Electrode sheet manufacturing system and battery manufacturing method

Abstract

The present invention provides an electrode sheet manufacturing system that can raise the temperature of the electrode body without increasing the ambient temperature and can make the thickness of the electrode body uniform after pressing, and a battery manufacturing method using the electrode sheet manufacturing system. [Solution] The electrode sheet manufacturing system according to the present disclosure is an electrode sheet manufacturing system that presses an electrode body to manufacture an electrode sheet, comprising: an irradiation means for irradiating an electrode body with a laser to raise the temperature of the electrode body; and a pressing means for pressing the electrode body heated by the irradiation means to manufacture an electrode sheet.

Description

Technical Field

[0001] The present disclosure relates to an electrode sheet manufacturing system and a method for manufacturing a battery.

Background Art

[0002] Patent Document 1 discloses a roll press device for an electrode for a battery, in which a heater for performing preliminary heating is arranged to suppress undulations, distortions, wrinkles, etc. of the electrode before pressing the electrode.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the roll press device disclosed in Patent Document 1, since not only the surface temperature of the electrode but also the space temperature rises due to the heater, the surface temperature of the electrode cannot be accurately obtained. Therefore, feedback control of the heater based on the surface temperature of the electrode cannot be performed, and there is a risk of uneven drying occurring on the electrode.

[0005] The present disclosure has been made in view of the above circumstances, and provides an electrode sheet manufacturing system capable of raising the temperature of an electrode body without raising the space temperature and making the thickness of the electrode body after pressing uniform, and a method for manufacturing a battery using the electrode sheet manufacturing system.

Means for Solving the Problems

[0006] An electrode sheet manufacturing system according to one aspect of the present disclosure is an electrode sheet manufacturing system for manufacturing an electrode sheet by pressing an electrode body, irradiation means for irradiating the electrode body with a laser to raise the temperature of the electrode body, The system includes a pressing means for pressing the electrode body, which has been heated by the irradiation means, to manufacture an electrode sheet.

[0007] A method for manufacturing a battery according to one aspect of this disclosure is: A method for manufacturing a battery using an electrode sheet manufactured by pressing an electrode body, An irradiation step in which a laser is irradiated onto an electrode body to raise the temperature of the electrode body, A temperature acquisition step is to acquire the surface temperature of the electrode body that has been heated in the irradiation step, A pressing step in which the heated electrode body is pressed to manufacture an electrode sheet in the irradiation step, A thickness acquisition step to obtain the thickness in the pressing direction of the electrode sheet formed by the pressing means, A laser control step that controls the laser based on the surface temperature and the thickness in the pressing direction, The system includes a housing step of housing the electrode sheet inside the battery container. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide an electrode sheet manufacturing system that can raise the temperature of the electrode body without raising the ambient temperature and make the thickness of the electrode body uniform after pressing, and a method for manufacturing a battery using the electrode sheet manufacturing system. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram of an electrode sheet manufacturing system according to an embodiment of the present disclosure. [Figure 2] This is a perspective view of an electrode sheet manufacturing system according to an embodiment of the present disclosure. [Figure 3] This is a side view of an electrode sheet manufacturing system according to an embodiment of the present disclosure. [Figure 4] This is a flowchart of a method for manufacturing a battery according to the embodiment of this disclosure. [Modes for carrying out the invention]

[0010] The following describes specific embodiments of this disclosure in detail with reference to the drawings. However, this disclosure is not limited to the following embodiments. Also, for clarity, the following descriptions and drawings have been simplified as appropriate.

[0011] <Configuration of the electrode sheet manufacturing system> Figure 1 is a block diagram of an electrode sheet manufacturing system according to an embodiment of the present disclosure. The electrode sheet manufacturing system 1 comprises a press roll 11, a semiconductor laser 12, a temperature sensor 13, a thickness sensor 14, and a control device 15, and manufactures an electrode sheet S by pressing an electrode body E. The press roll 11 is a pressing means, the semiconductor laser 12 is an irradiation means, the temperature sensor 13 is a temperature acquisition means, the thickness sensor 14 is a thickness acquisition means, and the control device 15 is a laser control means.

[0012] Figure 2 is a perspective view of the electrode sheet manufacturing system according to the present disclosure. Figure 3 is a side view of the electrode sheet manufacturing system according to the present disclosure. Note that the right-handed xyz Cartesian coordinate system shown in Figure 2 is for convenience in showing the positional relationships of the components. In Figure 2, the positive z-axis direction is vertically upward, and the xy-plane is the horizontal plane; this is common to all drawings. Also, the white arrows shown in Figures 2 and 3 indicate the transport direction of the electrode body E and electrode sheet S.

[0013] The electrode body E is heated by a laser irradiated by a semiconductor laser 12 and then pressed by a press roll 11 to form an electrode sheet S. The surface temperature of the electrode body E is measured by a temperature sensor 13, and the thickness of the electrode sheet S in the pressing direction is measured by a thickness sensor 14.

[0014] The electrode sheet S, which is pressed and formed into the electrode body E, is, for example, a bipolar electrode used to form a lithium-ion secondary battery. At this time, the electrode body E has a structure in which a positive electrode containing lithium iron phosphate, lithium cobaltate, lithium nickelate, lithium manganate, or the like and a negative electrode containing graphite, carbon, lithium titanate, or the like are laminated via a metal foil made of aluminum or copper. However, the electrode body E may have a laminated structure of electrodes used to form other batteries such as nickel-metal hydride batteries, lead-acid batteries, or all-solid-state batteries. Further, the electrode sheet S, which is pressed and formed into the electrode body E, may be a monopolar electrode having a positive electrode or a negative electrode and a metal foil. Further, the positive electrode and the negative electrode may optionally contain an electrolyte, a conductive assistant, and a binder.

[0015] Here, it is preferable that the positive electrode constituting the electrode body E contains lithium iron phosphate. When the wavelength of the laser irradiated by the semiconductor laser 12 resonates with the molecular vibration of the lithium iron phosphate contained in the positive electrode, the temperature increase effect of the positive electrode by laser irradiation is enhanced. Further, it is preferable that the negative electrode constituting the electrode body E contains graphite. When the wavelength of the laser irradiated by the semiconductor laser 12 resonates with the molecular vibration of the graphite contained in the negative electrode, the temperature increase effect of the negative electrode by laser irradiation is enhanced.

[0016] Note that when the temperature of the electrode body E rises, the workability of the electrode body E when pressed by the press roll 11 is improved. However, if the temperature of the electrode body E rises too much, the metal foil oxidizes and deteriorates. Therefore, the surface temperature of the electrode body E when pressed by the press roll 11 is preferably 180 to 190°C. Further, in order to make the thickness of the formed electrode sheet S uniform, it is preferable that the surface temperature of the electrode body E when pressed is uniform in the x-axis direction.

[0017] The press rolls 11 are arranged in a pair vertically side by side, and while rotating, press the electrode body E between the press rolls 11 in the z-axis direction, and form the electrode sheet S by compressing the electrodes. Note that the size of the press rolls 11 is appropriately determined according to the size of the electrode body E to be pressed, and the size and thickness of the target electrode sheet S. Also, the press pressure applied by the press rolls 11 is appropriately determined according to the material and thickness of the electrode body E to be pressed, and the thickness of the target electrode sheet. Also, the material of the press rolls 11 is an iron-based metal such as cast iron, cast steel, or carbon steel, and may be plated with chromium or the like on the surface. Also, in order to reduce the temperature drop of the electrode body E during pressing, the press rolls 11 may have a heating function.

[0018] Note that in FIGS. 2 and 3, only a pair of press rolls 11 arranged vertically side by side are drawn, but a plurality of press rolls 11 may be provided in the y-axis direction. By providing a plurality of press rolls 11 in the y-axis direction and newly providing either or both of the temperature sensor 13 and the thickness sensor 14 between the press rolls 11, the control accuracy of the semiconductor laser 12 is improved.

[0019] Also, in the electrode sheet manufacturing system 1 shown in FIGS. 2 and 3, a configuration in which the electrode body E is continuously pressed by the press rolls 11 to form the electrode sheet S is drawn, but the electrode sheet manufacturing system 1 may be a batch-type system that presses and sequentially conveys individual electrode bodies E. In this case, the pressing means may not have a roll shape and may have a configuration such as pressing the electrode body E by raising and lowering a slide using a crank.

[0020] The semiconductor laser 12 is connected to the control device 15 and irradiates the electrode body E with the laser before it is pressed by the press roll 11, thereby raising the temperature of the electrode body E. As shown in Figures 2 and 3, when the electrode body E is a bipolar electrode, one or more semiconductor lasers 12 are provided on the upper side of the electrode body E and one or more on the lower side. However, from the viewpoint of ease of control of the semiconductor laser 12, it is preferable that one semiconductor laser 12 capable of irradiating a wide area on the electrode body E is provided on the upper side of the electrode body E and one on the lower side.

[0021] The wavelength of the laser irradiated by the semiconductor laser 12 can be any wavelength that can cause a temperature rise by resonating with the molecular vibrations of the active material contained in the positive or negative electrode. However, from the viewpoint of the absorption wavelength of the active material contained in the positive or negative electrode, 700 to 1700 nm is preferred, and 700 to 900 nm is particularly preferred. Furthermore, since the active material contained in the positive electrode and the active material contained in the negative electrode are different, the wavelength of the laser may be different between the semiconductor laser 12 on the upper surface of the electrode body E and the semiconductor laser 12 on the lower surface of the electrode body E.

[0022] Furthermore, the output of the semiconductor laser 12 should be sufficient to raise the temperature of the electrode body E. However, from the viewpoint of accelerating the heating rate of the electrode body E and preventing electrode degradation, the energy density of the laser irradiated by the semiconductor laser 12 should be 1.3 to 1.5 W / cm². 2 It is preferable that this be the case.

[0023] Furthermore, in Figures 2 and 3, the laser emitted by the semiconductor laser 12 is directed not from the z-axis direction, but from a direction tilted from the z-axis direction in the negative y-axis direction (i.e., opposite to the transport direction of the electrode body E) onto the electrode body E. By irradiating the electrode body E from a direction tilted opposite to the transport direction of the electrode body E, it is possible to irradiate the electrode body E at a position closer to the pressing position. As a result, the time from when the electrode body E is heated by the laser until it is pressed by the press roll 11 is shortened, the temperature drop before pressing is reduced, and as a result the molding quality of the electrode sheet E is improved.

[0024] The temperature sensor 13 acquires the surface temperature of the electrode body E before it is pressed by the press roll 11 and transmits the acquired surface temperature information to the control device 15. The temperature sensor 13 acquires the surface temperature of the surface irradiated by the semiconductor laser 12, and is therefore provided on the upper and lower sides of the electrode body E, for example, when the electrode body E is a bipolar electrode. The temperature sensor 13 is preferably capable of acquiring the surface temperature of the electrode body E without contact, for example, it is a radiation thermometer.

[0025] The temperature acquisition position of the temperature sensor 13 is set so that the control device 15 can appropriately control the laser irradiated onto the electrode body E, for example, by acquiring the temperature at a single point on the surface of the electrode body E before it is pressed. However, the temperature may be acquired at multiple points aligned in both the x-axis and y-axis directions, or in either direction, and multiple temperature sensors 13 may be provided to acquire the temperatures at multiple points. In addition, the temperature sensor 13 may acquire the temperature distribution over a specific range on the surface of the electrode body E. By acquiring the temperature at multiple points or over a specific range, the laser irradiated onto the electrode body E can be controlled with higher precision.

[0026] Furthermore, it is preferable to set the temperature acquisition position of the temperature sensor 13 so that the y-axis distance between the press roll 11 and the temperature acquisition position is shortened. By shortening the y-axis distance between the press roll 11 and the temperature acquisition position, the surface temperature of the electrode body E when pressed by the press roll 11 can be estimated with higher accuracy, and the molding quality of the electrode sheet E is improved.

[0027] The thickness sensor 14 acquires the thickness of the electrode sheet S pressed by the press roll 11 in the pressing direction and transmits the acquired thickness information to the control device 15. The thickness sensor 14 is a non-contact thickness measuring instrument, for example, using a laser displacement meter.

[0028] The thickness acquisition position of the thickness sensor 14 is set so that the control device 15 can appropriately control the laser irradiated onto the electrode body E, and for example, the thickness in the press direction at a certain point on the surface of the electrode body E before it is pressed is acquired. However, the thickness in the press direction at multiple points aligned in the x-axis direction may also be acquired. Furthermore, if multiple press rolls 11 are provided in the y-axis direction, the thickness sensor 14 may be provided on the side of the electrode sheet S that is being transported for each press roll 11.

[0029] The control device 15 is connected to the semiconductor laser 12, the temperature sensor 13, and the thickness sensor 14. The control device 15 controls the semiconductor laser 12 based on the surface temperature information of the electrode body E acquired by the temperature sensor 13 and the thickness information of the electrode sheet S in the press direction acquired by the thickness sensor 14. The control device 15 is composed of, for example, a CPU, an MPU, working memory, and a non-volatile storage device that stores a control program.

[0030] The control method for the semiconductor laser 12 by the control device 15 is determined so as to appropriately control the surface temperature of the electrode body E when it is pressed by the press roll 11. For example, for a certain point A on the electrode body E during transport, surface temperature information at time t1 and thickness information at time t2 are combined to derive a relationship equation between surface temperature and thickness. Based on this relationship equation, the surface temperature at which the electrode sheet E reaches a predetermined thickness is estimated, and the semiconductor laser 12 is feedback-controlled to obtain that surface temperature. Alternatively, the surface temperature information and thickness information may be used to train artificial intelligence (AI), and the semiconductor laser 12 may be controlled based on the trained data.

[0031] Furthermore, as a specific method of controlling the semiconductor laser 12 by the control device 15, for example, the energy density of the laser is changed by changing the output of the semiconductor laser 12, thereby controlling the surface temperature of the electrode body E. Alternatively, the surface temperature of the electrode body E may be controlled by changing the irradiation area, irradiation time, irradiation angle, or irradiation position of the semiconductor laser 12.

[0032] As described above, the electrode sheet manufacturing system according to the embodiment of this disclosure heats the electrode body by laser irradiation before pressing, and controls the laser based on the surface temperature of the electrode body and the thickness of the electrode sheet in the pressing direction. This makes it possible to provide an electrode sheet manufacturing system that heats the electrode body without raising the ambient temperature and can make the thickness of the electrode body uniform after pressing.

[0033] <Battery manufacturing method> Next, with reference to Figure 4, a method for manufacturing a battery using an electrode sheet manufactured by the electrode sheet manufacturing system according to the embodiment of this disclosure will be described. Figure 4 is a flowchart of the battery manufacturing method according to the embodiment of this disclosure.

[0034] First, the electrode body E is irradiated with a semiconductor laser 12 to raise its temperature (step S1). Here, the laser energy density, irradiation area, and irradiation time are appropriately determined so that the desired electrode sheet S is obtained in step S3, which will be described later.

[0035] Next, the surface temperature of the electrode body E is acquired using the temperature sensor 13 (step S2). The surface temperature information of the electrode body E acquired by the temperature sensor 13 is transmitted to the control device 15.

[0036] Next, the electrode body E is pressed using the press roll 11 to form the electrode sheet S (step S3). Here, the rotation speed of the press roll 11 and the forming speed of the electrode sheet S are appropriately determined considering the desired manufacturing speed or quality of the electrode sheet S. Furthermore, the electrode sheet S formed in step S3 is transported by, for example, installing a winding machine on the positive y-axis side in Figure 3 and continuously winding the electrode sheet S using the winding machine. Alternatively, transport may be performed by using a conveying device such as a belt-type conveyor and placing the electrode sheet S on the conveyor.

[0037] Next, the thickness of the molded electrode sheet S in the press direction is obtained using the thickness sensor 14 (step S4). The thickness information of the electrode sheet S obtained by the thickness sensor 14 is transmitted to the control device 15.

[0038] Next, the control device 15 controls the semiconductor laser 12 based on the surface temperature information of the electrode body E received in step S2 and the thickness information of the electrode sheet S received in step S4, and controls the laser irradiated onto the electrode body E (step S5). The control method of the semiconductor laser 12 is as described above.

[0039] After controlling the semiconductor laser 12 in step S5, the process moves to determining whether or not the electrode sheet S has been formed (step S6). If the electrode sheet S has been formed (Yes in step S6), the process proceeds to step S7, in which the electrode sheet S is placed inside the battery container. On the other hand, if the electrode sheet S has not been formed (No in step S6), the process returns to step S1, and the laser continues to irradiate the electrode body E. By repeating steps S1 to S6, feedback control of the semiconductor laser 12 is performed based on the surface temperature information of the electrode body E and the thickness information of the electrode sheet S. The control interval of this feedback control is appropriately determined to obtain the desired electrode sheet S.

[0040] The molded electrode sheets S are placed inside the battery container, and the battery is manufactured (step S7). In step S7, separators, electrolytes, etc., which are to be placed between the electrode sheets S, may also be placed inside at the same time, according to the desired battery configuration.

[0041] Furthermore, step S7 may be placed between steps S5 and S6. That is, while the electrode sheet S is being molded, the already molded electrode sheet S may be placed in the battery container at any time to manufacture the battery.

[0042] As described above, the battery manufacturing method according to the embodiment of this disclosure involves forming an electrode sheet using a semiconductor laser that is feedback-controlled based on surface temperature information of the electrode body and thickness information of the electrode sheet, and then manufacturing a battery using the electrode sheet. This provides a battery manufacturing method using an electrode sheet manufacturing system that can raise the temperature of the electrode body without raising the ambient temperature and can make the thickness of the electrode body uniform after pressing. [Explanation of Symbols]

[0043] 1. Electrode Sheet Manufacturing System 11 Press Roll 12 Semiconductor lasers 13 Temperature sensor 14. Thickness Sensor 15 Control device E electrode body S electrode sheet

Claims

1. An electrode sheet manufacturing system that presses electrode bodies to manufacture electrode sheets, An irradiation means for irradiating the electrode body with a laser and raising the temperature of the electrode body, The system includes a pressing means for pressing the electrode body, which has been heated by the irradiation means, to form an electrode sheet. Electrode sheet manufacturing system.

2. A temperature acquisition means for acquiring the surface temperature of the electrode body that has been heated by the irradiation means, A thickness acquisition means for acquiring the thickness in the pressing direction of the electrode sheet formed by the pressing means, The system further comprises laser control means for controlling the laser based on the surface temperature and the thickness in the pressing direction, The electrode sheet manufacturing system according to claim 1.

3. The electrode body comprises lithium iron phosphate or graphite, The laser has a wavelength that causes molecular vibrations in the lithium iron phosphate or the graphite, causing it to heat up. The electrode sheet manufacturing system according to claim 1 or 2.

4. The laser irradiates the electrode body from a direction perpendicular to the main surface of the electrode body and inclined in the opposite direction to the transport direction of the electrode body. The electrode sheet manufacturing system according to claim 1 or 2.

5. A method for manufacturing a battery using an electrode sheet manufactured by pressing an electrode body, An irradiation step in which a laser is irradiated onto an electrode body to raise the temperature of the electrode body, A temperature acquisition step is to acquire the surface temperature of the electrode body that has been heated in the irradiation step, A pressing step in which the heated electrode body is pressed to manufacture an electrode sheet in the irradiation step, A thickness acquisition step to acquire the thickness in the pressing direction of the electrode sheet formed in the pressing step, A laser control step that controls the laser based on the surface temperature and the thickness in the pressing direction, The system includes a housing step of housing the electrode sheet inside the battery container. Battery manufacturing method.

Images