Secondary battery sealing device

Abstract

The present invention relates to a sealing device for a secondary battery, and more particularly to a sealing device for a secondary battery that seals a secondary battery including a pouch-type battery case. The present invention provides a sealing device for a secondary battery, comprising a pair of sealing portions arranged facing each other with a battery case having an electrode assembly built therein therebetween, the distance between which is adjustable, and at least one detection portion provided between the pair of sealing portions for detecting a change in pressure due to a change in the gap between the pair of sealing portions.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0015838 filed on February 7, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a sealing device for a secondary battery, and more particularly to a sealing device for a secondary battery that seals a secondary battery including a pouch-type battery case. [Background technology]

[0003] As technological development and demand for mobile devices increases, the demand for secondary batteries as energy sources is rapidly increasing. Among such secondary batteries, much research has been conducted on lithium secondary batteries, which have high energy density and discharge voltage, and they have also been commercialized and widely used.

[0004] In general, a lithium secondary battery is constructed by stacking or rolling up an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, and then incorporating the stacked or rolled electrode into a battery case made of a metal can or a laminate sheet, and then injecting or impregnating the electrolyte into the battery case.

[0005] In recent years, as secondary batteries have become more highly capacitive, there has been much interest in making cases larger and processing them into thinner materials. As a result, pouch-type secondary batteries, which have a structure in which a stack-type or stack / folding-type electrode assembly is built into a pouch-type battery case made of a laminate sheet, are gradually becoming more popular due to their low manufacturing costs, small weight, and easy shape modification.

[0006] Meanwhile, the battery case (S) of such a pouch-type secondary battery has a sealed structure by being sealed with a sealing device to prevent the electrode assembly and electrolyte inside the battery case (S) from leaking out and being damaged.

[0007] 1a and 1b show how a conventional sealing device 1 seals a battery case (S). As shown in Fig. 1a and 1b, a pair of conventional sealing devices 1 are generally provided, and are disposed above and below the secondary battery (S), respectively, and then a certain temperature and pressure are applied to seal the battery case (S).

[0008] Specifically, the conventional sealing device 1 may have a structure including a sealing block 2 that is arranged to move up and down toward the secondary battery (S) and pressurizes the secondary battery (S), and a protrusion 3 formed by protruding from one surface of the sealing block 2 at a predetermined height.

[0009] In particular, since the protrusions 3 of the pair of sealing devices 1 are arranged to face each other, when the sealing device 1 moves a certain distance or more toward the battery case (S), as shown in FIG. 1a, the protrusions 3 of the pair of sealing devices 1 abut against each other to restrict the movement of the sealing device 1, thereby preventing the battery case from being excessively crimped.

[0010] However, as shown in Fig. 1b, if the initial thickness of the sealed portion of the battery case (S) is set to be greater than a certain level due to the tolerance of the sealing material, etc., the protrusions 3 of a pair of sealing devices 1 cannot abut against each other and are spaced apart by a certain distance (G). Therefore, in the past, users would check the distance (G) between the protrusions 3 with the naked eye and adjust the distance between the sealing devices 1, but if it was difficult to check the distance (G) between the protrusions 3 with the naked eye, there was a problem that it was difficult for the user to notice an abnormality.

[0011] For this reason, there is a problem that the sealed portion of the battery case (S) cannot be sufficiently crimped and is formed with a thickness that exceeds a predetermined value. As a result, the thickness of the sealed portion of the battery case (S) becomes uneven, and the process conditions at the time of initial device setup differ from the process conditions after mass production, hindering process stability, and therefore a technology for solving the above problem is required. Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention has been made to solve the above problems, and an object of the present invention is to provide a sealing device for a secondary battery that can maintain a uniform thickness of the sealed portion of the battery case when sealing the battery case of a secondary battery. [Means for solving the problem]

[0013] The present invention provides a sealing device for a secondary battery, comprising a pair of sealing portions arranged facing each other with a battery case having an electrode assembly built therein therebetween, the distance between which is adjustable, and at least one detection portion provided between the pair of sealing portions for detecting a change in pressure due to a change in the gap between the pair of sealing portions.

[0014] The sealing portion may include a seal block that applies pressure to a sealing portion of the battery case to seal it, and a pair of protrusions formed to protrude from one surface of the seal block facing the battery case.

[0015] The protruding portions of the pair of seal portions may be disposed so as to face each other. The pair of protrusions may be formed to protrude from both ends of the seal block.

[0016] The detection portion may be fixed to the protrusion. The detection portion may be crimped between the protrusions of the pair of seal portions.

[0017] The detection portion may be fixedly supported by at least one of the pair of seal portions. The detection unit may include at least one pressure sensor.

[0018] Meanwhile, the sealing device for a secondary battery according to the present invention may further include an output interface for outputting an alarm in response to the pressure value detected by the detection unit.

[0019] In addition, the sealing device for a secondary battery according to the present invention may further include a control unit that compares the pressure value acquired by the detection unit with a preset pressure value and controls the movement distance of the sealing unit. Effect of the Invention

[0020] The present invention has the advantage that, by including at least one detection unit that detects pressure changes due to changes in the gap between the pair of sealing portions, the mutual gap between the pair of sealing portions can be controlled based on the pressure value detected by the detection unit, thereby ensuring a uniform thickness of the sealing area. [Brief description of the drawings]

[0021] [Figure 1a] FIG. 1 is a conceptual diagram showing how a conventional sealing device for a pair of secondary batteries seals the battery cases. [Figure 1b] 1b is a conceptual diagram showing how the sealing devices of the secondary battery in FIG. 1a seal the battery case in a state where they are not in contact with each other. FIG. [Figure 2a] 3 is a conceptual diagram showing a state in which sealing devices of a pair of secondary batteries according to the first embodiment of the present invention are spaced apart from each other. FIG. [Figure 2b] 2b is a conceptual diagram showing how the pair of sealing devices of the secondary battery in FIG. 2a come into contact with each other to seal the battery case. FIG. [Figure 3a] 13 is a conceptual diagram showing a state in which sealing devices of a pair of secondary batteries according to a second embodiment of the present invention are spaced apart from each other. FIG. [Figure 3b] 3b is a conceptual diagram showing how the pair of sealing devices of the secondary battery in FIG. 3a come into contact with each other to seal the battery case. FIG. [Figure 4] FIG. 11 is a schematic diagram showing a sealing device for a secondary battery according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in order to enable those skilled in the art to easily carry out the present invention. However, the present invention may be realized in various different forms, and is not limited to the following embodiments.

[0023] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or related known technologies that may unnecessarily obscure the gist of the present invention will be omitted, and when referring to components in each drawing in this specification, the same or similar reference symbols will be used for the same or similar components throughout the specification.

[0024] Furthermore, the terms and words used in this specification and the claims should not be interpreted in a limited manner to their ordinary or dictionary meanings, but should be interpreted in a manner that is consistent with the technical ideas of the present invention, based on the principle that the inventors can appropriately define the concepts of terms in order to best describe their invention.

[0025] The present invention provides a sealing device 10 for a secondary battery, comprising a pair of sealing portions 100 arranged facing each other with a battery case (S) having an electrode assembly (not shown) built in therebetween, the distance between which is adjustable, and at least one detection portion 200 disposed between the pair of sealing portions 100 and detecting a change in pressure due to a change in the gap between the pair of sealing portions 100.

[0026] Specifically, the sealing parts 100 are arranged to face each other with the battery case (S) having the electrode assembly built therein interposed therebetween, and the mutual distance is adjustable, and various configurations are possible.

[0027] Here, the electrode assembly may have a structure in which positive and negative electrodes and separators are alternately arranged. More specifically, the electrode assembly may have a structure in which a positive electrode current collector / a positive electrode active material layer / separator / a negative electrode active material layer / a negative electrode current collector are stacked in this order, and the positive electrode active material layer on one side of the separator faces the negative electrode active material layer on the other side. Such an electrode assembly may be built into a battery case (S).

[0028] The battery case (S) may have a sealed structure by being sealed by a secondary battery sealing device 10 to prevent the internal electrode assembly and electrolyte from leaking out and to prevent the electrode assembly and electrolyte from being damaged by exposure to external air and moisture.

[0029] For example, the sealing part 100 may include a sealing block 110 that applies pressure to seal the sealing portion of the battery case (S), and a pair of protrusions 120 formed by protruding from one surface of the sealing block 110 facing the battery case (S).

[0030] Here, the seal block 110 is configured to apply pressure to the sealing portion of the battery case (S) to seal it, and may have various configurations. In this case, the sealing portion is a portion of the battery case (S) to be sealed, and may include at least one side of the outer periphery of the battery case (S). For example, the sealing portion may be formed along the circumferential direction of the battery case (S).

[0031] Specifically, the sealing block 110 can pressurize and seal the sealing portion by moving in correspondence with the sealing portion of the battery case S. In this case, the sealing unit 100 can move the sealing block 110 by further including a connecting unit 130 having one end connected to the sealing block 110 and the other end connected to a moving means (not shown). Here, the moving means can include a driving device such as an actuator.

[0032] The sealing block 110 may further include a heating unit (not shown) for applying pressure to the sealing portion and simultaneously heating and sealing the sealing portion, and the heating unit may heat the sealing portion to a temperature above room temperature.

[0033] Here, the room temperature refers to the temperature range referred to in the art as "room temperature" or normal temperature. That is, it refers to the temperature in a laboratory, a research lab, etc., and is an expression of temperature conditions used when an experiment is performed without specifying or adjusting the temperature, or when a sample or substance is left indoors, and refers to the atmospheric temperature inside the room. Generally, it is a temperature at which humans can be comfortable, and is usually around 15°C to 20°C.

[0034] Accordingly, the temperature above room temperature may be a temperature of 20° C. or more, in particular, when the sealing layer to be heat-sealed at the sealing portion is made of polypropylene resin, it may be set to 160° C. to 190° C.

[0035] Meanwhile, the seal block 110 may have various shapes such as a bar shape, etc. In this case, one surface of the seal block 110 may be formed with a pair of protrusions 120 protruding in one direction as shown in Figs. 2a to 3b.

[0036] Specifically, the protrusions 120 are formed to protrude from one surface of the seal block 110 facing the battery case (S) and may have various configurations. More specifically, the pair of protrusions 120 may be formed to protrude from both ends of the seal block 110. In this case, the protrusions 120 of the pair of seal parts 100 may be disposed to face each other.

[0037] In other words, when a pair of sealing portions 100 move toward the battery case (S) a certain distance or more, at least one of the protrusions 120 arranged opposite each other abuts against the detection portion 200 described later, thereby restricting the movement of the sealing portions 100.

[0038] For example, as shown in Figures 2a to 3b, when a detection unit 200 (described later) is fixed to one of the protrusions 120 arranged opposite each other, the protrusion 120 on which the detection unit 200 is not provided abuts against the detection unit 200, thereby restricting the movement of the sealing portion 100.

[0039] Thus, the protrusion 120 can prevent the sealing portion of the battery case (S) from being excessively crimped, and can prevent the thickness of the sealing portion from becoming thinner than a preset thickness. Here, the thickness can be understood as the height in the Z direction based on Figures 2a to 3b, and can be understood in the same manner hereinafter.

[0040] Meanwhile, the sealing device 10 for a secondary battery according to the present invention may include a detection unit 200 to prevent the thickness of the sealed portion of the battery case (S) from exceeding a preset thickness due to insufficient crimping of the sealed portion.

[0041] Such a detection unit 200 is configured to include at least one detection unit 200 that is provided between the pair of sealing units 100 and detects a pressure change due to a change in the gap between the pair of sealing units 100, and various configurations are possible.

[0042] For example, the detection unit 200 may include at least one pressure sensor. Here, the pressure sensor may be any of various types of pressure sensors, such as a resonance type pressure sensor, a piezoelectric type pressure sensor, a strain gauge type pressure sensor, and a capacitance type pressure sensor.

[0043] Specifically, the detection unit 200 is provided between a pair of sealing parts 100 and can detect a pressure value that changes when the pair of sealing parts 100 contact each other. In this case, the change in the pressure value detected by the detection unit 200 may mean that the sealing portion of the battery case (S) is being crimped.

[0044] Meanwhile, when the pair of sealing units 100 move less than a certain distance and are unable to sufficiently pressurize the detection unit 200 or are unable to come into contact with the detection unit 200, the pressure value detected by the detection unit 200 may be less than a preset pressure value. Here, the preset pressure value may be understood as a pressure value detected by the detection unit 200 corresponding to a point in time when the thickness of the sealed portion of the battery case (S) has a preset thickness.

[0045] For example, if the detection unit 200 cannot contact the pair of seal parts 100, the pressure value of the detection unit 200 does not change from the initial setting value. Here, if the initial setting value is "0", the pressure value of the detection unit 200 may also be "0".

[0046] That is, if the pressure value of the detection unit 200 is less than a preset pressure value, the user can recognize that the sealed portion of the battery case (S) is not sufficiently crimped. Therefore, the user can sufficiently pressurize the sealed portion by controlling the distance between the pair of sealing units 100 to be close to each other. This allows the thickness of the sealed portion of the battery case (S) to be adjusted uniformly.

[0047] Such a detection unit 200 can be provided between the pair of sealing units 100, in which case it may be fixed to the pair of sealing units 100, or may be fixed by another device provided between the pair of sealing units 100.

[0048] However, in order to reduce manufacturing costs and simplify the structure, it is preferable that the detection unit 200 is fixed to the pair of seal parts 100. In this case, the detection unit 200 may be fixed and supported by at least one of the pair of seal parts 100.

[0049] As an example, the detection unit 200 may be fixed to the sealing unit 100 arranged on the lower side of the battery case (S) out of a pair of sealing units 100 as shown in Figures 2a to 2b. As another example, the detection unit 200 may be fixed to the sealing unit 100 arranged on the upper side of the battery case (S) out of a pair of sealing units 100 as shown in Figures 3a to 3b.

[0050] In this case, it is preferable that the detection unit 200 is fixed to the protrusion 120. That is, the detection unit 200 may be pressed between the protrusions 120 of the pair of seal units 100 as shown in Figs. 2b and 3b.

[0051] Meanwhile, the sealing device for a secondary battery according to the present invention may further include an output interface 300 for outputting an alarm in response to a pressure value detected by the detection unit 200, as shown in FIG.

[0052] Specifically, the output interface 300 is configured to output an alarm in response to the pressure value detected by the detection unit 200, and may be configured in various ways.

[0053] For example, the output interface 300 can receive the pressure value detected by the detection unit 200 via a short-range wired communication method such as CAN (Controller Area Network), serial communication, or Ethernet (registered trademark), or via a wireless communication method such as Bluetooth (registered trademark), Infrared data association, ZigBee (registered trademark), and Wi-Fi (registered trademark), and output the pressure value as an image and / or sound.

[0054] The output interface 300 may include a display module that outputs an alarm corresponding to the pressure value as an image, and / or a speaker module that outputs an alarm corresponding to the pressure value as a sound.

[0055] Meanwhile, the sealing device for a secondary battery according to the present invention may further include a control unit 400 for controlling the movement distance of the sealing unit 100 by comparing the pressure value acquired by the detection unit 200 with a preset pressure value.

[0056] Specifically, the control unit 400 is configured to compare the pressure value acquired by the detection unit 200 with a preset pressure value to control the movement distance of the sealing unit 100, and various configurations are possible.

[0057] For example, when the pressure value detected by the detection unit 200 is smaller than a preset pressure value, the control unit 400 can control the movement distance of the pair of sealing units 100 so that the sealing units 100 move closer to each other.

[0058] Furthermore, it goes without saying that when the pressure value detected by the detection unit 200 is greater than a preset pressure value, the control unit 400 can control the movement distance of the pair of sealing portions 100 so that the sealing portions 100 move closer to each other.

[0059] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the scope of the technical concept of the present invention and the scope of the claims described below by a person having ordinary knowledge in the technical field to which the present invention belongs. [Explanation of symbols]

[0060] 10: Secondary battery sealing device 100: Seal part 110: Seal block 120:Protrusion 130: Connection part 200: Detection unit 300: Output interface 400: Control unit

Claims

1. a pair of seals arranged to face each other with a battery case having an electrode assembly built therein therebetween, the seals being adjustable in distance from each other; At least one detector provided between the pair of seal portions and configured to detect a pressure change caused by a change in a gap between the pair of seal portions; A sealing device for a secondary battery comprising:

2. The seal portion is a seal block that applies pressure to a sealing portion of the battery case to seal it; 2 . The sealing device for a secondary battery according to claim 1 , further comprising: a pair of protruding portions formed protruding from one surface of the seal block facing the battery case.

3. The sealing device for a secondary battery according to claim 2 , wherein the protruding portions of the pair of seal portions are arranged to face each other.

4. The sealing device for a secondary battery according to claim 2 , wherein the pair of protrusions are formed to protrude from both ends of the seal block.

5. The sealing device for a secondary battery according to claim 2 , wherein the detection portion is fixed to the protrusion.

6. The sealing device for a secondary battery according to claim 2 , wherein the detection portion is crimped between the protrusions of the pair of seal portions.

7. The sealing device for a secondary battery according to claim 1 , wherein the detection portion is fixedly supported by at least one of the pair of sealing portions.

8. The sealing device for a secondary battery according to claim 1 , wherein the detection portion includes at least one pressure sensor.

9. The sealing device for a secondary battery according to claim 1 , further comprising an output interface that outputs an alarm in response to the pressure value detected by the detection unit.

10. The sealing device for a secondary battery according to claim 1 , further comprising a control unit that compares the pressure value acquired by the detection unit with a preset pressure value and controls a moving distance of the sealing unit.

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