Battery cell pressurizing device and battery cell charging / discharging device including the same

Abstract

As one embodiment, the present invention provides a battery cell pressurizing device including a case in which a battery cell is disposed, and a fluid that fills the inside of the case and pressurizes the battery cell, the case including a hole through which a conductive member that connects the battery cell to a charger / discharger and applies a current to the battery cell passes, and a battery cell charging / discharging device including the same.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0022268 filed on February 21, 2022, and all the contents disclosed in the corresponding Korean patent application are incorporated herein by reference.

[0002] The present disclosure relates to a battery cell pressurizing device and a battery cell charge / discharge device including the same.

Background Art

[0003] As technology development and demand for mobile devices increase, rechargeable secondary batteries are widely used as an energy source for various mobile devices. Also, secondary batteries are attracting attention as an energy source for electric vehicles, hybrid vehicles, etc., which are proposed as solutions to problems such as air pollution in existing gasoline and diesel vehicles.

[0004] Secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries according to the shape of the battery case. Among these, the pouch-type battery uses a multilayer film of a metal layer (foil) and synthetic resin layers coated on the upper and lower surfaces of the metal layer to form the appearance, so it can significantly reduce the weight of the battery compared to cylindrical or prismatic batteries using metal cans, enabling weight reduction of the battery, and has the advantage of being able to change into various forms, thus attracting great attention.

[0005] The pouch-type battery is generally manufactured through a process of activating the battery cell after the process of assembling the battery. Generally, the activation process includes a process of pressurizing the battery cell with a jig and applying a current to the battery cell up to a predetermined voltage to charge and discharge it. Such an activation process is essential for the activation of the positive electrode active material and the formation of a stable surface film (SEI, Solid Electrolyte Interface) on the negative electrode during the first cycle.

[0006] In this activation process, a large amount of gas is generated inside the battery cell. If the gas generated inside the battery cell is not efficiently removed, the central part of the pouch outer material will swell, inducing deformation of the battery. This will not only cause a decrease in battery performance such as capacity and output, but will also negatively affect the battery's lifespan. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Korean Published Patent Publication No. 10-2019-0072289 [Overview of the project] [Problems that the invention aims to solve]

[0008] One of the objectives of the present invention is to provide a battery cell pressurizing device capable of isotropically pressurizing a battery cell, and a battery cell charging and discharging device including the same.

[0009] Another object of the present invention is to provide a battery cell pressurizing device that can prevent damage to battery cells due to pressurization and short-circuit failures caused thereby, and a battery cell charging and discharging device including the same.

[0010] Another object of the present invention is to provide a battery cell pressurizing device that can prevent a decrease in the performance and lifespan of battery cells due to the activation process, and a battery cell charging and discharging device including the same. [Means for solving the problem]

[0011] As one embodiment, the present invention provides a battery cell pressurizing device comprising a case in which a battery cell is arranged, and a fluid that fills the inside of the case and pressurizes the battery cell, wherein the case includes a hole through which a conductive member passes, which connects the battery cell to a charger / discharger and applies an electric current to the battery cell.

[0012] As another embodiment, the present invention provides a battery cell charging and discharging apparatus that includes a battery cell pressurizing device and a charger / discharger for charging and discharging the battery cells pressurized by the battery cell pressurizing device. [Effects of the Invention]

[0013] One of the effects of the present invention is to provide a battery cell pressurizing device that can isotropically pressurize a battery cell, and a battery cell charging and discharging device including the same.

[0014] Another objective of the present invention is to provide a battery cell pressurizing device that can prevent damage to battery cells due to pressurization and the resulting short-circuit failure, and a battery cell charging / discharging device including the same.

[0015] Another objective of the present invention is to provide a battery cell pressurizing device that can prevent a decrease in the performance and lifespan of battery cells due to the activation process, and a battery cell charging and discharging device including the same. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view of a conventional battery cell pressurization device. [Figure 2] This is a cross-sectional view of a battery cell being pressurized by a conventional battery cell pressurizing device. [Figure 3] This is a perspective view of a battery cell pressurizing device and a battery cell charging / discharging device including the same, according to one embodiment of the present invention. [Figure 4] This is a cross-sectional view of a battery cell being pressurized by a battery cell pressurizing device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0017] The embodiments of the present invention will be described in detail below with reference to the attached drawings. For the sake of clarity, some or all of the components may be exaggerated in the drawings.

[0018] Moreover, it is obvious to those skilled in the art that the present invention is not limited to the contents described in the attached drawings and this specification, and the present invention can be embodied in various forms without departing from the technical idea of the present invention.

[0019] FIG. 1 shows a perspective view of a conventional battery cell pressurizing device.

[0020] FIG. 2 shows a cross-sectional view of a battery cell pressurized by a conventional battery cell pressurizing device.

[0021] In the activation step, the battery cell 10 may be pressurized by the battery cell pressurizing device 210 including the jigs 211 and 212. Specifically, the battery cell 10 may be disposed between the jigs 211 and 212 arranged opposite to each other in the battery cell pressurizing device 210, and both sides of the battery cell 10 may be pressurized. For example, Patent Document 1 discloses a pressurizing jig for charging and discharging a pouch-type secondary battery including a first plate-like member and a second plate-like member configured to be plate-shaped, facing each other and separated by a predetermined distance, and configured to pressurize one or more pouch-type secondary batteries inserted into the separation space.

[0022] The battery cell 10 pressurized by the battery cell pressurizing device may include a positive electrode 11, a negative electrode 12, and a solid electrolyte 13. Further, it may further include a positive electrode lead 14 and a negative electrode lead 15 respectively connected to the positive electrode 11 and the negative electrode 12.

[0023] The battery cell 10 may be a pouch-type battery cell in which the positive electrode 11, the negative electrode 12, and the solid electrolyte 13 are built in the pouch 16, and a part of the leads 14 and 15 is exposed outside the pouch 16. The pouch-type battery cell 10 arranges the solid electrolyte 13 between the positive electrode 11 and the negative electrode 12, performs cold isostatic pressing (CIP) or warm isostatic pressing (WIP) and layer bonding, and then houses the electrode assembly formed by attaching the positive electrode lead 14 and the negative electrode lead 15 in the pouch 16 and seals it to manufacture it. '

[0024] On the other hand, at least two of the sizes of the positive electrode 11, the negative electrode 12, and the solid electrolyte 13 of the battery cell 10 can differ from each other. For example, the size of the positive electrode 11 may be smaller than the size of the negative electrode 12 and the size of the solid electrolyte 13. Here, size can mean at least one of the length in the longitudinal direction L and the length in the width direction W.

[0025] When a battery cell 10 is uniaxially pressurized by a conventional battery cell pressurizing device 210, damage such as cracks in the battery cell and resulting short-circuit failures may occur due to differences in the sizes of the positive electrode 11, the negative electrode 12, and the solid electrolyte 13. For example, if the size of the positive electrode 11 is smaller than the size of the solid electrolyte 13, cracks may occur in the solid electrolyte 13 that is in contact with the positive electrode 11. This can cause the positive electrode 11 and the negative electrode 12 to come into contact with each other, or lithium deposition may occur during charging and discharging, resulting in a short-circuit failure. This can lead to a decrease in the performance and lifespan of the battery cell. Recently, there has been a trend to thin the solid electrolyte 13 to 30 μm or less, and in battery cells 10 containing such thin-film solid electrolytes 13, the possibility of the above-mentioned problems occurring is even higher.

[0026] Figure 3 shows a perspective view of a battery cell pressurizing device and a battery cell charging / discharging device including the same, according to one embodiment of the present invention.

[0027] Figure 4 shows a cross-sectional view of a battery cell being pressurized by a battery cell pressurizing device according to one embodiment of the present invention.

[0028] Referring to the drawings, one embodiment of the present invention, the battery cell charging and discharging device 100, includes a battery cell pressurizing device 110 and a charger / discharger 120 for charging and discharging the battery cell 10 pressurized by the battery cell pressurizing device 110. It may further include a conductive member 130 that connects the battery cell 10 to the charger / discharger 120 and applies current to the battery cell 10.

[0029] The battery cell pressurizing device 110 includes a case 111 in which the battery cells 10 are placed, and a fluid 112 that fills the inside of the case 111 and pressurizes the battery cells 10.

[0030] The shape of case 111 is not particularly limited and can, for example, have a rectangular shape. Case 111 may have pressure resistance so as not to deform under the pressure of fluid 112. For example, case 111 may not deform at pressures of several to tens of MPa or less, such as 20 MPa, 15 MPa, or 10 MPa or less. More specifically, case 111 may be pressurized by fluid 112 at pressures of 3 MPa to 10 MPa, 4 MPa to 8 MPa, or 5 MPa to 6 MPa and may not deform within the said pressure range. Case 111 may also have water resistance to prevent the penetration of fluid 112. From this viewpoint, the material used to form case 111 may be, but is not limited to, metals such as aluminum (Al), stainless steel (SUS), titanium (Ti), nickel (Ni), iron (Fe), copper (Cu), or alloys of two or more of these.

[0031] The case 111 may include holes 113 through which conductive members 130 that connect the battery cell 10 to the charger / discharger 120 and apply current to the battery cell 10 pass. The holes 113 may be a plurality of holes through which a plurality of conductive members 130, each connected to a positive electrode lead 14 and a negative electrode lead 15, passes.

[0032] A sealing member (not shown) can be placed around the hole 113 to prevent the fluid 112 filling the inside of the case 111 from being discharged to the outside of the case 111. In other words, a sealing member can be placed between the hole 113 and the conductive member 130 to prevent the fluid 112 from being discharged to the outside of the case 111. The size of the hole 113 may be smaller than the size of the injection section 114, which will be described later, but in some cases it may be the same size as or larger than the injection section 114.

[0033] Furthermore, the case 111 may further include an injection section 114, which is a path through which the fluid 112 is injected into the case 111. The injection section 114 may have a structure that prevents the fluid 112 from being discharged to the outside of the case 111, even under pressure from the fluid 112 inside the case 111. The injection section 114 may include a hole for injecting the fluid 112 into the case 111 and a plug for closing and sealing the hole after the fluid 112 has been injected. However, the structure of the injection section 114 is not limited thereto.

[0034] The fluid 112 can pressurize the battery cell 10 during the activation process in which the battery cell 10 is charged and discharged in the charger / discharger 120. In one embodiment of the present invention, by using the fluid 112 as a means of pressurizing the battery cell 10, the battery cell 10 can be pressurized isotropically and uniformly. That is, the fluid 112 can isotropically pressurize the battery cell 10.

[0035] The pressure at which the fluid 112 pressurizes the battery cell 10 can be 3 MPa to 10 MPa, 4 MPa to 8 MPa, or 5 MPa to 6 MPa. If the pressure at which the fluid 112 pressurizes the battery cell 10 is less than 3 MPa, the battery cell 10 may not be sufficiently pressurized, which could cause the battery cell 10 to expand due to gas. Also, if the pressure at which the fluid 112 pressurizes the battery cell 10 exceeds 10 MPa, it could cause physical or chemical damage to the battery cell 10. Preferably, the pressure at which the fluid 112 pressurizes the battery cell 10 can be about 5 MPa.

[0036] As the fluid 112, a substance that does not deform under its own pressure can be used. The fluid 112 can be a liquid, specifically in the form of an oil or gel. However, depending on the design, a gas, a fluid solid, etc., can also be used as the fluid 112.

[0037] Furthermore, it is preferable to use a material that does not deform in the temperature range of 0 to 100°C as the fluid 112. The above range includes the boundary values ​​of 0°C and 100°C. For example, it is preferable to use a material that does not harden and has little volume change in the above temperature range as the fluid 112.

[0038] Furthermore, the fluid 112 can be a substance that does not affect the performance or lifespan of the battery cell 10, and an insulating substance can be used.

[0039] Furthermore, the fluid 112 can be a substance that may have viscosity. For example, the viscosity of the fluid 112 may be 1000 cP or less, preferably about 100 cP. This allows the fluid 112 and its pressure to be uniformly distributed throughout the entire area of ​​the battery cell 10.

[0040] The charger / discharger 120 activates the battery cell 10 by applying current to it via the conductive member 130 and charging / discharging it. The charger / discharger 120 can be carried out using various known processes, such as a method in which the battery cell 10 is fully charged, then aged, an open-circuit voltage (OCV) defect is detected, and then it is fully discharged again to measure the discharge capacity, and then charged to 50% of the capacity for shipment. For example, the activation process can be carried out with a current of 0.05C to 1C and a voltage of 1.5V to 5.0V, but is not limited to these conditions.

[0041] The conductive member 130 can connect the battery cell 10 to the charger / discharger 120 and apply current to the battery cell 10. The conductive member 130 may consist of multiple conductive members 130, each connected to the positive electrode lead 14 and the negative electrode lead 15, respectively. Any conductive material can be used as the forming material for the conductive member 130 without limitation. For example, the conductive member 130 may be a conductor.

[0042] On the other hand, the battery cell 10 pressurized by the battery cell pressurizer is the same as described above in the explanation of Figures 1 and 2. Specifically, the battery cell 10 pressurized by the battery cell pressurizer may include a positive electrode 11, a negative electrode 12, and a solid electrolyte 13. It may also further include a positive electrode lead 14 and a negative electrode lead 15 connected to the positive electrode 11 and the negative electrode 12, respectively.

[0043] The battery cell 10 may be a pouch-type battery cell in which a positive electrode 11, a negative electrode 12, and a solid electrolyte 13 are housed in a pouch 16, with parts of the leads 14 and 15 exposed to the outside of the pouch 16. The pouch-type battery cell 10 can be manufactured by placing the solid electrolyte 13 between the positive electrode 11 and the negative electrode 12, bonding the layers by cold isostatic press (CIP) or hot isostatic press (WIP), and then attaching the positive electrode leads 14 and the negative electrode leads 15 to form an electrode assembly, which is then housed in a pouch 16 and sealed.

[0044] On the other hand, at least two of the sizes of the positive electrode 11, the negative electrode 12, and the solid electrolyte 13 of the battery cell 10 can differ from each other. For example, the size of the positive electrode 11 may be smaller than the size of the negative electrode 12 and the size of the solid electrolyte 13. Here, size can mean at least one of the length in the longitudinal direction L and the length in the width direction W.

[0045] However, the structure of the battery cell pressurized by the battery cell pressurizing device 110 according to one embodiment of the present invention and activated by the battery cell charging / discharging device 100 is not limited to the structure of the battery cell 10 shown in the drawings.

[0046] According to one embodiment of the present invention, a battery cell charge / discharge device 100 is injected into a case 111 via an injection section 114 of the case 111 in which a battery cell 10 is arranged, and the injected fluid 112 can uniformly and isotropically pressurize the battery cell 10. In this state, the battery cell 10 can be activated by charging and discharging in the charge / discharge device 120. Therefore, it is possible to prevent problems such as cracks in the battery cell and short-circuit failures caused by differences in the sizes of the positive electrode 11, the negative electrode 12, and the solid electrolyte 13. For example, even if the size of the positive electrode 11 is smaller than the size of the solid electrolyte 13, it is possible to prevent cracks from occurring in the solid electrolyte 13, thereby also preventing problems such as the positive electrode 11 and the negative electrode 12 coming into contact with each other, or lithium deposition occurring during charging and discharging, which can cause short-circuit failures. Furthermore, by preventing problems such as cracks in the battery cell and short-circuit failures caused by them, it is also possible to prevent a decrease in the performance and lifespan of the battery cell.

[0047] Although one embodiment of the present invention has been described illustratively above, the embodiments of the present invention are not intended to be limited to the above-described embodiment. Those skilled in the art can appropriately modify and implement one embodiment of the present invention by referring to this specification and the accompanying drawings, without departing from the technical spirit of the present invention, by omitting, changing, substituting all or part of the configuration of the present invention, or by adding other configurations.

[0048] In this specification, the order of elements, such as "first," "second," etc., is for the purpose of distinguishing elements from one another and does not imply any priority or absolute order among the elements. An element referred to as "first" in one part of this specification may be referred to as "second" in another part of this specification.

[0049] The terms and expressions herein shall be interpreted broadly and not restrictively. In this specification, the expression “including” shall not exclude the presence or addition of one or more other components beyond those mentioned.

[0050] In this specification, singular expressions include plural forms unless explicitly excluded from the context.

[0051] The examples described herein are combinable with respect to each other, and the information described in one example can be applied to other examples without being described in another, as long as it does not contradict the other examples. [Explanation of Symbols]

[0052] 10: Battery cell 11: Positive electrode 12: Negative electrode 13: Solid electrolyte 14: Positive lead 15: Negative lead 16: Pouch 100: Battery cell charging and discharging device 110, 210: Battery cell pressurization device 111: Case 112:Fluid 113: Hall 114: Injection part 120: Charger / discharger 130: Conductive material 211, 212: Jig

Claims

1. A case in which a battery cell is arranged inside, and A fluid that fills the inside of the case and pressurizes the battery cell, The fluid has a viscosity of 100 cP or more and 1000 cP or less. The battery cell includes a positive electrode, a negative electrode, and a solid electrolyte. The case includes a hole through which a conductive member passes, which connects the battery cell to a charger / discharger and applies current to the battery cell. The fluid is a battery cell pressurizing device that isotropically pressurizes the battery cell during the activation process in which the battery cell is charged and discharged in the charger / discharger.

2. The battery cell pressurizing device according to claim 1, wherein the case further includes an injection section which is a path through which the fluid is injected into the case.

3. The battery cell pressurizing device according to claim 1, wherein the pressure at which the fluid pressurizes the battery cell is 3 MPa or more and 10 MPa or less.

4. The battery cell pressurizing device according to claim 1, wherein the fluid is an insulating substance.

5. The battery cell pressurizing device according to claim 1, wherein the fluid is in the state of oil or gel.

6. The battery cell pressurizing device according to claim 1, wherein the case has pressure resistance so as not to deform at a pressure of 3 MPa or more and 10 MPa or less.

7. The battery cell pressurizing device according to claim 1, wherein at least two of the sizes of the positive electrode, the negative electrode, and the solid electrolyte are different from each other.

8. The battery cell pressurizing device according to claim 1, wherein the battery cell is a pouch-type battery cell.

9. A battery cell pressurizing device according to any one of claims 1 to 8, and A battery cell charging and discharging device, including a charger / discharger for charging and discharging battery cells that are pressurized by the aforementioned battery cell pressurizing device.

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