Pressurizing channel and secondary battery charge / discharge device including same

Abstract

The present invention relates to a pressure channel that can improve pressure drop at both ends of a secondary battery that occurs during a formation process, and a secondary battery charging / discharging device including the same. The pressure channel according to an embodiment of the present invention includes a pair of pressure plates that are arranged on both sides of the secondary battery, sandwiching the secondary battery, and the pressure plates include a body portion and an outer shell portion that is connected to both ends of the body portion and includes a tube therein that expands due to hydraulic pressure.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0137435 dated October 15, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a charging / discharging device for a secondary battery, and more particularly, to a pressure channel capable of improving a pressure drop at both ends of a secondary battery in a longitudinal direction that occurs during a formation process, and a charging / discharging device for a secondary battery including the same. [Background technology]

[0003] Generally, secondary batteries can be categorized into cylindrical, square, pouch, etc., depending on their shape. Among them, pouch-type secondary batteries are shaped using a pouch exterior material that is made up of a multi-layered film of a metal layer (foil) and a synthetic resin layer coated on the top and bottom of the metal layer, which significantly reduces the weight of the battery compared to cylindrical or square types that use metal cans. They are also attracting much attention due to their advantages of being able to reduce the weight of the battery and being able to be changed into various shapes.

[0004] In such a pouch-type secondary battery, electrode assemblies are housed in a stacked form, and electrode tabs and electrode leads are connected to the electrode assemblies, and the electrode leads protrude from the pouch exterior material. The electrode leads are electrically connected to an external device through contacts, and receive power from the external device.

[0005] A pouch-type secondary battery is manufactured through a process of assembling cells and a process of activating the battery. In the battery activation stage, the secondary battery cell is mounted in a charging / discharging device and charging and discharging are performed under the conditions required for activation. This process of performing a predetermined charging and discharging using a charging / discharging device for battery activation is called the formation process.

[0006] A conventional secondary battery charging / discharging device used in a formation process will be described with reference to Figures 1 and 2. Figures 1 and 2 are diagrams illustrating a conventional secondary battery charging / discharging device.

[0007] 1 and 2, a conventional secondary battery charge / discharge device includes a frame 1, a pressure plate 2, and a drive unit 3 (3a, 3b). The drive unit 3 includes a drive shaft 3a and a drive motor 3b.

[0008] A plurality of pressure plates 2 are arranged inside the frame 1, and secondary batteries B undergoing a formation process are arranged between the pressure plates 2.

[0009] As shown in FIG. 1, when the drive shaft 3a rotates due to the rotation of the drive motor 3b, the multiple pressure plates 2 engaged with it move in one direction, so that the pressure plates 2 apply pressure to both sides of the secondary battery B, as shown in FIG. 2.

[0010] A pair of pressure plates 2 arranged on both sides of a secondary battery B sandwiching the secondary battery B form a unit pressure channel CH, and the secondary battery charge / discharge device has a plurality of such unit pressure channels CH. Each pressure plate 2 constitutes one unit pressure channel CH and its adjacent unit pressure channel. In other words, two adjacent pressure channels share one pressure plate.

[0011] FIG. 3 is a cross-sectional view illustrating one unit pressure channel CH constituting a secondary battery charge / discharge device according to the prior art.

[0012] The pressure channel CH includes a pressure plate 2, a heating pad 2b formed on one side of the pressure plate, and silicon pads 2a formed on both sides of the pressure plate on which the heating pad 2b is formed. A secondary battery B is interposed between the pair of opposing pressure plates 2.

[0013] FIG. 4 is a graph for explaining problems caused by a secondary battery charging / discharging device according to the related art, and FIG. 5 is an image showing problems caused by a secondary battery charging / discharging device according to the related art.

[0014] 4 and 5, when the formation process is performed in the secondary battery charge / discharge device of the related art, a pressure non-uniformity phenomenon occurs at both ends Ba of the secondary battery B in the overall length direction.

[0015] Specifically, referring to Fig. 4, when one end of the secondary battery is located at 300 mm from the center (origin 0) of the secondary battery, a sudden pressure drop occurs at the 200 mm point. Also, referring to Fig. 5, a sudden pressure drop occurs at both ends of the secondary battery that has been subjected to the formation process using the conventional secondary battery charging / discharging device.

[0016] Such pressure unevenness causes quality degradation such as lithium precipitation, etc. Such pressure unevenness occurs due to the deviation in thickness along the entire length of secondary battery B, and the prior art secondary battery charging / discharging device is unable to sufficiently compensate for this. Summary of the Invention [Problem to be solved by the invention]

[0017] An object of the present invention is to provide a pressurizing channel capable of improving a pressure drop at both ends of a secondary battery that occurs during a formation process, and a secondary battery charge / discharge device including the same. [Means for solving the problem]

[0018] A pressure channel according to an embodiment of the present invention includes a pair of pressure plates arranged on both sides of a secondary battery with the secondary battery sandwiched therebetween, and the pressure plates are composed of a body portion and an outer shell portion connected to both ends of the body portion and containing a tube therein that expands due to hydraulic pressure.

[0019] In an embodiment of the present invention, the outer shell has an insertion space into which the tube is inserted.

[0020] The pressure channel according to an embodiment of the present invention includes a heating pad formed on at least one surface of the pressure plate, and silicone pads formed on both surfaces of the pressure plate on which the heating pad is formed.

[0021] The pressurized channel according to an embodiment of the present invention further includes a fluid supply portion that supplies fluid into the tube.

[0022] In one embodiment of the present invention, the fluid supply unit includes a fluid tank for storing the fluid to be supplied to the tube, a compressor for compressing the fluid to be supplied to the tube at a preset pressure, and a flow path for supplying the fluid compressed by the compressor to the tube and for recovering the fluid from the tube.

[0023] In one embodiment of the present invention, when the center of the pressure plate is defined as the origin 0 and the position of one end is defined as 1, the outer shell or the tube is formed at a position more than 2 / 3 of the way from the origin 0 of the pressure plate toward the one end.

[0024] A secondary battery charging / discharging device according to an embodiment of the present invention includes a frame that houses a plurality of secondary batteries therein, and a pair of pressure channels that are installed inside the frame and arranged on both sides of one of the plurality of secondary batteries, and the pressure plates are composed of a body portion and an outer shell portion that is connected to both ends of the body portion and includes a tube therein that expands due to hydraulic pressure.

[0025] In an embodiment of the present invention, the outer shell has an insertion space into which the tube is inserted.

[0026] In one embodiment of the present invention, the pressure plate includes a heating pad formed on at least one surface of the pressure plate, and silicone pads formed on both surfaces of the pressure plate on which the heating pad is formed.

[0027] In one embodiment of the present invention, the pressurized channel further includes a fluid supply for supplying fluid into the tube.

[0028] In one embodiment of the present invention, the fluid supply unit includes a fluid tank for storing the fluid to be supplied to the tube, a compressor for compressing the fluid to be supplied to the tube at a preset pressure, and a flow path for supplying the fluid compressed by the compressor to the tube and for recovering the fluid from the tube.

[0029] In one embodiment of the present invention, when the center of the pressure plate is defined as the origin 0 and the position of one end is defined as 1, the outer shell or the tube is formed at a position more than 2 / 3 of the way from the origin 0 of the pressure plate toward the one end.

[0030] Further, specific details of embodiments according to various aspects of the present invention are included in the following detailed description. Effect of the Invention

[0031] According to an embodiment of the present invention, it is possible to improve the pressure drop at both ends of a secondary battery that occurs during a formation process. [Brief description of the drawings]

[0032] [Figure 1] 1 is a diagram illustrating a secondary battery charging / discharging device according to the prior art; [Diagram 2] 1 is a diagram illustrating a secondary battery charging / discharging device according to the prior art; [Diagram 3] 1 is a cross-sectional view illustrating one unit pressure channel constituting a secondary battery charge / discharge device according to the related art; [Figure 4]1 is a graph for explaining problems caused by a secondary battery charge / discharge device according to the related art. [Diagram 5] 1 is an image showing problems caused by a secondary battery charging / discharging device according to the related art. [Figure 6] 1 is an exploded perspective view illustrating a secondary battery that is applied to a secondary battery charging / discharging device according to an embodiment of the present invention; [Figure 7] 3 is a cross-sectional view illustrating one unit pressure channel constituting a secondary battery charge / discharge device according to an embodiment of the present invention; [Figure 8] 1 is a conceptual diagram illustrating how the outer periphery of a pressure plate expands together with a tube expanded by hydraulic pressure. [Figure 9] 4 is a conceptual diagram illustrating a process of preventing a pressure drop at both ends of a secondary battery by a pressurizing channel according to an embodiment of the present invention; [Figure 10] FIG. 13 is a schematic diagram of a unit pressure channel according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The present invention can be modified in various ways and can have various embodiments, and a specific embodiment will be described in detail by way of example, but it is not intended to limit the present invention to the specific embodiment, and it should be understood that the present invention includes all modifications, equivalents, or alternatives within the spirit and technical scope of the present invention.

[0034] The terms used in the present invention are merely used to describe certain embodiments and are not intended to limit the present invention. A singular expression includes a plural expression unless the context clearly indicates otherwise. In the present invention, the terms "include" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0035] First, the secondary battery will be described with reference to Fig. 6. Fig. 6 is an exploded perspective view illustrating a secondary battery applied to a secondary battery charging / discharging device according to an embodiment of the present invention.

[0036] 6, the secondary battery B includes a battery case 10, an electrode assembly 20 and an electrolyte contained in the receiving portion 13 of the battery case 10. In this case, the electrode assembly 20 may include an electrode lead 30 electrically connected to the electrode 23.

[0037] The electrode assembly 20 is a power generating element capable of being charged and discharged, and may be formed by alternately stacking electrodes 23 and separators 24 .

[0038] The electrode 23 may be composed of a positive electrode 21 and a negative electrode 22. In this case, the electrode assembly 20 may have a structure in which the positive electrode 21 / separator 24 / negative electrode 22 are alternately laminated. The electrode lead 30 may include a positive electrode lead connected to the positive electrode 21 and a negative electrode lead connected to the negative electrode 22. Although the electrode lead 30 is illustrated as being formed in one direction of the electrode assembly 20 in FIG. 6, it may be formed in both directions of the electrode assembly 20.

[0039] The positive electrode 21 may include a positive electrode current collector and a positive electrode active material laminated on the positive electrode current collector. The positive electrode current collector may be made of an aluminum foil. The positive electrode active material may be made of lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or a compound or mixture containing at least one of these.

[0040] The negative electrode 22 may include a negative current collector and a negative active material laminated on the negative current collector. The negative current collector may be, for example, a foil made of copper (Cu). The negative active material may be a compound or mixture containing a graphite-based material.

[0041] The separator 24 is made of an insulating material and electrically insulates the positive electrode 21 from the negative electrode 22. The separator 24 may be made of a polyolefin resin film such as polyethylene or polypropylene having microporosity.

[0042] Next, a unit pressure channel according to an embodiment of the present invention will be described with reference to Figures 7 to 9. Figure 7 is a cross-sectional view illustrating one unit pressure channel constituting a secondary battery charge / discharge device according to an embodiment of the present invention, Figure 8 is a conceptual diagram illustrating that as the thermal expansion part expands due to heat, the outer periphery of the pressure plate also expands, and Figure 9 is a conceptual diagram illustrating a process of preventing a pressure drop at both ends of a secondary battery by the pressure channel according to an embodiment of the present invention.

[0043] As shown in FIG. 7, a unit pressure channel 100 according to an embodiment of the present invention includes a pressure plate 110, a silicon pad 120, and a heating pad .

[0044] The heating pad 130 is formed on at least one surface of the pressure plate 110 to supply heat to the pressure plate 110 .

[0045] The silicon pads 120 are formed on both sides of the pressure plate 110 on which the heating pads 130 are formed, and apply pressure to the secondary battery B.

[0046] A pair of pressure plates 110 are disposed on both sides of one secondary battery B, sandwiching the secondary battery B. Here, "disposed on both sides" can include a state of being spaced apart from or in contact with both sides of the secondary battery B. During the formation process, when the pressure plates 110 press the secondary battery B, the pair of pressure plates 110 are in contact with both sides of the secondary battery B, and when the pressure is released, the pair of pressure plates 110 are in a spaced apart state from both sides of the secondary battery B.

[0047] Specifically, the pressure plate 110 includes a body portion 111 and an outer shell portion 112, and the outer shell portion 112 includes a tube 113 therein. In the following description, the body portion 111 and the outer shell portion 112 are described as separate regions, but in reality, the body portion 111 and the outer shell portion 112 each mean one region of the pressure plate 110.

[0048] The body portion 111 is a central region of the pressing plate 110 where the occurrence of pressure drop in the secondary battery B during the formation process is relatively small. The body portion 111 is formed over a predetermined length region O-A1 from the center of the pressing plate 110 as the origin O toward both ends of the pressing plate 110 (O-A2 direction).

[0049] The position of end A1 of body part 111 is the position where a sudden pressure drop occurs in secondary battery B, and referring to the above-mentioned Figures 4 and 5, it can be seen that the position of end A1 of body part 111 is approximately 2 / 3 of the distance from the origin O of the pressure plate 110 to one side end A2 of the pressure plate 110.

[0050] Thus, the outer shell 112 formed and connected to the body part 111 may be formed at a position approximately 2 / 3 or more away from the origin O of the pressure plate in the direction toward one end of the pressure plate 110. The thermal expansion part (tube) 113 formed in the outer shell 112 may also be formed at a position approximately 2 / 3 or more away from the origin O of the pressure plate in the direction toward one end of the pressure plate 110.

[0051] The outer portion 112 is an outer region of the pressure plate 110 where a pressure drop in the secondary battery B occurs suddenly during the formation process. Referring to Fig. 4 and Fig. 5, the outer portion 112 is formed from the end A1 of the body portion 111 to one side end A2 of the pressure plate 110. That is, the outer portion 112 has a predetermined length region A1-A2.

[0052] The body part 111 and the outer part 112 are each a region of the pressure plate 110 and are made of the same material. The body part 111 and the outer part 112 may be made of metal. The metal may be, for example, aluminum (Al).

[0053] The outer shell 112 includes a tube 113 therein. The outer shell 112 may be formed to have an insertion space 114 into which the tube is inserted.

[0054] The tube is preferably made of an expandable material having elasticity capable of withstanding the expansion pressure when the space inside the tube is expanded by hydraulic pressure. Specifically, the tube may include one or more materials selected from the group consisting of natural rubber, polyurethane, and silicon-based rubber.

[0055] More specifically, the tube 113 expands due to hydraulic pressure under the temperature conditions of the formation process (approximately 60°C), and the expanded tube can expand the outer pressure plate surrounding the outer periphery of the tube by approximately 55 to 65 μm in the thickness direction (see 112 and 113 in Figure 8).

[0056] Furthermore, as shown in FIG. 9, the heating pad and the silicone pad formed in the outer shell 112 area also expand together to compensate for the thickness deviation at both ends of the secondary battery B, thereby eliminating the uneven pressure.

[0057] Meanwhile, the secondary battery charging / discharging device according to the embodiment of the present invention is substantially the same as the configuration of FIG. 1 and FIG. 2 except for the configuration of the unit pressure channel CH, and therefore a duplicated description thereof will be omitted.

[0058] Next, a unit pressure channel according to another embodiment of the present invention will be described with reference to Fig. 10. Fig. 10 is a schematic diagram of a unit pressure channel according to another embodiment of the present invention.

[0059] 10, the pressurized channel further includes a fluid supply that supplies fluid into the tube. The fluid supply can also withdraw fluid from the tube 113.

[0060] The fluid supply units 140-170 include a fluid tank 140 for storing the fluid to be supplied to the tubes, a compressor 150 for compressing the fluid to be supplied to the tubes at a preset pressure, and a flow path 160 for supplying the fluid compressed by the compressor to the tubes and recovering the fluid from the tubes. Optionally, the fluid supply unit may further include a control valve 170 and a control unit (not shown).

[0061] The fluid tank stores the fluid that is delivered to the tube. The fluid may be a gas or a liquid.

[0062] The compressor compresses the fluid at a preset pressure, and the fluid expands the tube, causing the tube to expand the pressure plate portion of the outer shell. Also, the pressure channel of the present invention may further include a heating unit that heats the fluid supplied to the tube in order to accelerate the expansion of the outer shell due to the expansion of the tube.

[0063] The flow path guides the fluid stored in the fluid tank through the tube and supplies it, and guides the fluid inside the tube back to the fluid tank after the formation process is completed.

[0064] The control valves control the flow (supply and withdrawal) of fluids.

[0065] The first control valve V1 is formed between the fluid tank and the compressor to control the supply of fluid to the compressor.

[0066] A second control valve V2 is formed between the compressor and the tube to control the supply of fluid to the tube.

[0067] The control unit controls the operation of the control valves to control the flow (supply and recovery) of the fluid. Specifically, the control unit controls the operation of the first control valve and the second control valve in response to a formation process start / end signal.

[0068] Although one embodiment of the present invention has been described above, a person having ordinary knowledge in the art may modify and change the present invention in various ways by adding, changing, deleting or adding components within the scope of the concept of the present invention described in the claims, and this may also be considered to be included in the scope of the present invention.

Claims

1. a pair of pressure plates disposed on both sides of the secondary battery with the secondary battery sandwiched therebetween; The pressure plate is The hydraulic pump includes a body portion and an outer shell portion that is connected to both ends of the body portion and includes a tube that expands by hydraulic pressure. When the center of the pressure plate is defined as an origin 0 and the position of one end of the pressure plate is defined as 1, the outer shell or the tube is formed at a position 2 / 3 or more from the origin 0 of the pressure plate toward the one end of the pressure plate. Pressurized channel.

2. The outer shell portion is The pressurization channel according to claim 1 , comprising an insertion space into which the tube is inserted.

3. A heating pad formed on at least one surface of the pressure plate; and The pressure channel of claim 1 , comprising silicone pads formed on both sides of the pressure plate on which the heating pads are formed.

4. The pressurized channel of claim 1 , further comprising a fluid supply that supplies fluid into the tube.

5. The fluid supply unit includes: a fluid tank for storing a fluid to be supplied to the tube; a compressor for compressing the fluid supplied to the tube at a preset pressure; The pressurized channel of claim 4 , further comprising: a flow path for supplying fluid compressed by the compressor to the tube and for withdrawing fluid from the tube.

6. A frame that houses a plurality of secondary batteries therein; and a pressure channel including a pair of pressure plates disposed on both sides of the frame and sandwiching one of the plurality of secondary batteries therebetween; The pressure plate is The hydraulic pump includes a body portion and an outer shell portion that is connected to both ends of the body portion and includes a tube that expands by hydraulic pressure. When the center of the pressure plate is defined as an origin 0 and the position of one end of the pressure plate is defined as 1, the outer shell or the tube is formed at a position 2 / 3 or more from the origin 0 of the pressure plate toward the one end of the pressure plate. Secondary battery charging and discharging equipment.

7. The outer shell portion is The secondary battery charge / discharge device according to claim 6 , further comprising an insertion space into which the tube is inserted.

8. A heating pad formed on at least one surface of the pressure plate; and The secondary battery charge / discharge device according to claim 6 , further comprising silicone pads formed on both sides of the pressure plate on which the heating pad is formed.

9. The secondary battery charge / discharge device according to claim 6 , wherein the pressurized channel further includes a fluid supply portion that supplies a fluid into the tube.

10. The fluid supply unit includes: a fluid tank for storing a fluid to be supplied to the tube; a compressor for compressing the fluid supplied to the tube at a preset pressure; The secondary battery charge / discharge device according to claim 9 , further comprising: a flow path for supplying the fluid compressed by the compressor to the tube and for recovering the fluid from the tube.

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