JP2013089311A - Controller of laminated lithium ion battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cell controller capable of detecting generation of gas appropriately during fast charging of a laminated lithium ion battery.SOLUTION: When a first voltage change value, i.e. the voltage change of a cell in a laminated lithium ion battery during fast charging, deviates from a predetermined first reference value by a predetermined value or more, a predetermined constant current is input to the laminated lithium ion battery. When the difference between a second voltage change value, i.e. the voltage change of a cell, and a predetermined second reference value is larger than a predetermined threshold, a determination is made that gas has generated in the laminated lithium ion battery.

Description

  The present invention relates to a control device for a laminated lithium ion battery.

Utilizing the characteristic that the internal impedance of the battery suddenly increases when gas is generated inside the storage battery, when the amount of change in internal impedance per unit time exceeds the specified value, this is detected to detect gas generation The technique to do is known (for example, refer patent document 1).

JP-A-10-92473

Here, the generation of gas inside the battery, which is one of the causes of battery deterioration, is particularly rapid during rapid charging of the battery, and since the phenomenon is also rapidly accelerated, When charging, it is necessary to detect gas generation inside the battery at an early stage.
However, in a lithium ion battery, the internal impedance changes greatly depending on the state of charge or reaction such as film formation. Therefore, if the amount of change in internal impedance is only measured, the increase in internal impedance is caused only by gas generation. There is a problem that gas generation cannot be properly detected by the method of Patent Document 1 that cannot be specified. Furthermore, in order to apply the technique of Patent Document 1, it is necessary to attach a device for measuring internal impedance to the battery, resulting in a problem that the battery becomes large.

On the other hand, a method of attaching a gas sensor to the battery is also conceivable. However, even in this method, it is necessary to attach a device for detecting gas generation to the battery, resulting in a problem that the battery becomes large. In addition, a method of detecting gas generation using a change in internal pressure or volume of a battery when gas is generated is also conceivable. However, the method of detecting the change in internal pressure has a problem that in a laminate type battery, even if gas is generated inside the battery, the internal pressure hardly changes, so it is difficult to detect the change in internal pressure and gas generation cannot be detected properly. is there. In addition, the method for detecting the volume change has a problem in that it is difficult to measure the volume change with high accuracy while using the battery, and thus gas generation cannot be detected appropriately.

  The problem to be solved by the present invention is to provide a battery control device capable of appropriately detecting gas generation inside a battery during rapid charging of a laminated lithium ion battery.

  According to the present invention, when a first voltage change value, which is a battery voltage change at the time of rapid charging of a laminated lithium ion battery, deviates from a predetermined first reference value by a predetermined value or more, a predetermined value is applied to the laminated lithium ion battery. When a second voltage change value, which is a voltage change of the battery at that time, is larger than a predetermined second reference value, a diagnosis is made that gas is generated inside the laminated lithium ion battery. Solve the above problems.

  According to the present invention, it is possible to detect a voltage change due to gas generation at the time of rapid charging of the laminated lithium ion battery, and thus it is possible to appropriately detect gas generation inside the battery.

FIG. 1 is a configuration diagram showing a rapid charging system for a laminated lithium ion battery according to this embodiment. FIG. 2 is a plan view of the laminated lithium ion battery according to the present embodiment. FIG. 3 is a cross-sectional view of a laminated lithium ion battery taken along line III-III in FIG. FIG. 4 is a graph showing an example of voltage change when rapid charging is performed on a laminated lithium ion battery. FIG. 5 is a graph showing a change in voltage when a constant current for diagnosis is input to the laminated lithium ion battery. FIG. 6 is a graph showing the relationship between the number of cycles of a laminated lithium ion battery and the voltage change when a constant current for diagnosis is input. FIG. 7 is a flowchart showing an example of a gas generation diagnosis method in the present embodiment. FIG. 8 shows the _relationship between the difference (ΔV _bat −ΔV _{ref — 2_Cur} ) between the current voltage change value ΔV _bat and the normal voltage change ΔV _{ref — 2_Cur} and the amount of gas generated inside the laminated lithium ion battery.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram showing a rapid charging system for a laminated lithium ion battery according to this embodiment. As shown in FIG. 1, a rapid charging system for a laminated lithium ion battery according to this embodiment is abbreviated as a laminated lithium ion battery 10 (hereinafter, “battery 10”) mounted in an electric vehicle, a hybrid vehicle, or the like. ), And includes a charging device 20, a battery controller 30, a voltmeter 40, and an ammeter 50.

  As shown in FIGS. 2 and 3, the battery 10 is connected to an electrode laminate 101 having three positive plates 102, seven separators 103, and three negative plates 104, and the electrode laminate 101. The positive electrode tab 105 and the negative electrode tab 106, the upper exterior member 107 and the lower exterior member 108 that contain and seal the electrode laminate 101, the positive electrode tab 105, and the negative electrode tab 106, and an electrolyte solution that is not particularly illustrated. It is configured.

  Note that the number of the positive electrode plate 102, the separator 103, and the negative electrode plate 104 is not particularly limited, and the electrode laminate 101 may be configured by one positive electrode plate 102, three separators 103, and one negative electrode plate 104. Moreover, the number of the positive electrode plate 102, the separator 103, and the negative electrode plate 104 may be appropriately selected as necessary.

  The positive electrode plate 102 constituting the electrode laminate 101 includes a positive electrode side current collector 102a extending to the positive electrode tab 105, and a positive electrode active material layer formed on both main surfaces of a part of the positive electrode side current collector 102a. have. The positive electrode side current collector 102a constituting the positive electrode plate 102 is made of, for example, an electrochemically stable metal foil such as an aluminum foil, an aluminum alloy foil, a copper foil, or a nickel foil having a thickness of about 20 μm. Can do.

In addition, the positive electrode active material layer constituting the positive electrode plate 102 is bonded to a positive electrode active material such as a metal oxide, a conductive agent such as carbon black, and an aqueous dispersion of polyvinylidene fluoride or polytetrafluoroethylene. It is formed by applying a mixture of an agent to a part of the main surface of the positive electrode side current collector 104a, drying and rolling. Examples of the positive electrode active material include lithium composite oxides such as lithium nickelate (LiNiO ₂ ), lithium manganate (LiMn ₂ O ₄ ), and lithium cobaltate (LiCoO ₂ ).

  The positive electrode current collectors 102 a constituting the three positive electrode plates 102 are joined to the positive electrode tab 105. As the positive electrode tab 105, for example, an aluminum foil having a thickness of about 0.2 mm, an aluminum alloy foil, a copper foil, or a nickel foil can be used.

  The negative electrode plate 104 constituting the electrode laminate 101 includes a negative electrode current collector 104a extending to the negative electrode tab 106, and a negative electrode active material layer formed on both main surfaces of a part of the negative electrode current collector 104a. And have.

  The separator 103 of the electrode laminated body 101 prevents a short circuit between the positive electrode plate 102 and the negative electrode plate 104 described above, and may have a function of holding an electrolyte. The separator 103 is a microporous film made of, for example, a polyolefin such as polyethylene (PE) or polypropylene (PP) having a thickness of about 25 μm. When an overcurrent flows, the separator 103 generates pores due to heat generation. Is closed and also has a function of cutting off current.

  And as shown in FIG. 3, the positive electrode plate 102 and the negative electrode plate 104 are alternately laminated via the separator 103, and further, the separator 103 is laminated on the uppermost layer and the lowermost layer, respectively. The electrode laminate 101 is formed.

The electrolyte contained in the laminate-type lithium ion battery 1 includes lithium perchlorate (LiClO ₄ ), lithium borofluoride (LiBF ₄ ), lithium hexafluorophosphate (LiPF ₆ ), and arsenic hexafluoride as organic liquid solvents. A liquid in which a lithium salt such as lithium (LiAsF ₆ ) is dissolved as a solute. Examples of the organic liquid solvent constituting the electrolytic solution include propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), Examples include ester solvents such as methyl formate (MF), methyl acetate (MA), and methyl propionate (MP), and these can be used as a mixture.

  The electrode laminate 101 configured as described above is housed and sealed in the upper exterior member 107 and the lower exterior member 108 (sealing means). The upper exterior member 107 and the lower exterior member 108 for sealing the electrode laminate 101 are, for example, laminated with a resin film such as polyethylene or polypropylene, or a metal foil such as aluminum laminated with a resin such as polyethylene or polypropylene. It is made of a flexible material such as a resin-metal thin film laminate material, and the upper exterior member 107 and the lower exterior member 108 are heat-sealed to lead the positive electrode tab 105 and the negative electrode tab 106 to the outside. In this state, the electrode laminate 101 is sealed.

  When the electrode laminate 101 is sealed with the upper exterior member 107 and the lower exterior member 108, the upper exterior member 107 and the lower exterior member 108 are heat-sealed in a reduced pressure state so that the inside of the battery 10 is obtained. It can seal in the state which removed the remaining air, and can be set as the state by which the pressure was applied by the external pressure by this.

  In addition, the positive electrode tab 105 and the negative electrode tab 106 are provided with a seal film 109 in order to ensure adhesion between the upper exterior member 107 and the lower exterior member 108 in a portion in contact with the upper exterior member 107 and the lower exterior member 108. Is provided. Although it does not specifically limit as the sealing film 109, For example, it can comprise from the synthetic resin material excellent in electrolyte solution resistance and heat-fusion property, such as polyethylene, modified polyethylene, a polypropylene, a modified polypropylene, or an ionomer.

  The battery 10 of this embodiment is configured as described above.

  Charging device 20 is a device for charging battery 10. For example, when battery 10 and battery controller 30 are mounted on an electric vehicle, a hybrid vehicle, or the like, they are connected to these as external power sources. Used. The charging device 20 performs the rapid charging of the battery 10 via the high-power line 60 based on the rapid charging command from the battery controller 30. In addition, as quick charge, it is a method of charging to about 80% with respect to full charge in 30 minutes from the start of charge by charging the battery 10 with a large electric current compared with normal charge. . Examples of the quick charging method include a constant current constant voltage charging method and a constant power charging method.

  The voltmeter 40 is a sensor that detects the terminal voltage of the battery 10, and a signal detected by the voltmeter 40 is sent to the battery controller 30.

  The ammeter 50 is a sensor that detects the current of the battery 10, and a signal detected by the ammeter 50 is sent to the battery controller 30.

  The battery controller 30 is a device for controlling rapid charging of the battery 10 based on the terminal voltage of the battery 10 detected by the voltmeter 40 and the current value of the battery 10 detected by the ammeter 50. Specifically, the battery controller 30 is operated, for example, by the user to start rapid charging in a state where the charging device 20 is electrically connected to the battery 10 via the high-voltage line 60. In this case, a rapid charge command for causing the charging device 20 to perform rapid charging of the battery 10 is sent out, whereby the charging device 20 executes the rapid charging.

In the present embodiment, the battery controller 30 diagnoses the presence or absence of gas generation inside the battery 10 while the charging device 20 is performing the rapid charging of the battery 10.
Hereinafter, a specific diagnosis method for the presence / absence of gas generation in the battery 10 during the quick charge will be described.

  Here, FIG. 4 is a diagram illustrating an example of a voltage change during rapid charging of the battery 10. In FIG. 4, a voltage change at normal time when no gas is generated in the battery 10 and a voltage change when gas generation occurs are shown. As shown in FIG. 4, when gas is generated inside the battery 10 during rapid charging, charging such as decomposition reaction of the electrolytic solution and side reactions such as deposition of Li on the negative electrode plate 104 is caused by the gas generation. A reaction other than the above occurs, and the voltage increase of the battery 10 with respect to the charge capacity tends to be insufficient.

Therefore, in the present embodiment, it is determined whether or not there is a possibility that gas is generated inside the battery 10 at the time of rapid charging using such characteristics. Specifically, the battery controller 30 detects the terminal voltage of the battery 10 at the time of quick charging as a voltage V _bat at the time of quick charging, and is a voltage change at normal time when a preset gas is not generated. _{From ref_1} , a first reference value V _{ref_1_Cur} that is a normal voltage in the current charge capacity is calculated. Then, the battery controller 30 calculates a difference (V _{ref — 1_Cur} −V _bat ) between the fast charging voltage V _bat and the first reference value V _{ref — 1_Cur,} and the calculated difference (V _{ref — 1_Cur −} V _bat ) It is determined whether or not the threshold value Vα is equal to or greater than the threshold value Vα. Note that the current charging capacity of the battery 10 at the time of rapid charging is, for example, the battery at the start of rapid charging using a map indicating the terminal voltage of the battery 10 at the start of rapid charging and the relationship between the terminal voltage and the charging capacity. It can be calculated by obtaining 10 charging capacities and adding to this the integrated value of the current value during rapid charging.

_Further, as V _{ref — 1} , a preset value for each number of cycles of the battery 10 may be used, or the voltage change value of the battery 10 at the time of the previous rapid charge is stored as V _{ref — 1.} Alternatively, this may be used.

Furthermore, the predetermined threshold value Vα may be set to a value that can detect such a voltage change due to gas generation when gas is generated inside the battery 10, but the voltage drop due to gas generation is usually Since it is 5% or more, for example, it can be set to about 5% of the first reference value V _{ref — 1_Cur} .

  As described above, the battery controller 30 can determine the possibility of gas generation inside the battery during the rapid charging of the battery 10. However, on the other hand, when the battery 10 is rapidly charged, for example, even in an abnormal mode other than gas generation, specifically, when a short circuit occurs inside the battery, as shown in FIG. The voltage rise of the battery 10 tends to be insufficient.

Therefore, even when a micro short-circuit occurs inside the battery 10, the difference (V _{ref — 1_Cur} −V _bat ) between the rapid charging voltage V _bat and the first reference value V _{ref — 1_Cur} may be a predetermined threshold value Vα or more. Therefore, in this case, it may not be possible to distinguish whether gas is generated inside the battery 10 or whether a micro short circuit is occurring.

Therefore, in this embodiment, when it is determined by the above-described method that there is a possibility of gas generation inside the battery 10, the quick charging is interrupted, and the diagnosis for diagnosing the presence or absence of gas generation for the battery 10 is performed. Conduct a constant current input test. Specifically, when it is _determined that the difference (V _{ref — 1_Cur−} V _bat ) between the current voltage V _bat and the first reference value V _{ref — 1_Cur} is greater than or _equal to a predetermined threshold value Vα, the battery controller 30 performs rapid charging. A quick charge interruption command for interrupting the quick charge and a diagnostic input command for executing a constant current input test for diagnosis are sent to the device 20. Thereby, a constant current input test for diagnosis is executed by the charging device 20.

Here, FIG. 5 shows an example of a voltage change when a predetermined constant current is input to the battery 10. As shown in FIG. 5, the voltage of the battery 10 is in immediately after a predetermined constant current is input, and the time t ₀ ~t _1, the time t ₁ ~t _2, and the time t ₂ later, the response speed of each reaction Therefore, the voltage rises with different slopes. Specifically, after input of a constant current is started, charge separation occurs at the surfaces of the positive electrode plate 102 and the negative electrode plate 104 at time t _{0 to} t ₁ , and an electric double layer is formed. Next, at time t _{1 to} t ₂ , electrons are transferred between the positive electrode plate 102 and the negative electrode plate 104. Subsequently, after time t ₂ , lithium is exchanged between the positive electrode plate 102 and the negative electrode plate 104 via the separator 103. Ions will be exchanged.

  In such a case, when gas is generated inside the battery 10, the surface of the positive electrode plate 102 and the negative electrode plate 104 in the portion where the gas exists on the surface of the positive electrode plate 102 and the negative electrode plate 104. In this case, no electrolyte solution is present, and the electrode reaction cannot be performed, so that no electron transfer is performed. Therefore, when a constant current is input, electron transfer is concentrated on the surface of the positive electrode plate 102 and the negative electrode plate 104 where gas is not present, resulting in an increase in current density. It will be.

That is, when gas is generated in the battery 10 and a predetermined constant current input is executed, the current density increases in the process of electron transfer, so that the current value according to the following equation (1) ΔI rises, so that the voltage change value ΔV becomes larger than in a normal case where no gas is generated.
ΔV = ΔI · R (1)
In the above formula (1), R is battery resistance.

  On the other hand, when a micro short circuit occurs inside the battery 10, a current flows in the micro short circuit part, so that the battery resistance R decreases. For this reason, when a predetermined short-current input is executed in the case where a micro short circuit occurs in the battery 10, the battery resistance R decreases, and therefore, the micro short circuit does not occur from the above equation (1). Compared with the normal case, the voltage change value ΔV becomes smaller.

  Therefore, in this embodiment, the voltage change value ΔV when a predetermined constant current is input is detected using such characteristics, and the gas is generated inside the battery 10 based on the detected voltage change value ΔV. Diagnose whether it has occurred or whether a short circuit has occurred.

Specifically, for the battery 10, a predetermined constant current is input for a predetermined time t, a voltage change value when the constant current input is performed is detected as ΔV _bat , and the detected voltage change value ΔV _bat is the second It is determined whether or not the reference value ΔV _{ref — 2_Cur is} greater. If the detected voltage change value ΔV _bat is larger than the second reference value ΔV _{ref — 2_Cur,} it is diagnosed that gas is generated inside the battery 10, and the detected voltage change value ΔV _bat is less than or equal to the second reference value ΔV _{ref — 2_Cur.} If so, it is diagnosed that a micro short circuit has occurred inside the battery 10.

Here, the second reference value ΔV _{ref — 2_Cur} is a voltage change value of the battery 10 when a predetermined constant current is input to a normal battery 10 in which no gas generation or minute short circuit occurs, as shown in FIG. The battery 10 has a property of increasing according to the number of charge / discharge cycles of the battery 10. Therefore, in the present embodiment, as shown in FIG. 6, the voltage change value of the battery 10 when a predetermined constant current is input to a normal battery 10 in which gas generation or micro short-circuit does not occur is expressed as a normal voltage. The second reference value ΔV _{ref — 2_Cur} is stored in advance as the change value ΔV _{ref —} 2, the second reference value ΔV _{ref — 2_Cur} is calculated from the normal voltage change value ΔV _{ref — 2} and the current cycle number of the battery 10, and the calculated second reference value ΔV _{ref — 2_Cur} The voltage change value ΔV _bat is compared.

In the present embodiment, for example, as shown in FIG. 6, when the second reference value [Delta] V _{Ref_2_Cur} when carrying out the predetermined constant current input 100 cycle _{C 100} and [Delta] V _{(C 100),} 100 cycle _{C 100} If the voltage change value ΔV _{bat at} is larger than the second reference value ΔV (C ₁₀₀ ), it is diagnosed that gas is generated inside the battery, and if it is smaller than the second reference value ΔV (C ₁₀₀ ), a micro short circuit occurs inside the battery. Diagnose. As the number of charge / discharge cycles of the battery 10, for example, a method in which the battery controller 30 counts the number of times that the battery 10 is rapidly charged can be employed.

  In addition, as a predetermined time t for inputting a constant current when inputting a constant current for diagnosis, electrons are transferred between the positive electrode plate 102 and the negative electrode plate 104 after a predetermined constant current is input to the battery 10. However, since the time until the electronic transfer is usually about 1 ms, it can be set to 1 ms, for example.

  Furthermore, the constant current at the time of inputting a constant current for diagnosis can be arbitrarily set within a range in which a voltage change at the time of electron transfer can be appropriately detected in the positive electrode plate 102 and the negative electrode plate 104. For example, the current of 0.5 C in the initial state of the battery 10 can be set.

  As described above, the generation of gas inside the battery during the rapid charging of the battery 10 is detected.

  Next, an operation example of this embodiment will be described. FIG. 7 is a flowchart showing an example of a gas generation diagnosis method in the present embodiment.

  First, in step S <b> 1, the battery controller 30 sends a quick charging command for causing the charging device 20 to perform rapid charging of the battery 10, and thereby the charging device 20 executes the rapid charging.

  In step S <b> 2, the battery controller 30 determines whether or not the battery 10 is charged up to a predetermined charging end condition. The predetermined charging end condition can be arbitrarily set, and for example, it can be set as a state where 80% of the capacity of the battery 10 is charged. If it is determined that the battery 10 has been charged up to a predetermined charge termination condition, the battery controller 30 executes a process for terminating the quick charge, and terminates this process. If it is determined that the battery has not been charged up to a predetermined charge termination condition, the process proceeds to step S3.

  In step S <b> 3, the battery controller 30 determines whether or not the battery 10 has been charged by a predetermined charge amount by rapid charging. If the battery 10 is not charged with a predetermined charge amount, the process returns to step S2, and the rapid charge of the battery 10 is continued. On the other hand, when the battery 10 is charged by a predetermined charge amount, the process proceeds to step S4 in order to diagnose whether or not an abnormality such as gas generation has occurred inside the battery 10 during the quick charge. In this case, the predetermined charge amount can be arbitrarily set, but can be set to, for example, about several percent to 10% of the battery capacity, and will be described in steps S4 to S15 described later. The gas generation detection process can be executed every time the battery 10 is rapidly charged and charged by about several to 10% of the battery capacity. Note that the amount of charge of the battery 10 can be obtained, for example, by integrating the amount of current detected by the ammeter 50 by the battery controller 30, and in this case, the gas described in steps S4 to S15 described later Each time the occurrence detection process is performed, the integrated value of the current amount is reset.

In step S4, the current terminal voltage value V _bat of the battery 10 at the time of rapid charging is detected in order to determine the presence or absence of gas generation inside the battery 10, and the detected terminal voltage value V _bat and the first reference are detected. Processing for calculating a difference from the value V _{ref — 1_Cur} is performed. Specifically, first, the battery controller 30 detects the current terminal voltage value V _bat of the battery 10 at the time of rapid charging by the voltmeter 40 and V _{ref — 1} which is a normal voltage change when no gas is generated. Then, the first reference value V _{ref — 1_Cur} at the current charge capacity is calculated. Then, the battery controller 30 calculates a difference (V _{ref — 1_Cur} −V _bat ) between the current terminal voltage value V _bat and the first reference value V _{ref — 1_Cur} .

Then, the process proceeds to step S5, based on the difference calculated in step S4 described above _{(V ref_1_Cur} -V _bat), determines the presence or absence of the possibility of gas generation inside the battery 10. Specifically, it is determined whether or not the difference (V _{ref — 1_Cur−} V _bat ) is equal to or greater than a predetermined threshold value Vα. If the difference is equal to or greater than the predetermined threshold value Vα, it is determined that there is a possibility of gas generation. Proceed to step S6. On the other hand, if the difference (V _{ref — 1_Cur} −V _bat ) is less than the predetermined threshold value Vα, it is determined that there is no possibility of gas generation inside the battery 10, and the _{process proceeds} to step S2 in order to continue rapid charging. Return. For example, as shown in FIG. 4, when gas is generated inside the battery 10 when the battery 10 is rapidly charged, the voltage rises compared to a normal voltage change in which no gas is generated. As a result, the difference (V _{ref — 1_Cur} −V _bat ) increases. As a result, when the difference (V _{ref — 1_Cur} −V _bat ) is equal to or greater than a predetermined threshold value Vα, it is determined that there is a possibility of gas generation, and the process proceeds to step S6.

  In step S6, the quick charging is interrupted, and a process of executing a constant current input for diagnosis is performed on the battery 10. Specifically, the battery controller 30 sends to the charging device 20 a quick charge interruption command for interrupting the quick charge and a diagnostic input command for executing a constant current input test for diagnosis. Then, the charging device 20 performs a diagnostic constant current input test on the battery 10 for a predetermined time t based on the command. In addition, the constant current input test for diagnosis is a test for diagnosing whether gas is generated in the battery 10 or a micro short circuit has occurred, as described above.

In step S7, the battery controller 30 detects the voltage change value ΔV _bat when a predetermined constant current is input to the battery 10 for a predetermined time t.

In step S8, the battery controller 30 diagnoses whether gas is generated inside the battery 10 or whether a minute short circuit has occurred based on the voltage change value ΔV _bat detected in step S7. Specifically, first, the battery controller 30 determines whether or not the voltage change value ΔV _bat detected in step S7 is larger than the second reference value ΔV _{ref — 2_Cur} . If the voltage change value ΔV _bat detected in step S7 is larger than the second reference value ΔV _{ref — 2_Cur,} it is diagnosed that gas is generated inside the battery, and the process proceeds to step S10. On the other hand, if the voltage change value ΔV _bat detected in step S7 is equal to or _smaller than the second reference value ΔV _{ref — 2_Cur} , it is diagnosed that a minute short circuit has occurred inside the battery 10, and the process proceeds to step S9.

That is, for example, in the example shown in FIG. 6, in the 100th cycle _{C 100,} when the voltage change value [Delta] V _bat detected in step S7, it is determined second reference value [Delta] V _{(C 100)} and greater than the battery 10. Diagnose that gas has been generated inside 10, and proceed to step S10. On the other hand, if it is determined that the voltage change value ΔV _bat detected in step S7 is equal to or _smaller than the second reference value ΔV (C ₁₀₀ ), it is diagnosed that a micro short circuit has occurred inside the battery 10, and step S9 Proceed to

  If it is determined in step S8 that a micro short circuit has occurred inside the battery 10, the process proceeds to step S9. In step S9, the battery controller 30 indicates that a micro short circuit has occurred in the battery 10. And a process of terminating the rapid charging of the battery 10 is executed. Here, as a method of warning the user, for example, a method of warning from the charging device 20 by voice or screen display can be cited. Alternatively, when the battery 10 is mounted on a vehicle such as an electric vehicle or a hybrid vehicle, a method of warning by voice or screen display via a navigation device mounted on the vehicle or a mobile terminal of a user registered in advance To send a warning to In step S9, when a warning is given to the user, instead of the information that a micro short circuit has occurred inside the battery 10, or together with such information, a warning is given to replace the battery 10. Also good.

On the other hand, if it is determined in step S8 that gas is generated inside the battery 10, the process proceeds to step S10. In step S10, the battery controller 30 determines whether the voltage change value ΔV _bat detected in step S7 and the second _Based on the difference (ΔV _bat −ΔV _{ref — 2_Cur} ) from the reference value ΔV _{ref — 2_Cur} , the degree of gas generation is determined. Here, FIG. 8 shows the relationship between the difference (ΔV _bat −ΔV _{ref — 2_Cur} ) and the amount of gas generated inside the battery 10. In FIG. 8, ΔV ₅ is a voltage change value when the battery internal volume increase rate due to gas generation of the battery 10 is 5%, and ΔV ₄₀ is a battery internal volume increase rate due to gas generation of the battery 10. It is a voltage change value in the case of 40%. Therefore, for example, if the difference (ΔV _bat −ΔV _{ref — 2_Cur} ) is a value near ΔV ₅ , the battery internal volume increase rate due to gas generation can be estimated to be about 5%, and if the value is near ΔV ₄₀ , It can be estimated that the battery internal volume increase rate due to gas generation is about 40%.

In step S10, ΔV ₅ is set as the first threshold value, ΔV ₄₀ is set as the second threshold value, and these are compared with the difference (ΔV _bat −ΔV _{ref — 2_Cur} ) calculated above. Detect the degree of gas generation. Specifically, when the difference (ΔV _bat −ΔV _{ref — 2_Cur} ) calculated above is less than the first threshold value ΔV ₅ , the degree of gas generation is set to “small”, and the first threshold value ΔV ₅ above, the case where [Delta] V ₄₀ follows a second threshold value, the degree of gas generation and "medium", in the case of [Delta] V ₄₀ exceeds a second threshold value, the extent of gassing as "large" To detect.

In step S11, the battery controller 30 determines whether or not the difference (ΔV _bat −ΔV _{ref — 2_Cur} ) calculated in step S10 is greater than the second threshold value ΔV ₄₀ . That is, it is determined whether or not the degree of gas generation is “high”. When the difference (ΔV _bat −ΔV _{ref — 2_Cur} ) calculated in step S10 is larger than ΔV ₄₀ that is the second threshold value, the process proceeds to step S12, whereas when it is equal to or smaller than ΔV ₄₀ that is the second threshold value, step S13. Proceed to

  In step S <b> 12, since it is determined that the degree of gas generation is “large”, the battery controller 30 warns the user that gas has been generated inside the battery 10 and terminates the rapid charging of the battery 10. Execute. Here, as a method for warning the user, the method described in step S9 described above can be used (the same applies to steps S14 and S15 described later). Similarly to step S9, when a warning is given to the user, a warning is given to replace the battery 10 instead of or together with the information that a micro short circuit has occurred inside the battery 10. It is good also as a structure.

On the other hand, if it is determined in step S11 that the difference (ΔV _bat −ΔV _{ref — 2_Cur} ) calculated in step S10 is equal to or less than the second threshold value ΔV ₄₀ , the process proceeds to step S13, and in step S13, the battery The controller 30 determines whether or not the difference (ΔV _bat −ΔV _{ref — 2_Cur} ) calculated in step S10 is equal to or _larger than the first threshold value ΔV _{5 and} equal to or smaller than the second threshold value ΔV ₄₀ . That is, it is determined whether or not the degree of gas generation is “medium”. If the difference (ΔV _bat −ΔV _{ref — 2_Cur} ) calculated in step S10 is greater than or equal to ΔV ₅ that is the first threshold and less than or equal to ΔV ₄₀ that is the second threshold, the process proceeds to step S14. If it is less than the threshold value ΔV ₅ , the process proceeds to step S15.

  In step S14, since it is determined that the degree of gas generation is “medium”, the battery controller 30 warns the user that gas has been generated inside the battery 10 and rapidly decreases the charge rate of the quick charge. By sending a command to the charging device 20 so as to perform charging, the charging device 20 is caused to decrease the charging rate and restart rapid charging.

  On the other hand, in step S15, since it is determined that the degree of gas generation is “low”, the battery controller 30 warns the user that gas has been generated inside the battery 10 and changes the charging conditions for rapid charging. The charging device 20 is restarted under the same conditions by sending a command to the charging device 20 so as to execute the quick charging without using the same.

  As described above, the diagnosis of gas generation inside the battery 10 during the rapid charging of the battery 10 is performed.

In the present embodiment, the current terminal voltage value V _bat of the battery 10 is detected during rapid charging, and the difference (V _{ref — 1_Cur} −V _bat ) between the detected terminal voltage value V _bat and the first reference value V _{ref — 1_Cur} is _calculated. It is determined whether or not the calculated difference (V _{ref — 1_Cur} −V _bat ) is equal to or greater than a predetermined threshold value Vα. If the difference is equal to or greater than the predetermined threshold value Vα, a constant current input for diagnosis is executed. Based on the voltage change value ΔV _bat when a constant current for diagnosis is input, it is detected whether gas generation has occurred in the battery 10 or whether a micro short circuit has occurred. Specifically, the voltage change value [Delta] V _bat of the constant current input for the diagnosis, is greater than the second reference value [Delta] V _{Ref_2_Cur} diagnoses the gas inside the battery is generated, following the second reference value [Delta] V _{Ref_2_Cur} If it is, it is diagnosed that a micro short circuit has occurred inside the battery 10. Therefore, according to the present embodiment, it is possible to appropriately detect gas generation inside the battery 10 which is a laminate type battery in which detection of gas generation due to internal pressure is difficult. In particular, according to the present embodiment, gas generation inside the battery 10 can be appropriately detected without using a gas sensor, an impedance measuring device, or the like.

In addition, in the present embodiment, when gas generation inside the battery 10 is detected, the difference (ΔV _bat −) between the voltage change value ΔV _bat and the second reference value ΔV _ref — _{2_Cur} when a constant current is input. ΔV _{ref — 2_Cur} ) That is, the amount of gas increase is calculated by calculating the amount of voltage increase due to gas generation, and the calculated voltage increase amount (ΔV _bat −ΔV _{ref — 2_Cur} ) is compared with a predetermined first threshold value and second threshold value. Is detected. In this embodiment, depending on the degree of gas generation, the rapid charging is stopped, or the rapid charging is continued, but the charging rate is lowered, or the rapid charging is continued without changing the charging condition. Select whether to do. Therefore, according to the present embodiment, when the degree of gas generation is large, it is possible to effectively avoid breakage of the battery 10 due to gas generation during the quick charge by stopping the quick charge, When the degree of gas generation is medium, rapid charging can be continued more safely by reducing the charging rate of rapid charging.

  Further, according to the present embodiment, when gas generation inside the battery 10 is detected, a warning is given to the user regardless of the degree of gas generation, so that gas generation is occurring inside the battery 10. Thus, it is possible to effectively alert the user, thereby preventing the battery 10 from being damaged.

  In addition, according to the present embodiment, when it is diagnosed that a short-circuit has occurred rather than gas generation as a result of executing a constant current input for diagnosis, a warning is given to the user and rapid charging is performed. By canceling, it is possible to effectively avoid the damage of the battery 10 due to a micro short circuit during the rapid charging, and thus the safety of the rapid charging can be enhanced.

  In the above-described embodiment, the battery controller 30 includes the first detection means, the first determination means, the second detection means, the second determination means, the diagnosis means, the gas generation amount detection means, and the first charge control means of the present invention. , And the second charge control means.

  As mentioned above, although embodiment of this invention was described, these embodiment was described in order to make an understanding of this invention easy, and was not described in order to limit this invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, in the above-described embodiment, ΔV ₅ that is a voltage change value corresponding to a battery internal volume increase rate of 5% is used as the first threshold value for determining the degree of gas generation inside the battery 10. The example in which ΔV ₄₀ , which is a voltage change value corresponding to a battery internal volume increase rate of 40%, is exemplified as the two threshold values, but the first threshold value and the second threshold value are not limited to such examples, and are appropriately set. be able to.

  In the above-described embodiment, the battery 10 that is a single battery is illustrated as an example to detect gas generation. However, the embodiment is not particularly limited to a single battery, and is a module that includes a plurality of batteries 10. Furthermore, gas generation can be similarly detected in an assembled battery including a plurality of modules.

DESCRIPTION OF SYMBOLS 10 ... Laminate type lithium ion battery 101 ... Electrode laminated body 102 ... Positive electrode plate 103 ... Separator 104 ... Negative electrode plate 105 ... Positive electrode tab 106 ... Negative electrode tab 20 ... Charger 30 ... Battery controller 40 ... Voltmeter 50 ... Ammeter 60 ... Strong electricity line

Claims (5)

A control device for a laminate-type lithium ion battery in which a power generation element is sealed with a laminate film,
A first detecting means for detecting a voltage change at the time of rapid charging when the laminate-type lithium ion battery is rapidly charged, as a first voltage change value;
A first determination unit that compares the first voltage change value with a predetermined first reference value, and determines whether the first voltage change value deviates from the first reference value by a predetermined value or more;
When the first determination unit determines that the first voltage change value deviates from the first reference value by the predetermined value or more, a predetermined constant current is input to the laminate type lithium ion battery. A second detecting means for detecting a voltage change of the laminated lithium ion battery when the constant current is input as a second voltage change value;
Second determination means for determining whether or not the second voltage change value is larger than a predetermined second reference value set according to the number of cycles of the laminated lithium ion battery;
The first determination means determines that the first voltage change value has deviated from the first reference value by the predetermined value or more, and the second determination means determines that the second voltage change value is A diagnostic means for diagnosing that gas is generated inside the laminated lithium ion battery when it is determined to be greater than a second reference value;
A laminate type lithium ion battery control apparatus comprising: The control device for a laminated lithium ion battery according to claim 1,
The diagnostic means diagnoses that a micro short circuit has occurred inside the laminated lithium ion battery when it is determined that the second voltage change value is less than the second reference value. Type lithium-ion battery control device. In the control apparatus of the laminate type lithium ion battery according to claim 1 or 2,
A gas that calculates the difference between the second voltage change value and the second reference value and detects the amount of gas generation based on the difference when it is diagnosed that gas is generated inside the laminated lithium ion battery Further comprising a generation amount detection means,
The control apparatus for a laminated lithium ion battery, wherein the gas generation amount detecting means determines that the larger the difference is, the more generated gas is generated in the laminated lithium ion battery. In the control apparatus of the laminate type lithium ion battery according to claim 3,
A first charge control means for controlling charging according to the gas generation amount detected by the gas generation amount detection means;
The first charge control means notifies the user that gas has been generated inside the laminated lithium ion battery when the gas generation amount detected by the gas generation amount detection means is less than a predetermined first threshold value. In addition, the laminate-type lithium ion battery is continuously charged rapidly.
When the gas generation amount detected by the gas generation amount detection means is not less than the first threshold value and not more than a predetermined second threshold value, the user is notified that gas has been generated inside the laminated lithium ion battery. In addition, the charging of the quick charge of the laminated lithium ion battery is reduced to continue charging,
When the gas generation amount detected by the gas generation amount detection means is larger than the second threshold, the user is notified that the laminate type lithium ion battery needs to be replaced, and the laminate type lithium ion battery. The laminate type lithium ion battery control device is characterized in that the charging of the battery is stopped. In the control apparatus of the laminate type lithium ion battery according to claim 2,
When the diagnostic means diagnoses that a micro short circuit has occurred inside the laminated lithium ion battery, the diagnostic means informs the user that the laminated lithium ion battery needs to be replaced, and the laminated lithium ion A laminate type lithium ion battery control device, further comprising second charge control means for stopping charging of the battery.

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