JPWO2014104280A1 - Secondary battery control method and control device - Google Patents

Abstract

Deterioration of the negative electrode during use of a secondary battery that includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode and outputs a voltage of 4.5 V in a state where the charging rate is maximum is suppressed. The control device for the secondary battery includes a battery temperature detection unit that detects the temperature of the secondary battery, a charge rate detection unit that detects the charge rate of the secondary battery, and detection results of the battery temperature detection unit and the charge rate detection unit. The charging rate of the secondary battery is controlled by changing the maximum value and the minimum value of the charging rate so that the charging rate of the secondary battery does not deviate from a preset range according to the temperature of the secondary battery, A controller that changes the minimum value of the charging rate to 10% when the temperature of the secondary battery is in the normal temperature range, and changes the maximum value of the charging rate to 90% when the temperature of the secondary battery is high; ing.

Description

  The present invention relates to a control method and a control device for a secondary battery, and more particularly to a control method and a control device for a secondary battery including a negative electrode that performs an alloying reaction.

Secondary batteries are widely used as a power source because they can be recharged and used repeatedly. The discharge voltage of a lithium ion secondary battery is higher than that of a nickel-hydrogen secondary battery or a nickel-cadmium secondary battery. However, with the widespread use of hybrid vehicles and electric vehicles, it is desired to increase the capacity of lithium ion secondary batteries. In the current mainstream lithium ion secondary battery, a lithium ion oxide such as LiCoO ₂ , LiMn ₂ O ₄ , or LiNiO ₂ is used for the positive electrode, and a carbon material such as graphite is used for the negative electrode. However, the use of a negative electrode that undergoes an alloying reaction has been studied for higher capacity. In a negative electrode made of a carbon material, discharge is performed when lithium ions enter the negative electrode by intercalation. In contrast, in a negative electrode that performs an alloying reaction, lithium ions form an alloy with the negative electrode. Hereinafter, the negative electrode that performs the alloying reaction may be referred to as an alloy-based negative electrode.

Si-based negative electrodes have been studied as high-capacity alloy-based negative electrodes. The SiO negative electrode is a Si-based negative electrode and has better cycle characteristics than that of the Si negative electrode. Note that SiO forming the SiO negative electrode is a mixture of Si and SiO ₂ formed by disproportionation of SiO. To be precise, not SiO (silicon monoxide) alone, but SiO _x (0 < x <2).

  However, at the end of discharge, since the SiO negative electrode is in a high potential state with respect to Li, SEI undergoes oxidative decomposition. On the other hand, when trying to use a lithium ion secondary battery having a SiO negative electrode at a high voltage of 4.5 V and a high temperature (for example, 60 ° C.), the SEI decay of the negative electrode due to the elution of the positive electrode transition metal is promoted and the cycle deterioration becomes severe. . That is, when used at a low temperature (for example, 25 ° C.), the deterioration due to the influence at the time of discharging is large, and at a high temperature (for example, 60 ° C.), the deterioration due to the high voltage at the time of charging is large. Therefore, if charging / discharging is performed without considering the operating temperature, the cycle characteristics deteriorate.

  Conventionally, there has been proposed a battery management device for an electric vehicle that can increase the average charging rate and obtain high output characteristics without sacrificing the life of the secondary battery (see Patent Document 1). The battery management device of Patent Document 1 includes a secondary battery that is a drive source of an electric vehicle, and a motor that is driven by the secondary battery. This battery management device controls the secondary battery so that the charging rate of the secondary battery becomes a predetermined target charging rate while repeating charging and discharging of the secondary battery. The battery management device includes battery temperature detection means for detecting the temperature of the secondary battery (battery temperature), and decreases the target charging rate as the battery temperature increases. In addition, when the secondary battery is controlled so that the charging rate is within the predetermined upper and lower limits, the battery management device decreases the upper limit charging rate as the battery temperature increases.

JP 2001-292533 A

  In Patent Document 1, when the battery temperature detecting means detects that the temperature of the secondary battery is increased, the battery management device decreases the target charging rate or the upper limit charging rate of the secondary battery. Therefore, the secondary battery tends to discharge, and the average charging rate decreases, so the life characteristics of the secondary battery are improved. On the other hand, although the average charging rate is lowered, the battery temperature is high, so that the output density is large and the necessary high output can be ensured.

  However, in patent document 1, when charging / discharging of a secondary battery is controlled so that a charging rate may be in the range of a target charging rate, it is a premise that discharging is performed by driving a motor. Therefore, after charging the secondary battery, if the charging rate exceeds the target charging rate due to the temperature of the secondary battery rising due to the influence of the environmental temperature while the electric vehicle is stopped, or the temperature of the secondary battery increases or decreases When the charging rate deviates from the predetermined upper and lower limits, the secondary battery is discharged under an inappropriate condition for a while from the start of the motor driving. As a result, the deterioration of the secondary battery is promoted.

  An object of the present invention is to provide a negative electrode for performing an alloying reaction and a lithium transition metal oxide positive electrode, and the deterioration of the negative electrode during use of a secondary battery that outputs a voltage of 4.5 V when the charging rate is maximum. The present invention provides a control method and a control device for a secondary battery that can suppress the battery.

  A secondary battery control method that solves the above problem includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode, and outputs a voltage of 4.5 V in a state where the charging rate is maximum. The secondary battery is controlled by changing the maximum value and the minimum value of the charge rate so that the charge rate of the secondary battery does not deviate from a preset range according to the temperature of the secondary battery. When the temperature of the secondary battery is high, the maximum value of the charging rate is changed to 90%. Here, the “negative electrode that performs an alloying reaction” means that lithium ions do not discharge when lithium ions enter into the negative electrode by intercalation like a negative electrode made of a carbon material, but forms an alloy with lithium ions. Means negative electrode.

  According to this configuration, charging and discharging are controlled by changing the maximum value and the minimum value of the charging rate (SOC) so that the charging rate of the secondary battery does not deviate from the range set in advance according to the temperature of the secondary battery. However, when the temperature of the secondary battery is high, charging / discharging is controlled so that the charging rate does not exceed 90%. Examples of the method for performing control so that the charging rate of the secondary battery does not exceed 90% include, for example, a method for adjusting the temperature of the secondary battery and a load for discharging without adjusting the temperature of the secondary battery. There are a method of using the power of the battery depending on the load, and a method of using the temperature control and the power usage of the load in combination. When the temperature of the secondary battery is high, control is performed so that the charging rate (SOC) of the secondary battery does not exceed 90%. Therefore, when the operating temperature of the secondary battery is high (for example, 60 ° C.) Deterioration of the negative electrode during use of the secondary battery can be suppressed. Therefore, it is possible to suppress deterioration of the negative electrode during use of a secondary battery that includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode and outputs a voltage of 4.5 V at the maximum charging rate.

  When the temperature of the secondary battery is normal temperature (25 ° C. ± 5 ° C., that is, a range of 20 ° C. or higher and 30 ° C. or lower), the minimum charging rate is changed to 10%, and the maximum charging rate at the normal temperature is changed. The value is preferably 100%. According to this configuration, the charge / discharge amount of the secondary battery is larger than the case where control is performed so that the charging rate (SOC) does not exceed 90% regardless of whether the temperature of the secondary battery is normal temperature or high temperature. When a secondary battery is used as a power source for a vehicle, the travel distance of the vehicle can be increased.

  The high temperature is 55 ° C. or higher, and the minimum value of the charging rate at the high temperature is preferably 0%. According to this configuration, the charge / discharge amount of the secondary battery becomes larger at high temperatures than when used at a charging rate of 10% or more as in the normal temperature, and the secondary battery is used as a power source for the vehicle. In this case, the travel distance of the vehicle can be increased.

  The lithium transition metal oxide positive electrode is preferably composed mainly of a mixture of lithium nickelate, lithium cobaltate and lithium manganate. According to this configuration, an appropriate lithium transition metal oxide positive electrode can be obtained by adjusting the mixing ratio of a lithium transition metal oxide that has a proven track record as a transition metal oxide constituting the positive electrode of a lithium ion secondary battery. .

  A control device for a secondary battery that solves the above problem is a control device for a secondary battery that includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode. The control device includes a battery temperature detection unit that detects a temperature of the secondary battery, a charge rate detection unit that detects a charge rate of the secondary battery, and detection results of the battery temperature detection unit and the charge rate detection unit. A control unit that controls charging / discharging of the secondary battery by changing a maximum value and a minimum value of the charging rate so that the charging rate of the secondary battery does not deviate from a preset range according to temperature based on With. When the temperature of the secondary battery is in a first temperature range that is a normal temperature range, the control unit changes the minimum value of the charging rate to 10%, and the temperature of the secondary battery is When it is in the second temperature range higher than the first temperature range, the maximum value of the charging rate is changed to 90%.

  According to this configuration, the battery temperature detector detects the temperature of the secondary battery, and the charge rate detector detects the charge rate of the secondary battery. The control unit changes the maximum value and the minimum value of the charging rate so that the charging rate of the secondary battery does not deviate from a preset range according to the temperature based on the detection results of the battery temperature detecting unit and the charging rate detecting unit. Charge / discharge is controlled, and when the temperature of the secondary battery is normal temperature, the charge / discharge is controlled so that the charge rate is 10% or more. When the temperature of the secondary battery is high, the charge rate is Charge / discharge is controlled so as not to exceed 90%. Examples of the method of controlling the charging rate so as not to exceed 90% include the method of controlling the temperature adjusting unit that adjusts the temperature of the secondary battery and the discharging circuit that supplies power to the discharging load. There are a method of performing and a method of using both together. Therefore, it is possible to suppress the deterioration of the negative electrode during use of the secondary battery including the negative electrode that performs the alloying reaction and the lithium transition metal oxide positive electrode.

The block diagram which shows one Embodiment. The figure which shows the relationship between the working voltage range of a secondary battery, and the range of SOC. The figure which shows the relationship between the discharge capacity maintenance factor for every use condition of a secondary battery in 25 degreeC, and the number of cycles. The figure which shows the relationship between the discharge capacity maintenance factor for every use condition of a secondary battery in 60 degreeC, and the frequency | count of a cycle. The figure which shows the relationship between the operating temperature of a secondary battery, and the range of SOC.

Hereinafter, an embodiment of a control method and a control device for a lithium ion secondary battery mounted as a battery in a hybrid vehicle will be described with reference to FIGS.
As shown in FIG. 1, the hybrid type vehicle includes an internal combustion engine (hereinafter referred to as an engine) 11, a generator 12, a secondary battery module 13 as a battery, and a travel motor 14. The secondary battery module 13 is composed of a plurality of lithium ion secondary batteries connected to each other. Each lithium ion secondary battery includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode, and outputs a voltage of 4.5 V in a state where the charging rate is maximum. Here, the “negative electrode that performs an alloying reaction” means a negative electrode that forms an alloy with lithium ions. The generator 12 and the traveling motor 14 are connected to the secondary battery module 13 via a power control unit (PCU) 15. The PCU 15 includes an inverter, a boost converter, and a control device. The PCU 15 charges the secondary battery module 13 with the electric power generated by the generator 12 or supplies it to the traveling motor 14 based on a command from the ECU 16 that controls the entire vehicle.

  The ECU 16 is electrically connected to the engine 11, the PCU 15, and the secondary battery control device 17. The ECU 16 controls the throttle of the engine 11 so as to make the output of the engine 11 as constant as possible, and also controls power supply to the travel motor 14 and charge / discharge of the secondary battery module 13 via the PCU 15. The ECU 16 sends a command signal to the PCU 15 so as to supply electric power required by the traveling motor 14. The electric power generated by the generator 12 is preferentially supplied, and the insufficient electric power is supplied from the secondary battery module 13. As a result, when the generated power of the generator 12 exceeds the required power of the traveling motor 14, the ECU 16 sends a charge signal to the PCU 15 to send power to the secondary battery module 13. On the contrary, when the generated power is lower than the required power of the traveling motor 14, the ECU 16 sends a discharge signal to the PCU 15 to take out the power from the secondary battery module 13.

  The secondary battery control device 17 includes a temperature of the secondary battery module 13, that is, a battery temperature detection means (battery temperature detection unit) 18 for detecting the temperature of the secondary battery, a charging rate (SOC) of the secondary battery module 13, That is, a range in which the charging rate of the secondary battery is set in advance according to the temperature of the secondary battery based on the detection result with the charging rate detecting means (charging rate detecting unit) 19 for detecting the charging rate of the secondary battery. Control means (control unit) for controlling charging / discharging of the secondary battery by changing the maximum value and the minimum value of the charging rate so as not to deviate. When the temperature of the secondary battery is high, the secondary battery control device 17 charges and discharges the secondary battery so that the charging rate does not exceed 90%, that is, the maximum value of the charging rate is 90%. To control. In order to control charging / discharging of the secondary battery so that the charging rate of the secondary battery does not exceed 90%, for example, a method of adjusting the temperature of the secondary battery is used. Instead, the secondary battery may be provided with a discharge load and a discharge circuit for supplying power to the load, and the power of the battery may be used by the load. Furthermore, the method of adjusting the temperature of the secondary battery and the use of power by the load may be used in combination. When the temperature of the secondary battery is high (for example, 60 ° C.), the charge / discharge of the secondary battery is controlled so that the charging rate (SOC) of the secondary battery does not exceed 90%. Even when the temperature is high, deterioration of the negative electrode during use of the secondary battery can be suppressed. High temperature means 55 degreeC or more, for example. More specifically, the secondary battery module 13 includes a battery temperature detection unit 18, a voltage detection unit (voltage detection unit) 19 a that detects the voltage of the secondary battery module 13, and a current flow into and out of the secondary battery module 13. Current detection means (current detection unit) 19b.

  The secondary battery control device 17 stores a voltage-charge rate comparison table in a memory. The secondary battery control device 17 determines the initial value of the charging rate by reading the charging rate corresponding to the open voltage Vo of the secondary battery module 13 detected by the voltage detecting means 19a from the voltage-charging rate comparison table. . At this time, a plurality of types of voltage-charge rate comparison tables corresponding to the temperature of the secondary battery module 13 are prepared so as not to cause an error due to the temperature of the secondary battery module 13. The secondary battery control device 17 uses a table corresponding to the temperature of the secondary battery module 13 detected by the battery temperature detection means 18. The voltage detection means 19a detects the voltage of the secondary battery module 13, and the current detection means 19b detects the flow of current into and out of the secondary battery module 13. The charging rate of the secondary battery module 13 that changes as the vehicle travels, that is, the charging rate of the secondary battery, is based on the voltage of the secondary battery module 13 and the flow of power to and from the secondary battery module 13. It is obtained by adjusting the capacity of the secondary battery calculated from the initial value of the rate. In this embodiment, the voltage detection means 19 a and the current detection means 19 b constitute the charging rate detection means 19.

  The secondary battery module 13 includes a thermoelectric conversion element as the temperature adjusting means (temperature adjusting unit) 20. The thermoelectric conversion element includes a thermoelectric conversion element having a surface that exhibits an action that is in conflict with the polarity of energization, that is, a heat dissipation action or an endothermic action. The power of the secondary battery module 13 is supplied to the temperature adjusting means 20 via the PCU 15. The temperature adjusting means 20 can be used for cooling and heating the secondary battery module 13 by changing the energization direction.

  The ECU 16 obtains information on the temperature and charging rate of the secondary battery module 13 from the secondary battery control device 17, and the charging rate of the secondary battery module 13 (secondary battery) is preset according to the temperature of the secondary battery. Control means for controlling charging / discharging of the secondary battery is configured by changing the maximum value and the minimum value of the charging rate so as not to deviate from the specified range. The ECU 16 charges the secondary battery module 13 via the PCU 15 so that the charging rate does not exceed 90% when the temperature of the secondary battery is high, that is, the maximum value of the charging rate is 90%. It controls the discharge and the power supply to the traveling motor 14 and the temperature adjusting means 20. The PCU 15, the ECU 16 and the secondary battery control device 17, based on the detection results of the battery temperature detection means 18 and the charge rate detection means 19, change the charging rate of the secondary battery module 13 (secondary battery) to the temperature of the secondary battery. Accordingly, a control unit is configured to control charging / discharging of the secondary battery by changing the maximum value and the minimum value of the charging rate so as not to deviate from the preset range. When the temperature of the secondary battery is high, the secondary battery control device 17 charges and discharges the secondary battery so that the charging rate does not exceed 90%, that is, the maximum value of the charging rate is 90%. To control.

The structure of the positive electrode of the lithium ion secondary battery which comprises the secondary battery module 13, a negative electrode, and electrolyte solution is as follows.
Positive electrode: LiNi _0.5 Co _0.2 Mn _0.3 O ₂ / AB / PVdF (94/3/3)
Negative electrode: SiO / graphite / AB / binder (32/50/8/10)
Electrolyte: 1M LiPF ₆ FEC / EC / EMC / DMC (4/26/30/40)
Positive electrode: 12 mg / cm ² , Negative electrode: 3.3 mg / cm ²
Here, AB is acetylene black and PVdF is polyvinylidene fluoride.

  Next, charging and discharging are controlled by changing the maximum and minimum values of the charging rate so that the charging rate of the secondary battery module 13 (secondary battery) does not deviate from a preset range according to the temperature of the secondary battery. In addition, the basis for controlling charging / discharging of the secondary battery so that the charging rate does not exceed 90% when the temperature of the secondary battery is high will be described.

  When the temperature of the secondary battery was 25 ° C. and 60 ° C., the secondary battery was charged and discharged by 1C constant current charging and constant current discharging. Charging / discharging was repeated under the four conditions A to D shown in FIG. 2, and the capacity retention rate after discharge in each cycle was determined. The relationship between the discharge capacity retention rate and the number of cycles when the temperature of the secondary battery is 25 ° C. and 60 ° C. is shown in FIGS. 3 and 4, respectively.

  In FIG. 2, Condition A indicates that the secondary battery was charged and discharged at a charge rate (SOC) in the range of 0 to 100% and a voltage in the range of 2.50 to 4.50 V. Similarly, the condition B corresponds to a charging rate in the range of 10 to 90% and a voltage in the range of 3.26 to 4.32V. Condition C corresponds to a charging rate in the range of 10 to 100% and a voltage in the range of 3.26 to 4.50V. Condition D corresponds to a charging rate in the range of 0 to 90% and a voltage in the range of 2.50 to 4.32V. 3 and 4, the relationship between the discharge capacity maintenance rate and the number of cycles is indicated by line types corresponding to the conditions A, B, C, and D in FIG. 3 and 4, the discharge capacity retention rate (vertical axis) is shown with respect to the square root (horizontal axis) of the cycle number. This is based on an empirical rule that the relationship between the discharge capacity retention rate and the square root of the number of cycles is almost linear.

  2 to 4, it can be seen that the discharge capacity retention rate at 25 ° C. (FIG. 3) is better than the discharge capacity retention rate at 60 ° C. (FIG. 4) under the same SOC range. In addition, when the SiO negative electrode is used up to 4.5 V, the cycle characteristic of condition C is better than that of condition D at 25 ° C., and the cycle characteristic of condition D is better than that of condition C at 60 ° C. . From this, it can be seen that degradation is accelerated when the SOC = 0 to 10% region is used at 25 ° C., but degradation is accelerated at 60 ° C. when the SOC = 90 to 100% region is used. Therefore, when the difference between the maximum charging rate and the minimum charging rate is 90%, by controlling to use the SOC range of SOC = 10 to 100% at 25 ° C. and SOC = 0 to 90% at 60 ° C. Degradation is effectively suppressed. In FIG. 4, there is a portion where the discharge capacity retention rate under condition C is slightly higher than that under condition D at 60 ° C. However, it has been found that at a high temperature (55 ° C. or higher), the transition metal eluted from the positive electrode attacks the SEI of the negative electrode, causing the negative electrode to deteriorate. Therefore, when the number of cycles increases from the upper limit of the number of cycles shown in FIG. 4, the discharge capacity maintenance rate of condition D is higher than that of condition C, and the difference between the two conditions is considered to be significant.

  Even when the secondary battery is not used, the temperature of the secondary battery may increase due to the environmental temperature. If the secondary battery is charged to SOC = 100% at 25 ° C. and then the secondary battery temperature rises due to the environmental temperature without using the secondary battery, the battery is discharged to SOC = 90% as the temperature rises. If the secondary battery is controlled or the SOC reaches 100%, the temperature adjustment means 20 controls the secondary battery so that the temperature of the secondary battery does not rise to 25 ° C. or more. Can be suppressed.

  Furthermore, if the secondary battery is discharged at 60 ° C. until the SOC becomes less than 10% and the use of the secondary battery is stopped as it is, the deterioration is accelerated when the temperature of the secondary battery is lowered. When the SOC becomes less than 10%, it may be displayed that the secondary battery needs to be charged.

Next, the operation of the secondary battery control device, that is, the control method of the secondary battery by the control device will be described.
The ECU 16 obtains information on the temperature and charging rate of the secondary battery module 13 from the secondary battery control device 17, and the charging rate of the secondary battery of the secondary battery module 13 is preset according to the temperature of the secondary battery. The charging and discharging are controlled by changing the maximum value and the minimum value of the charging rate so as not to deviate from the specified range. When the temperature of the secondary battery is high, the ECU 16 charges and discharges the secondary battery module 13 and supplies power to the traveling motor 14 and the temperature adjusting means 20 via the PCU 15 so that the charging rate does not exceed 90%. To control.

  As shown in FIG. 5, the ECU 16 changes the upper limit, the lower limit, or both of the charging rate according to the temperature of the secondary battery module 13. In the case of a vehicle, ΔSOC (charge / discharge amount) affects the travel distance of the vehicle, so a wider SOC range is better. From the results of FIGS. 2 to 4, in this embodiment, according to the temperature of the secondary battery, the ECU 16 sets the SOC region in the range of SOC = 10 to 100% at normal temperature and the range of SOC = 0 to 90% at high temperature. Control to Here, normal temperature means 20 ° C. or higher and 30 ° C. or lower (that is, 25 ° C. ± 5 ° C.). The high temperature is, for example, 60 ° C.

  When the temperature of the secondary battery module 13 rises due to the environmental temperature while the vehicle is stopped while the secondary battery module 13 is charged to the maximum charging rate at that temperature, the ECU 16 uses the power of the secondary battery module 13. A control command is sent to the PCU 15 to be used by the temperature adjusting means 20. As a result, even if the temperature of the secondary battery module 13 rises, the SOC of the secondary battery module 13 can be prevented from exceeding the upper limit value of the SOC at the temperature.

According to this embodiment, the following effects can be obtained.
(1) The secondary battery includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode, and outputs a voltage of 4.5 V at a maximum charging rate (SOC). In the secondary battery control method, the secondary battery is changed by changing the maximum and minimum values of the charging rate so that the charging rate of the secondary battery does not deviate from a preset range according to the temperature of the secondary battery. Controls charging and discharging of When the temperature of the secondary battery is high, charging / discharging is controlled so that the maximum value of the charging rate is 90%. Therefore, deterioration of the negative electrode during use of the secondary battery can be suppressed.

  (2) When the temperature of the secondary battery is normal temperature (25 ° C. ± 5 ° C.), charge / discharge is controlled so that the minimum value of the charging rate is 10% and the maximum value of the charging rate is 100%. Therefore, the charging / discharging amount of the secondary battery is larger than when the charging rate is controlled so that the charging rate (SOC) does not exceed 90% when the temperature of the secondary battery is normal or high. can do. Therefore, when the secondary battery is used as a power source for the vehicle, the travel distance of the vehicle can be increased.

  (3) High temperature is 55 ° C. or higher, and the minimum charging rate at high temperature is 0%. Therefore, the amount of charge / discharge of the secondary battery can be increased even at a high temperature as compared with the case where the secondary battery is used at a charging rate of 10% or more as at the normal temperature. Therefore, when the secondary battery is used as a power source for the vehicle, the travel distance of the vehicle can be increased.

  (4) The lithium transition metal oxide positive electrode of the secondary battery contains a mixture of lithium nickelate, lithium cobaltate, and lithium manganate as a main component. In other words, the lithium transition metal oxide positive electrode of the secondary battery mainly includes a mixture of lithium nickelate, lithium cobaltate, and lithium manganate. In the mixture, an appropriate lithium transition metal oxide positive electrode can be obtained by adjusting the ratio of a lithium transition metal oxide that has a proven record as a transition metal oxide constituting the positive electrode of a lithium ion secondary battery.

  (5) The control device for the secondary battery includes a battery temperature detecting means 18 for detecting the temperature of the secondary battery (secondary battery module 13), a charging rate detecting means 19 for detecting the charging rate of the secondary battery, and a battery. Based on the detection results of the temperature detecting means 18 and the charging rate detecting means 19, the maximum and minimum charging rates are set so that the charging rate of the secondary battery does not deviate from a preset range according to the temperature of the secondary battery. Control means (PCU15, ECU16, secondary battery control device 17) for controlling charging / discharging of the secondary battery by changing the value. When the temperature of the secondary battery is in a first temperature range (for example, a normal temperature range), the minimum value of the charging rate is 10% or more, and the temperature of the secondary battery is higher than the first temperature range. In the case of the temperature range (for example, high temperature), charging / discharging is controlled so that the maximum value of the charging rate is 90%. Therefore, by performing the secondary battery control method shown in the above effect (1), it is possible to suppress deterioration of the negative electrode during use of the secondary battery.

  (6) The secondary battery module 13 includes a thermoelectric conversion element as the temperature adjusting means 20. The temperature adjusting means 20 is supplied with power from the secondary battery module 13 via the PCU 15. Therefore, in the state where the secondary battery module 13 is charged to the target charging rate, when the temperature of the secondary battery module 13 is going to rise due to an increase in the environmental temperature or the like, for example, when the temperature of the secondary battery becomes high The power of the secondary battery module 13 is consumed by driving the temperature adjusting means 20. Thereby, since the charging rate of the secondary battery module 13 can be reduced, it is possible to efficiently prevent the charging rate of the secondary battery module 13 from exceeding the upper limit of the charging rate at the temperature. Moreover, this can reduce the temperature of the secondary battery module 13. Therefore, the time required for reducing the charging rate to the appropriate charging rate is shorter than that in the case where only one of temperature adjustment (temperature reduction) and use of the power of the secondary battery is performed.

The embodiment is not limited to the above, and may be embodied as follows, for example.
○ Charge / discharge is controlled by changing the maximum and minimum values of the charging rate so as not to deviate from the preset range according to the temperature of the secondary battery, and charging is performed when the temperature of the secondary battery is high. Charge / discharge may be controlled so that the rate does not exceed 90%, and ΔSOC (charge / discharge amount) does not need to be constant. Further, the SOC range may be changed according to the temperature. For example, when the temperature of the secondary battery is in the temperature range of 25 ° C. ± 5 ° C. where the deterioration accelerates in the SOC = 0 to 10% region, the SOC is set in the range of 15 to 100%, and the SOC = 90 to In the case of a temperature of 55 ° C. or higher at which deterioration accelerates in the 100% region, the SOC may be in the range of 0 to 85%. In this case, when the temperature changes in a state where the charging rate of the secondary battery module 13 is at the upper limit or the lower limit of the setting range, there is no problem even if the temperature control by the temperature adjusting means 20 is somewhat delayed from the change.

  ○ When the ΔSOC of the secondary battery module 13 is constant at 90% and the temperature of the secondary battery is in a temperature range of 25 ° C. ± 5 ° C. where the deterioration accelerates in the SOC = 0 to 10% region. When the SOC is in the range of 10 to 100% and the temperature is 55 ° C. or higher at which the deterioration accelerates in the SOC = 90 to 100% region, use the secondary battery with the SOC in the range of 0 to 90%. Also good.

  ○ The minimum value of the charging rate at high temperature may be 10%, similar to that at normal temperature. In this case, in a state where the secondary battery is discharged to a state close to the minimum value of the charging rate at a high temperature, and even when the temperature of the usage environment is below room temperature, the secondary battery is likely to deteriorate. Driving can be avoided.

  If the charging rate of the secondary battery module 13 may exceed the upper limit according to the temperature of the secondary battery module 13 while the travel motor 14 driven by the secondary battery module 13 is stopped, the secondary battery module 13 The charging rate may be lowered by consuming electric power by a load.

  If the charging rate of the secondary battery module 13 may exceed the upper limit according to the temperature of the secondary battery module 13 while the travel motor 14 driven by the secondary battery module 13 is stopped, the secondary battery module 13 Electric power may be supplied to the capacitor and stored in the capacitor. When the charging rate of the secondary battery module 13 decreases, the energy of the capacitor may be returned to the secondary battery module 13 as appropriate.

  The secondary battery constituting the secondary battery module 13 includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode, and outputs a voltage of 4.5 V at the maximum charging rate. The configurations of the positive electrode, the negative electrode, and the electrolytic solution of the secondary battery need not be as described in the above embodiment. For example, the mixing ratio of the positive electrode active material may be slightly changed, the ratio of SiO and graphite of the negative electrode may be slightly changed, or the composition ratio of the electrolytic solution may be slightly changed.

The material for the negative electrode is not limited to SiO, and other alloy-based negative electrode materials such as tin (Sn) may be used.
The vehicle on which the secondary battery module 13 is mounted is not limited to a general vehicle provided with the travel motor 14, but may be an industrial vehicle such as a forklift or an excavator loader. Further, the vehicle is not limited to a vehicle that requires a driver, and may be an automatic guided vehicle.

The vehicle on which the secondary battery module 13 is mounted is not limited to a hybrid type vehicle provided with the traveling motor 14 but may be an electric vehicle.
The control method of the secondary battery is not limited to the method of controlling the secondary battery (secondary battery module 13) mounted on the vehicle. For example, the present invention may be applied to control of a secondary battery (secondary battery module 13) as a power source used in a factory or home.

The control method for the secondary battery may be applied when a charged secondary battery is stored.
The following technical idea (invention) can be understood from the embodiment.

  (1) A control device for a secondary battery, wherein the secondary battery includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode, and the control device has a charge rate of the secondary battery. When the temperature of the secondary battery rises in the state of 100%, the secondary battery is discharged until the charging rate of the secondary battery reaches 90%.

  (2) In the invention described in claim 5 or the technical idea (1), the secondary battery further includes a load for using the power of the secondary battery, and the control device includes the secondary battery. When the charging rate of the battery is higher than the charging rate that is appropriate for the temperature of the secondary battery, the charging rate of the secondary battery is set to the appropriate charging rate by causing the power of the secondary battery to be used in the load. To lower.

  (3) In the invention described in the technical idea (2), the load is a thermoelectric conversion element. In this configuration, when the secondary battery becomes hot due to the environmental temperature, the secondary battery power is reduced by using the power of the secondary battery in the thermoelectric conversion element, and the temperature of the secondary battery is lowered. As a result, the time required to reduce the charging rate of the secondary battery to the appropriate charging rate is lower than when either the temperature of the secondary battery is lowered or the power of the secondary battery is used. Shorter.

A secondary battery control method that solves the above problem includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode, and outputs a voltage of 4.5 V in a state where the charging rate is maximum. The secondary battery is controlled by changing the maximum value and the minimum value of the charge rate so that the charge rate of the secondary battery does not deviate from a preset range according to the temperature of the secondary battery. When the temperature of the secondary battery is a high temperature of 55 ° C. or higher and 60 ° C. or lower, the maximum value of the charging rate is changed from 100% to 90%. Here, the “negative electrode that performs an alloying reaction” means that lithium ions do not discharge when lithium ions enter into the negative electrode by intercalation like a negative electrode made of a carbon material, but forms an alloy with lithium ions. Means negative electrode.

When the temperature of the secondary battery is a normal temperature (25 ° C. ± 5 ° C., that is, a range of 20 ° C. or higher and 30 ° C. or lower), the minimum charging rate is changed from 0% to 10%, and the charging at the normal temperature is performed. The maximum value of the rate is preferably 100%. According to this configuration, the charge / discharge amount of the secondary battery is larger than the case where control is performed so that the charging rate (SOC) does not exceed 90% regardless of whether the temperature of the secondary battery is normal temperature or high temperature. When a secondary battery is used as a power source for a vehicle, the travel distance of the vehicle can be increased.

Minimum value of the charging rate at the high temperature is preferably 0%. According to this configuration, the charge / discharge amount of the secondary battery becomes larger at high temperatures than when used at a charging rate of 10% or more as in the normal temperature, and the secondary battery is used as a power source for the vehicle. In this case, the travel distance of the vehicle can be increased.

A control device for a secondary battery that solves the above problem is a control device for a secondary battery that includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode. The control device includes a battery temperature detection unit that detects a temperature of the secondary battery, a charge rate detection unit that detects a charge rate of the secondary battery, and detection results of the battery temperature detection unit and the charge rate detection unit. A control unit that controls charging / discharging of the secondary battery by changing a maximum value and a minimum value of the charging rate so that the charging rate of the secondary battery does not deviate from a preset range according to temperature based on With. Wherein, when the temperature of the previous SL secondary battery is below a 30 ° C. 20 ° C. or more is normal temperature range, to change the minimum value of the charging rate 10% 0%, temperature of the secondary battery When the temperature is 55 ° C. or higher and 60 ° C. or lower higher than 20 ° C. or higher and 30 ° C. or lower , the maximum value of the charging rate is changed from 100% to 90%.

According to this embodiment, the following effects can be obtained.
(1) The secondary battery includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode, and outputs a voltage of 4.5 V at a maximum charging rate (SOC). In the secondary battery control method, the secondary battery is changed by changing the maximum and minimum values of the charging rate so that the charging rate of the secondary battery does not deviate from a preset range according to the temperature of the secondary battery. Controls charging and discharging of When the temperature of the secondary battery is a high temperature of 55 ° C. or higher and 60 ° C. or lower , charging / discharging is controlled so that the maximum value of the charging rate is 100% to 90%. Therefore, deterioration of the negative electrode during use of the secondary battery can be suppressed.

(2) When the temperature of the secondary battery is normal temperature (25 ° C ± 5 ° C), charge / discharge is controlled so that the minimum value of the charging rate is 0% to 10% and the maximum value of the charging rate is 100%. To do. Therefore, the charging / discharging amount of the secondary battery is larger than when the charging rate is controlled so that the charging rate (SOC) does not exceed 90% when the temperature of the secondary battery is normal or high. can do. Therefore, when the secondary battery is used as a power source for the vehicle, the travel distance of the vehicle can be increased.

(3) The minimum value of the charging rate at Atsushi Ko is 0%. Therefore, the amount of charge / discharge of the secondary battery can be increased even at a high temperature as compared with the case where the secondary battery is used at a charging rate of 10% or more as at the normal temperature. Therefore, when the secondary battery is used as a power source for the vehicle, the travel distance of the vehicle can be increased.

(5) The control device for the secondary battery includes a battery temperature detecting means 18 for detecting the temperature of the secondary battery (secondary battery module 13), a charging rate detecting means 19 for detecting the charging rate of the secondary battery, and a battery. Based on the detection results of the temperature detecting means 18 and the charging rate detecting means 19, the maximum and minimum charging rates are set so that the charging rate of the secondary battery does not deviate from a preset range according to the temperature of the secondary battery. Control means (PCU15, ECU16, secondary battery control device 17) for controlling charging / discharging of the secondary battery by changing the value. If the temperature of the secondary battery is in a 20 ° C. or higher 30 ° C. or less (normal temperature range), the minimum value of the charging rate is 10% or more, the temperature of the secondary battery temperatures above 55 ℃ than the first temperature range If it is 60 ° C. or less (Atsushi Ko), to control the charging and discharging to 90% the maximum value of the charging rate of 100%. Therefore, by performing the secondary battery control method shown in the above effect (1), it is possible to suppress deterioration of the negative electrode during use of the secondary battery.

(1) A control device for a secondary battery, wherein the secondary battery includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode, and the control device has a charge rate of the secondary battery. When the temperature of the secondary battery rises to 55 ° C. or higher and 60 ° C. or lower in the state of 100%, the secondary battery is discharged until the charging rate of the secondary battery reaches 90%.

Claims (10)

A method for controlling a secondary battery, wherein the secondary battery includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode, and outputs a voltage of 4.5 V in a state where the charging rate is maximum. And the method
Controlling the charging and discharging of the secondary battery by changing the maximum value and the minimum value of the charging rate so that the charging rate of the secondary battery does not deviate from a preset range according to the temperature of the secondary battery;
The method of changing the maximum value of the charging rate to 90% when the temperature of the secondary battery is high.   When the temperature of the secondary battery is in a normal temperature range of 20 ° C or higher and 30 ° C or lower, the minimum value of the charging rate is changed to 10%, and the maximum charging rate at the normal temperature is 100%. The method according to 1.   The method according to claim 1, wherein the high temperature is 55 ° C. or more, and a minimum value of the charging rate at the high temperature is 0%.   The method of claim 1, wherein the lithium transition metal oxide cathode comprises primarily a mixture of lithium nickelate, lithium cobaltate and lithium manganate. A control device for a secondary battery, wherein the secondary battery includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode, and the control device includes:
A battery temperature detector for detecting the temperature of the secondary battery;
A charge rate detector for detecting a charge rate of the secondary battery;
Based on the detection results of the battery temperature detection unit and the charging rate detection unit, the charging rate maximum value so that the charging rate of the secondary battery does not deviate from a preset range according to the temperature of the secondary battery. And a controller that controls charging and discharging of the secondary battery by changing the minimum value,
When the temperature of the secondary battery is in a first temperature range that is a normal temperature range, the control unit changes the minimum value of the charging rate to 10%, and the temperature of the secondary battery is in the first temperature range. The control device changes the maximum value of the charging rate to 90% when the temperature is in the second temperature range higher than the second temperature range. A control device for a secondary battery, wherein the secondary battery includes a negative electrode that performs an alloying reaction, and a lithium transition metal oxide positive electrode.
When the temperature of the secondary battery rises in a state where the charging rate of the secondary battery is 100%, the control device discharges the secondary battery until the charging rate of the secondary battery reaches 90%.   The secondary battery further includes a load for using the power of the secondary battery, and the control device has an appropriate charging rate at which the charging rate of the secondary battery is appropriate with respect to the temperature of the secondary battery. 7. The control device according to claim 5, wherein when it is higher, the charging rate of the secondary battery is reduced to the appropriate charging rate by causing the power of the secondary battery to be used in the load.   The control device according to claim 7, wherein the load is a thermoelectric conversion element. A control device for a secondary battery, wherein the secondary battery includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode, and the control device includes:
A battery temperature detector for detecting the temperature of the secondary battery;
A charge rate detector for detecting a charge rate of the secondary battery;
A temperature adjusting unit for adjusting the temperature of the secondary battery;
Based on the detection results of the battery temperature detection unit and the charge rate detection unit, when the charge rate of the secondary battery is 100%, the temperature adjustment unit is controlled so that the temperature of the secondary battery does not become high. A control unit. A control device for a secondary battery, wherein the secondary battery includes a negative electrode that performs an alloying reaction and a lithium transition metal oxide positive electrode, and the control device includes:
A battery temperature detector for detecting the temperature of the secondary battery;
A charge rate detector for detecting a charge rate of the secondary battery;
A temperature adjusting unit for adjusting the temperature of the secondary battery;
Based on the detection results of the battery temperature detection unit and the charge rate detection unit, when the charge rate of the secondary battery is 10% or less, the temperature adjustment is performed so that the temperature of the secondary battery is higher than 25 ° C. A control unit for controlling the unit.

Images