JP7282555B2 - System for checking abnormal operation of secondary battery, secondary battery for test, method for manufacturing secondary battery for test, and method for checking operation of secondary battery protection circuit - Google Patents

Description

One aspect of the present invention relates to an article, method, or manufacturing method. Alternatively, the invention relates to a process, machine, manufacture, or composition of matter. One embodiment of the present invention relates to a method for manufacturing a semiconductor device, a display device, a light-emitting device, a power storage device, a lighting device, or an electronic device. One aspect of the present invention relates to a vehicle or a vehicle electronic device provided in the vehicle. More particularly, it relates to a secondary battery protection circuit, a secondary battery charging control method, a secondary battery abnormality detection system, and an electronic device having a secondary battery.

Note that in this specification, a power storage device generally refers to elements and devices having a power storage function. Examples include a power storage device (also referred to as a secondary battery) such as a lithium ion secondary battery, a lithium ion capacitor, an electric double layer capacitor, and the like.

In recent years, various power storage devices such as lithium ion secondary batteries, lithium ion capacitors, and air batteries have been actively developed. In particular, lithium-ion secondary batteries, which have high output and high energy density, are used in portable information terminals such as mobile phones, smart phones, tablets, or notebook computers, portable music players, digital cameras, medical equipment, or hybrid vehicles (HEV). , electric vehicles (EV), and next-generation clean energy vehicles such as plug-in hybrid vehicles (PHEV). It has become an indispensable part of the modernized society.

In personal digital assistants, electric vehicles, and the like, a plurality of secondary batteries are connected in series or in parallel to provide a protection circuit, and used as a battery pack (also called assembled battery). A battery pack refers to a container (metal can, film package) containing a plurality of secondary batteries together with a predetermined circuit for easy handling of the secondary batteries. The battery pack is provided with an ECU (Electronic Control Unit) to manage the operating state.

Patent Literature 1 discloses a battery state detection device that detects a minute short circuit (also referred to as a micro short circuit) in a secondary battery and a battery pack containing the same.

JP 2010-66161

Ordinary secondary batteries are inspected at the time of shipment, and any secondary battery that has an abnormality is removed. Improvements in manufacturing technology for secondary batteries have reduced the number of secondary batteries in which abnormalities occur. However, it is difficult to eliminate the number of secondary batteries that malfunction after long-term use.

Also, a normal secondary battery that has been inspected at the time of shipment is shipped, and is repeatedly charged and discharged multiple times by the user. In some cases, a micro-short may occur, but it may take a long time to occur. In addition, the secondary battery does not function after short-circuiting after multiple micro-shorts have occurred. Therefore, the operation of a circuit for detecting a micro-short is sometimes checked using a pseudo waveform using an emulator or the like.

A circuit that can reliably detect micro-shorts in a short period of time is desired, and a secondary battery for demonstrating such a circuit is desired. That is, there is a demand for a secondary battery in which there is no abnormality at the time of initial operation and in which micro-shorts occur reliably thereafter. A safety test has been conducted in which a needle-shaped piece of nickel is inserted into a secondary battery and pressed to cause a short circuit. An object is to provide a system for confirming the operation of a protection circuit using a secondary battery in which a micro-short is sure to occur.

A micro-short refers to a minute short circuit inside a secondary battery, and it does not mean that the positive electrode and negative electrode of the secondary battery are short-circuited and cannot be charged or discharged. It refers to a phenomenon in which a slight short-circuit current flows for a period of 10 nanoseconds or more and less than 1 microsecond. The cause of the micro-short is that the non-uniform distribution of the positive electrode active material due to repeated charging and discharging causes local current concentration in part of the positive electrode and part of the negative electrode, and part of the separator The problem lies in the generation of sites that fail to function or the generation of side reactions.

In order to reduce the size of secondary batteries, thinner separators are desired, and charging by rapid power supply at high voltage is also desired. there is In addition, repeated occurrence of micro-shorts may lead to serious accidents such as abnormal heat generation and ignition of the secondary battery.

Therefore, in this specification, a secondary battery capable of intentionally generating a micro-short is manufactured, and a system is provided in which the operation of a micro-short detection device can be confirmed.

The configuration disclosed herein is to prepare a test battery cell that develops an abnormality that exhibits a specific behavior after multiple charging and discharging, electrically connect the test battery cell and an abnormality detection circuit, A charge-discharge cycle test is performed on the test battery cell to which the abnormality detection circuit is connected, and it is confirmed that the test battery cell generates an abnormality that exhibits a specific behavior and that the abnormality detection circuit detects the abnormality. , an abnormal operation confirmation system for a secondary battery in which a test battery cell is removed from an abnormality detection circuit.

In the above configuration, an abnormality that exhibits a specific behavior specifically at 50 cycles or more and 150 cycles or less after multiple charge/discharge cycles under a normal temperature (25° C.) environment is a micro-short. In a low temperature environment of less than 25° C. or in a high temperature environment of more than 25° C., a micro-short occurs at the initial stage of 50 cycles or less depending on the configuration of the negative electrode or electrolyte. In addition, by setting the average pore diameter of the pores of the separator to 15 μm or more, the occurrence of micro-shorts occurs even after 50 cycles or less.

Further, in the above configuration, the test battery cell has a positive electrode active material, a separator, and a negative electrode active material, metal nanoparticles adhere to the surface of the negative electrode active material, and the particle size of the metal nanoparticles is smaller than the pore size of Therefore, a test battery cell is also one aspect of the present invention. In addition, a normal cell structure having a capacity ratio of the positive electrode to the negative electrode of 70% or more and 95% or less is used.

The test battery cell disclosed in this specification has a positive electrode active material, a separator, and a negative electrode active material, and after several cycles of charging and discharging, metal nanoparticles adhere to the surface of the negative electrode active material, The particle size of the metal nanoparticles is smaller than the pore size of the separator. Moreover, after several cycles of charging and discharging, not only the metal nanoparticles but also the metal (for example, manganese) used for the positive electrode active material adheres to the surface of the negative electrode active material.

In addition, the manufacturing method is also characterized, and the configuration related to the manufacturing method is as follows. A battery cell is produced by stacking an active material layer, a separator having a plurality of holes, and a layer containing a negative electrode active material, and by performing several cycles of charging and discharging, the metal nanoparticles that have passed through the holes of the separator are transferred to the negative electrode. Adhere to the surface of the active material.

In the above manufacturing method, pressing is performed after stacking the positive electrode active material layer, the separator having a plurality of holes, and the layer containing the negative electrode active material. If the pressure here is too weak, micro-shorts will not occur, and if the pressure is too strong, initial short-circuiting will occur.

A method for checking the operation of a protection circuit for a secondary battery is also one aspect of the present invention.

The configuration of the operation confirmation method disclosed in this specification is to apply a positive electrode active material and a solvent in which metal nanoparticles are dispersed on the positive electrode active material, dry it to form a positive electrode active material layer, and Then, a separator having a plurality of holes and a layer containing a negative electrode active material are stacked to form a battery cell, a charging circuit and a micro-short detection circuit are electrically connected to the battery cell, and the battery cell is charged or discharged. By performing, the metal nanoparticles that have passed through the pores of the separator are attached to the surface of the negative electrode active material, and the battery cell is charged or discharged, so that the metal nanoparticles attached to the surface of the negative electrode active material are used as nuclei. A protection circuit for a secondary battery in which a micro short circuit is used to detect a short circuit when a deposit is grown through the pores of the separator and the tip of the deposit reaches the positive electrode active material due to the growth of the deposit, causing a short circuit. This is the operation confirmation method.

In order to ensure the long-term reliability of secondary batteries, it is believed that micro-shorts are unlikely to occur in a short period of time, as they are manufactured so that deposits such as starting points and lithium do not grow on the surface of the negative electrode active material. . In detecting an abnormality in a secondary battery that ensures long-term reliability, it takes a long time to detect a micro-short because it takes a long time. This is particularly effective because it is possible to provide a secondary battery that can cause micro-shorts in a fast cycle by only partially changing the manufacturing process of a secondary battery that ensures long-term reliability.

Deposits of lithium or the like grow starting from the metal nanoparticles attached to the surface of the negative electrode active material (which can be said to be nuclei), enter the pores of the separator, penetrate the separator, and cause a short circuit between the positive and negative electrodes.

A time lag can be provided because the process of moving the metal nanoparticles adhered to the positive electrode active material to the surface of the negative electrode active material requires time or multiple charge/discharge cycles. Due to this time lag, the secondary battery operates without problems in the initial operation, and after that, when charging and discharging are repeated, a micro-short can be reliably generated at an early stage.

By fabricating such a battery cell, it is possible to cause micro-shorts in early cycles without causing initial failures. By using such a battery cell, it is possible to check the operation using a device for detecting the occurrence of a micro-short.

Therefore, such a battery cell can also be said to be a battery cell for abnormality occurrence detection or a test battery cell. Of course, this test battery cell has a normal capacity ratio.

That is, such a battery cell is also one of the present invention, and has a positive electrode active material, a separator, and a negative electrode active material, metal nanoparticles adhere to the surface of the negative electrode active material, and the particle size of the metal nanoparticles is a battery cell whose pore size is smaller than that of the separator.

For example, a material containing element A, element X, and oxygen can be used as the positive electrode active material of the secondary battery. Element A is preferably one or more selected from Group 1 elements and Group 2 elements. Alkali metals such as lithium, sodium, and potassium can be used as the Group 1 elements. Also, for example, calcium, beryllium, magnesium, or the like can be used as the Group 2 element. As the element X, for example, one or more selected from metal elements, silicon and phosphorus can be used. Also, the element X is preferably one or more selected from cobalt, nickel, manganese, iron, and vanadium. Typical examples include nickel manganese cobalt oxide (NCM) and lithium cobalt composite oxide (LiCoO ₂ ). When nickel-manganese-cobalt oxide (NCM) is used as the positive electrode material, manganese also adheres to the negative electrode after several cycles of charging and discharging, and forms a deposit (conductor) together with the metal nanoparticles, causing micro-shorts. can encourage

As the negative electrode active material of the secondary battery, in addition to graphite, an element capable of undergoing charge/discharge reaction by alloying/dealloying reaction with lithium can be used. For example, materials containing at least one of silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, indium, etc. can be used. Such an element has a larger capacity than carbon, and silicon in particular has a high theoretical capacity of 4200 mAh/g.

The metal nanoparticles are fine metal particles having an average particle size of 1 nm or more and 100 nm or less, and are smaller than the pores of the separator.

Examples of separators include fibers containing cellulose such as paper, non-woven fabrics, glass fibers, ceramics, synthetic fibers using nylon (polyamide), vinylon (polyvinyl alcohol-based fiber), polyester, acrylic, polyolefin, and polyurethane. can be used. Since the separator allows the metal nanoparticles to pass through the pores of the separator, it is preferable to use a microporous resin film. The average pore diameter of the pores of the separator is 0.1 μm or more and 15 μm or less. Two layers of these can be used for the separator, and a separator having ceramics such as alumina adhered to the surface of the separator can also be used.

The material of the metal nanoparticles is at least one selected from copper, tin, zinc, nickel and silver.

Conventionally, it was only possible to generate a signal waveform using an emulator or the like and use a pseudo signal to check the operation of the abnormality detection circuit. In addition, it is difficult to identify battery cells in which micro-shorts occur at the time of shipment, and the number of such cells is not large.

By using the battery cell disclosed in this specification for verification of the protection circuit, the operation of the protection circuit can be confirmed when a micro-short occurs. It can also be called a test battery cell for a protection circuit. Before shipment, the test battery cell is charged and discharged several times to generate micro-shorts and the protection circuit is inspected. Reconnect to the cell and ship. By doing so, it is possible to mount a protection circuit whose operation has been confirmed in the event of an abnormality in the product.

By providing a battery cell in which a micro-short occurs, it is possible to check the operation of a protection circuit when a micro-short occurs, which has been difficult in the past. Therefore, it is possible to check the operation of the protection circuit before shipping the device or product. This can ensure the safety of the device or product. It is possible to easily acquire a large number of charge/discharge data before and when a micro-short occurs. By using this data and learning using artificial intelligence (AI), it is possible to create a system that can predict micro-shorts with higher accuracy.

The operation of the protection circuit can be checked not only for the secondary battery of a small device but also for the secondary battery of a large uninterruptible power supply, and safety can be improved.

FIG. 3 is a diagram showing a flow chart illustrating one aspect of the present invention; It is a perspective view showing one mode of the present invention. It is a perspective view showing one mode of the present invention. This is an application example of the anomaly detection system. This is an application example of the anomaly detection system. 4 is a graph showing charging characteristics before and after occurrence of a micro-short. It is a SEM photograph. FIG. 8 is an SEM photograph in which a part of FIG. 7 is enlarged;

Embodiments of the present invention will be described in detail below with reference to the drawings. However, those skilled in the art will easily understand that the present invention is not limited to the following description, and that the forms and details thereof can be variously changed. Moreover, the present invention should not be construed as being limited to the description of the embodiments shown below.

(Embodiment 1)
In this embodiment, a procedure for manufacturing a test battery cell (also referred to as a test cell) and mounting a shipping battery cell after confirming the operation of the protection circuit will be described below with reference to FIG.

First, a test cell in which a micro-short occurs when a cycle test is performed is produced. (S1)

Fabricate an anomaly detection circuit. (S2) The abnormality detection circuit functions as a protection circuit. Either the abnormality detection circuit or the test cell may be produced first.

The test cell is then connected to an anomaly detection circuit. (S3) Since the test cell and the abnormality detection circuit are scheduled to be removed later, they are electrically connected so as to be detachable.

Next, a charge/discharge cycle test is performed while the test cell and the abnormality detection circuit are electrically connected. (S4)

Charging and discharging are repeated several times, and micro-shorts occur during the charging and discharging cycles. (S5)

If a micro-short occurs in the test cell and can be detected by the abnormality detection circuit, confirmation of the abnormality detection function is complete. (S6)

The test cell is then removed from the fault detection circuit. (S7)

Then, the battery cell for shipment is connected to the abnormality detection circuit. (S8)

Finally, the battery cells to which the abnormality detection circuits are connected are shipped, or the battery modules having the abnormality detection circuits or the electronic devices having the battery modules are shipped. (S9)

Conventionally, the occurrence of an abnormality such as a micro-short could not be confirmed by a protection circuit before shipment of a product such as a battery cell, a battery module, or an electronic device having an abnormality detection circuit. According to the present invention, the product can be shipped after confirming in advance whether the protection circuit such as the abnormality detection circuit functions. A test cell capable of intentionally causing a micro-short will be described in detail in a second embodiment later.

(Embodiment 2)
The procedure for fabricating the test cell used in Embodiment 1 is shown below. An example of manufacturing a laminated secondary battery is shown in FIGS.

FIG. 2A shows an external view of the positive electrode 503 and the negative electrode 506. FIG. The positive electrode 503 has a positive electrode current collector 501 , and the positive electrode active material layer 502 is formed on the surface of the positive electrode current collector 501 .

In addition, the positive electrode 503 has a region where the positive electrode current collector 501 is partially exposed (hereinafter referred to as a tab region). The negative electrode 506 has a negative electrode current collector 504 , and the negative electrode active material layer 505 is formed on the surface of the negative electrode current collector 504 . Further, the negative electrode 506 has a region where the negative electrode current collector 504 is partially exposed, that is, a tab region. The area and shape of the tab regions of the positive and negative electrodes are not limited to the example shown in FIG.

First, the negative electrode 506, the separator 507, and the positive electrode 503 are stacked. The separator 507 uses a microporous resin film having pores with an average pore size of 0.1 μm or more and 15 μm or less. FIG. 2B shows the negative electrode 506, the separator 507, and the positive electrode 503 which are stacked. Here, an example is shown in which five sets of negative electrodes and four sets of positive electrodes are used. Next, the tab regions of the positive electrode 503 are joined together, and the positive electrode lead electrode 510 is joined to the tab region of the outermost positive electrode. For joining, for example, ultrasonic welding or the like may be used. Similarly, bonding between the tab regions of the negative electrode 506 and bonding of the negative electrode lead electrode 511 to the tab region of the outermost negative electrode are performed.

Next, the negative electrode 506 , the separator 507 , and the positive electrode 503 are arranged over the exterior body 509 .

Next, as shown in FIG. 2C, the exterior body 509 is bent at the portion indicated by the broken line. After that, the outer peripheral portion of the exterior body 509 is joined. A laminate film obtained by laminating a metal foil and an organic resin film, such as an aluminum foil or a stainless steel foil, may be used for the exterior body 509, and the bonding may be performed by, for example, thermocompression bonding. After bonding the three sides, the positive electrode is dried and heated, and the electrolytic solution in which the copper nanoparticles are dispersed is applied on the positive electrode and dried once. The metal nanoparticles mixed in the dispersion are adhered to the positive electrode active material and vacuum dried. In this embodiment, copper powder having an average particle size of 1 nm or more and 100 nm or less is used as the metal nanoparticles.

Then, an electrolytic solution is injected and pressed to seal. The dispersion liquid containing copper nanoparticles is not particularly limited to the above timing, and may be applied onto the positive electrode before overlapping with the negative electrode 506 and the separator 507 . If a dispersion containing copper nanoparticles is first applied to the positive electrode, there is a risk of contamination of the manufacturing apparatus in the subsequent process. After that, an electrolytic solution is injected and pressed to seal.

Note that the electrolytic solution has a solvent and an electrolyte. As the solvent for the electrolytic solution, aprotic organic solvents are preferred, such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, chloroethylene carbonate, vinylene carbonate, γ-butyrolactone, γ-valerolactone, and 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 - one of dioxane, dimethoxyethane (DME), dimethyl sulfoxide, diethyl ether, methyl diglyme, acetonitrile, benzonitrile, tetrahydrofuran, sulfolane, sultone, etc., or two or more of these in any combination and ratio be able to.

An initial short circuit may occur depending on the pressing conditions. It is important to regulate the pressure because too high a pressure will cause an initial short circuit. In this embodiment, a laminated cell is sandwiched between two stainless steel plates and fixed with screws provided at the four corners. Pressing is performed by fixing the four corners with a torque of 30 cN·m per screw. If the torque is 50 cN·m or more, the secondary battery becomes a laminate type that causes an initial short circuit. Below.

In this manner, the laminated secondary battery 500 illustrated in FIG. 2D can be manufactured. In addition, although an example of bonding using one laminate film is shown here, it is also possible to stack two laminate films and adhere and seal the peripheral edge portions.

Next, the secondary battery 500 is charged and discharged. By charging or discharging, the metal nanoparticles adhering to the positive electrode active material are allowed to pass through the pores of the separator, and the metal nanoparticles are adhered to the negative electrode active material.

A test cell is completed through the above steps.

It should be noted that an initial short circuit will occur if only the fine particles of copper are added to the electrolytic solution. In addition, initial short-circuiting also occurs when the material is attached to the negative electrode active material from the beginning. As shown in the present embodiment, it is important to adhere to the positive electrode active material first, then fabricate a battery cell, and charge and discharge the battery cell to adhere to the negative electrode active material. In order to disperse the copper nanoparticles in the electrolyte or organic solvent when adhering to the positive electrode, an appropriate amount of copper nanoparticles is collected and applied while being diffused using a stirrer or the like.

Further, although an example of manufacturing a laminated secondary battery is described in this embodiment, the invention is not particularly limited, and a wound secondary battery can also be manufactured.

An example of a wound type secondary battery is shown in FIG. A wound body 993 illustrated in FIG. 3A includes a negative electrode 994 , a positive electrode 995 , and a separator 996 .

A wound body 993 is obtained by laminating a negative electrode 994 and a positive electrode 995 with a separator 996 interposed therebetween, and winding the laminated sheet. A rectangular storage battery is fabricated by covering the wound body 993 with a rectangular sealed container or the like.

For example, before winding the positive electrode, an electrolytic solution containing copper nanoparticles is applied and dried, the winding torque is adjusted, the positive electrode 995, the separator 996, and the negative electrode 994 are wound, and the winding type secondary battery outer body. It can be sealed in a container and an electrolyte solution can be injected. In addition, when performing lamination after injecting the electrolytic solution, pressing is performed. After lamination, the laminated cell is sandwiched between two flat metal plates and fixed with screws provided at the four corners. The torque per screw is 10 cN·m or more and less than 50 cN·m, preferably 20 cN·m or more and 40 cN·m or less.

Note that the number of laminated layers composed of the negative electrode 994, the positive electrode 995, and the separator 996 may be appropriately designed according to the required capacity and device volume. The negative electrode 994 is connected to a negative current collector (not shown) through one of the lead electrodes 997 and 998, and the positive electrode 995 is connected to a positive current collector (not shown) through the other of the lead electrodes 997 and 998. connected).

A wound body 993 has a lead electrode 997 and a lead electrode 998 and is impregnated with an electrolytic solution inside the exterior bodies 991 and 992 . For the exterior bodies 991 and 992, for example, a metal material such as aluminum or a resin material can be used. If a resin material is used as the material of the exterior bodies 991 and 992, the exterior bodies 991 and 992 can be deformed when force is applied from the outside, and a flexible thin storage battery can be manufactured.

This embodiment can be freely combined with other embodiments.

(Embodiment 3)
By using the test cell obtained in the first embodiment or the second embodiment, it is possible to detect a micro-short at an early stage and check the operation of the protection circuit to prevent a serious accident.

According to this embodiment, it is possible to check the operation of the protection circuit before shipping the uninterruptible power supply 8700 . After inspecting the protection circuit using a test cell in which an abnormality (specifically, a micro-short occurs) is used, the protection circuit is used in a secondary battery.

For an ideal secondary battery, a thin separator is desired for miniaturization of the secondary battery, and charging by rapid power supply at a high voltage is also desired. The structure is such that micro-shorts are likely to occur. In addition, repeated occurrence of micro-shorts may lead to serious accidents such as abnormal heat generation and ignition of the secondary battery.

Therefore, before shipment, the test cell of this embodiment is used to detect micro-shorts at an early stage and check the operation of the protective circuit to prevent serious accidents. Then, after the operation of the protection circuit is confirmed, the protection circuit is attached to the secondary battery, and an abnormality detection system incorporating the protection circuit with high safety can be configured.

In this embodiment, a test cell which is one embodiment of the present invention is used to test a protection circuit, and the protection circuit after the test is used in an electronic device, whereby safety can be improved.

For example, portable information terminals such as mobile phones, hearing aids, imaging devices, vacuum cleaners, power tools, electric shavers, lighting equipment, toys, medical equipment, robots, driving power sources such as electric vehicles (hybrid vehicles), and construction including housing It can be used by being mounted on a power source for power storage of objects.

In addition to supplying power to various parts, the new power storage device can be charged, so it can store power from other power sources, and can be used as a power storage device in power generation equipment such as solar cells. can be used. Therefore, it leads to energy saving and _CO2 reduction.

FIG. 4A shows an example of a mobile phone. A mobile phone 7400 includes a display portion 7402 incorporated in a housing 7401, operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like. Note that the mobile phone 7400 includes a power storage device 7407 .

FIG. 4B is a projection diagram illustrating an example of the appearance of the information processing apparatus 200. As shown in FIG. Information processing device 200 described in the present embodiment includes arithmetic device 210 , input/output device 220 , display unit 230 , and power storage device 250 .

The information processing apparatus 200 has a communication section, and the communication section has a function of supplying information to a network and acquiring information from the network. Alternatively, information distributed to a specific space may be received using the communication unit 290, and image information may be generated based on the received information. For example, it is possible to receive and display teaching materials distributed in classrooms at schools, universities, etc., and use them as textbooks. Alternatively, it is possible to receive and display materials distributed in a conference room of a company or the like.

Further, an example in which a protection circuit is inspected using a test cell that is one embodiment of the present invention and the protection circuit after the inspection is mounted in a vehicle will be described. Vehicles include, for example, automobiles, two-wheeled vehicles, and bicycles.

A next-generation clean energy vehicle such as a hybrid vehicle (HEV), an electric vehicle (EV), or a plug-in hybrid vehicle (PHEV) can be realized by installing a power storage system including a secondary battery protection circuit in a vehicle.

FIG. 4 illustrates a vehicle using a secondary battery protection circuit. A vehicle 8500 shown in FIG. 4 is an electric vehicle that uses an electric motor as a power source for running. Alternatively, it is a hybrid vehicle in which an electric motor and an engine can be appropriately selected and used as power sources for running. Vehicle 8500 charges secondary battery 8024 of vehicle 8500 from charger 8021 via cable 8022 . An automobile 8500 has a power storage system equipped with a plurality of secondary batteries and a battery module having a protection circuit. In addition to driving the electric motor of the automobile 8500, the power storage system can also supply power to light emitting devices such as headlights and room lights (not shown). Devices used in cars are driven by a voltage of 11.5V to 14.5V, so the power supply voltage from the battery is appropriately changed by a booster circuit or the like.

In addition, the power storage system can supply power to display devices such as a speedometer and a tachometer of the automobile 8500 . In addition, the power storage system can supply power to a navigation system or the like included in automobile 8500 .

Also, although not shown, the power receiving device can be mounted on a vehicle, and power can be supplied from a power transmission device on the ground in a non-contact manner for charging. In the case of this non-contact power supply system, it is possible to charge the battery not only while the vehicle is stopped but also while the vehicle is running by installing a power transmission device on the road or on the outer wall. In addition, electric power may be transmitted and received between vehicles using this contactless power supply method. Furthermore, a solar battery may be provided on the exterior of the vehicle to charge the secondary battery while the vehicle is stopped or running. An electromagnetic induction method or a magnetic resonance method can be used for such contactless power supply.

This embodiment can be appropriately combined with the description of other embodiments. The test cell described in Embodiment 2 is used to detect a micro-short at an early stage and check the operation of a protective circuit to prevent a serious accident. Then, after the operation check of the protection circuit is completed, the protection circuit is attached to the secondary battery, and a power storage system incorporating the protection circuit with high safety can be configured. It is possible to check whether the protection circuit of the secondary battery functions normally before the car is shipped.

FIG. 5 shows an example of another power storage system and electronic device. FIG. 5A shows an example of a house having a power storage system 8200 including the capacity estimation system of one embodiment of the present invention and a solar panel 8230 . It is more preferable that the house is equipped with a ground-mounted charging device 8240 . Moreover, the power storage system 8200 preferably includes a protection circuit and a control circuit. Electric power obtained by the solar panel 8230 is stored in the secondary battery of the power storage system 8200 . Before installing the secondary battery, test cells are used to check the operation of the protection circuit and power storage system, and if it is confirmed that an abnormality can be detected, the permanently installed secondary battery is installed in place of the test cell.

In addition, when a protection circuit is provided in the ground-mounted charging device 8240, a test cell is used to check the operation of the protection circuit and the power storage system. Installed in place of the cell. The test cell can be used to check the operation of the protection circuit incorporated in the ground-mounted charging device 8240 .

The test cell can be used to check the operation of the secondary battery protection circuit, and after that, the protection circuit can detect an abnormality in the secondary battery of the automobile 8250 and notify the user.

If the test cell is used to check the operation of the secondary battery protection circuit in advance, malfunction of the secondary battery protection circuit of the automobile 8250 can be prevented from becoming a serious situation.

A power storage system 8200, a solar panel 8230, and a charging device 8240 are electrically connected through a wiring 8231 or the like. The power storage system 8200 can be charged with the power obtained from the solar panel 8230 . Electric power stored in the power storage system 8200 can be charged to a storage battery 8251 included in the vehicle 8250 via a ground-mounted charging device 8240 . The automobile 8400 is an electric automobile or a plug-in hybrid automobile.

The power stored in the power storage system 8200 can also supply power to other electronic devices installed indoors. For example, as shown in FIG. 5B, a power storage system 8200 and a stationary lighting device 8100 can be electrically connected to supply power to the lighting device 8100 . A lighting device 8100 includes a housing 8101, a light source 8102, a control circuit 8103, and the like. The lighting device 8100 can receive power from a commercial power supply, or can use power stored in the power storage system 8200 . Therefore, even when power cannot be supplied from a commercial power supply due to a power failure or the like, the lighting device 8100 can be used by using the power storage system 8200 as an uninterruptible power supply.

Note that FIG. 5 illustrates the stationary lighting device 8100 provided on the ceiling 8104, but the power storage system 8200 can be applied to stationary lighting devices other than the ceiling 8104, such as side walls, floors, windows, and the like. Power may be supplied, or power may be supplied to a desktop lighting device or the like.

For the light source 8102, an artificial light source that artificially obtains light using electric power can be used. Specifically, incandescent lamps, discharge lamps such as fluorescent lamps, and light-emitting elements such as LEDs and organic EL elements are examples of the artificial light sources.

Similarly, the power storage system 8200 can power the display device 8000 . A display device 8000 includes a housing 8001, a display portion 8002, a speaker portion 8003, a control circuit 8004, and the like. The display device 8000 can receive power from a commercial power source or can use power stored in the power storage system 8200 .

The display unit 8002 includes a liquid crystal display device, a light emitting device having a light emitting element such as an organic EL element in each pixel, an electrophoretic display device, a DMD (Digital Micromirror Device), a PDP (Plasma Display Panel), and an FED (Field Emission Display). ) can be used.

The display device includes all display devices for information display, such as for TV broadcast reception, personal computer, advertisement display, and the like.

Similarly, the power storage system 8200 can power an air conditioner having an indoor unit 8300 and an outdoor unit 8304 . The indoor unit 8300 has a housing 8301, an air outlet 8302, a control circuit 8303, and the like. The air conditioner can receive power from a commercial power supply, or can use power stored in power storage system 8200 .

Note that FIG. 5B illustrates a separate type air conditioner composed of an indoor unit and an outdoor unit. Electric power may be supplied to the air conditioner from a secondary battery.

In this example, a test cell was produced according to the second embodiment, and charging and discharging were performed to obtain cycle characteristics.

The pressing conditions for fabricating the test cell were that the test cell was sandwiched between two metal flat plates, and the torque of the four screws for fixing the four corners of the metal flat plates was 30 cN·m.

The conditions of the cycle test in the pressed state were as follows: charging at CCCV (0.2C, 4.4V, final current 0.02C) and discharging at CCV (0.2C, 2.5V) at 25°C. did C rate was set to 180 mA/g.

Nickel-cobalt-manganese oxide (also called NCM) was used as the positive electrode material. 1 mol/L lithium hexafluorophosphate (LiPF ₆ ) is used as the electrolyte in the electrolytic solution, and the electrolytic solution contains ethylene carbonate (EC) and diethyl carbonate (DEC) in a ratio of EC:DEC=3:7 ( volume ratio), was used. Graphite was used as the negative electrode active material. The secondary battery has a capacity ratio of 80%.

150 cycles of charging and discharging were measured. Then, an abnormality occurred in the 63rd cycle of the charge/discharge test. The characteristic at this time is the projected portion in FIG. 6(A). Further, in order to confirm the reproducibility, another test cell manufactured by the same procedure was used to measure the cycle characteristics in the same manner, and an abnormality occurred at the 71st cycle. The characteristics at this time are shown in FIG.

FIG. 7 is a SEM photograph of the surface of the negative electrode of the disassembled test cell in which an abnormality occurred after the cycle test. FIG. 8 is a partially enlarged view of FIG. 7, and copper was detected when EDX analysis was performed on the portion identified as the lithium deposit in FIG. Manganese used for the positive electrode active material was also detected.

In this way, it was confirmed that a battery cell in which micro-shorts intentionally occurred after several tens of charge/discharge cycles could be produced. It was also confirmed that copper adhered to the negative electrode active material. By using this battery cell as a test cell, it is possible to check the operation of a protection circuit having an abnormality detection circuit.

200 Information processing device 210 Arithmetic device 220 Input/output device 230 Display unit 250 Power storage device 290 Communication unit 500 Secondary battery 501 Positive electrode current collector 502 Positive electrode active material layer 503 Positive electrode 504 Negative electrode current collector 505 Negative electrode active material layer 506 Negative electrode 507 Separator 509 Outer body 510 Positive electrode lead electrode 511 Negative lead electrode 991 Outer body 992 Outer body 993 Wound body 994 Negative electrode 995 Positive electrode 996 Separator 997 Lead electrode 998 Lead electrode 7400 Mobile phone 7401 Housing 7402 Display unit 7403 Operation button 7404 External connection port 7405 Speaker 7406 Microphone 7407 Power storage device 8000 Display device 8001 Housing 8002 Display portion 8003 Speaker portion 8004 Control circuit 8021 Charger 8022 Cable 8024 Secondary battery 8100 Lighting device 8101 Housing 8102 Light source 8103 Control circuit 8104 Ceiling 8200 Power storage system 8230 Solar panel 8231 Wiring 8240 Charging device 8250 Automobile 8251 Storage battery 8300 Indoor unit 8301 Housing 8302 Air outlet 8303 Control circuit 8304 Outdoor unit 8400 Automobile 8500 Automobile 8700 Uninterruptible power supply

Claims (16)

Using a test secondary battery that develops a micro -short after multiple charging and discharging, and an abnormality detection circuit electrically connected to the test secondary battery, for the test secondary battery After a charge-discharge cycle test is performed and the abnormality detection circuit detects a micro-short that has occurred in the test secondary battery, the test secondary battery is removed from the abnormality detection circuit. An abnormal operation confirmation system ,
The micro-short is a phenomenon in which the positive electrode and the negative electrode of the test secondary battery are short-circuited and a current flows for a period of 10 nanoseconds or more and less than 1 microsecond.
Abnormal operation confirmation system for secondary batteries . In claim 1,
The charge-discharge cycle test for the test secondary battery is set to 50 cycles or more and 150 cycles or less in an environment of 25 ° C.
Abnormal operation confirmation system for secondary batteries. In claim 1,
The charge-discharge cycle test for the test secondary battery is 50 cycles or less in an environment of less than 25 ° C. or higher than 25 ° C.
Abnormal operation confirmation system for secondary batteries. In any one of claims 1 to 3 ,
The test secondary battery has the positive electrode, the separator, and the negative electrode ,
The positive electrode has a positive electrode current collector and a positive electrode active material on the positive electrode current collector ,
The negative electrode has a negative electrode current collector, a negative electrode active material on the negative electrode current collector, and metal nanoparticles attached to the surface of the negative electrode active material,
The particle size of the metal nanoparticles is smaller than the pore size of the separator ,
Abnormal operation confirmation system for secondary batteries. A positive electrode active material, a separator, a negative electrode active material , and metal nanoparticles attached to the surface of the negative electrode active material, wherein the metal nanoparticles have a particle size smaller than the pore size of the separator. next battery . A positive electrode active material, a separator, a negative electrode active material, metal nanoparticles attached to the surface of the negative electrode active material, and a metal used in the positive electrode active material attached to the surface of the negative electrode active material, A test secondary battery in which the particle size of the metal nanoparticles is smaller than the pore size of the separator. A positive electrode active material, a separator, a negative electrode active material, metal nanoparticles attached to the surface of the negative electrode active material, a metal used in the positive electrode active material attached to the surface of the negative electrode active material, and the metal nanoparticles. and a precipitate grown from a starting point, wherein the particle size of the metal nanoparticles is smaller than the pore size of the separator, and the precipitate reaches the positive electrode active material. In any one of claims 5 to 7,
A secondary battery for testing, wherein the positive electrode active material comprises a nickel manganese cobalt oxide or a lithium cobalt composite oxide. In any one of claims 5 to 8,
A secondary battery for testing, wherein the metal nanoparticles comprise one selected from copper, tin, zinc, nickel and silver. In any one of claims 5 to 9,
A secondary battery for testing, wherein the separator has a resin microporous film. In any one of claims 5 to 9,
A secondary battery for testing, wherein the separator has a fiber containing cellulose, a non-woven fabric, a glass fiber, or a synthetic fiber using ceramics, polyamide, polyvinyl alcohol, polyester, acrylic, polyolefin or polyurethane. In any one of claims 5 to 11,
A secondary battery for testing, wherein the separator has an average pore size of 0.1 μm or more and 15 μm or less. A solvent in which metal nanoparticles are dispersed is coated on a positive electrode active material and dried to form a positive electrode active material layer, and a negative electrode including the positive electrode active material layer, a separator having a plurality of pores, and a negative electrode active material. A secondary battery for testing is prepared by stacking the active material layer, and a charge-discharge cycle test is performed on the secondary battery for testing , so that the metal nanoparticles that have passed through the pores of the separator are removed as described above. A method for manufacturing a test secondary battery that is attached to the surface of a negative electrode active material. 14. The method of manufacturing a test secondary battery according to claim 13 , wherein pressing is performed after the positive electrode active material layer, the separator, and the negative electrode active material layer are stacked. Using a test secondary battery that develops a micro-short after multiple charging and discharging, and a charging circuit and a protection circuit electrically connected to the test secondary battery, the test secondary battery A charge-discharge cycle test is performed on the test secondary battery to confirm whether the protection circuit operates when a micro-short occurs in the test secondary battery, and then the protection circuit is removed from the test secondary battery. A method for checking the operation of a protection circuit for a next battery,
The micro-short is a phenomenon in which the positive electrode and the negative electrode of the test secondary battery are short-circuited and a current flows for a period of 10 nanoseconds or more and less than 1 microsecond.
A method for checking the operation of a protection circuit for a secondary battery. A solvent in which metal nanoparticles are dispersed is coated on a positive electrode active material, dried to form a positive electrode active material layer, and a negative electrode active material layer, a separator having a plurality of pores, and a negative electrode active material including a negative electrode active material. A secondary battery for testing is prepared by stacking a material layer, and after electrically connecting a charging circuit and a protection circuit to the secondary battery for testing, charging and discharging cycles are performed on the secondary battery for testing. By conducting a test , the metal nanoparticles passed through the pores of the separator are attached to the surface of the negative electrode active material, and the secondary battery for test is subjected to a charge-discharge cycle test to obtain the negative electrode. Starting from the metal nanoparticles attached to the surface of the active material, a precipitate is grown through the pores of the separator, and the tip of the precipitate reaches the positive electrode active material layer due to the growth of the precipitate, and the test is performed. A method for checking the operation of a secondary battery protection circuit for checking whether the protection circuit operates when a micro-short occurs in a secondary battery for use, and then removing the protection circuit, comprising:
The micro-short is a phenomenon in which the positive electrode and the negative electrode of the test secondary battery are short-circuited and a current flows for a period of 10 nanoseconds or more and less than 1 microsecond.
A method for checking the operation of a protection circuit for a secondary battery.

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