Method and system for utilizing hydrogen gas discharged from lithium-ion batteries

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]

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

[0002] Lithium-ion batteries used to power hybrid vehicles tend to generate gas when used at high temperatures, overcharged, or deteriorate over time. The gas is primarily hydrogen gas, but also other gases that are toxic to the human body.

[0003] Lithium-ion batteries are made up of multiple cells that are sealed in a can, but depending on the amount of gas generated, the internal pressure inside the can can increase, which could cause various problems, including deformation of the can.

[0004] Patent Document 1 discloses a battery pack consisting of multiple unit cells, each of which is provided with a safety valve that opens to relieve internal pressure buildup caused by hydrogen gas generation when the internal pressure reaches a predetermined pressure, and discloses a configuration in which the outlets of these safety valves are connected to an exhaust gas tube that is connected to an external exhaust section.

[0005] In addition, the connection between each safety valve outlet of the exhaust gas tube is made of a bellows structure, so that even if the unit battery expands and deforms due to internal pressure, this deformation is absorbed by the bellows structure, maintaining a good connection between each safety valve outlet and the exhaust gas tube, and ensuring that the exhaust hydrogen gas can be released outside the vehicle without leaking inside. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-110377 DISCLOSURE OF THE INVENTION [Problem to be solved by 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 released hydrogen gas contains components that are harmful to the human body, and even if it can be released outside the vehicle, environmental problems remain.

[0008] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a method and system for utilizing hydrogen gas discharged from lithium ion batteries, which can use the hydrogen gas discharged from lithium ion batteries safely and effectively without causing environmental problems. [Means for solving the problem]

[0009] To achieve the above objectives, According to one embodiment of the present invention The method for utilizing hydrogen gas emitted from lithium-ion batteries is as follows: a discharged hydrogen gas delivery step for delivering 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 and combustion process in which the supplied hydrogen gas is injected into the engine combustion chamber and burned together with gasoline; The present invention is characterized by having the following.

[0010] With this method, hydrogen gas emitted from the lithium-ion battery is burned in the engine combustion chamber without being emitted to the outside. The components contained in the hydrogen gas that are harmful to the human body are neutralized by the combustion. In this way, the emitted hydrogen gas can be reliably incinerated, and it is also possible to add a positive effect in improving engine output. In other words, the effective use and neutralization of the emitted hydrogen gas is achieved.

[0011] Moreover, one embodiment of the present invention is the above-mentioned In a method for utilizing hydrogen gas discharged from lithium-ion batteries, a discharged hydrogen gas storage step of taking 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 is performed for each cell according to the hydrogen gas generation status of each cell. The discharged hydrogen gas delivery step is characterized in that it is carried out by delivering the stored hydrogen gas.

[0012] This allows hydrogen gas to be drawn in according to the need for discharge from each cell, and by temporarily storing the gas, it becomes possible to control the timing of delivery to the combustion chamber.

[0013] Moreover, one embodiment of the present invention is the above-mentioned In a method for utilizing hydrogen gas discharged from lithium-ion batteries, The determination of the hydrogen gas generation status of each cell is made by: an operation information acquisition operation for acquiring operation information including a current value, a voltage value, and a temperature value for each cell while the vehicle is running; The calculation and estimation of the amount of hydrogen gas emitted from each cell is performed based on the operation information.

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

[0015] Moreover, one embodiment of the present invention is the above-mentioned In a method for utilizing hydrogen gas discharged from lithium-ion batteries, the discharged hydrogen gas supply The combustion process is This is characterized by being performed when the engine is started in a cold state when the temperature is below a predetermined level.

[0016] This method promotes better starting, particularly when starting the engine in cold weather, for example, in an environment below -10°C, because hydrogen gas combustion is added to gasoline combustion.

[0017] To achieve the above objectives, According to one embodiment of the present invention The lithium-ion battery exhaust hydrogen gas utilization system is The aforementioned A system for utilizing hydrogen gas discharged from a lithium ion battery for carrying out a method for utilizing hydrogen gas discharged from a lithium ion battery, 、 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 unit for calculating and estimating the amount of hydrogen gas emitted from each cell based on the operation information; a discharged hydrogen gas storage process unit that takes in the hydrogen gas discharged from each of the cells and stores 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; The hydrogen storage device is characterized by comprising a control unit that controls the operation information acquisition operation unit, the calculation and estimation operation unit, the discharged hydrogen gas storage process unit, and the discharged hydrogen gas supply and combustion process unit.

[0018] With this configuration, hydrogen gas discharged from the lithium-ion battery is burned in the engine combustion chamber without being emitted to the outside. The components contained in the hydrogen gas that are harmful to the human body are neutralized by the combustion. In this way, the discharged hydrogen gas can be reliably incinerated, and it is also possible to add a positive effect in improving engine output. In other words, the effective use and neutralization of discharged hydrogen gas is achieved. [Effects of the Invention]

[0019] According to the method and system for utilizing hydrogen gas emitted from lithium-ion batteries of the present invention, hydrogen gas, which contains substances harmful to the human body and is generated in each cell of a lithium-ion battery, is combusted together with gasoline in the engine combustion chamber. This prevents the hydrogen gas from being emitted to the outside and renders it harmless. Furthermore, the combustion of hydrogen gas contributes to improving engine output. This reduces the problem of adverse effects on the natural environment and promotes the use of lithium-ion batteries in hybrid vehicles. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic diagram of a system for utilizing hydrogen gas discharged from a lithium ion battery according to the present invention. [Figure 2] 1 is a flowchart of a method for utilizing hydrogen gas discharged from a lithium ion battery according to the present invention, particularly showing the control flow (first half) of the discharged hydrogen gas calculation step. [Figure 3] 1 is a flowchart of a method for utilizing hydrogen gas discharged from a lithium ion battery according to the present invention, particularly showing the control flow (second half) of the discharged hydrogen gas calculation step. [Figure 4] 1 is a flowchart of a method for utilizing hydrogen gas discharged from a lithium ion battery according to the present invention, particularly showing the control flow of a discharged hydrogen gas storage step. [Figure 5] 1 is a flowchart of a method for utilizing hydrogen gas discharged from a lithium-ion battery according to the present invention, particularly showing the control flow of the discharged hydrogen gas supply and combustion process section. DETAILED DESCRIPTION OF THE INVENTION

[0021] The method and system for utilizing hydrogen gas discharged from a lithium-ion battery according to the present invention will be described in detail below with reference to the drawings. In this embodiment, the lithium-ion battery is composed of four cells, and the hydrogen gas is utilized by injecting the discharged hydrogen gas into the engine combustion chamber and burning it together with gasoline.

[0022] 1 is a schematic diagram of a lithium-ion battery discharge hydrogen gas utilization system according to the present embodiment. The lithium-ion battery discharge hydrogen gas utilization system 10 includes a discharge hydrogen gas calculation process unit 12 that calculates and estimates discharge hydrogen gas, a discharge hydrogen gas storage process unit 30 that performs a discharge hydrogen gas storage process, and a discharge hydrogen gas supply and combustion process unit 40 that performs a discharge hydrogen gas supply and combustion process.

[0023] The exhaust hydrogen gas delivery process is a process of delivering hydrogen gas discharged from each cell 14-1 to 14-4 constituting the lithium-ion battery 14 to the engine combustion chamber 46 while the hybrid vehicle is running. In this embodiment, this refers to the process of taking in the exhaust hydrogen gas from the cell whose hydrogen gas emission has been estimated in the exhaust hydrogen gas calculation process unit 12 using the intake device 32 of the exhaust hydrogen gas storage process unit 30 and storing it in the storage tank 34, and then injecting the hydrogen gas stored in the storage tank 34 into the engine combustion chamber 46 using the hydrogen gas injection device 42 of the exhaust hydrogen gas supply / combustion process unit 40.

[0024] The hydrogen gas emission calculation process unit 12 includes a lithium ion battery 14 consisting of four cells 14-1 to 14-4, an operation information acquisition operation unit 22 that acquires operation information including the current value, voltage value, and temperature value for each cell while the vehicle is running, a calculation estimation 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 about 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 the discharged hydrogen gas from each of the cells 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 has 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 units is controlled by a control unit 48. Below, the operation of each process unit will be explained, and then the control flow of each process unit will be described in detail.

[0027] The discharged hydrogen gas calculation process unit 12 calculates and estimates whether or not hydrogen gas is discharged 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 a calculation and estimation operation unit 24 (see the flow chart and FIG. 2 described later for details).

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

[0029] When it is estimated that hydrogen gas is being discharged from the four cells 14-1 to 14-4, the hydrogen gas storage process unit 30 draws the discharged hydrogen gas into 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 an on-off valve 16-1 to 16-4 is attached to the top of each can of each cell. Each on-off valve 16-1 to 16-4 opens and closes in response to commands from a control unit 48, and each of the outlets 18-1 to 18-4 of the on-off valves 16-1 to 16-4 is connected in communication with a single exhaust duct 20. The exhaust duct 20 is connected to an intake device 32 of a hydrogen gas storage process unit 30 by a connection pipe 28. The on-off valve 16 of the cell for which the discharged hydrogen gas has been calculated and estimated is opened, and the hydrogen gas is taken in by the intake device 32.

[0031] The hydrogen gas supply and combustion process unit 40 combusts the hydrogen gas stored in the storage tank 34 together with gasoline in the engine combustion chamber 46 when the engine is started in cold weather. 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 from the injector 44 to the engine combustion chamber 46, and hydrogen gas is injected from the gas injection device 42 into the engine combustion chamber 46. When the engine is started, these are mixed and combusted.

[0032] 2 and 3 are control flow diagrams of the discharged hydrogen gas calculation process unit 12. In FIG.

[0033] First, the ignition (IG) is turned ON (step S23). By turning ON the IG, the power to each part including the control unit 48 is turned ON. 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 can be driven.

[0034] The following control is performed while the hybrid vehicle is running. 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). These pieces of operation information are acquired using a voltmeter, ammeter, and thermometer provided in operation information acquisition unit 22, and the measured values ​​are sent to control unit 48.

[0035] The calculation / estimation operation unit 24 determines whether the four cells 14-1 to 14-4 exceed a specified value (threshold) for hydrogen discharge (step S28). The specified value (threshold) for hydrogen discharge is determined from the current, voltage, and temperature values ​​measured for each of the four cells 14-1 to 14-4. If the specified value (threshold) is exceeded (step S28, Yes), the "cell number" and "discharged hydrogen gas present" are recorded in the cell information recording unit 24 (step S29), and step S30 is executed. Here, the specified value (threshold) is, for example, the sum of the increments of the measured values ​​of current, voltage, and temperature, with standard values ​​(minimum values) determined in advance. By creating a correspondence table of the amount of hydrogen gas actually discharged up to that point, the amount of discharged hydrogen gas can be immediately estimated based on the specified value (threshold). If the answer is NO in step S28, 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, it means that the vehicle is still scheduled to run, and if a connection command has not been received, it means that 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, the cell information of the four cells 14-1 to 14-4 is obtained from the cell information recording unit 26 (step S32), and it is determined whether hydrogen gas has been generated during the current trip (step S33). This determination is made by collecting the cell information of each cell. Specifically, the sum of the amount of hydrogen gas discharged calculated and estimated for each cell is calculated.

[0038] If it is determined in step S33 that there is generation, the activation of the "discharged hydrogen gas storage process unit" 30 is set to "reserved" (step S34). After this, as will be described later, the discharged hydrogen gas in the cell is sucked out and disappears, so "no discharged 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 passed, or if it is late at night and there are no plans to use the hybrid vehicle, the hybrid vehicle will self-wake up (step S37). This operation enables various controls in the control unit 48. Next, it is determined whether there is a "reservation" in the hydrogen gas storage process unit 30 (step S38). If there is a reservation, the "hydrogen gas storage process unit" 30 is activated and the control flow of the discharged hydrogen gas calculation process unit 12 is terminated. If there is no reservation in the hydrogen gas storage process unit 30, the control flow of the discharged hydrogen gas calculation process unit 12 is also terminated.

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

[0041] 4 shows the control flow of the hydrogen gas storage process unit 30. First, the number of the cell for which the discharged hydrogen gas has been 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 in response to a command from the control unit 48. Then, the discharged hydrogen gas is sucked (inhaled) 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 using a capacity meter or the like built into the storage tank 34.

[0042] Next, it is determined whether the amount stored in the storage tank 34 exceeds the injection permitted amount (step S45). If it exceeds the amount, "injection permitted" is recorded in the gas storage information recording unit 36 ​​(step S46). Then, whether the answer is Yes or No in step S45, it is next determined whether the storage amount exceeds the limit amount (step S47). If it exceeds the limit amount, "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 ends. If it does not exceed the limit amount, the control flow of the hydrogen gas storage process unit ends as well.

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

[0044] FIG. 5 shows the control flow of the hydrogen gas supply and combustion process unit 40. To start the engine, the ignition is turned on (step S51). Next, it is determined whether the engine is being started in cold weather (step S52). Cold weather can be defined as, for example, an ambient temperature of -10°C or below. However, this is not limited to this. If the engine is being started in cold weather, it is determined whether or not there is a record of "injection permitted" in the gas storage information recording unit 36 ​​(step S53). If there is a record of "injection permitted," the stored hydrogen gas is injected into the engine combustion chamber 46 (step S54) and burned together with gasoline. Then, the gas storage information recording unit 36 ​​records "no storage" (step S55), and the control flow of the hydrogen gas supply and combustion process unit 40 ends.

[0045] If the engine is not being started in cold weather (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 and combustion process unit 40 ends. 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 gasoline. Then, the gas storage information recording unit 36 ​​records "no storage" (step S55), and the control flow of the hydrogen gas supply process unit 40 ends.

[0046] According to the method and system for utilizing hydrogen gas discharged from a lithium-ion battery of this embodiment, hydrogen gas discharged from the lithium-ion battery 14 is combusted in the engine combustion chamber 46 without being emitted to the outside. The components contained in the hydrogen gas that are harmful to the human body are rendered harmless by the combustion. In this way, the discharged hydrogen gas can be reliably incinerated, and it is also possible to improve engine output. In other words, the effective utilization and detoxification of discharged hydrogen gas are achieved, promoting the use of lithium-ion batteries in hybrid vehicles.

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

[0048] 10. Lithium-ion battery hydrogen gas utilization system 12. Hydrogen gas emission calculation process 14 Lithium-ion battery 14-1~14-4 cells 16-1~16-4 On-off valve 18-1~18-4 Outlet 20 Exhaust duct 22 Operation information acquisition unit 24 Calculation and estimation operation unit 26 Cell information recording section 28, 38 Connecting pipe 30. Exhaust hydrogen gas storage process section 32 Intake system 34 Storage Tank 36 Tank information recording unit 40 Exhaust hydrogen gas supply and combustion process section 42 Hydrogen gas injection device 44 injector 46 Engine combustion chamber 48 Control Unit

Claims

1. a discharged hydrogen gas delivery step for delivering 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 and combustion step of injecting and supplying the supplied hydrogen gas into the engine combustion chamber and burning it together with gasoline; A method for utilizing hydrogen gas discharged from a lithium ion battery, comprising: a discharged hydrogen gas storage step of taking 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 is performed for each cell according to the hydrogen gas generation status of each cell. A method for utilizing hydrogen gas discharged from a lithium ion battery, characterized in that the discharged hydrogen gas delivery step is carried out by delivering the stored hydrogen gas.

2. The determination of the hydrogen gas generation status of each cell is made by: an operation information acquisition operation for acquiring operation information including a current value, a voltage value, and a temperature value for each cell while the vehicle is running; 2. The method for utilizing hydrogen gas discharged from a lithium ion battery according to claim 1, wherein the method is carried out based on an operation of calculating and estimating the amount of hydrogen gas discharged from each cell, which is carried out based on the operation information.

3. The exhaust hydrogen gas supply and combustion step includes:

3. 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 the engine when the engine temperature is below a predetermined temperature.

4. 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 3, 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 unit for calculating and estimating the amount of hydrogen gas emitted from each cell based on the operation information; a discharged hydrogen gas storage process unit that takes in the hydrogen gas discharged from each of the cells and stores 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 and estimation unit, the discharged hydrogen gas storage unit, and the discharged hydrogen gas supply and combustion unit; A system for utilizing hydrogen gas discharged from a lithium ion battery, comprising:

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