Multi-point injection device and method for soft-pack battery

Abstract

The present invention relates to a multi-point injection device and method for a soft-pack battery. It solves the defects of the prior art such as unreasonable design. The multi-point injection device for a soft-pack battery includes a fixed injection needle and a movable injection needle; the movable injection needle and the fixed injection needle are arranged side by side; the movable injection needle is inserted into the soft-pack injection port at the farthest point relative to the fixed injection needle and stops at the farthest point for injection; and after the movable injection needle stops at the fixed point for injection, the movable injection needle moves at a uniform speed relative to the fixed injection needle and continues to inject; the structure of the fixed injection needle is the same as that of the movable injection needle, including a cylindrical body with a closed lower end, and an injection hole inclined from top to bottom and outward is provided on the side wall of the cylindrical body, and the injection hole allows the injection liquid flowing out from the lower end of the injection hole to flow downward along the inner wall of the soft-pack injection port. Advantages of this application: shortening the immersion time cycle and preventing injection splashing.

Description

Technical Field

[0001] The present invention belongs to the technical field of soft-pack battery processing, and in particular relates to a multi-point liquid injection device and method for soft-pack batteries. Background Art

[0002] The existing soft pack lithium battery filling generally adopts the following method: Figure 1 The method is to use an injection needle. After the battery is injected, it is left to stand in a vacuum state and then sealed in a vacuum state. The next step is to leave it to stand at a high temperature for about 24 hours before entering the formation process.

[0003] The purpose of high-temperature standing is mainly to increase the activity of the electrolyte through high temperature, and then through capillary action, the electrolyte fully infiltrates the electrode. Since there is only one injection needle, the electrolyte penetrates from the middle part to area a, then disperses to both sides, and then penetrates to the blank area b, blank area c and the entire battery cell through vacuum and capillary action to infiltrate the electrode. When the length of the battery cell exceeds a certain length and width (above 150mm), under the same standing time, the battery cell with shorter length and width has a longer infiltration period than the longer battery cell, which affects production capacity.

[0004] For example, CN214336875U discloses a liquid injection mechanism for a soft-pack power battery, comprising: a liquid injection assembly, wherein the liquid injection assembly comprises a plurality of liquid injection cups, wherein the liquid injection cups are used to store electrolyte, and an injection needle is connected to the outlet end of each of the liquid injection cups. The plurality of liquid injection needles in the liquid injection assembly are arranged at intervals, and the plurality of liquid injection needles are configured to be able to communicate with the inner cavity of a soft-pack power battery to be injected, so as to inject the electrolyte into the soft-pack power battery.

[0005] The above scheme uses multiple injection needles to inject liquid into the same soft bag, which can improve the injection efficiency and shorten the subsequent infiltration time. Although this scheme has the above advantages, the above scheme has the following defects: the multiple injection needles that inject liquid into the same soft bag have a fixed distance between each other, and the infiltration of the local area is still from bottom to top and the injection is dispersed horizontally. The infiltration efficiency and the consistency of the infiltration quality need to be further improved.

[0006] Secondly, in the existing liquid injection method, when the liquid injection needle is injected into the soft package, the liquid is injected perpendicularly to the upper side of the electrode. This method of liquid injection will cause splashing, which not only affects the total amount of liquid injected in the final soft package, but also pollutes the work station, which is an unreasonable design. Summary of the invention

[0007] The purpose of the present invention is to provide a multi-point liquid injection device and method for soft-pack batteries that can solve the above technical problems.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] The multi-point injection device for soft-pack batteries includes a fixed injection needle;

[0010] A movable injection needle, the movable injection needle and the fixed injection needle are arranged side by side; the movable injection needle is inserted into the soft bag injection port at the farthest point relative to the fixed injection needle and stops at the farthest point to inject liquid; and after the movable injection needle stops at the fixed point to inject liquid, the movable injection needle moves at a uniform speed relative to the fixed injection needle and continues to inject liquid;

[0011] The structure of the fixed injection needle is the same as that of the movable injection needle, including a cylindrical body with a closed lower end, and an injection hole inclined from top to bottom and outward is provided on the side wall of the cylindrical body. The injection hole allows the injection liquid flowing out from the lower end of the injection hole to flow downward along the inner wall of the soft bag injection port.

[0012] In the above-mentioned multi-point liquid injection device for soft-pack batteries, the side wall of the cylindrical body is provided with two liquid injection holes which are symmetrically distributed with respect to the axis of the cylindrical body.

[0013] In the above-mentioned multi-point injection device for soft-pack batteries, the interior of the cylindrical body has a large inner diameter channel and a small inner diameter channel that pass through in sequence from top to bottom, and the upper ends of the injection holes are respectively connected to the small inner diameter channels.

[0014] In the above-mentioned multi-point injection device for soft-pack batteries, the number of the movable injection needles is two, and the fixed injection needle is located at a central position between the two movable injection needles.

[0015] In the above-mentioned multi-point injection device for soft-pack batteries, the total injection amount of each of the movable injection needles is greater than the total injection amount of the fixed injection needles.

[0016] In the above-mentioned multi-point injection device for soft-pack batteries, the total amount of injection of the movable injection needle when it stays at the fixed point at the farthest point is equal to the total amount of injection of the fixed injection needle, and the total amount of injection of the movable injection needle when it moves at a uniform speed relative to the fixed injection needle is equal to the total amount of injection of the fixed injection needle.

[0017] In the above-mentioned multi-point injection device for soft-pack batteries, the two movable injection needles move synchronously toward each other with the fixed injection needle as the center; or the two movable injection needles move asynchronously toward each other with the fixed injection needle as the center.

[0018] In the above-mentioned multi-point injection device for soft-pack batteries, the fixed injection needle and the movable injection needle are connected to the lifting drive assembly.

[0019] The present application also provides a multi-point liquid injection method for a soft-pack battery, using the multi-point liquid injection device for a soft-pack battery, the multi-point liquid injection method for a soft-pack battery comprises the following steps:

[0020] S1. Before inserting the soft bag injection port, set the total movement stroke of the movable injection needle relative to the fixed injection needle, and the movable injection needle is at the farthest point of the total stroke away from the fixed injection needle;

[0021] S2, inserting the fixed injection needle and the movable injection needle in S1 into the soft bag injection port from top to bottom;

[0022] S3, the fixed injection needle in S2 injects liquid; the movable injection needle in S2 stops at a fixed point farthest from the fixed injection needle in the total stroke to inject liquid, and after the movable injection needle stops at a fixed point to inject liquid, it approaches the fixed injection needle at a uniform speed and continues to inject liquid when the movable injection needle moves at a uniform speed.

[0023] In the above-mentioned multi-point liquid injection method for soft-pack batteries, the structure of the fixed liquid injection needle is the same as that of the movable liquid injection needle, including a cylindrical body with a closed lower end, and a liquid injection hole inclined from top to bottom and outward is provided on the side wall of the cylindrical body, and the lower end opening of the liquid injection hole is close to the inner wall of the soft-pack injection port so that the injection liquid flowing out from the lower end of the liquid injection hole flows downward along the inner wall of the soft-pack injection port.

[0024] Compared with the existing technology, the advantages of this application are:

[0025] The combination of fixed-point and mobile injection can greatly shorten the injection time and the subsequent wetting time. That is, the electrolyte has initially infiltrated the entire battery cell during injection. After injection, the electrolyte diffuses and penetrates the blank area through vacuum and capillary action at the same time, shortening the wetting distance and wetting area for each action point, thereby shortening the shelf time of the infiltrated electrode and ensuring the electrode wetting effect.

[0026] By utilizing the injection hole structure of the injection needle to inject liquid at an angle, the splashing phenomenon of injection can be perfectly solved, so that the total amount of injection can be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the existing liquid injection structure.

[0028] Figure 2 It is a schematic structural diagram of a multi-point liquid injection device for a soft-pack battery provided by the present invention.

[0029] Figure 3 The multi-point liquid injection device for soft-pack batteries provided by the present invention has a multi-point moving structure schematic diagram.

[0030] Figure 4It is a three-dimensional schematic diagram of the state in which the injection needle of the multi-point injection device for soft-pack batteries provided by the present invention is inserted into the injection port of the soft-pack battery.

[0031] Figure 5 It is a schematic diagram of a state in which a liquid injection needle of the multi-point liquid injection device for a soft-pack battery provided by the present invention is inserted into a soft-pack injection port.

[0032] Figure 6 yes Figure 5 Schematic diagram of the movable injection needle after movement.

[0033] Figure 7 It is a schematic diagram of the state of the multi-point liquid injection device for soft-pack batteries provided by the present invention after liquid is injected into three areas a, b and c.

[0034] Figure 8 It is a schematic diagram of the state of the multi-point liquid injection device for soft-pack batteries provided by the present invention after liquid is injected into areas d and e.

[0035] Fig. 9 The figure is a schematic diagram of the cross-sectional structure of the injection needle provided by the present invention.

[0036] Fig.10 The figure is a schematic diagram of the cross-sectional structure of the injection needle provided by the present invention.

[0037] Fig.11 It is a block diagram of the control system provided by the present invention.

[0038] In the figure, there are a fixed injection needle 1, a cylindrical body 10, an injection hole 11, a large inner diameter channel 12, a small inner diameter channel 13, a movable injection needle 2, a soft bag C, and a soft bag injection port C0. DETAILED DESCRIPTION

[0039] The following are specific embodiments of the invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0040] Embodiment 1

[0041] like Figure 2 and Figure 3 As shown, the multi-point injection device for soft-pack batteries includes a fixed injection needle 1 and a movable injection needle 2. The number of the movable injection needles 2 is 1-3. Figure 3-Figure 6 As shown, the preferred solution is two. When there are two movable injection needles 2, the fixed injection needle 1 is located in the middle of the two movable injection needles 2 which are parallel to each other.

[0042] The movable injection needle 2 is in translation, and at this time the movable injection needle 2 is in a vertical state perpendicular to the translation plane. The movable injection needle 2 can be driven by any one of a screw motor, a cylinder, an oil cylinder and a linear motor.

[0043] Secondly, the total amount of liquid injected by each movable injection needle 2 in this embodiment is greater than the total amount of liquid injected by the fixed injection needle 1. For example, taking three injection needles as an example, the present application has three injection points a, b, and c, and the total amount of liquid injected by the movable injection needle 2 at the farthest point is equal to the total amount of liquid injected by the fixed injection needle 1, and the total amount of liquid injected by the movable injection needle 2 moving at a uniform speed relative to the fixed injection needle 1 is equal to the total amount of liquid injected by the fixed injection needle 1.

[0044] In this way, the electrolyte has initially infiltrated the entire battery cell during injection. After injection, the electrolyte diffuses and penetrates the blank area through vacuum and capillary action at the same time, shortening the infiltration distance and infiltration area for each action point, thereby shortening the shelf time of the infiltrated electrode and ensuring the infiltration effect of the electrode. The blue area in the figure represents the infiltration area during electrolyte injection.

[0045] In a preferred embodiment, the two movable injection needles 2 of this embodiment move synchronously toward each other with the fixed injection needle 1 as the center. The synchronous movement toward each other can further shorten the injection time and the subsequent infiltration time.

[0046] In order to achieve liquid injection, the fixed liquid injection needle 1 and the movable liquid injection needle 2 of this embodiment are connected to a lifting drive assembly. The lifting drive assembly includes any one of an air cylinder and an oil cylinder, or a lifting drive motor group.

[0047] like Figure 4-Figure 6 As shown, the lifting drive assembly drives the fixed injection needle 1 and the movable injection needle 2 to perform lifting movements in the vertical direction to insert into and detach from the soft bag injection port C0.

[0048] In the preferred embodiment, the soft package C with the soft package injection port C0 is positioned in the lower mold, and an upper mold is arranged above the lower mold, and the fixed injection needle 1 and the movable injection needle 2 are located in the inner chamber of the upper mold. The upper mold is driven by the lifting drive assembly to make the upper mold descend and form a closed cavity with the lower mold. Of course, the drive of the upper mold can also be controlled by another mold lifting drive. The mold lifting drive can also be driven by a cylinder, an oil cylinder, etc.

[0049] The closure of the lower mold and the upper mold forms a closed cavity, which can provide a relatively safe environment during liquid injection. At the same time, it can also prevent external pollutants from entering the soft package along the injection needle during liquid injection, thereby improving product quality.

[0050] Specifically, the multi-point liquid injection method for soft-pack batteries of this embodiment includes the following steps:

[0051] S1. Before inserting the soft pack injection port C0, set the total movement stroke of the movable injection needle 2 relative to the fixed injection needle 1, and the movable injection needle 2 is at the farthest point of the total stroke away from the fixed injection needle 1;

[0052] From the overall diffusion effect of the electrolyte, Figure 7-Figure 8 As shown, the entire battery has five areas a, b, c, d, and e. The fixed injection needle 1 does not move in area a, and the electrolyte distributed is 1 / 5 of the total injection volume M of the process design. The movable injection needle 2-the electrolyte distributed in areas b and c is 2 / 5 of the total injection volume each.

[0053] S2, inserting the fixed injection needle 1 and the movable injection needle 2 in S1 into the soft bag injection port C0 from top to bottom;

[0054] S3, the fixed injection needle 1 in S2 injects liquid; the movable injection needle 2 in S2 stops at the farthest point in the total stroke away from the fixed injection needle 1 to inject liquid, and the movable injection needle 2 approaches the fixed injection needle 1 at a uniform speed after stopping at the fixed point to inject liquid and continues to inject liquid when the movable injection needle 2 moves at a uniform speed.

[0055] When the two movable injection needles 2 are injecting liquid, they are moved toward the middle a zone through the mobile driving device. Taking one of the movable injection needles 2 as an example, assuming that the distance from the movable injection needle 2 to the fixed injection needle 1 is D1 (the distance from the other movable injection needle 2 to the fixed injection needle 1 is D2=D1), the moving speed from needle b to needle a is V1 (the speed from needle c to needle a is V2=V1), and the time from the movable injection needle 2 to the fixed injection needle 1 is T1=D1 / V1. The electrolyte density is ρ, and the volume of the injection amount required for process design is L=M / ρ, and the injection flow rate from the movable injection needle 2 to the fixed injection needle 1 is Q1=L*2 / 5÷T1. This constitutes an intelligent control system for injection, which inputs the total injection volume M1, the distance D1 from the movable injection needle 2 to the fixed injection needle 1, the moving speed V1 from the movable injection needle 2 to the fixed injection needle 1 and the density ρ of the electrolyte. The speed of the injection pump is automatically controlled to adjust the injection flow rate so that the electrolyte evenly covers the area from b to a.

[0056] As can be seen from the injection process, this embodiment first injects liquid into area a, area b and / or area c at fixed points, and when the total amount of fixed-point injection reaches the set injection amount, the movable injection needle 2 at this time starts mobile injection, that is, the movable injection needle 2 injects liquid into the inverted triangular blank area (area d) between area a and area b, and of course, area e can also be injected, and area d and area e can be injected at the same time. The above method can greatly improve the injection efficiency. On the premise of ensuring the infiltration quality, it can also greatly shorten the subsequent infiltration time period, thereby greatly reducing the production cost.

[0057] Embodiment 2

[0058] The structure and working principle of this embodiment are basically the same as those of the first embodiment, and the difference lies in that the two movable injection needles 2 move toward each other asynchronously with the fixed injection needle 1 as the center.

[0059] Embodiment 3

[0060] like Figure 9-11 As shown, based on Example 1 or Example 2, this embodiment further provides a specific injection needle structure. For example, the structure of the fixed injection needle 1 of this embodiment is the same as the structure of the movable injection needle 2, including a cylindrical body 10 with a closed lower end, the upper end of the cylindrical body 10 is connected to the injection pipeline, and a flow control detection, such as a flow detection sensor, and an injection pump are installed on the injection pipeline. The flow detection sensor and the injection pump are connected to the control processor via wired or wireless communication methods, respectively, to achieve the purpose of real-time detection of the injection flow and dynamic adjustment.

[0061] After the flow detection sensor detects the flow rate, it feeds back to the control processor, such as a PLC controller. At this time, the control processor controls the power of the injection pump to achieve the set liquid supply volume.

[0062] like Fig.10 As shown, a liquid injection hole 11 inclined from top to bottom and outward is provided on the side wall of the cylindrical body 10, and the axis of the liquid injection hole 11 forms an angle of 30° with the inner wall of the soft bag injection port C0. The liquid injection hole 11 allows the injection liquid flowing out from the lower end of the liquid injection hole 11 to flow downward along the inner wall of the soft bag injection port C0.

[0063] The present embodiment designs an inclined injection hole 11, which allows the injection liquid to adhere to the inner wall of the soft bag injection port C0 and flow downward along the inner wall of the soft bag injection port C0. In this process, splashing of the injection liquid can be prevented to improve the injection efficiency.

[0064] Of course, as a preferred solution, the side wall of the cylindrical body 10 of this embodiment is provided with two injection holes 11 which are symmetrically distributed with respect to the axis of the cylindrical body 10. The axis of the two injection holes 11 is at an acute angle so that the injection liquid flows downward along the wall.

[0065] The inner part of the cylindrical body 10 has a large inner diameter channel 12 and a small inner diameter channel 13 which are sequentially connected from top to bottom, and the upper end of the injection hole 11 is respectively connected to the small inner diameter channel 13. The small inner diameter channel 13 forms pressure compression for injection, thereby improving injection speed and efficiency.

[0066] The injection needle adopts anti-splash and overflow design: 1. The injection direction adopts a 30° angle design, the electrolyte flows into the battery cell along the inner wall of the battery shell, and both the front and back sides of the battery cell are wetted from top to bottom, which improves the wetting effect.

[0067] Using two or more injection needles to inject liquid at the same time can greatly increase the injection speed and shorten the injection time. This also increases the diffusion points of the electrolyte. The injection needle can be moved so that the electrode is initially wetted during injection, shortening the time for the electrolyte to wet the electrode.

[0068] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A multi-point injection device for a soft-pack battery, comprising a fixed injection needle (1), characterized in that: The multi-point liquid injection device for soft-pack batteries also includes: A movable injection needle (2), the movable injection needle (2) and the fixed injection needle (1) being arranged side by side; the movable injection needle (2) is inserted into the soft bag injection port (C0) at the farthest point relative to the fixed injection needle (1) and stops at the farthest point to inject liquid; and after the movable injection needle (2) stops at the fixed point to inject liquid, the movable injection needle (2) moves at a uniform speed relative to the fixed injection needle (1) and continues to inject liquid; The structure of the fixed injection needle (1) is the same as that of the movable injection needle (2), comprising a cylindrical body (10) with a closed lower end, a liquid injection hole (11) inclined downward and outward from top to bottom is provided on the side wall of the cylindrical body (10), and the liquid injection hole (11) allows the injection liquid flowing out from the lower end of the liquid injection hole (11) to flow downward along the inner wall of the soft bag injection port (C0); The total amount of liquid injected by each of the movable injection needles (2) is greater than the total amount of liquid injected by the fixed injection needle (1); the total amount of liquid injected by the movable injection needle (2) when it stops at the farthest point is equal to the total amount of liquid injected by the fixed injection needle (1); and the total amount of liquid injected by the movable injection needle (2) moving at a uniform speed relative to the fixed injection needle (1) is equal to the total amount of liquid injected by the fixed injection needle (1).

2. The multi-point liquid injection device for soft-pack batteries according to claim 1, characterized in that: The side wall of the cylindrical body (10) is provided with two injection holes (11) which are symmetrically distributed with respect to the axis of the cylindrical body (10).

3. The multi-point liquid injection device for soft-pack batteries according to claim 2, characterized in that: The interior of the cylindrical body (10) comprises a large inner diameter channel (12) and a small inner diameter channel (13) which are sequentially connected from top to bottom, and the upper ends of the injection holes (11) are respectively connected to the small inner diameter channels (13).

4. The multi-point liquid injection device for soft-pack batteries according to claim 1, characterized in that: The number of the movable injection needles (2) is two, and the fixed injection needle (1) is located at a central position between the two movable injection needles (2).

5. The multi-point liquid injection device for soft-pack batteries according to claim 4, characterized in that: The two movable injection needles (2) move synchronously towards each other with the fixed injection needle (1) as the center; or the two movable injection needles (2) move asynchronously towards each other with the fixed injection needle (1) as the center.

6. The multi-point liquid injection device for soft-pack batteries according to any one of claims 1 to 5, characterized in that: The fixed injection needle (1) and the movable injection needle (2) are connected to a lifting drive assembly.

7. A multi-point injection method for a soft-pack battery, characterized in that: The multi-point liquid injection method for a soft-pack battery adopts the multi-point liquid injection device for a soft-pack battery according to any one of claims 1 to 6, and the multi-point liquid injection method for a soft-pack battery comprises the following steps: S1. Before inserting the soft bag injection port (C0), the total movement stroke of the movable injection needle (2) relative to the fixed injection needle (1) is set, and the movable injection needle (2) is at the farthest point in the total stroke away from the fixed injection needle (1); S2, inserting the fixed injection needle (1) and the movable injection needle (2) in S1 from top to bottom into the soft bag injection port (C0); S3, the fixed injection needle (1) in S2 injects liquid; the movable injection needle (2) in S2 stops at a fixed point at the farthest point in the total stroke away from the fixed injection needle (1) to inject liquid, and after the movable injection needle (2) stops at a fixed point to inject liquid, it approaches the fixed injection needle (1) at a uniform speed and continues to inject liquid when the movable injection needle (2) moves at a uniform speed.

8. The multi-point liquid injection method for soft-pack batteries according to claim 7, characterized in that: The structure of the fixed injection needle (1) is the same as that of the movable injection needle (2), comprising a cylindrical body (10) with a closed lower end, a liquid injection hole (11) inclined outward from top to bottom is provided on the side wall of the cylindrical body (10), and the lower end opening of the liquid injection hole (11) is close to the inner wall of the soft bag injection port (C0) so that the injection liquid flowing out from the lower end of the liquid injection hole (11) flows downward along the inner wall of the soft bag injection port (C0).

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