Lithium ion battery discharge hydrogen gas utilization method and system therefor

Abstract

To provide a lithium ion battery discharge hydrogen gas utilization method and a system therefor that can use hydrogen gas discharged from a lithium ion battery safely and effectively without any environmental problem.SOLUTION: A lithium ion battery discharge hydrogen gas utilization method has a discharge gas feed process for feeding hydrogen gas, discharged from respective cells 14-1 to 14-4 constituting a lithium ion battery 14 during a travel of the hybrid vehicle mounted with the lithium ion battery 14 to the side of an engine combustion chamber 46; and a discharge hydrogen gas supply and combustion process of injecting and supplying the fed hydrogen gas to the engine combustion chamber 46 and burning it together with gasoline.SELECTED DRAWING: Figure 1

Description

Technical Field

[0004]

[0001] The present invention relates to a method for utilizing hydrogen gas discharged from a lithium-ion battery and a system therefor, and particularly to a method for utilizing hydrogen gas generated from a lithium-ion battery in a hybrid vehicle and a system therefor.

Background Art

[0002] A lithium-ion battery for driving a hybrid vehicle has the property of generating gas due to use at high temperature, overcharging, or deterioration over time. The gas is mainly hydrogen gas and also includes other gases toxic to the human body.

[0003] Although a lithium-ion battery is sealed in a can for each of the plurality of cells constituting it, depending on the amount of gas generated, the internal pressure in the can may increase, and there is a risk of various problems such as deformation of the can.

[0004] Patent Document 1 discloses a battery pack composed of a plurality of unit batteries, and each unit battery is provided with a safety valve that is opened to eliminate the internal pressure when it reaches a predetermined pressure against the increase in internal pressure due to hydrogen gas generation. And a configuration is disclosed in which the discharge ports of these safety valves are connected to an exhaust gas tube connected to an external exhaust portion.

[0005] Moreover, the connection portions between the discharge ports of the safety valves of each exhaust gas tube have a bellows structure, and even if the unit battery expands and deforms due to internal pressure, this deformation is absorbed by the bellows structure, and the connection state between each safety valve discharge port and the exhaust gas tube is kept good, and the discharged hydrogen gas can be surely discharged to the outside of the vehicle without leaking into the vehicle.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Disclosure of the Invention

[0007] According to the configuration of Patent Document 1, hydrogen gas generated from the battery is reliably released outside the vehicle without leaking into the vehicle. However, the emitted hydrogen gas contains components harmful to the human body, and even if it can be released outside the vehicle, environmental problems remain.

[0008] This invention has been made in view of the above-mentioned problems, and its purpose is to provide a method and system for utilizing hydrogen gas emitted from lithium-ion batteries, which can be used safely and effectively without causing environmental problems. [Means for solving the problem]

[0009] To achieve the above objective, the lithium-ion battery emission hydrogen gas utilization method described in claim 1 is: A hydrogen gas supply process for supplying hydrogen gas emitted from each cell constituting the lithium-ion battery to the engine combustion chamber side while a hybrid vehicle equipped with a lithium-ion battery is in operation, The supplied hydrogen gas is injected into the engine combustion chamber and burned together with gasoline in an exhaust hydrogen gas supply and combustion process, It is characterized by having the following features.

[0010] In this method, hydrogen gas emitted from lithium-ion batteries is burned in the engine combustion chamber without being released to the outside. Combustion neutralizes harmful components in the hydrogen gas. In this way, the emitted hydrogen gas can be reliably incinerated, and it also has a positive effect on improving engine output. In other words, the effective utilization and detoxification of emitted hydrogen gas are achieved.

[0011] The lithium-ion battery discharge hydrogen gas utilization method described in claim 2 is the lithium-ion battery discharge hydrogen gas utilization method described in claim 1, Prior to the hydrogen gas supply process, there is a discharged hydrogen gas storage process in which hydrogen gas discharged from each cell is drawn in and stored in a predetermined location. The hydrogen gas storage process is as follows: This is performed for each cell according to the hydrogen gas generation status of each cell. The hydrogen gas supply process is characterized by being carried out by supplying the stored hydrogen gas.

[0012] This allows for intake of hydrogen gas according to the need for hydrogen gas emission from each cell, and also enables control such as supplying hydrogen to the combustion chamber at the appropriate timing by temporarily storing it.

[0013] The lithium-ion battery hydrogen gas utilization method described in claim 3 is the lithium-ion battery hydrogen gas utilization method described in claim 1 or 2, The determination of the hydrogen gas generation status in each of the aforementioned cells is as follows: Operation information acquisition operation, which acquires operation information including current value, voltage value, and temperature value for each cell while the vehicle is running, The operation is characterized by performing a calculation and estimation operation of the amount of hydrogen gas emitted from each cell based on the aforementioned operating information.

[0014] This method makes it possible to calculate and estimate the amount of hydrogen gas emitted from each lithium-ion battery cell without actually measuring it for each cell, to determine the hydrogen gas generation situation in each cell, and to select a cell suitable for storing the emitted hydrogen gas by intake.

[0015] The lithium-ion battery discharge hydrogen gas utilization method described in claim 4 is the lithium-ion battery discharge hydrogen gas utilization method described in any one of claims 1 to 3, The aforementioned hydrogen gas supply and combustion process is: This is characterized by being performed during cold-start operation when the engine is below a predetermined temperature.

[0016] By this method, especially during cold seasons, for example, when starting the engine in an environment of -10°C or lower, in addition to the combustion of gasoline, the combustion of hydrogen gas is added, thus promoting better starting.

[0017] To achieve the above object, the lithium-ion battery discharged hydrogen gas utilization system according to claim 5 is A lithium-ion battery discharged hydrogen gas utilization system for executing the lithium-ion battery discharged hydrogen gas utilization method according to any one of claims 1 to 4, An operation information acquisition operation unit that acquires operation information including the current value, voltage value, and temperature value of each cell of the lithium-ion battery during vehicle running, A calculation and estimation operation unit for calculating and estimating the discharge amount of hydrogen gas of each cell based on the operation information, An exhaust hydrogen gas storage engineering department that inhales the hydrogen gas discharged from each cell and stores it at a predetermined location, An exhaust hydrogen gas supply and combustion engineering department that injects and supplies the stored hydrogen gas into the engine combustion chamber and burns it together with gasoline, It is characterized by having a control unit that controls the operation information acquisition operation unit, the calculation and estimation operation unit, the exhaust hydrogen gas storage engineering department, and the exhaust hydrogen gas supply and combustion engineering department.

[0018] With this configuration, the hydrogen gas discharged from the lithium-ion battery is burned in the engine combustion chamber without being discharged to the outside. The components harmful to the human body contained in the hydrogen gas are rendered harmless by combustion. In this way, the discharged hydrogen gas can be reliably incinerated, and it is also possible to add a beneficial effect to improving the output of the engine. That is, the effective utilization and detoxification of the exhaust hydrogen gas are achieved.

Effects of the Invention

[0019] According to the method for utilizing the hydrogen gas discharged from a lithium-ion battery and its system of the present invention, hydrogen gas containing components harmful to the human body generated in each cell of the lithium-ion battery is burned together with gasoline in the engine combustion chamber. Therefore, the discharge of hydrogen gas to the outside is prevented and its detoxification is achieved. Furthermore, the combustion of hydrogen gas also contributes to improving the output of the engine. As a result, the problem of adverse effects on the natural environment is also suppressed, and the use of lithium-ion batteries in hybrid vehicles is promoted.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic configuration diagram of the system for utilizing the hydrogen gas discharged from a lithium-ion battery of the present invention. [Figure 2] It is a flowchart of the method for utilizing the hydrogen gas discharged from a lithium-ion battery of the present invention. In particular, it is the control flow (first half) of the discharged hydrogen gas calculation and engineering department. [Figure 3] It is a flowchart of the method for utilizing the hydrogen gas discharged from a lithium-ion battery of the present invention. In particular, it is the control flow (second half) of the discharged hydrogen gas calculation and engineering department. [Figure 4] It is a flowchart of the method for utilizing the hydrogen gas discharged from a lithium-ion battery of the present invention. In particular, it is the control flow of the discharged hydrogen gas storage and engineering department. [Figure 5] It is a flowchart of the method for utilizing the hydrogen gas discharged from a lithium-ion battery of the present invention. In particular, it is the control flow of the discharged hydrogen gas supply and combustion engineering department.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, the method for utilizing the hydrogen gas discharged from a lithium-ion battery and its system of the present invention will be described in detail with reference to the drawings. In this embodiment, the lithium-ion battery consists of four cells, and the method for utilizing hydrogen gas is to inject the discharged hydrogen gas into the engine combustion chamber and burn it together with gasoline.

[0022] Figure 1 is a schematic diagram of the lithium-ion battery exhaust hydrogen gas utilization system in this embodiment. The lithium-ion battery exhaust hydrogen gas utilization system 10 includes an exhaust hydrogen gas calculation process unit 12 that calculates and estimates the amount of exhaust hydrogen gas, an exhaust hydrogen gas storage process unit 30 that carries out an exhaust hydrogen gas storage process, and an exhaust hydrogen gas supply and combustion process unit 40 that carries out an exhaust hydrogen gas supply and combustion process.

[0023] The exhaust hydrogen gas supply process is a process of supplying hydrogen gas emitted from each cell 14-1 to 14-4 that make up the lithium-ion battery 14 while the hybrid vehicle is running to the engine combustion chamber 46. In this embodiment, however, it refers to the process from when the exhaust hydrogen gas calculation process unit 12 estimates the emission of hydrogen gas from the cells, when the intake device 32 of the exhaust hydrogen gas storage process unit 30 takes in the hydrogen gas and stores it in the storage tank 34, until the hydrogen gas injection device 42 of the exhaust hydrogen gas supply and combustion process unit 40 injects the hydrogen gas stored in the storage tank 34 into the engine combustion chamber 46.

[0024] The hydrogen gas emission calculation unit 12 includes a lithium-ion battery 14 composed of four cells 14-1 to 14-4, an operation information acquisition unit 22 that acquires operation information including current value, voltage value, and temperature value for each cell during vehicle operation, an operation unit 24 that calculates and estimates the amount of hydrogen gas emitted from each cell based on this operation information, and a cell information recording unit 26 that records information for each cell.

[0025] The discharged hydrogen gas storage process unit 30 includes a hydrogen gas storage tank 34 for storing hydrogen gas, an intake device 32 for drawing in discharged hydrogen gas from each cell 14-1 to 14-4, and a storage tank information recording unit 36 ​​for recording information about the hydrogen gas storage tank 34.

[0026] The exhaust hydrogen gas supply and combustion process unit 40 includes an engine combustion chamber 46, an injector 44, and a hydrogen gas injection device 42 that injects stored exhaust hydrogen gas into the engine combustion chamber 46. Each of the above-mentioned parts is controlled by a control unit 48. The operation of each process unit will be described below, followed by a detailed description of the control flow of each process unit.

[0027] The hydrogen gas emission calculation unit 12 calculates and estimates whether hydrogen gas is emitted from the four cells 14-1 to 14-4 of the lithium-ion battery 14 while the hybrid vehicle is running. This calculation and estimation is performed by the calculation and estimation operation unit 24 (see the flowchart and Figure 2 described later for details).

[0028] Operating information, including current, voltage, and temperature values ​​of cells 14-1 to 14-4 during hybrid vehicle operation, is acquired by the operating information acquisition unit 22. Based on this operating information, the calculation and estimation operation unit 24 estimates whether or not hydrogen gas is being emitted. An example of the estimation method is explained in the control flow described later. Information for each cell, such as whether or not hydrogen gas emission is estimated, is recorded in the cell information recording unit 26.

[0029] When hydrogen gas emissions are estimated in the four cells 14-1 to 14-4, the hydrogen gas storage process unit 30 takes in the emitted hydrogen gas with the intake device 32 and stores it in the storage tank 34 while the hybrid vehicle is stopped.

[0030] In this embodiment, each cell is housed in a can, and each cell's can is fitted with an on-off valve 16-1 to 16-4. Each on-off valve 16-1 to 16-4 is opened and closed by a command from the control unit 48, and the respective discharge ports 18-1 to 18-4 of the on-off valves 16-1 to 16-4 are connected by a single exhaust duct 20. The exhaust duct 20 is connected to the intake device 32 of the hydrogen gas storage process section 30 by a connecting pipe 28. The on-off valve 16 of the cell whose discharge hydrogen gas has been calculated and estimated is opened, and hydrogen gas is drawn in by the intake device 32.

[0031] The hydrogen gas supply and combustion process unit 40 burns the hydrogen gas stored in the storage tank 34 together with gasoline in the engine's combustion chamber 46 when starting the engine in a cold state. The storage tank 34 of the exhaust hydrogen gas storage process unit 30 is connected to the hydrogen gas injection device 44 of the exhaust hydrogen gas supply and combustion process unit 40 by a connecting pipe 38. Gasoline is supplied to the engine combustion chamber 46 from the injector 44, and hydrogen gas is injected into the engine combustion chamber 46 from the gas injection device 42. When the engine starts, these are mixed and burned.

[0032] Figures 2 and 3 are control flow diagrams of the hydrogen gas emission calculation process unit 12.

[0033] First, the ignition (IG) is turned ON (step S23). Turning the IG ON turns on the power to each part, including the control unit 48. Next, the contactor is connected (step S24). By connecting the contactor, the lithium-ion battery 14 is connected to the electric motor (not shown), and the hybrid vehicle becomes capable of running.

[0034] The following control is performed while the hybrid vehicle is in motion. The voltage values ​​of the four cells 14-1 to 14-4 are acquired (step S25), the temperature value of each cell is acquired (step S26), and the current value of each cell is acquired (step S27). This operational information is obtained by measuring the voltage, current, and temperature of the operational information acquisition unit 22, and the measured values ​​are sent to the control unit 48.

[0035] The calculation and estimation unit 24 determines whether the four cells 14-1 to 14-4 exceed the specified value (threshold) for hydrogen emission (step S28). The specified value (threshold) for hydrogen emission is determined from the current value, voltage value, and temperature value measured for each of the four cells 14-1 to 14-4. If the specified value (threshold) is exceeded (step S28, Yes), the cell information recording unit 24 records the "cell number" and "hydrogen gas emission present" (step S29), and step S30 is executed. Here, the specified value (threshold) is, for example, the sum of the increases in each measured value after determining standard values ​​(minimum values) for the current value, voltage value, and temperature value. By creating a correspondence table of the amount of hydrogen gas actually emitted so far, the amount of emitted hydrogen gas can be immediately estimated using the specified value (threshold). If the answer in step S28 is NO, step S30 is executed.

[0036] In step S30, it is determined whether a contactor connection command has been received. If a connection command has been received, the vehicle is still scheduled to travel; if no connection command has been received, the vehicle will stop. If no command has been received, the contactor is disconnected (step S31) and the vehicle is stopped. If a connection command has been received, step S25 is executed.

[0037] Next, cell information for the four cells 14-1 to 14-4 is obtained from the cell information recording unit 26 (step S32), and it is determined whether or not hydrogen gas is generated during the current trip (step S33). This determination is made by collecting the cell information from each cell. Specifically, the sum of the estimated amount of emitted hydrogen gas calculated from each cell is obtained.

[0038] If it is determined in step S33 that hydrogen gas has been released, the startup of the "exhaust hydrogen gas storage process unit" 30 is set to "reserved" (step S34). After this, as will be described later, the exhaust hydrogen gas in the cell is drawn in and removed, so "no exhaust hydrogen gas" is recorded in the corresponding cell of the cell information recording unit 24 (step S35).

[0039] Next, the ignition is turned OFF (step S36). This operation turns off all power to the hybrid vehicle. After a predetermined time has elapsed, or if the hybrid vehicle is not scheduled to be used at night, it is self-wake up (step S37). This operation enables various controls by the control unit 48. Next, it is determined whether there is a "reservation" for the hydrogen gas storage process unit 30 (step S38). If there is a reservation, the hydrogen gas storage process unit 30 is started and the control flow of the emission hydrogen gas calculation process unit 12 is terminated. If there is no reservation for the hydrogen gas storage process unit 30, the control flow of the emission hydrogen gas calculation process unit 12 is also terminated.

[0040] In the control flow of the hydrogen gas emission calculation process unit 12, if the hydrogen gas storage process unit 30 is started, the following control flow of the hydrogen storage process unit 30 is executed.

[0041] Figure 4 shows the control flow of the hydrogen gas storage process unit 30. First, the cell number from which the discharged hydrogen gas is estimated is read from the cell information recording unit 26, and the on / off valve 16 for the corresponding cell number is opened (step S42). This opening is performed by a command from the control unit 48. Then, the discharged hydrogen gas is drawn into the storage tank 34 by the intake device 32 (step S43), and the amount of gas in the storage tank 34 is measured (step S44). This measurement is performed by a volume meter or the like built into the storage tank 34.

[0042] Next, it is determined whether the amount of gas stored in the storage tank 34 has reached the permitted injection amount (step S45). If it has, "Injection permitted" is recorded in the gas storage information recording unit 36 ​​(step S46). Then, in both the case of Yes and No in step S45, it is determined whether the amount of gas stored has exceeded the limit (step S47). If it has exceeded the limit, "Storage limit" is recorded in the gas storage information recording unit 36 ​​(step S48), and the control flow of the hydrogen gas storage process unit 30 is terminated. The control flow of the hydrogen gas storage process unit is also terminated if it has not exceeded the limit.

[0043] In the hydrogen gas storage process unit 30, if the gas storage information recording unit 36 ​​has a record of "injection permission" and / or a record of "storage limit", the following control flow of the hydrogen gas supply and combustion process unit 40 is executed.

[0044] Figure 5 shows the control flow of the hydrogen gas supply and combustion process unit 40. The ignition is turned ON to start the engine (step S51). Next, it is determined whether the engine is being started in a cold state (step S52). A cold state can be set, for example, when the ambient temperature is below -10°C. However, it is not limited to this. If the engine is being started in a cold state, it is determined whether there is a record of "injection permission" in the gas storage information recording unit 36 ​​(step S53). If there is a record of "injection permission", the stored hydrogen gas is injected into the engine combustion chamber 46 (step S54) and burned together with the gasoline. Then, the gas storage information recording unit 36 ​​is recorded as "no storage" (step S55), and the control flow of the hydrogen gas supply and combustion process unit 40 is terminated.

[0045] If the engine is not being started while cold (Step S52, No), it is determined whether there is a record of "storage limit" in the gas storage information recording unit 36 ​​(Step S56). If there is no record, the control flow of the hydrogen gas supply / combustion process unit 40 is terminated. If there is a record of "storage limit" (Step S56, YES), the stored hydrogen gas is injected into the engine combustion chamber 46 (Step S54) and burned together with the gasoline. Then, the gas storage information recording unit 36 ​​is recorded as "no storage" (Step S55), and the control flow of the hydrogen gas supply process unit 40 is terminated.

[0046] According to the lithium-ion battery exhaust hydrogen gas utilization method and system of this embodiment, the hydrogen gas emitted from the lithium-ion battery 14 is burned in the engine combustion chamber 46 without being released to the outside. Combustion neutralizes components in the hydrogen gas that are harmful to the human body. In this way, the emitted hydrogen gas can be reliably incinerated, and it also has a positive effect on improving engine output. In other words, the effective utilization and neutralization of emitted hydrogen gas is achieved, promoting the use of lithium-ion batteries in hybrid vehicles.

[0047] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. For example, although the on-off valves provided for each cell are connected by a single exhaust duct 20, an exhaust duct may be provided for each cell. Also, although the injector 44 and the injection device 42 are shown separately in the exhaust hydrogen gas supply process section 40, they may be integrated into a single device. [Explanation of symbols]

[0048] 10. Lithium-ion battery hydrogen gas utilization system 12. Hydrogen Gas Emission Calculation Process Section 14 Lithium-ion batteries Cells 14-1 to 14-4 16-1~16-4 Shut-off valves 18-1~18-4 Outlet 20 Exhaust duct 22 Operation Information Acquisition Unit 24 Calculation and Estimation Operation Unit 26 Cell Information Recording Unit 28, 38 connecting pipes 30. Emission Hydrogen Gas Storage Process Section 32 Intake system 34 Storage Tanks 36 Tank Information Recording Unit 40. Hydrogen Gas Supply and Combustion Process Section 42 Hydrogen gas injection device 44 Injectors 46 Engine Combustion Chamber 48 Control Unit

Claims

1. a discharged hydrogen gas supply step for supplying hydrogen gas discharged from each cell constituting the lithium ion battery to an engine combustion chamber while the hybrid vehicle equipped with the lithium ion battery is running; an exhaust hydrogen gas supply / combustion process for injecting and supplying the delivered hydrogen gas into the engine combustion chamber and combusting it together with gasoline; A method for utilizing hydrogen gas discharged from a lithium ion battery, comprising:

2. a discharged hydrogen gas storage step of sucking in the hydrogen gas discharged from each of the cells and storing it in a predetermined location before the discharged hydrogen gas delivery step; The discharged hydrogen gas storage step includes: The hydrogen gas generation in each cell is performed according to the hydrogen gas generation status of each cell.

2. The method for utilizing hydrogen gas discharged from a lithium ion battery according to claim 1, wherein the step of delivering the discharged hydrogen gas is performed by delivering the stored hydrogen gas.

3. The determination of the hydrogen gas generation status of each cell is performed by: an operation information acquisition operation for acquiring operation information including a current value, a voltage value, and a temperature value for each of the cells while the vehicle is running; 3. The method for utilizing hydrogen gas discharged from a lithium ion battery according to claim 1, further comprising: calculating and estimating the amount of hydrogen gas discharged from each cell based on the operation information.

4. The exhaust hydrogen gas supply and combustion process includes:

4. The method for utilizing hydrogen gas discharged from a lithium ion battery according to claim 1, wherein the method is carried out during a cold start of an engine at a temperature equal to or lower than a predetermined temperature.

5. A system for utilizing hydrogen gas discharged from a lithium ion battery for carrying out the method for utilizing hydrogen gas discharged from a lithium ion battery according to any one of claims 1 to 4, an operation information acquisition unit that acquires operation information including a current value, a voltage value, and a temperature value of each cell of the lithium ion battery while the vehicle is running; a calculation and estimation operation unit for calculating and estimating the amount of hydrogen gas discharged from each cell based on the operation information; a discharged hydrogen gas storage process section for sucking in the hydrogen gas discharged from each of the cells and storing it in a predetermined location; an exhaust hydrogen gas supply and combustion process unit that injects and supplies the stored hydrogen gas into the engine combustion chamber and burns it together with gasoline; a control unit that controls the operation information acquisition unit, the calculation / estimation unit, the discharged hydrogen gas storage unit, and the discharged hydrogen gas supply / combustion unit; The present invention is characterized by having the following.

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