Battery module

Abstract

Provided is a battery module that uses space efficiently and has high impact resistance. This battery module comprises a cylindrical hollow frame body, and a battery that is accommodated in the frame body. The frame body has a flat annular base portion, and a first column group and a second column group that are fixed to the flat surface of the base portion. The first column group is fixed to a flat annular first beam at a portion that extends vertically with respect to the flat surface of the base portion. The second column group is fixed to a flat annular second beam that has the same central axis as the first beam at a portion that extends vertically with respect to the flat surface of the base portion. The outside diameter of the first beam is less than the inside diameter of the second beam. The battery is positioned between the base portion, the first column group, and the second column group.

Description

Battery module 【0001】 One aspect of the present invention relates to a product, a method, or a method of making a product. Alternatively, the present invention relates to a process, a machine, a manufacture, or a composition of matter. Another aspect of the present invention relates to an energy storage device, a semiconductor device, a display device, a light-emitting device, a lighting device, an electronic device, or a method of manufacturing the same. 【0002】 In this specification, "electronic equipment" refers to all devices that have an energy storage device, and all electro-optical devices with an energy storage device, information terminal devices with an energy storage device, etc., are considered electronic equipment. 【0003】 In this specification, the term "energy storage device" refers to all elements and devices that have an energy storage function, and includes, for example, energy storage devices such as lithium-ion batteries (also called secondary batteries), lithium-ion capacitors, and electric double-layer capacitors. 【0004】 As secondary batteries, various energy storage devices such as lithium-ion batteries, lithium-ion capacitors, and air batteries are being actively developed. In particular, lithium-ion batteries, which offer high output and high energy density, are installed in mobile information terminals such as mobile phones, smartphones, tablets, and notebook computers, as well as portable music players, digital cameras, medical equipment, clean energy vehicles (hybrid vehicles (HV), electric vehicles (EV), plug-in hybrid vehicles (PHV), etc.), agricultural machinery, motorized bicycles including electric-assist bicycles, motorcycles, electric wheelchairs, electric carts, ships, submarines, aircraft, rockets, artificial satellites, space probes, planetary probes, and spacecraft. Thus, the demand for lithium-ion secondary batteries has expanded rapidly in conjunction with the development of the semiconductor industry, and they have become indispensable as a source of rechargeable energy in today's information society. 【0005】 In recent years, wearable devices have been actively developed. Due to their nature as devices worn on the body, it is preferable for wearable devices to have a curved shape that conforms to the curves of the body, or to bend in accordance with body movements. Therefore, it is preferable for the rechargeable battery installed in a wearable device to be flexible, just like the display and other components of the housing. 【0006】 Furthermore, even in devices other than wearable devices, it is preferable for secondary batteries to be flexible, as being able to deform them when they are installed can improve the efficiency of utilizing the internal space of the device. 【0007】 As examples of flexible secondary batteries, Patent Documents 1 and 2 disclose electrochemical devices (e.g., secondary batteries, capacitors, etc.) that are coated with a metal laminate and have a structure that is easy to bend and maintain in a bent state. 【0008】 Furthermore, there is a growing demand for electronic equipment that can withstand harsh environments, specifically low temperatures (e.g., -50°C) or high temperatures (e.g., 100°C), and is intended for use across a wide range of operating temperatures. Examples include observation equipment around the Antarctic or Arctic, seismometers installed around the craters of active volcanoes, artificial satellites orbiting the Earth, and probes intended for use in exploring other planets. 【0009】 Furthermore, it is desirable that seismometers or probes have excellent shock resistance, such as from drops. It would be convenient if seismometers could be dropped from unmanned aircraft into dangerous areas near craters where humans cannot carry measuring instruments. There are also plans to drop penetrators from orbiting satellites of planets to install seismometers from the planet's surface into its interior. A penetrator is a probe equipped with a two-axis seismometer. 【0010】 Traditionally, 18650 type cylindrical batteries have been used as power sources for such electronic devices. In the past, primary batteries were used for single-use devices, and after short-term use, they were disposable and could function as power sources. 【0011】 However, considering factors such as long-term measurement or weight limitations during transport, it is desirable to use rechargeable batteries that can be charged using solar power. Furthermore, it is desirable to collect the measuring equipment after installation and reuse it. 【0012】 A rechargeable battery that can bend even when external force is applied is disclosed in Patent Documents 3 and 4. 【0013】 Furthermore, a frame for fixing a secondary battery is disclosed in Patent Documents 5 and 6. 【0014】 Japanese Patent Publication No. 2004-241250, Japanese Patent Publication No. 2018-6336, Japanese Patent Publication No. 2015-233004, Japanese Patent Publication No. 2016-139609, Japanese Patent Publication No. 2011-181369, Japanese Patent Publication No. 2020-47573 【0015】 One type of astronomical observation instrument is a rocket-shaped, autonomous observation probe called a penetrator. The rechargeable battery mounted on the penetrator needs to have high shock resistance. While it's possible to enclose the battery with thick metal plates to achieve shock resistance, this would significantly increase the total weight of the penetrator. 【0016】 Conventional 18650-type cylindrical lithium-ion batteries fill a cylindrical casing with electrolyte, and connect the internal winding to the external terminals. Because a large amount of electrolyte is used to fill the casing, the winding may shift position due to impact. In addition, temperature changes may cause the electrolyte to expand or gasify. Therefore, conventional secondary batteries using cylindrical casings are vulnerable to impact from drops and may leak. 【0017】 Furthermore, because all-solid-state batteries are composed of ceramics, at least partially, they are brittle when subjected to impact. If cracks occur, they may lose conductivity and become unusable. 【0018】 Therefore, as a secondary battery with high impact resistance, it is preferable to use a laminated type battery that uses a lightweight laminate film as its outer casing, rather than a cylindrical or coin-shaped battery. Furthermore, as shown in Patent Document 4, it is possible to manufacture a flexible secondary battery as a laminated type battery. A flexible secondary battery can be mounted in the curved space of equipment such as a penetrator, so it is expected to improve space utilization efficiency. However, methods for fixing a flexible secondary battery inside equipment have not been sufficiently studied until now. In addition, a battery module having a flexible secondary battery and high space utilization efficiency and impact resistance has not been realized. 【0019】 In view of these problems, one aspect of the present invention aims to provide a battery module that has high space utilization efficiency and high impact resistance. 【0020】 Furthermore, there is still room for improvement in various aspects of secondary batteries, including discharge capacity, cycle characteristics, reliability, safety, and cost. For example, in order to suppress changes in the crystal structure of the surface of the positive electrode active material, the surface of the positive electrode active material is sometimes coated with an inert oxide, but this coating may inhibit the insertion and removal of lithium. If the insertion and removal of lithium ions is inhibited, there is a concern that the characteristics of the secondary battery will deteriorate, such as a decrease in rate characteristics and a decrease in charge and discharge capacity in low-temperature environments. 【0021】 Therefore, one aspect of the present invention aims to provide a positive electrode active material that can be used in lithium-ion secondary batteries and promotes the insertion and removal of lithium ions. Alternatively, it aims to provide a positive electrode active material in which the decrease in discharge capacity in low-temperature environments is suppressed. Alternatively, it aims to provide a positive electrode active material in which the decrease in discharge capacity in high-speed discharge is suppressed. Alternatively, it aims to provide a positive electrode active material in which the decrease in discharge capacity in charge-discharge cycles is suppressed. Alternatively, it aims to provide a positive electrode active material whose crystal structure is less likely to collapse even after repeated charge-discharge cycles. Alternatively, it aims to provide a positive electrode active material with a large discharge capacity. 【0022】 Alternatively, one aspect of the present invention aims to provide a secondary battery that has high shock resistance and suppresses the decrease in discharge capacity in low-temperature environments. 【0023】 Alternatively, in one aspect of the present invention, one objective is to provide a battery module that has a temperature control function and high space utilization efficiency and shock resistance. 【0024】 Alternatively, one aspect of the present invention aims to provide a battery module with a novel structure. Alternatively, one aspect of the present invention aims to provide a secondary battery with a novel structure. Alternatively, one aspect of the present invention aims to provide a novel energy storage device, an electronic device equipped with a novel secondary battery, etc. 【0025】 Furthermore, the description of these problems does not preclude the existence of other problems. Moreover, one aspect of the present invention does not necessarily have to solve all of these problems. Furthermore, those skilled in the art can naturally identify other problems from the description in the specification, drawings, and claims, and it is possible to extract other problems from the description in the specification, drawings, and claims. 【0026】 One aspect of the present invention is a battery module comprising a cylindrical hollow frame and a battery housed within the frame, wherein the frame comprises a flat annular base portion and a first group of columns and a second group of columns fixed to the flat surface of the base portion, the first group of columns being fixed to a first annular beam portion in a portion extending perpendicular to the flat surface, the second group of columns being fixed to a second annular beam portion having the same central axis as the first beam portion in a portion extending perpendicular to the flat surface, the outer diameter of the first beam portion being smaller than the inner diameter of the second beam portion, and the battery being located between the base portion, the first group of columns, and the second group of columns. 【0027】 In the above, it is preferable that the first column group and / or the second column group are connected to a temperature control device. Furthermore, it is even more preferable that there are multiple temperature sensors between the first column group or the second column group and the battery, and that the temperature control device has a function to control the temperature so that the temperature difference between the multiple temperature sensors is within 5°C. 【0028】 According to one aspect of the present invention, a battery module with high space utilization efficiency and high impact resistance can be provided. 【0029】According to one aspect of the present invention, a positive electrode active material can be provided that can be used in lithium-ion secondary batteries and that promotes the insertion and removal of lithium ions. Alternatively, a positive electrode active material can be provided in which the decrease in discharge capacity in low-temperature environments is suppressed. Alternatively, according to one aspect of the present invention, a positive electrode active material can be provided in which the decrease in discharge capacity in high-speed discharge is suppressed. Alternatively, according to one aspect of the present invention, a positive electrode active material can be provided in which the decrease in discharge capacity in charge-discharge cycles is suppressed. Alternatively, according to one aspect of the present invention, a positive electrode active material can be provided in which the crystal structure is less likely to collapse even after repeated charging and discharging. Alternatively, according to one aspect of the present invention, a positive electrode active material with a large discharge capacity can be provided. 【0030】 Alternatively, one aspect of the present invention can provide a secondary battery that has high shock resistance and suppresses the decrease in discharge capacity in low-temperature environments. 【0031】 Alternatively, in one aspect of the present invention, a battery module can be provided that has a temperature control function and high space utilization efficiency and shock resistance. 【0032】 Alternatively, one aspect of the present invention can provide a battery module with a novel structure. Alternatively, one aspect of the present invention can provide a secondary battery with a novel structure. Alternatively, one aspect of the present invention can provide a novel energy storage device, an electronic device equipped with a novel secondary battery, and the like. 【0033】 Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one aspect of the present invention does not necessarily have to possess all of these effects. Furthermore, those skilled in the art can naturally discover other effects from the description in the specification, drawings, and claims, and it is possible to extract other effects from the description in the specification, drawings, and claims. 【0034】Figures 1A, 1B, and 1C are perspective views illustrating an example of the configuration of a battery module. Figures 2A, 2B, and 2C are perspective views illustrating an example of the configuration of a battery module. Figures 3A, 3B, and 3C are top views illustrating the frame. Figures 4A and 4B are schematic diagrams illustrating a secondary battery and a temperature control device. Figures 5A, 5B, 5C, and 5D are top views illustrating the frame. Figures 6A and 6B are perspective views illustrating an example of the configuration of a battery module. Figure 7 is a perspective view illustrating an example of mounting a battery module on a penetrator. Figures 8A and 8B are perspective views illustrating an example of mounting a battery module on a penetrator. Figure 9 is a perspective view illustrating an example of mounting a battery module on a penetrator. Figures 10A, 10B, 10C, 10D, and 10E are diagrams illustrating an example of the configuration of a battery. Figures 11A, 11B, and 11C are diagrams illustrating an example of the configuration of a battery. Figures 12A, 12B, and 12C show examples of battery configurations. Figures 13A, 13B, and 13C show examples of battery configurations. Figure 14 is a diagram illustrating a film processing method. Figures 15A, 15B, 15C, 15D, and 15E are diagrams illustrating a film processing method. Figures 16A and 16B are diagrams illustrating a film processing method. Figure 16C is a perspective view of a curved battery. Figures 17A and 17B are diagrams illustrating a film processing method. Figure 17C is a perspective view of a curved battery. Figures 18A and 18B illustrate an example of an electronic device. 【0035】 Embodiments of the present invention will be described in detail below with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and its form and details can be modified in various ways. Furthermore, the present invention is not to be interpreted as being limited to the embodiments described below. 【0036】 The positions, sizes, and ranges of each component shown in the drawings may not represent their actual positions, sizes, and ranges in order to facilitate understanding. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and ranges disclosed in the drawings. 【0037】Furthermore, in the diagrams illustrating the present invention, some components (such as the ratio of electrode size to thickness) may be exaggerated to facilitate understanding. Also, some components may be omitted from the diagrams to avoid making them cluttered. 【0038】 Ordinal numbers such as "first," "second," and "third" are added to avoid confusion among the constituent elements. 【0039】 In this specification, "parallel" means a state in which two lines are positioned at an angle of -10° or more and 10° or less. Therefore, the case of -5° or more and 5° or less is also included. Furthermore, "approximately parallel" or "roughly parallel" means a state in which two lines are positioned at an angle of -30° or more and 30° or less. 【0040】 In this specification, "perpendicular" means a state in which two lines are arranged at an angle of 80° to 100°. Therefore, the case of 85° to 95° is also included. Furthermore, "approximately perpendicular" or "roughly perpendicular" means a state in which two lines are arranged at an angle of 60° to 120°. 【0041】 Furthermore, in this specification, flexibility refers to the property of an object being flexible and able to bend. It is the property of an object being able to deform in response to an external force applied to it, and does not concern itself with elasticity or the ability to return to its original shape. Deformation in response to an external force means that it can be deformed by an average adult's hand without requiring excessive force. Flexibility can be quantified as an object's deformation in response to an external force using a testing machine capable of measuring stress-strain (such as a tensile tester or compression tester). 【0042】 Furthermore, in this specification, when an object is described as having flexibility, it means that at least a part of the object is flexible. In other words, a flexible object may also have parts that are not flexible (also called rigid parts). 【0043】Furthermore, in this specification, a highly flexible object is defined as the object that deforms more when two objects are deformed with the same external force. Also, when a first part and a second part of an object are deformed with the same external force, the part that deforms more is considered to be the highly flexible part. 【0044】 (Embodiment 1) In this embodiment, an example of the configuration of a battery module according to one aspect of the present invention will be described with reference to Figures 1 to 6. 【0045】 [Battery Module] Figures 1A to 1C show schematic diagrams of a battery module 10 according to one embodiment of the present invention. Figure 1A is a perspective view of the battery module 10. Figure 1B is a perspective view of the frame 100 of the battery module 10. Figure 1C is a perspective view of the secondary battery 150 of the battery module 10. 【0046】 As shown in Figure 1A, the battery module 10 has a cylindrical hollow frame 100 and a secondary battery 150 housed in the frame 100. 【0047】 The secondary battery 150 has the capability to be bent and is held in the frame 100 in a curved state. The secondary battery 150 in the curved state is shown in Figure 1C. The secondary battery 150 with the capability as shown in Figure 1C is sometimes called a flexible battery, a bendable battery, a battery that can be bent, a curved battery, a battery that can be bent, etc. 【0048】 Figure 1B shows the frame 100 from which the secondary battery 150 has been removed from the battery module 10. 【0049】 The frame 100 will be described using Figures 1B, 2A to 2C. Figure 2A is a top view of the frame 100 shown in Figure 1B. As shown in Figures 1B and 2A, the frame 100 has a base portion 101, a first beam portion 111, a second beam portion 112, a first column portion 121, and a second column portion 122. In the frame 100, the base portion 101 and the first beam portion 111 are connected via the first column portion 121. Also, in the frame 100, the base portion 101 and the second beam portion 112 are connected via the second column portion 122. 【0050】 Figure 2B is a top view of the first beam section 111, the second beam section 112, the first column section 121, the second column section 122, and the secondary battery 150. As shown in Figure 2B, the first beam section 111 and the second beam section 112 are each in the shape of a flat plate annular. Figure 2C is a top view of the base section 101, the first column section 121, and the second column section 122. As shown in Figure 2C, the base section 101 is in the shape of a flat plate annular. 【0051】 The positional relationship between the first beam section 111, the second beam section 112, and the base section 101 will be explained using the top view of Figure 2A. As shown in Figure 2A, in a top view, the first beam section 111, the second beam section 112, and the base section 101 are each in the shape of a flat plate annular, and it is preferable that these annular sections are parallel and have the same central axis. Furthermore, the length of the inner diameter of the first beam section 111 is greater than or equal to the length of the inner diameter of the base section 101, the length of the inner diameter of the second beam section 112 is greater than or equal to the length of the outer diameter of the first beam section 111, and the length of the outer diameter of the base section 101 is greater than or equal to the length of the outer diameter of the second beam section 112. 【0052】 Furthermore, it is preferable that the first column portion 121 and the second column portion 122 are cylindrical in shape and extend perpendicularly to the flat surface of the first beam portion 111, the second beam portion 112, and the base portion 101. 【0053】 As shown in Figures 1B and 2B, the first beam section 111 has a portion that connects to the first column sections 121 (121_1, 121_2, 121_3, 121_4, 121_5, 121_6, 121_7, and 121_8). Similarly, the second beam section 112 has a portion that connects to the second column sections 122 (122_1, 122_2, 122_3, 122_4, 122_5, 122_6, 122_7, and 122_8). In other words, the frame 100 has a plurality of first column sections 121, and each of the plurality of first column sections 121 has a portion that connects to the first beam section 111. Similarly, the frame 100 has a plurality of second column portions 122, each of which has a portion connected to a second beam portion 112. In addition, the plurality of first column portions 121 are provided on the inner circumference side of the base portion 101, and the plurality of second column portions 122 are provided on the outer circumference side of the base portion 101. 【0054】Furthermore, the multiple first column sections 121 can be referred to as the first column group, and the multiple second column sections 122 can be referred to as the second column group. Therefore, in explaining the above configuration, the first column group can be described as being fixed to the flat surface of the base section 101 and fixed to the first beam section 111 in the portion that extends perpendicularly to the flat surface of the base section 101. Similarly, the second column group can be described as being fixed to the flat surface of the base section 101 and fixed to the second beam section 112 in the portion that extends perpendicularly to the flat surface of the base section 101. 【0055】 Although Figure 2B and other figures show an example configuration with eight first column sections 121 and eight second column sections 122, the number of first column sections 121 and second column sections 122 is not limited to these. In other words, the number of first column sections 121 can be less than eight or more than eight. Similarly, the number of second column sections 122 can be less than eight or more than eight. Furthermore, the number of first column sections 121 and the number of second column sections 122 can be different. 【0056】 As shown in Figures 1A and 2B, the secondary battery 150 is provided between the base portion 101, the first column portion 121, and the second column portion 122. It is also preferable that the secondary battery 150 is in contact with both the first column portion 121 and the second column portion 122. Furthermore, it is more preferable that the secondary battery 150 is sandwiched between the first column portion 121 and the second column portion 122. In other words, the secondary battery 150 is provided between the base portion 101, the first column group, and the second column group. It is also preferable that the secondary battery 150 is in contact with both the first column group and the second column group. Furthermore, it is more preferable that the secondary battery 150 is sandwiched between the first column group and the second column group. Furthermore, in the above configuration, since the secondary battery 150 is provided in a bent state, the gap between electrodes inside the secondary battery 150 can be reduced, making it easier to improve battery characteristics, which is preferable. 【0057】 As shown in Figure 2C, the base portion 101 has a portion that connects to the first column portion 121. The base portion 101 also has a portion that connects to the second column portion 122. 【0058】As explained in Figures 1A to 2C above, the frame 100 of the battery module 10 according to one aspect of the present invention can hold the secondary battery 150 in a curved state. 【0059】 The base portion 101, first beam portion 111, second beam portion 112, first column portion 121, and second column portion 122 of the frame 100 are preferably made using one or more of the following materials: resin materials such as polypropylene resin, polytetrafluoroethylene (PTFE) resin, acrylonitrile butadiene styrene (ABS) resin, polycarbonate (PC) resin, engineering plastics, lightweight metal materials such as aluminum, and alloys. 【0060】 In one embodiment of the present invention, the battery module 10 preferably has a temperature control device in addition to the above configuration. Figure 3A shows a perspective view of an example of a battery module 10 having a temperature control device 200. 【0061】 Figure 3A shows an example configuration in which the temperature control device 200 is located in contact with the lower surface of the base portion 101 of the frame 100. Figure 3B is a schematic diagram illustrating the connection relationship between the temperature control device 200 and the first column portion 121 and the second column portion 122. Figure 3C is a schematic diagram illustrating the contact relationship between the first column portion 121 and the second column portion 122 connected to the temperature control device 200 and the secondary battery 150. 【0062】 As shown in Figure 3B, it is preferable that the temperature control device 200 is connected to the first column section 121 and the second column section 122. Although not shown, it is preferable that the first column section 121 and the second column section 122 are connected to the temperature control device 200 and also to the base section 101. 【0063】As shown in Figure 3C, the secondary battery 150 is preferably sandwiched between a first column 121 and a second column 122, and the first column 121 and the second column 122 are preferably metal cylinders or cylindrical shapes. Alternatively, the first column 121 and the second column 122 are preferably metal-coated cylinders. The metal is preferably a material with high thermal conductivity such as aluminum, copper, or nickel. Furthermore, in the case of a metal-coated cylinder, the base material may be, for example, a resin material such as polypropylene resin, PTFE resin, ABS resin, PC resin, or engineering plastic. 【0064】 Having the first column portion 121 and the second column portion 122 as described above is preferable because, as shown in Figure 3C, the temperature control device 200 can control the temperature of the secondary battery 150 via the first column portion 121 and the second column portion 122. 【0065】 The temperature control device 200 includes a controller 201 and a temperature control unit 202. As shown in Figure 4A, for example, the temperature control unit 202 can be connected to a first column 121 and a second column 122. The controller 201 can heat or cool the temperature control unit 202 by referring to the value of a temperature sensor (not shown) separately provided in contact with the secondary battery 150 and a set temperature value. As a result, the temperature control device 200 can control the temperature of the secondary battery 150 via the first column 121 and the second column 122. 【0066】Furthermore, as shown in Figure 4B, temperature control units 202 (202_1, 202_2, 202_3, 202_4, 202_5, 202_6, 202_7, 202_8, 202_9, 202_10, and 202_11) can be provided for each of the first column section 121 and the second column section 122, and in this case, temperature control can be performed using each of the first column section 121 and the second column section 122. As shown in Figure 4B, a configuration with multiple temperature control units 202 is preferable because it can reduce temperature unevenness, such as some parts of the secondary battery 150 being too high or too low. In the case of a configuration with multiple temperature control units 202, it is preferable to have multiple temperature sensors (not shown) separately provided in contact with the secondary battery 150. In this case, it is preferable to control the temperature control unit 202 so that the temperature difference detected by the multiple temperature sensors is within 20°C, more preferably within 10°C, and even more preferably within 5°C. By having a temperature control function as described above, it is possible to suppress uneven battery reaction within the secondary battery 150, and as a result, the deterioration of the secondary battery 150 can be suppressed. 【0067】 For example, a heater with a heating element, a Peltier element, etc., can be used as the temperature control unit 202. 【0068】 In Figure 2B, etc., an example is shown in which the beam portion of the frame 100 is divided into two parts, a first beam portion 111 and a second beam portion 112. However, the shape of the beam portion of the frame 100 in one embodiment of the present invention is not limited to the above, and a beam portion with the shape shown in Figure 5A, which is a third beam portion 113A formed by joining the first beam portion 111 and the second beam portion 112, may also be used. 【0069】Furthermore, in the schematic diagrams used to describe the first beam section 111, the second beam section 112, and the third beam section 113A, the locations for connection with the first column section 121 or the second column section 122 are shown as circular holes, and the circular holes (beam section) and the shaft (column section) can be fixed by fitting them together. However, the connection between the beam section and the column section is not limited to this configuration example, and can be fixed by connection parts of the shapes shown in Figures 5B to 5D. Figure 5B is a top view showing the third beam section 113B, a modified example of the third beam section 113A, Figure 5C is a schematic diagram showing an enlarged view of the area indicated by the dashed line in Figure 5B, and Figure 5D is a schematic diagram illustrating how the beam section and the column section are connected at the location shown in Figure 5C. 【0070】 In one embodiment of the present invention, a battery module 10 has a frame 100 in which one first beam portion 111 and one second beam portion 112 are described in Figure 1A and the like. However, the number of first beam portions 111 and second beam portions 112 is not limited to one. For example, as shown in Figure 6A, it is possible to have a configuration in which there are two first beam portions 111 (111_1, 111_2) and two second beam portions 112 (112_1, 112_2), and it is also possible to have a configuration in which there are three or more. 【0071】 Furthermore, as shown in the example of fabrication in Figure 6B, the structure may have three third beam sections 113B (113B_1, 113B_2, 113B_3). 【0072】 A battery module 10 according to one aspect of the present invention has a hollow frame 100 constructed using a flat, annular-shaped beam portion or the like. Therefore, there is a space inside the hollow frame 100, specifically inside the first beam portion 111. Functional components such as electronic circuits and sensors can be mounted in this space. As an example, the configuration of a battery module 10 according to one aspect of the present invention used in a penetrator will be explained with reference to Figures 7 to 9. 【0073】Figure 7 is a perspective view showing how the circuit section 11 and sensor section 12 are housed in the internal space of the battery module 10. As shown in Figure 7, components such as the circuit section 11 and sensor section 12 can be housed in the internal space of the battery module 10. In this way, one embodiment of the present invention provides high space utilization efficiency by housing components such as the circuit section 11 and sensor section 12 in its internal space. In other words, the battery module 10 according to one embodiment of the present invention is suitable for applications where multiple components need to be mounted in a limited space, such as penetrators. Note that Figure 7 is just an example, and the components housed in the internal space of the battery module 10 are not limited to those shown above, and the application example is not limited to penetrators, but may also be used in general-purpose electronic devices. 【0074】 Furthermore, when a battery module 10 according to one embodiment of the present invention is used in a penetrator, it is preferable that the battery module 10 and the components housed in the space inside it be fixed with resin or the like. This fixing with resin or the like is also called potting. 【0075】 Figures 8A and 8B are perspective views showing the potting process of a battery module 10, which houses the circuit section 11 and the sensor section 12 in its internal space. Potting is performed to improve the mechanical stability of the circuit section 11, the sensor section 12, the battery module 10, etc., and involves filling the gaps around various components, connectors, wires, etc., with a potting material such as resin. As the potting material, a material with high insulation properties, high temperature resistance, and high weather resistance is preferred, and resin materials such as epoxy resin, silicone, fluororesin, and polyurethane can be used. 【0076】Figure 8A shows a cylindrical container, prepared to match the inner diameter of the penetrator, into which a battery module 10 is placed, and potting material 20a is poured in. The potting material 20a, poured in in a liquid state, hardens into potting material 20 after undergoing a predetermined hardening treatment, allowing the battery module 10 to be fixed inside. The frame 100 of the battery module 10 in one embodiment of the present invention has a structure with many gaps, as shown in Figure 1, etc., and is a preferred structure because it is less likely to cause air pockets when pouring in potting material 20a as in Figure 8A, and degassing is easy. 【0077】 A schematic diagram in Figure 9 shows an example of mounting the battery module 10, etc., in the state shown in Figure 8B after potting, onto a penetrator. By performing this potting process, it becomes possible to withstand vibrations and shocks when mounted on and operated by the penetrator. 【0078】 Although Figures 1 to 9 show an example configuration of a battery module 10 having one secondary battery 150, the number of secondary batteries 150 in the battery module 10 is not limited to one, and it may have two or more. In this case, they can be connected in series, in parallel, or a combination of direct and parallel connections. 【0079】 The contents of this embodiment can be freely combined with the contents of other embodiments. 【0080】 (Embodiment 2) In this embodiment, an example of the configuration of a secondary battery 150 in a battery module according to one aspect of the present invention will be described. 【0081】 The secondary battery 150 in a battery module according to one aspect of the present invention is preferably flexible. Alternatively, the secondary battery 150 in a battery module according to one aspect of the present invention is preferably curved. 【0082】 [Secondary Battery] An example of a flexible secondary battery 150 is shown in Figures 10A to 17C. 【0083】The secondary battery 150 is preferably a lithium-ion battery having a negative electrode, a positive electrode, an electrolyte, a separator, and an outer casing. 【0084】 [Negative electrode] The negative electrode comprises a negative electrode active material layer and a negative electrode current collector. The negative electrode active material layer may also contain a negative electrode active material, a conductive material, and a binder. 【0085】 For example, a metal foil can be used as the current collector. The negative electrode can be formed by applying a slurry to the metal foil and drying it. Pressing may also be applied after drying. The negative electrode is formed by creating an active material layer on the current collector. 【0086】 A slurry is a liquid material used to form an active material layer on a current collector. It contains an active material, a binder, and a solvent, and preferably also contains a conductive material. Slurries are sometimes called electrode slurries or active material slurries, and when forming a negative electrode active material layer, they are sometimes called negative electrode slurries. 【0087】 [Negative electrode active material] For example, carbon materials or alloy materials can be used as the negative electrode active material. 【0088】 As carbon materials, for example, graphite (natural graphite, artificial graphite), easily graphitizable carbon (soft carbon), difficult-to-graphitize carbon (hard carbon), carbon fibers (carbon nanotubes), graphene, carbon black, etc. can be used. 【0089】 Examples of graphite include artificial graphite and natural graphite. Examples of artificial graphite include mesocarbon microbeads (MCMB), coke-based artificial graphite, and pitch-based artificial graphite. Here, spheroidal graphite having a spherical shape can be used as artificial graphite. For example, MCMB may have a spherical shape and is therefore preferable. Furthermore, it is relatively easy to reduce the surface area of ​​MCMB, which may also be preferable. Examples of natural graphite include flake graphite and spheroidized natural graphite. 【0090】When lithium ions are inserted into graphite (when forming a lithium-graphite intercalation compound), graphite exhibits a potential as low as that of metallic lithium (0.05 V or more and 0.3 V or less vs. Li / Li ＋ ). Therefore, a lithium-ion battery using graphite can exhibit a high operating voltage. Furthermore, graphite has advantages such as a relatively high capacity per unit volume, relatively small volume expansion, low cost, and high safety compared to metallic lithium, so it is preferable. 【0091】 The graphitizable carbon is obtained, for example, by firing synthetic resins such as phenol resins and plant-derived organic substances. The graphitizable carbon possessed by the negative electrode active material of a lithium-ion battery according to one embodiment of the present invention preferably has an interlayer spacing of the (002) plane measured by X-ray diffraction (XRD) of 0.34 nm or more and 0.50 nm or less, and more preferably 0.35 nm or more and 0.42 nm or less. 【0092】 In addition, the negative electrode active material can use an element capable of performing a charge / discharge reaction by an alloying / dealloying reaction with lithium. For example, a material containing at least one of silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, indium, etc. can be used. Such elements have a larger capacity compared to carbon, and particularly silicon has a high theoretical capacity of 4200 mAh / g. Therefore, it is preferable to use silicon for the negative electrode active material. Also, compounds containing these elements may be used. For example, SiO, Mg ２ Si, Mg ２ Ge, SnO, SnO ２ 、Mg ２ Sn, SnS ２ 、V ２ Sn ３ 、FeSn ２ 、CoSn ２ 、Ni ３ Sn ２ 、Cu ６ Sn ５ 、Ag ３ Sn、Ag ３ 、Sb、Ni ２ MnSb、CeSb ３ 、LaSn ３ 、La３ Co ２ Sn ７ CoSb ３ Examples include InSb and SbSn. For example, compounds of Si, SiO, or SiC with Ti may also be used. Here, elements capable of undergoing charge-discharge reactions through alloying and de-alloying reactions with lithium, and compounds containing such elements, are sometimes referred to as alloying materials. 【0093】 In this specification, "SiO" refers to silicon monoxide, for example. Alternatively, SiO refers to SiO ｘ It can also be expressed as follows. Here, x preferably has a value of 1 or a value in the vicinity of 1. For example, x is preferably 0.2 or more and 1.5 or less, and more preferably 0.3 or more and 1.2 or less. 【0094】 Furthermore, titanium dioxide (TiO) is used as the negative electrode active material. ２ ), lithium titanium oxide (Li ４ Ti ５ O １２ ), lithium-graphite intercalation compound (Li ｘ C ６ ), niobium pentoxide (Nb ２ O ５ ), tungsten dioxide (WO ２ ), molybdenum dioxide (MoO ２ Oxides such as those listed above can be used. 【0095】 Furthermore, as the negative electrode active material, lithium and a nitride of a transition metal, Li ３ Li with an N-type structure ３−ｘ M ｘ N (M = Co, Ni, Cu) can be used. For example, Li ２．６ Co ０．４ N has a large discharge capacity (900 mAh / g, 1890 mAh / cm²). ３ ) indicates a preference. 【0096】 When lithium and transition metal nitrides are used, lithium ions are contained in the negative electrode active material, so the positive electrode active material does not contain lithium ions. ２ O ５ , Cr ３ O ８It is preferable that it be combined with materials such as the above. Furthermore, even when a material containing lithium ions is used as the positive electrode active material, lithium and a nitride of a transition metal can be used as the negative electrode active material by desorbing the lithium ions contained in the positive electrode active material beforehand. 【0097】 Furthermore, materials that undergo a conversion reaction can also be used as the negative electrode active material. For example, transition metal oxides that do not form alloys with lithium, such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO), may be used as the negative electrode active material. As for materials that undergo a conversion reaction, Fe ２ O ３ ,CuO,Cu ２ O, RuO ２ , Cr ２ O ３ Oxides such as CoS ０．８９ , sulfides such as NiS and CuS, Zn ３ N ２ ,Cd ３ N, Ge ３ N ４ Nitrides such as NiP ２ FeP ２ CoP ３ Phosphates such as FeF ３ BiF ３ Examples of fluorides include the following. 【0098】 While one type of negative electrode active material can be used from those listed above, multiple types can also be used in combination. For example, a combination of carbon material and silicon, or a combination of carbon material and silicon monoxide can be used. 【0099】 Furthermore, lithium may be pre-doped into the negative electrode active material. As a method of lithium pre-doping, a lithium layer may be formed on the surface of the negative electrode active material layer by sputtering. Alternatively, lithium may be pre-doped into the negative electrode active material layer by providing lithium foil on its surface. Alternatively, lithium may be pre-doped into the negative electrode active material layer by fabricating a pre-doping battery using a dummy positive electrode containing lithium and then charging it. 【0100】Alternatively, the negative electrode may have no negative electrode active material at the end of battery manufacturing. For example, a negative electrode without negative electrode active material may have only a negative electrode current collector at the end of battery manufacturing, in which lithium ions that detach from the positive electrode active material during battery charging deposit as lithium metal on the negative electrode current collector, forming a negative electrode active material layer. Batteries using such a negative electrode are sometimes called negative electrode-free (anode-free) batteries or negative electrode-less (anode-less) batteries. 【0101】 When using a negative electrode without a negative electrode active material, a film may be provided on the negative electrode current collector to homogenize the deposition of lithium. As a film to homogenize the deposition of lithium, for example, a solid electrolyte having lithium ion conductivity can be used. As a solid electrolyte, sulfide-based solid electrolytes, oxide-based solid electrolytes, and polymer-based solid electrolytes can be used. Among these, polymer-based solid electrolytes are suitable as a film to homogenize the deposition of lithium because it is relatively easy to form a uniform film on the negative electrode current collector. Alternatively, as a film to homogenize the deposition of lithium, for example, a metal film that forms an alloy with lithium can be used. As a metal film that forms an alloy with lithium, for example, a magnesium metal film can be used. Since lithium and magnesium form a solid solution over a wide composition range, it is suitable as a film to homogenize the deposition of lithium. 【0102】 Furthermore, when using a negative electrode without negative electrode active material, a negative electrode current collector with irregularities can be used. When using a negative electrode current collector with irregularities, the recesses in the negative electrode current collector become cavities where lithium can easily be deposited, thus suppressing the formation of dendrite-like shapes when lithium is deposited. 【0103】 [Binder] As a binder, it is preferable to use rubber materials such as styrene-butadiene rubber (SBR), styrene-isoprene-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, or ethylene-propylene-diene copolymer. Fluororubber can also be used as a binder. 【0104】 Furthermore, it is preferable to use a water-soluble polymer as the binder. Examples of water-soluble polymers include polysaccharides. Examples of polysaccharides include cellulose derivatives such as carboxymethylcellulose (CMC), methylcellulose, ethylcellulose, hydroxypropylcellulose, diacetylcellulose, and regenerated cellulose, or starch. It is even preferable to use these water-soluble polymers in combination with the aforementioned rubber material. 【0105】 Alternatively, it is preferable to use materials such as polystyrene, methyl polyacrylate, polymethyl methacrylate (polymethyl methacrylate, PMMA), sodium polyacrylate, polyvinyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide, polyimide, polyvinyl chloride, polytetrafluoroethylene, polyethylene, polypropylene, polyisobutylene, polyethylene terephthalate, nylon, polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), ethylene propylene diene polymer, polyvinyl acetate, or nitrocellulose as the binder. 【0106】 You may use a combination of several of the binders mentioned above. 【0107】 For example, a material with particularly excellent viscosity-modifying properties may be used in combination with other materials. For instance, rubber materials have excellent adhesive and elastic properties, but their viscosity can be difficult to adjust when mixed with a solvent. In such cases, it is preferable to mix them with a material with particularly excellent viscosity-modifying properties. As a material with particularly excellent viscosity-modifying properties, a water-soluble polymer may be used. As a water-soluble polymer with particularly excellent viscosity-modifying properties, the aforementioned polysaccharides, such as carboxymethylcellulose (CMC), methylcellulose, ethylcellulose, hydroxypropylcellulose, and diacetylcellulose, cellulose derivatives such as regenerated cellulose, or starch can be used. 【0108】Furthermore, cellulose derivatives such as carboxymethylcellulose can be made more soluble by using salts such as sodium or ammonium salts of carboxymethylcellulose, thereby increasing their effectiveness as viscosity modifiers. Increased solubility also improves the dispersibility with active materials or other components when preparing electrode slurries. In this specification, cellulose and cellulose derivatives used as electrode binders include their salts. 【0109】 Water-soluble polymers stabilize viscosity by dissolving in water, allowing for stable dispersion of active materials and other materials used as binders, such as styrene-butadiene rubber, in aqueous solutions. Furthermore, their functional groups are expected to facilitate stable adsorption to the surface of the active material. Additionally, cellulose derivatives such as carboxymethylcellulose often possess functional groups like hydroxyl or carboxyl groups, and these functional groups allow the polymers to interact with each other, resulting in a broad coverage of the active material surface. 【0110】 When a binder covers or is in contact with the surface of the active material, it is expected to act as a passivation film, suppressing the decomposition of the electrolyte. Here, a "passivation film" is a film that does not conduct electricity, or has extremely low electrical conductivity. For example, when a passivation film is formed on the surface of the active material, the decomposition of the electrolyte can be suppressed at the battery reaction potential. Furthermore, it is even more desirable for the passivation film to suppress electrical conductivity while still allowing lithium ions to conduct. 【0111】 [Conductive Material] Conductive materials, also called conductivity imparters or conductivity enhancers, are typically made of carbon. By attaching a conductive material between multiple active materials, the active materials are electrically connected to each other, increasing conductivity. Note that "attachment" does not only refer to physical contact between the active materials and the conductive material, but also includes cases where covalent bonding occurs, bonding occurs due to van der Waals forces, the conductive material covers part of the surface of the active material, the conductive material fits into surface irregularities of the active material, or where they are electrically connected even without physical contact. 【0112】The active material layers, such as the positive electrode active material layer and the negative electrode active material layer, preferably contain a conductive material. 【0113】 As conductive materials, one or more of the following can be used: carbon black such as acetylene black and furnace black; graphite such as artificial graphite and natural graphite; carbon fibers such as carbon nanofibers and carbon nanotubes; and graphene compounds. 【0114】 As carbon fibers, for example, mesophase pitch carbon fibers and isotropic pitch carbon fibers can be used. Alternatively, carbon nanofibers or carbon nanotubes can be used. Carbon nanotubes can be fabricated, for example, by vapor deposition. 【0115】 In this specification, graphene compounds include graphene, multilayer graphene, multigraphene, graphene oxide, multilayer graphene oxide, multigraphene oxide, reduced graphene oxide, reduced multilayer graphene oxide, reduced multigraphene oxide, graphene quantum dots, etc. A graphene compound is defined as a material having carbon, having a plate-like or sheet-like shape, and possessing a two-dimensional structure formed by a six-membered carbon ring. This two-dimensional structure formed by a six-membered carbon ring may also be called a carbon sheet. Graphene compounds may have functional groups. Furthermore, graphene compounds preferably have a bent shape. Graphene compounds may also be rolled up to resemble carbon nanofibers. 【0116】 The active material layer may also contain metal powders or metal fibers such as copper, nickel, aluminum, silver, or gold, or conductive ceramic materials as conductive materials. 【0117】 The content of conductive material relative to the total amount of active material layer is preferably 1 wt% to 10 wt%, and more preferably 1 wt% to 5 wt%. 【0118】Unlike granular conductive materials such as carbon black, which make point contact with the active material, graphene compounds enable surface contact with low contact resistance. Therefore, a smaller amount of graphene compound can improve the electrical conductivity between the granular active material and the graphene compound compared to conventional conductive materials. Consequently, the ratio of the active material in the active material layer can be increased. This, in turn, can increase the discharge capacity of the battery. 【0119】 Particulate carbon-containing compounds such as carbon black and graphite, or fibrous carbon-containing compounds such as carbon nanotubes, readily penetrate minute spaces. These minute spaces refer, for example, to regions between multiple active materials. By using a carbon-containing compound that readily penetrates minute spaces in combination with a sheet-like carbon-containing compound such as graphene, which can impart conductivity across multiple particles, the electrode density can be increased, and excellent conductive paths can be formed. A battery obtained by the manufacturing method according to one embodiment of the present invention can have a high capacity density per unit volume and possess stability, making it effective as an in-vehicle battery. 【0120】 [Current Collector] As the current collector, materials with high conductivity that do not alloy with carrier ions such as lithium can be used, such as metals like stainless steel, gold, platinum, zinc, iron, copper, aluminum, and titanium, and their alloys. The current collector can be in the shape of a sheet, mesh, perforated metal, expanded metal, etc., as appropriate. 【0121】 Furthermore, a resin current collector can be used as the current collector. As the resin current collector, for example, a resin current collector can be used that has a resin such as polyolefin (polypropylene, polyethylene, etc.), nylon (polyamide), polyimide, vinylon, polyester, acrylic, polyurethane, and a particulate or fibrous conductive material (also called a conductive filler). 【0122】As the conductive material of the resin current collector, one or more of the following can be used: conductive carbon materials and metallic materials such as aluminum, titanium, stainless steel, gold, platinum, zinc, iron, and copper. As the conductive carbon material, one or more of the following can be used: carbon black such as acetylene black and furnace black; graphite such as artificial graphite and natural graphite; carbon fibers such as carbon nanofibers and carbon nanotubes; graphene; and graphene compounds. When the resin current collector is used as a positive electrode current collector, it is preferable to further include an antioxidant such as a hindered phenolic material. 【0123】 As carbon fibers, for example, mesophase pitch carbon fibers and isotropic pitch carbon fibers can be used. Alternatively, carbon nanofibers or carbon nanotubes can be used. Carbon nanotubes can be fabricated, for example, by vapor deposition. 【0124】 Furthermore, the particle size of the conductive material in the resin current collector can be an average particle diameter of 10 nm or more and 10 μm or less, and preferably 30 nm or more and 5 μm or less. 【0125】 The current collector should ideally have a thickness of 5 μm to 30 μm. 【0126】 Furthermore, it is preferable to use a material for the negative electrode current collector that does not alloy with carrier ions such as lithium. 【0127】Furthermore, a laminated current collector having a structure with metal layers on both sides of an organic material film can be used as the current collector. Organic material films such as polypropylene, polyethylene, nylon, and polyethylene terephthalate can be used. As the metal layer, highly conductive materials such as stainless steel, gold, platinum, aluminum, titanium, and their alloys can be used. The laminated current collector can be manufactured by laminating an organic material film and a metal foil (metal layer), in which case an adhesive layer is present between the organic material film and the metal layer. Alternatively, the laminated current collector may be manufactured by depositing metal layers on both sides of the organic material film using methods such as sputtering or vapor deposition. When using the laminated current collector as a negative electrode current collector, copper is preferably used as the metal layer. Alternatively, when using the laminated current collector as a positive electrode current collector, aluminum is preferably used as the metal layer. Furthermore, as an example of the configuration of the laminated current collector, a graphene layer may be used instead of the above-mentioned metal layer. 【0128】 Furthermore, an undercoat layer may be provided on a part of the surface of the current collector. Providing an undercoat layer can reduce the contact resistance between the current collector and the active material layer. It can also improve the adhesion between the current collector and the active material layer. Note that the undercoat layer does not have to be formed on the entire surface of the current collector, but may be formed in an island-like (partial) manner. The undercoat layer may also exhibit capacity as an active material. As the undercoat layer, for example, a carbon material can be used. As the carbon material, for example, graphite, carbon black such as acetylene black, carbon nanotubes, etc., can be used. In addition, a metal layer, a layer containing carbon and polymer, and a layer containing metal and polymer can also be used as the undercoat layer. As the binder for the undercoat layer, the materials described in [Binder] can be used. Having an undercoat layer between the current collector and the active material layer can suppress the detachment of the active material layer from the current collector when the battery is bent, so it is preferable to have an undercoat layer in a flexible battery. 【0129】[Positive Electrode] The positive electrode comprises a positive electrode active material layer and a positive electrode current collector. The positive electrode active material layer contains a positive electrode active material and may further contain at least one of a conductive material and a binder. The positive electrode current collector, conductive material, and binder can be those described in [Negative Electrode]. 【0130】 The current collector can be made of, for example, metal foil. The positive electrode can be formed by applying a slurry to the metal foil and drying it. Pressing may also be applied after drying. The positive electrode is formed by creating an active material layer on the current collector. 【0131】 A slurry is a liquid material used to form an active material layer on a current collector. It contains an active material, a binder, and a solvent, and preferably also contains a conductive material. Slurries are sometimes called electrode slurries or active material slurries, and when forming a positive electrode active material layer, they are sometimes called positive electrode slurries. 【0132】 [Positive electrode active material] As the positive electrode active material, one or more of the following can be used: a composite oxide with a layered rock salt structure, a composite oxide with an olivine structure, and a composite oxide with a spinel structure. 【0133】 As a composite oxide with a layered rock salt structure, one or more of the following can be used: lithium cobaltate, lithium nickel-cobalt-manganate, lithium nickel-cobalt-aluminate, and lithium nickel-manganese-aluminate. The compositional formula is LiM1O. ２ It can be expressed as (M1 is one or more elements selected from nickel, cobalt, manganese, and aluminum), but the coefficients in the empirical formula are not limited to integers. 【0134】For example, one or more of the following can be used as lithium cobalt oxide: lithium cobalt oxide having magnesium, lithium cobalt oxide having magnesium and aluminum, lithium cobalt oxide having magnesium, aluminum and titanium, lithium cobalt oxide having magnesium and nickel, lithium cobalt oxide having magnesium, aluminum and nickel, lithium cobalt oxide having magnesium, aluminum, titanium and nickel, lithium cobalt oxide having magnesium and fluorine, lithium cobalt oxide having magnesium, fluorine and titanium, lithium cobalt oxide having magnesium, fluorine and aluminum, lithium cobalt oxide having magnesium, fluorine and nickel, lithium cobalt oxide having magnesium, fluorine, nickel and aluminum, lithium cobalt oxide having magnesium, fluorine, aluminum, titanium and nickel, etc. 【0135】 For example, lithium nickel-cobalt-manganate can be used in ratios such as nickel:cobalt:manganese = 1:1:1, nickel:cobalt:manganese = 6:2:2, nickel:cobalt:manganese = 8:1:1, and nickel:cobalt:manganese = 9:0.5:0.5. Furthermore, it is preferable to use lithium nickel-cobalt-manganate to which one or more of aluminum, calcium, barium, strontium, and gallium have been added. 【0136】 As the olivine-type complex oxide, one or more of lithium iron phosphate, lithium manganese phosphate, lithium cobalt phosphate, and lithium iron manganese phosphate can be used. The compositional formula is LiM2PO ４ It can be shown that (M2 is one or more elements selected from iron, manganese, and cobalt), but the coefficients in the empirical formula are not limited to integers. 【0137】 Also, LiMn ２ O ４Composite oxides with spinel-type structures such as these can be used. 【0138】 [Electrolyte] As one form of electrolyte, an electrolyte solution can be used, which comprises a solvent and an electrolyte dissolved in the solvent. The electrolyte solution contains a solvent and a lithium salt. As the solvent for the electrolyte solution, an aprotic organic solvent is preferred, and for example, one of the following can be used, or two or more of these can be used in any combination and ratio: ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, chloroethylene carbonate, vinylene carbonate, γ-butyrolactone, γ-valerolactone, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, diethyl ether, methyl diglyme, acetonitrile, benzonitrile, tetrahydrofuran, sulfolane, sultone, etc. 【0139】 When the electrolyte contains ethylene carbonate (EC) and diethyl carbonate (DEC), a solvent with a volume ratio of x:100-x (where 20 ≤ x ≤ 40) can be used, assuming a total content of ethylene carbonate and diethyl carbonate of 100 vol%. More specifically, a mixed organic solvent containing EC and DEC in a volume ratio of EC:DEC = 30:70 can be used. 【0140】Alternatively, when the solvent used in the electrolyte contains ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC), a mixture can be used in which, when the total content of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate is 100 vol%, the volume ratio of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate is x:y:100-x-y (where 5 ≤ x ≤ 35 and 0 < y < 65). More specifically, a mixed organic solvent containing EC, EMC, and DMC in the volume ratio EC:EMC:DMC = 30:35:35 can be used. 【0141】 Alternatively, a mixed organic solvent containing cyclic fluoride carbonate (sometimes referred to as fluorinated cyclic carbonate) or fluorinated chain ester (sometimes referred to as fluorinated chain ester) can be used as the solvent for the electrolyte. Furthermore, it is preferable that the above mixed organic solvent contains both cyclic fluoride carbonate and fluorinated chain ester. Both cyclic fluoride carbonate and fluorinated chain ester have substituents that exhibit electron-withdrawing properties, which is preferable as it lowers the solvation energy of lithium ions. For this reason, both cyclic fluoride carbonate and fluorinated chain ester are suitable for electrolytes, and these mixed organic solvents are suitable for secondary batteries that require charging and discharging at low temperatures. 【0142】 Examples of cyclic fluoride carbonates that can be used include fluoroethylene carbonate (fluoroethylene carbonate, FEC, F1EC), difluoroethylene carbonate (DFEC, F2EC), trifluoroethylene carbonate (F3EC), or tetrafluoroethylene carbonate (F4EC). DFEC has isomers such as cis-4,5 and trans-4,5. Since all of these cyclic fluoride carbonates have electron-withdrawing substituents, they can be considered to have a low solvation energy of lithium ions. In FEC, the electron-withdrawing substituent is the fluorine group. 【0143】One example of a fluorinated chain ester is methyl 3,3,3-trifluoropropionate. The abbreviation for methyl 3,3,3-trifluoropropionate is "MTFP". In MTFP, the electron-withdrawing substituent is CF ３ It is the basis. 【0144】 FEC is a cyclic carbonate with a high dielectric constant, and when used in organic solvents, it promotes the dissociation of lithium salts. On the other hand, because FEC has electron-withdrawing substituents, desolvation with lithium ions proceeds more easily than with ethylene carbonate (EC). Specifically, the solvation energy of lithium ions in FEC is lower than that of EC without electron-withdrawing substituents. Therefore, lithium ions are more easily released from the positive electrode active material surface and the negative electrode active material surface, which can lower the internal resistance of the secondary battery. Furthermore, because FEC has a deep Highest Occupied Molecular Orbital (HOMO) level, it is less susceptible to oxidation, improving oxidation resistance. However, the high viscosity of FEC is a concern. Therefore, it is preferable to use a mixed organic solvent containing not only FEC but also MTFP as the electrolyte. MTF is a type of linear ester that can lower the viscosity of an electrolyte or maintain its viscosity at room temperature (typically 25°C) even at low temperatures (typically 0°C). Furthermore, although MTF has a lower solvation energy than methyl propionate (abbreviated as "MP") which does not have electron-withdrawing substituents, it may still generate solvation with lithium ions when used in an electrolyte. 【0145】 The organic solvents mentioned above contain particulate debris or molecules other than the constituent molecules of the organic solvent (hereinafter also simply referred to as "impurities"), and oxygen (O ２ ), water (H ２ It is preferable that the content of (O) or water is low and that the purity is high. It is also preferable that reaction by-products during synthesis are suppressed through appropriate purification. Specifically, the electrolyte impurities should be 100 ppm or less, preferably 50 ppm or less, and more preferably less than 10 ppm. The concentration of water among the impurities can be detected by Karl Fischer titration. 【0146】 Furthermore, it is preferable that the above-mentioned organic solvent shows virtually no peaks attributable to impurities when measured by NMR or other methods. "Very virtually undetectable" means that the ratio of the integrated area of ​​the peaks attributable to impurities to the integrated area of ​​the peaks attributable to the main component (simply called the integral ratio) is 0.005 or less, preferably 0.002 or less. The apparatus used for NMR measurement is not particularly limited, but for example, Bruker's "AVANCE III 400" can be used. Also, in 1H-NMR measurement, the central peak among the five peaks of acetonitrile derived from acetonitrile-d3 used as the solvent can be set to 1.94 ppm. 【0147】 For example, in the case of MTF, when 1H-NMR is measured using acetonitrile-d3 solvent, it is known that four peaks occur with δ between 3.29 ppm and 3.43 ppm. However, if other peaks occur in the vicinity of this, for example, if a peak occurs with δ between 3.24 ppm and 3.29 ppm, that peak can be considered to be due to impurities. Therefore, if the ratio (integral ratio) of the peak area between 3.24 ppm and 3.29 ppm to the peak area between 3.29 ppm and 3.43 ppm is 0.005 or less, preferably 0.002 or less, it can be said that peaks due to impurities are almost not detectable. 【0148】 It is preferable to use a mixed organic solvent containing FEC and MTFP having such physical properties, with a total content of 100 vol%, and a volume ratio of x:100-x (where 5 ≤ x ≤ 30, preferably 10 ≤ x ≤ 20). In other words, it is preferable to mix the organic solvent so that the amount of MTFP is greater than the amount of FEC. 【0149】Also, by using one or more ionic liquids (room temperature molten salts) that are flame retardant and have low volatility as the solvent of the electrolytic solution, even if the internal temperature rises due to internal short circuit or overcharging of the battery, etc., battery rupture and / or ignition can be prevented. An ionic liquid consists of a cation and an anion, and includes an organic cation and an anion. Examples of the organic cation used in the electrolytic solution include aliphatic onium cations such as quaternary ammonium cations, tertiary sulfonium cations, and quaternary phosphonium cations, and aromatic cations such as imidazolium cations and pyridinium cations. Examples of the anion used in the electrolytic solution include monovalent amide-based anions, monovalent methide-based anions, fluorosulfonic acid anions, perfluoroalkylsulfonic acid anions, tetrafluoroborate anions, perfluoroalkylborate anions, hexafluorophosphate anions, or perfluoroalkylphosphate anions, etc. 【0150】 [Lithium salt] As the lithium salt dissolved in the above solvent, for example, LiPF ６ , LiClO ４ , LiAsF ６ , LiBF ４ , LiAlCl ４ , LiSCN, LiBr, LiI, Li ２ SO ４ , Li ２ B １０ Cl １０ , Li ２ B １２ Cl １２ , LiCF ３ SO ３ , LiC ４ F ９ SO ３ , LiC(CF ３ SO ２ ) ３ , LiC(C ２ F ５ SO ２ ) ３ , LiN(CF ３ SO ２ ) ２ , LiN(C ４ F ９ SO​​​SO ２ ), LiN(C ２ F ５ SO ２ ) ２ LiPF4 is a fluoride. One or more lithium salts of these types can be used in any combination and ratio. The lithium salt is preferably present in a concentration of 0.5 mol / L to 3.0 mol / L relative to the solvent. ６ LiBF ４ Using such methods improves the safety of lithium-ion batteries. 【0151】 The electrolyte described above preferably uses a highly purified electrolyte with a low content of particulate matter or elements other than the constituent elements of the electrolyte (hereinafter also simply referred to as "impurities"). Specifically, the weight ratio of impurities to the electrolyte is 1 wt% or less, preferably 0.1 wt% or less, and more preferably 0.01 wt% or less. 【0152】 [Additives] The electrolyte may contain additives. Additives can suppress the reaction decomposition of the electrolyte that may occur on the positive or negative electrode surface when the battery is operated at high voltage and / or high temperature. Examples of additives include vinylene carbonate (VC), propane sultone (PS), tert-butylbenzene (TBB), fluoroethylene carbonate (FEC), tris(trimethylsilyl) phosphate (TMSP) lithium bis(oxalate) borate (LiBOB). LiBOB is particularly preferred because it easily forms a good film. VC or FEC are preferred because they can form a good film on the negative electrode during battery aging or initial charging, thereby improving cycle characteristics. 【0153】 One or more dinitrile compounds can be used as additives. Specific examples of dinitrile compounds include succinonitrile, glutalonitrile, adiponitrile (ADN), or ethylene glycol bis(propionitrile) ether (EGBE). 【0154】Furthermore, fluorobenzene may be added to the above organic solvent. The concentration of the additive can be, for example, 0.1 wt% to 5 wt% of the total electrolyte. PS or EGBE is preferred because it can form a good film on the positive electrode during charging and discharging, improving cycle characteristics. FB is preferred because it improves the wettability of the organic solvent to the positive and negative electrodes. Dinitrile compounds are preferred because the nitrile groups are oriented toward the positive and negative electrodes, inhibiting oxidative decomposition of the organic solvent, thus improving high-voltage resistance. Furthermore, when a current collector having copper is used in the negative electrode, dinitrile compounds are preferred because they can prevent the dissolution of copper during over-discharge. Considering the use of batteries at high voltages, it is preferable to add nitrile compounds. 【0155】 [Gel Electrolyte] A polymer gel, obtained by swelling a polymer with an electrolyte, may be used as the gel electrolyte. By using a polymer gel electrolyte, a semi-solid electrolyte layer can be provided, increasing safety against leakage and other issues. In addition, it is possible to make the battery thinner and lighter. 【0156】 As the polymer to be gelled, silicone gels, acrylic gels, acrylonitrile gels, polyethylene oxide-based gels, polypropylene oxide-based gels, fluorine-based polymer gels, and the like can be used. 【0157】 Examples of polymers that can be used include polymers having a polyalkylene oxide structure such as polyethylene oxide (PEO), PVDF, polyacrylonitrile, and copolymers containing these. For example, PVDF-HFP, a copolymer of PVDF and hexafluoropropylene (HFP), can be used. The resulting polymer may also have a porous structure. 【0158】[Separator] A separator is placed between the positive electrode and the negative electrode. As the separator, for example, materials such as paper and other cellulose fibers, nonwoven fabrics, glass fibers, ceramics, or porous films made of nylon (polyamide), vinylon (polyvinyl alcohol-based fiber), polyester, acrylic, polyolefin, polyimide, or polyurethane can be used. It is preferable that the separator is processed into a bag shape and placed so as to enclose either the positive or negative electrode. 【0159】 The separator may have a multilayer structure. For example, an organic material film such as polypropylene or polyethylene can be coated with a ceramic material, a fluorine material, a polyamide material, or a mixture thereof. Examples of ceramic materials include aluminum oxide particles and silicon oxide particles. Examples of fluorine materials include PVDF and polytetrafluoroethylene. Examples of polyamide materials include nylon and aramid (meta-aramid, para-aramid). 【0160】 Coating with ceramic materials improves oxidation resistance, suppressing separator degradation during high-voltage charging and improving the reliability of secondary batteries. Coating with fluorine-based materials facilitates better adhesion between the separator and electrodes, improving output characteristics. Coating with polyamide materials, particularly aramid, improves heat resistance, thereby enhancing the safety of secondary batteries. 【0161】 For example, a polypropylene film may be coated on both sides with a mixture of aluminum oxide and aramid. Alternatively, the side of the polypropylene film in contact with the positive electrode may be coated with a mixture of aluminum oxide and aramid, and the side in contact with the negative electrode may be coated with a fluorine-based material. 【0162】 By using a multi-layered separator, the safety of the secondary battery can be maintained even if the overall thickness of the separator is thin, thus increasing the capacity per unit volume of the secondary battery. 【0163】[Example of an electrode stack] The following describes an example of the configuration of a stack having multiple stacked electrodes. 【0164】 Figure 10A shows the top view of the positive electrode current collector 321, Figure 10B shows the separator 340, Figure 10C shows the negative electrode current collector 331, Figure 10D shows the positive electrode lead 323 and the negative electrode lead 333, and Figure 10E shows the top view of the film-like outer casing 350. The positive electrode lead 323 has a sealing layer 375 and a lead metal 376a, and the negative electrode lead 333 has a sealing layer 375 and a lead metal 376b. 【0165】 In each figure of Figure 10, the dimensions are approximately equal, and the area B enclosed by the dashed line in Figure 10E is almost identical in dimensions to the separator in Figure 10B. Also, the areas between the dashed line and the end in Figure 10E are sealing portions 351 and 352, respectively. 【0166】 Furthermore, the protruding portion of the positive electrode current collector 321 (dashed line portion in Figure 10A) and the protruding portion of the negative electrode current collector 331 (dashed line portion in Figure 10C) are called tab portions. 【0167】 Figure 11A shows an example in which positive electrode active material layers 322 are provided on both sides of the positive electrode current collector 321. More specifically, the layers are arranged in the following order: negative electrode current collector 331, negative electrode active material layer 332, separator 340, positive electrode active material layer 322, positive electrode current collector 321, positive electrode active material layer 322, separator 340, negative electrode active material layer 332, and negative electrode current collector 331. Figure 11B shows a cross-sectional view of this laminated structure when it is cut by a plane 370. 【0168】 Although Figure 11A shows an example using two separators, it is also possible to fold a single separator, seal both ends to form a bag, and house the positive electrode current collector 321 in between. A positive electrode active material layer 322 is formed on both sides of the positive electrode current collector 321 housed in the bag-shaped separator. 【0169】Furthermore, it is also possible to provide negative electrode active material layers 332 on both sides of the negative electrode current collector 331. Figure 11C shows an example of a secondary battery in which three negative electrode current collectors 331, each having a negative electrode active material layer 332 on one side, three positive electrode current collectors 321, each having a positive electrode active material layer 322 on both sides, and eight separators 340 are sandwiched between two negative electrode current collectors 331, each having a negative electrode active material layer 332 on one side. In this case as well, instead of using eight separators, four bag-shaped separators may be used. 【0170】 The capacity of the secondary battery can be increased by increasing the number of layers. In addition, the thickness of the secondary battery can be reduced by providing positive electrode active material layers 322 on both sides of the positive electrode current collector 321 and negative electrode active material layers 332 on both sides of the negative electrode current collector 331. 【0171】 Figure 12A shows a secondary battery formed by providing a positive electrode active material layer 322 on only one side of the positive electrode current collector 321 and a negative electrode active material layer 332 on only one side of the negative electrode current collector 331. More specifically, a negative electrode active material layer 332 is provided on one side of the negative electrode current collector 331, and a separator 340 is stacked so as to be in contact with the negative electrode active material layer 332. The surface of the separator 340 on the side not in contact with the negative electrode active material layer 332 is in contact with the positive electrode active material layer 322 of the positive electrode current collector 321, which has a positive electrode active material layer 322 formed on one side. Another positive electrode current collector 321, which has another positive electrode active material layer 322 formed on one side, is in contact with the surface of the positive electrode current collector 321. In this case, the positive electrode current collectors 321 are arranged so that the sides without positive electrode active material layers 322 face each other. Then, a separator 340 is formed, and the negative electrode current collector 331, which has a negative electrode active material layer 332 formed on one side, is laminated so that the negative electrode active material layer 332 is in contact with the separator. Figure 12B shows a cross-sectional view of the laminated structure of Figure 12A when cut by a plane 371. 【0172】 Although Figure 12A uses two separators, one separator can be folded and both ends sealed to form a bag, and two positive electrode current collectors 321, each with a positive electrode active material layer 322 on one side, can be sandwiched between them. 【0173】Figure 12C shows a diagram of multiple stacked structures of Figure 12A. In Figure 12C, the negative electrode current collectors 331 are arranged with their non-negative active material layers 332 facing each other. Figure 12C shows a stacked configuration of 12 positive electrode current collectors 321, 12 negative electrode current collectors 331, and 12 separators 340. 【0174】 In a structure where a positive electrode active material layer 322 is provided on only one side of a positive electrode current collector 321 and a negative electrode active material layer 332 is provided on only one side of a negative electrode current collector 331, and these are stacked, the thickness of the secondary battery is greater compared to a structure where a positive electrode active material layer 322 is provided on both sides of a positive electrode current collector 321 and a negative electrode active material layer 332 is provided on both sides of a negative electrode current collector 331. However, the side of a positive electrode current collector 321 where a positive electrode active material layer 322 is not formed faces the side of another positive electrode current collector 321 where a positive electrode active material layer 322 is not formed, and the current collectors are in contact with each other. Similarly, the side of a negative electrode current collector 331 where a negative electrode active material layer 332 is not formed faces the side of another negative electrode current collector 331 where a negative electrode active material layer 332 is not formed, and the current collectors are in contact with each other. For example, if a treatment is applied to the surface of the positive electrode current collector 321 where the positive electrode active material layer 322 is not formed, and / or the surface of the negative electrode current collector 331 where the negative electrode active material layer 332 is not formed, the frictional force acting on the surfaces where the current collectors come into contact with each other will not be large, and the surfaces of the contacting current collectors will be able to slide more easily. In other words, when bending a secondary battery, the current collectors slide inside the secondary battery, making it easier to bend the battery. Examples of treatments that can be applied to the current collectors to improve their sliding properties include fluororesin (polytetrafluoroethylene, etc.) coating, graphene coating, and graphene compound coating. 【0175】 As shown in Figures 11A to 12C, the positive electrode current collectors 321 are stacked and all fixed and connected. Similarly, the negative electrode current collectors 331 are all fixed and connected. 【0176】 Here, it is preferable to fix and connect the positive electrode lead 323 to the multiple positive electrode current collectors 321. Similarly, it is preferable to fix and connect the negative electrode lead 333 to the multiple negative electrode current collectors 331. By connecting multiple current collectors and electrode leads in this way, manufacturing can be carried out efficiently. 【0177】 In the above, an example of connecting one positive lead 323 to multiple positive current collectors 321 was described using Figures 11A to 12C. However, the configuration of the secondary battery 150 is not limited to the above example, and it can be configured to have two or more positive leads, each of which is connected to multiple positive current collectors. In this case, the casing and the positive current collectors are fixed by the multiple positive leads, which is preferable as it can increase the shock resistance of the secondary battery 150. Similarly, it can be configured to have two or more negative leads, each of which is connected to multiple negative current collectors. 【0178】 Furthermore, it is preferable that the separator 340 be shaped in a way that makes it difficult for the positive electrode 320 and the negative electrode 330 to short-circuit electrically. For example, as shown in Figure 13A, it is preferable to make the width of each separator 340 larger than that of the positive electrode 320 and the negative electrode 330, because even if the relative positions of the positive electrode 320 and the negative electrode 330 shift due to deformation such as bending, they will be less likely to come into contact. Also, it is preferable to have a shape in which one separator 340 is folded in an accordion shape, as shown in Figure 13B, or a shape in which one separator 340 has the positive electrode 320 and the negative electrode 330 alternately wrapped around it, as shown in Figure 13C, because they will not come into contact even if the relative positions of the positive electrode 320 and the negative electrode 330 shift. Figures 13B and 13C also show an example in which a part of the separator 340 is provided so as to cover the side surface of the laminated structure of the positive electrode 320 and the negative electrode 330. 【0179】 Although the details of the positive electrode 320 and negative electrode 330 are not shown in each of the figures in Figure 13, their formation methods can be found by referring to the above. Also, although an example in which one positive electrode 320 and one negative electrode 330 are arranged alternately is shown here, a configuration in which two positive electrodes 320 or two negative electrodes 330 are arranged consecutively, as shown in Figure 12, is also possible. 【0180】 In this embodiment, an example of a structure in which a single rectangular film is folded in the middle and the two ends are overlapped and sealed is shown, but the shape of the film is not limited to a rectangle. It can be any symmetrical shape other than a rectangle, such as a triangle, square, pentagon, or other polygon, or a circle or star shape. 【0181】A lithium-ion battery can be manufactured by housing the laminate described in Figures 11 to 13 above and the electrolyte described above in an outer casing, and then sealing the outer casing. 【0182】 [Outer Covering] The outer covering of a battery can be made of metal materials such as aluminum, stainless steel, or titanium, or resin materials. A film-like outer covering can also be used. As a film, for example, a three-layer film can be used, in which a highly flexible metal thin film or metal foil made of aluminum, stainless steel, titanium, copper, nickel, etc. is placed on a film made of materials such as polyethylene, polypropylene, polycarbonate, ionomer, or polyamide, and an insulating synthetic resin film such as polyamide resin or polyester resin is further placed on the metal thin film as the outer surface of the outer covering. Such a multilayer film can be called a laminate film. In this case, the name of the material of the metal layer in the laminate film may be used to refer to it, such as aluminum laminate film, stainless steel laminate film, titanium laminate film, copper laminate film, nickel laminate film, etc. 【0183】 The material or thickness of the metal layer in the laminate film can affect the flexibility of the battery. For an outer casing used in a battery with excellent flexibility (bendable), it is preferable to use an aluminum laminate film having a polypropylene layer, an aluminum layer, and nylon. Here, the thickness of the aluminum layer is preferably 50 μm or less, more preferably 40 μm or less, more preferably 30 μm or less, and more preferably 20 μm or less. If the aluminum layer is thinner than 10 μm, there is a concern that the gas barrier properties will decrease due to pinholes in the aluminum layer, so it is desirable that the thickness of the aluminum layer be 10 μm or more. 【0184】Alternatively, a graphene sheet may be used as the laminate film instead of the metal layer described above. A multilayer graphene sheet with a thickness of 100 nm to 30 μm, preferably 200 nm to 20 μm, can be used. Because the graphene sheet is flexible and has an interlayer distance of 0.34 nm, providing gas barrier properties, it is suitable as a film for use in the casing of a secondary battery. 【0185】 [Method for processing a film having recesses and protrusions] Next, a method for processing a film that can be used for exterior bodies will be described. As the film, the laminate film described above can be used. 【0186】 For example, a laminated film can be used as the laminating film. For example, a laminated film can be used that has a heat-seal layer on one or both sides of a metal film. The adhesive layer can be a heat-sealable resin film containing polypropylene or polyethylene. In this embodiment, an aluminum laminate film is used in which a nylon resin is provided on one side of the aluminum foil, and an acid-resistant polypropylene film and a polypropylene film lamination are provided on the other side of the aluminum foil. 【0187】 Next, this film is embossed. As a result, a film with an uneven surface can be produced. The film has multiple uneven areas, giving it a visible wave-like pattern. 【0188】 The following is an explanation of embossing, a type of press work. 【0189】 Figure 14 is a cross-sectional view showing an example of embossing. Embossing is a type of press work in which an embossing roll with a textured surface is pressed against a film, forming textures on the film that correspond to the textures of the embossing roll. The embossing roll is a roll with a pattern engraved on its surface. 【0190】 Figure 14 also shows an example of embossing on both sides of a film. It also describes a method for forming a film with a convex portion having a peak on one side. 【0191】 Figure 14 shows a film 390 sandwiched between an embossing roll 395 in contact with one side of the film and an embossing roll 396 in contact with the other side, and the film 390 being fed in the direction of film travel 391. A pattern is formed on the film surface by pressure or heat. Alternatively, the pattern may be formed on the film surface by both pressure and heat. 【0192】 Embossing rolls can be made from metal rolls, ceramic rolls, plastic rolls, rubber rolls, organic resin rolls, wood rolls, etc., as appropriate. 【0193】 Figure 14 shows an embossing process using an embossing roll 396, which is a male embossing roll, and an embossing roll 395, which is a female embossing roll. The male embossing roll 396 has a plurality of protrusions 396a. These protrusions correspond to the protrusions that will be formed on the film being processed. The female embossing roll 395 has a plurality of protrusions 395a. The adjacent protrusions 395a form recesses into which the protrusions 396a on the male embossing roll 396 fit onto the protrusions that will be formed on the film. 【0194】 By continuously performing embossing to raise a portion of the film 390 and blind embossing to indent a portion of the film 390, convex and flat areas can be continuously formed. As a result, a pattern can be formed on the film 390. 【0195】 Next, a film having multiple protrusions with a different shape from that in Figure 14 will be described using Figures 15A to 15E. By changing the shape of the protrusions on the embossing rolls 395 and 396 in Figure 14 to a different shape from that in Figure 14, it is possible to perform embossing with various cross-sectional shapes shown in Figures 15A to 15E. 【0196】 Figure 15A is a schematic cross-sectional view of an embossed surface with a wavy shape, and Figures 15B to 15E are modified examples of Figure 15A. Figures 15B and 15C show examples of forming the wavy shape in a stepped manner, Figure 15D shows an example of forming the wavy shape in a rectangular shape, and Figure 15E shows an example of forming the wavy shape with sharp valleys and trapezoidal peaks. 【0197】 Figures 16A and 16B are perspective views showing the finished shape when the embossing process shown in Figures 14 to 15E is performed twice, with the direction of the film 390 changed. Specifically, by embossing the film 390 in a first direction, and then embossing the film 390 in a second direction rotated 90 degrees from the first direction, a film 381 (film 381a, film 381b, film 381c) having the embossed shape (which can be called a cross-wave shape) shown in Figures 16A and 16B can be obtained. Note that the film 381a with the cross-wave shape shown in Figure 16A shows the outer shape used when manufacturing a secondary battery with a single film 381a, and can be used by folding it in half along the dashed line. Furthermore, the multiple films (film 381b, film 381c) having a crossed wave shape shown in Figure 16B represent the external shape used when manufacturing a secondary battery with two films (film 381b, film 381c), and film 381b and film 381c can be used stacked on top of each other. 【0198】 As described above, using an embossing roll makes it possible to miniaturize the equipment. Furthermore, since the film can be processed without cutting, it offers excellent mass-production capabilities. Note that the process is not limited to using an embossing roll; for example, the film may be processed by pressing a pair of embossing plates, each with a textured surface, onto the film. In this case, one of the embossing plates may be flat, and the processing may be carried out in multiple steps. 【0199】 Figure 16C is a perspective view showing a curved secondary battery 150A, which was made using a laminate film with a unidirectional wave-shaped embossed surface as its outer casing 350A. As shown above, using a laminate film with a unidirectional wave-shaped embossed surface as its outer casing makes it possible to create a battery that is easily bent in one direction. 【0200】The above-mentioned example of a secondary battery configuration shows an example in which the outer casing on one side of the secondary battery and the outer casing on the other side have similar embossed shapes. However, the configuration of a secondary battery according to one aspect of the present invention is not limited to this. For example, as shown in Figures 17A to 17C, a secondary battery 150B can be made in which the outer casing on one side of the secondary battery has an embossed shape, but the outer casing on the other side does not. Figures 17A and 17B show an example of a configuration in which, as shown in Figures 16A and 16B, the outer casing on one side of the battery has an embossed shape, but the outer casing on the other side does not. Figure 17C also shows an example of a configuration in which, as shown in Figure 16C, the outer casing on one side of the battery has an embossed shape, but the outer casing on the other side does not. 【0201】 Furthermore, the outer casing on one side of the secondary battery and the outer casing on the other side may have different embossed shapes. 【0202】 The contents of this embodiment can be freely combined with the contents of other embodiments. 【0203】 (Embodiment 3) In this embodiment, an example of the use of a battery module according to one aspect of the present invention will be described with reference to Figures 18A and 18B. 【0204】 The battery module 10 according to one aspect of the present invention is not limited to the penetrator described in Embodiment 1, but may also be used in general-purpose electronic devices. As an example, Figure 18A shows a configuration in which the battery module 10 is used in a drink holder 300 with a temperature control function. 【0205】 Figure 18A is a perspective view showing a drink holder 300 and a beverage container 310. Figure 18B is a cross-sectional view of the drink holder 300 at the dashed line in Figure 18A. 【0206】 The drink holder 300 includes a battery module 10, a temperature control device 200, a housing 301, and a heat dissipation section 302. In addition, the drink holder 300 may also include a temperature sensor, a control controller, a heat retention member, etc. 【0207】As shown in Figure 18B, the battery module 10, the temperature control device 200, and the heat dissipation unit 302 can be structured to be covered by the housing 301. Preferably, the housing 301 has a heat-insulating material. 【0208】 The battery module 10 is connected to a temperature control device 200, which can cool the secondary battery and / or beverage container 310 contained in the battery module. In this case, it is preferable that the temperature control device 200 has a heat dissipation section 302 for the purpose of dissipating heat associated with the cooling. 【0209】 The secondary battery in the battery module 10 of the drink holder 300 shown in Figures 18A and 18B is preferably configured to have excellent charge and discharge characteristics at low temperatures. With such a configuration, the entire drink holder 300 containing the beverage container 310 can be cooled directly in the refrigeration equipment. Furthermore, the cooling by the drink holder 300 can rapidly lower the temperature of the beverage container 310 and its contents. 【0210】 The above example shows a drink holder 300 that accommodates a beverage container 310, but the configuration is not limited to this. The beverage container 310 and the drink holder 300 can be integrated to create a water bottle with a cooling function. 【0211】 The contents of this embodiment can be freely combined with the contents of other embodiments. 【0212】 10: Battery module, 100: Frame, 101: Base, 111: First beam, 112: Second beam, 121: First column, 122: Second column, 150: Secondary battery, 200: Temperature control device, 300: Drink holder, 301: Housing, 302: Heat dissipation section, 310: Beverage container

Claims

It comprises a cylindrical hollow frame and a battery housed within the frame, The frame comprises a flat, annular base portion and a first group of columns and a second group of columns fixed to the flat surface of the base portion. The first group of columns is fixed to the first annular beam section of the flat plate in the portion that extends perpendicularly to the flat plate surface. The second group of columns is fixed to a second annular beam section having the same central axis as the first beam section in the portion that extends perpendicularly to the flat plate surface. The outer diameter of the first beam is smaller than the inner diameter of the second beam. The battery is located between the base, the first group of columns, and the second group of columns. Battery module. 　 In claim 1, The first group of columns and / or the second group of columns are connected to a temperature control device. Battery module. 　 In claim 2, A plurality of temperature sensors are provided between the first group of columns or the second group of columns and the battery. The temperature control device has a function to control the temperature so that the temperature difference between the temperatures detected by the multiple temperature sensors is within 5°C. Battery module.

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