealed. To improve the sealing performance, a sealing ring can be sandwiched between the first cavity 12 and the second cavity 13 to prevent gas leakage from affecting the vacuum level inside the sealed cavity 1. Of course, the structure of the first cavity 12 and the second cavity 13 is not limited to this. In other embodiments, other structural forms can be used to form a sealed space and facilitate the installation and removal of the battery 100.

[0054] Furthermore, to prevent the battery 100 from shifting within the sealed cavity 11, such as... Figure 1 As shown, the battery electrolyte injection device also includes a fixing mechanism 5, which is disposed on the second cavity 13 and is used to fix the battery 100 so that the battery 100 is positioned so that the air bag 200 and the injection nozzle 2 are aligned, preventing the electrolyte 300 from being sprayed into the sealed cavity 11 due to the displacement of the battery 100.

[0055] In one embodiment, the fixing mechanism 5 is configured as a fixing block with a limiting groove. The battery 100 is housed within the limiting groove, eliminating the need for additional fasteners to secure the battery 100. The fixing block can be integrally formed with the second cavity 13, facilitating processing and providing a more robust connection.

[0056] In other embodiments, the fixing mechanism 5 can also be configured as a clamp to hold and fix the battery 100. The clamping force of the clamp on the battery 100 should not be too large to prevent damage to the surface of the battery 100. Optionally, the clamping force of the clamp on the battery 100 can be set to zero, only to maintain the positioning of the battery 100. Of course, the fixing mechanism 5 can also be configured in other forms, as long as it can achieve the fixed and limited positioning of the battery 100, which is not limited here.

[0057] Furthermore, the injection mechanism includes an external injection machine, an injection tube, and an injection nozzle 2. The external injection machine is located outside the first cavity 12. One end of the injection tube is connected to the outlet of the external injection machine, and the other end is connected to the upper end of the injection nozzle 2. The lower end of the injection nozzle 2 is sealed and extends through the first cavity 12 into the airbag 200, thereby enabling the external injection machine to deliver electrolyte 300 into the airbag 200 through the injection tube and the injection nozzle 2. Optionally, a flow valve is provided on the injection tube to regulate the injection rate of the electrolyte 300.

[0058] Furthermore, the inert gas supply mechanism includes an inert gas storage device, a gas guide pipe, and a proportional valve 4. The proportional valve 4 is disposed on the gas guide pipe and is used to regulate the gas flow rate in the gas guide pipe. The inert gas storage device is disposed outside the first cavity 12. One end of the gas guide pipe is connected to the gas outlet of the inert gas storage device, and the other end of the gas guide pipe is sealed and extends through the first cavity 12 into the sealed cavity 11. The inert gas in the inert gas storage device is introduced into the sealed cavity 11 through the gas guide pipe.

[0059] Furthermore, the battery electrolyte injection device also includes a level sensor, which is used to detect the electrolyte level 300 inside the airbag 200. The level sensor can be an ultrasonic level sensor.

[0060] Optionally, a transparent window is provided on the first cavity 12 to facilitate direct observation of the electrolyte level 300 inside the airbag 200.

[0061] Furthermore, the battery electrolyte injection device also includes a vacuum gauge, which is used to detect the vacuum level inside the sealed cavity 1.

[0062] like Figure 3As shown, this embodiment also provides a battery electrolyte injection method, which uses the battery electrolyte injection device described above to inject electrolyte 300 into the battery 100. The battery electrolyte injection method includes the following steps:

[0063] S1: Place the battery 100 to be injected into the sealed cavity 1, and keep the airbag 200, battery 100 and sealed cavity 1 in communication.

[0064] S2: Evacuate the sealed cavity 1 until the vacuum level inside the sealed cavity 1 reaches K1 and then stop;

[0065] S3: Inject electrolyte 300 into the airbag 200 to seal the battery 100;

[0066] S4: Inject inert gas into the sealed cavity 1 to make the vacuum degree inside the sealed cavity 1 reach K2, and a pressure difference K0 is generated between the sealed cavity 1 and the inside of the battery 100. Under the action of the pressure difference K0, the electrolyte 300 in the airbag 200 is drawn into the battery 100.

[0067] The ratio of the electrolyte level 300 inside the airbag 200 to the height of the airbag 200 is h1. It can be understood that the difference between K1 and K2, K0, is positively correlated with h1. When h1 is large, K0 can be increased to further improve the injection speed; when h1 is small, the difference in K0 must be decreased to reduce the injection speed. Therefore, K2 needs to be adjusted according to the size of h1 to regulate the pressure difference K0 between the sealed cavity 1 and the shell 110, ensuring that the electrolyte 300 inside the airbag 200 maintains a liquid seal on the shell 110. The adjustment of K2 is achieved by controlling the amount of inert gas introduced.

[0068] After the battery 100 is placed in the sealed cavity 1, the sealed cavity 1 and the battery 100 are first evacuated. Then, the electrolyte 300 is injected into the airbag 200. The electrolyte 300 accumulates in the airbag 200, and the liquid seal separates the inside of the battery 100 from the sealed cavity 1, forming two independent spaces. Initially, the pressure inside the battery 100 and the sealed cavity 1 are the same. In step S4, after the inert gas is injected into the sealed cavity 1, the vacuum degree inside the sealed cavity 1 will decrease. Due to the sealing effect of the electrolyte 300, the vacuum degree in the space where the battery cell 120 is located will not decrease. As a result, a certain pressure difference K0 is generated between the upper and lower surfaces of the electrolyte 300 in the airbag 200. The pressure difference K0 is used to accelerate the penetration of the electrolyte 300 into the battery 100.

[0069] To achieve the liquid sealing effect of the electrolyte 300, the ratio h1 between the liquid level of the electrolyte 300 inside the airbag 200 and the height of the airbag 200 is set to be no less than 0.2. If h1 is too small, it indicates that the liquid level of the electrolyte 300 inside the airbag 200 is too low, which can easily cause the electrolyte 300 to lose its liquid sealing effect. The sealed cavity 1 will then be connected to the inside of the battery 100, losing the pressure difference. The electrolyte 300 inside the airbag 200 can only seep into the battery 100 under the action of gravity, and the seepage rate will be significantly slowed down.

[0070] Preferably, h1 is equal to 0.45-0.55. Within this range, the electrolyte 300 can achieve good isolation, ensuring a certain pressure difference K0 between the inside of the battery 100 and the sealed cavity 11, and ensuring that the electrolyte 300 enters the inside of the battery 100 at a relatively fast speed.

[0071] Optionally, K0 is equal to 20 kPa-55 kPa. K0 should not be too large. When K0 is too large, the electrolyte 300 enters the battery 100 too quickly, and the electrolyte 300 in the airbag 200 is prone to forming vortices, losing its sealing effect. The pressure inside the sealed cavity 1 and the cell 120 quickly returns to the same state, and the electrolyte 300 can only enter the cell 120 by gravity, thus prolonging the entire electrolyte injection process.

[0072] Furthermore, the time for injecting inert gas into the sealed cavity 1 is set to T1, and the time for the battery 100 to complete the liquid injection is set to T0, with T1 / T0 equal to 0.3-0.6. Similarly, the smaller the ratio, the faster the vacuum level drops, which can easily cause the electrolyte 300 to enter the battery 100 too quickly, resulting in the electrolyte 300 losing its liquid sealing function.

[0073] Optionally, the injection rate of the inert gas can be controlled to make the vacuum level K1 change uniformly to the vacuum level K2.

[0074] In one embodiment, inert gas can be repeatedly injected into the sealed cavity 1 to adjust the vacuum level K2 within the sealed cavity 1. That is, K2 exhibits a changing trend, successively dividing into K... 20 K 21 ...K 2n And K 2n >K 2n-1 This causes the vacuum level inside the sealed cavity 1 to decrease gradually.

[0075] Furthermore, the battery electrolyte injection method also includes step S5: after the injection is completed, the electrolyte 300 inside the airbag bag 200 is recovered.

[0076] Specifically, after the electrolyte injection is completed, the ratio of the electrolyte level 300 inside the airbag 200 to the height of the airbag 200 is h2, and h2 is set to ≥ 0.2. In a specific embodiment, to avoid waste, h2 satisfies 0.2 ≤ h2 ≤ 0.3.

[0077] In one embodiment, during step S4, the rapid permeation of electrolyte 300 is performed while adjusting the vacuum level of the sealed cavity 1, which further saves permeation time. Furthermore, the liquid level of electrolyte 300 within the airbag 200 can be effectively controlled, eliminating the need for heightening the aluminum-plastic film and airbag 200, effectively saving the amount of airbag 200 and aluminum-plastic film used and reducing production costs.

[0078] Example 1

[0079] This embodiment provides an injection method as described above:

[0080] S1: Place the battery 100 to be injected into the sealed cavity 1;

[0081] S2: Evacuate the sealed cavity 1 until the vacuum level inside the sealed cavity 1 reaches K1 = -85 kPa and then stop;

[0082] S3: Inject electrolyte 300 into the airbag 200 until the ratio of the height of electrolyte 300 to the height of the airbag 200 is h1 = 0.5;

[0083] S4: Inject inert gas into the sealed cavity 1 to make the vacuum degree inside the sealed cavity 1 reach -50kpa. The time for the vacuum degree to change from K1 to K2 is T1=10s. A pressure difference K0=30kpa is generated between the sealed cavity 1 and the inside of the battery 100. The electrolyte 300 in the airbag 200 is drawn into the battery 100 under the action of the pressure difference.

[0084] The mass of the electrolyte 300 injected into the airbag 200 is 300g.

[0085] Example 2

[0086] This embodiment is basically the same as the scheme in Embodiment 1, the difference being that h1 = 0.35;

[0087] Example 3

[0088] This embodiment is basically the same as the scheme in Embodiment 1, the difference being that K0 = 45 kPa;

[0089] Example 4

[0090] This embodiment is basically the same as the scheme of Embodiment 1, the difference in technical features is: T1 = 15s;

[0091] Example 5

[0092] This embodiment is basically the same as the scheme of Embodiment 1, the difference being that: the amount of electrolyte injected into the battery 100 is 400g, and the process of the vacuum degree changing from K1 to K2 is as follows: from K1 to K 20 Then to K 21。 From K1 to K 20 The time is 6 seconds, from K 20 Then to K 21 The time is 4 seconds, where K1 = -85 kPa, K 20 = -65 kPa, K 21 = -50kPa

[0093] Comparative Example 1

[0094] The technical feature that distinguishes Comparative Example 1 from Example 1 is that K0 = 65 kPa;

[0095] Comparative Example 2

[0096] The technical feature that distinguishes Comparative Example 2 from Example 1 is that T1 = 5s;

[0097] Comparative Example 3

[0098] The technical feature that distinguishes Comparative Example 3 from Example 1 is that h1 = 0.1;

[0099] Comparative Example 4

[0100] In Comparative Example 4, during the electrolyte injection process of battery 100, the electrolyte 300 is injected using its own gravity, which increases the height and width of the casing 110 and the airbag 200, increasing the volume of the airbag 200 by 20%-40%. The electrolyte injection rate of Comparative Example 4 into the airbag 200 is the same as that in Example 1.

[0101] The table below shows the relevant conditions and injection times for Examples 1-5 and Comparative Examples 1-4.

[0102]

[0103] From Examples 1 to 5, the electrolyte injection method of this application can be used to quickly inject the electrolyte 300, shorten the injection time, and eliminate the need for modifications to the housing 110.

[0104] Compared with Example 1, if the difference between K1 and K2 is too large, the large pressure difference will force the electrolyte 300 to enter the battery 100 quickly. The electrolyte 300 in the airbag 200 cannot isolate the battery 100 from the sealed cavity 1. On the other hand, if the electrolyte 300 enters the battery 100 too quickly, it is easy to cause impact on the electrode sheets, etc., and it is easy to generate bubbles, which is not conducive to the subsequent wetting of the cell 120 by the electrolyte 300, thereby causing the performance of the cell 120 to deteriorate.

[0105] Compared with Example 1 and Comparative Example 2, the rapid decrease in vacuum will cause the electrolyte 300 inside the airbag 200 to form a vortex, affecting the liquid injection process.

[0106] Compared with Example 1 and Comparative Example 3, when the ratio h1 of the height of the electrolyte 300 in the airbag 200 to the height of the airbag 200 is too small, the electrolyte 300 in the airbag 200 cannot isolate the vacuum between the battery 100 and the sealed cavity 1. After the electrolyte 300 in the airbag 200 is quickly pressed into the battery 100, the vacuum between the battery 100 and the sealed cavity 1 remains consistent. In the latter half of the liquid injection process, the electrolyte 300 enters the battery 100 by its own gravity.

[0107] In Comparative Example 4, the shell 110 and the airbag 200 were heightened and widened, increasing the volume of the airbag 200 by 20%-40%. In Comparative Example 1, the electrolyte 300 inside the airbag 200 entered the battery cell 120 by gravity, increasing the cost of the aluminum-plastic film of the entire battery cell 120 by 15%-20%. However, the total injection time T0 in Comparative Example 4 was still as high as 50 seconds, while in Example 1, the total injection time T0 was only 25 seconds, saving about half the injection time.

[0108] The battery electrolyte injection method and device proposed in this embodiment greatly improve the injection speed and reduce production costs.

[0109] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for injecting battery electrolyte, characterized in that, include: The battery (100) to be injected with liquid is placed in the sealed cavity (1), and the airbag (200) for injecting liquid into the battery (100), the battery (100) and the sealed cavity (1) are kept in communication. The sealed cavity (1) is evacuated until the vacuum level inside the sealed cavity (1) reaches K1 and then the evacuation stops. Electrolyte (300) is injected into the airbag (200) to seal the battery (100). Inert gas is injected into the sealed cavity (1) to make the vacuum degree inside the sealed cavity (1) reach K2, and a pressure difference K0 is generated between the sealed cavity (1) and the inside of the battery (100). The electrolyte (300) in the airbag (200) is drawn into the battery (100) under the action of the pressure difference K0. The ratio of the height of the electrolyte (300) inside the airbag (200) to the height of the airbag (200) is h1. K2 is adjusted according to the size of h1 to keep the electrolyte (300) inside the airbag (200) sealed to the battery (100); h1 is not less than 0.

35. After the liquid injection is completed, the ratio of the liquid level of the electrolyte (300) in the airbag (200) to the height of the airbag (200) is h2, and h2 is set to be greater than or equal to 0.

2.

2. The battery electrolyte injection method according to claim 1, characterized in that, h1 equals 0.45-0.

55.

3. The battery electrolyte injection method according to claim 1, characterized in that, K0 equals 20 kPa - 55 kPa.

4. The battery electrolyte injection method according to any one of claims 1-3, characterized in that, The time for injecting the inert gas into the sealed cavity (1) is set as T1, and the time for the battery (100) to complete the liquid injection is set as T0, where T1 / T0 equals 0.3-0.

6.

5. The battery electrolyte injection method according to any one of claims 1-3, characterized in that, The injection rate of the inert gas is controlled so that the vacuum level K1 changes uniformly to the vacuum level K2.

6. The battery electrolyte injection method according to any one of claims 1-3, characterized in that, The inert gas is repeatedly injected into the sealed cavity (1) to adjust the vacuum degree K2 in the sealed cavity (1).

7. A battery electrolyte injection device, characterized in that, The battery electrolyte injection device, applicable to the battery electrolyte injection method as described in any one of claims 1-6, comprises: A sealed cavity (1) is provided inside the sealed cavity (11), and the battery (100) to be injected with liquid is contained in the sealed cavity (11). An airbag (200) is recessed on the upper side of the battery (100), and the airbag (200) is connected to the inside of the battery (100). The liquid injection mechanism is provided on the sealed cavity (1), and the liquid injection nozzle (2) of the liquid injection mechanism can seal through the sealed cavity (1) to inject electrolyte (300) into the airbag (200). A vacuum pumping mechanism (3) is disposed on the sealed cavity (1), and the vacuum pumping mechanism (3) is configured to evacuate the sealed cavity (1); An inert gas supply mechanism is provided on the sealed cavity (1), and the inert gas supply mechanism is configured to introduce inert gas into the sealed cavity (1).

8. The battery electrolyte injection device according to claim 7, characterized in that, The battery electrolyte injection device further includes: A liquid level sensor is used to detect the liquid level of the electrolyte (300) inside the airbag (200).

9. The battery electrolyte injection device according to claim 7, characterized in that, The battery electrolyte injection device further includes: A vacuum gauge is used to detect the vacuum level inside the sealed cavity (1).

10. The battery electrolyte injection device according to claim 7, characterized in that, The sealed cavity (1) includes a first cavity (12) and a second cavity (13). The second cavity (13) is used to install the battery (100). The first cavity (12) is fastened to the second cavity (13) and sealed to the second cavity (13). The liquid injection mechanism, the vacuum mechanism (3) and the inert gas supply mechanism are all disposed on the first cavity (12).

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