Battery system

Abstract

To provide a battery system capable of accurately calculating an internal pressure of a battery.SOLUTION: A battery system according to the present invention is configured to: select a time transition map to be used in a subsequent process from among a plurality of pre-stored time transition maps of battery temperature based on the battery temperature and an ambient temperature immediately before an ignition power supply is turned off; acquire the battery temperature when the ignition power supply is turned on; estimate the battery temperature based on a selected time transition map and an off duration of the ignition power supply; and when the acquired battery temperature is less than the estimated battery temperature, calculate an internal pressure of the battery using the estimated battery temperature, or when the acquired battery temperature is equal to or higher than the estimated battery temperature, calculate the internal pressure of the battery using the acquired battery temperature.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a battery system. [Background technology]

[0002] Patent document 1 describes a battery system that calculates the internal pressure of a battery cell based on the SOC and time of the battery cell while the ignition power is off and the temperature of the battery cell immediately after the ignition power is turned on, and determines the deterioration of the battery cell over time based on the calculated internal pressure value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-141790 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the battery system described in Patent Document 1, since information regarding the temperature history of the battery cell while the ignition power is off is not taken into consideration, the internal pressure of the battery cell cannot be calculated accurately, and as a result, it may not be possible to accurately determine the deterioration of the battery cell over time.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a battery system that can accurately calculate the internal pressure of a battery. [Means for solving the problem]

[0006] The battery system of the present invention selects a time progression map to be used in subsequent processing from among multiple pre-stored time progression maps of battery temperature based on the battery temperature and ambient temperature immediately before the ignition power is turned off, obtains the battery temperature when the ignition power is on, estimates the battery temperature based on the selected time progression map and the duration of time the ignition power is off, and if the obtained battery temperature is lower than the estimated battery temperature, calculates the internal pressure of the battery using the estimated battery temperature, and if the obtained battery temperature is higher than or equal to the estimated battery temperature, calculates the internal pressure of the battery using the obtained battery temperature. [Effects of the Invention]

[0007] According to the battery system of the present invention, the internal pressure of the battery can be calculated with high accuracy. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing the configuration of a vehicle to which a battery system according to one embodiment of the present invention is applied. [Figure 2] FIG. 2 is a flowchart showing the flow of an internal pressure calculation process according to one embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing a map of battery temperature over time. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the configuration of a battery system according to one embodiment of the present invention will be described with reference to the drawings.

[0010] 〔composition〕 Fig. 1 is a block diagram showing the configuration of a vehicle to which a battery system according to one embodiment of the present invention is applied. As shown in Fig. 1, a vehicle 1 to which a battery system according to one embodiment of the present invention is applied is configured to include a battery 2 and an ignition power supply (not shown). The battery system includes the battery 2, an ECU (Electronic Control Unit) 10, a battery temperature sensor 11, and an ambient temperature sensor 12.

[0011] The ECU 10 is configured with an information processing device such as a computer. In this embodiment, the ECU 10 calculates the internal pressure of the battery 2 and determines the deterioration over time of the components of the battery 2 based on the calculated internal pressure of the battery 2. The ECU 10 also includes a timer 10a and a battery temperature transition map 10b to calculate the internal pressure of the battery 2. The timer 10a and the battery temperature transition map 10b will be described in detail later.

[0012] The battery temperature sensor 11 is configured by a temperature sensor capable of measuring the temperature of the battery 2, and inputs an electrical signal indicating the measured temperature of the battery 2 to the ECU 10. The ambient temperature sensor 12 is configured by a temperature sensor capable of measuring the ambient temperature of the battery 2, and inputs an electrical signal indicating the measured ambient temperature to the ECU 10.

[0013] In the vehicle 1 having such a configuration, the ECU 10 executes the internal pressure calculation process described below to accurately calculate the internal pressure of the battery 2. Hereinafter, the operation of the ECU 10 when executing the internal pressure calculation process will be described with reference to Figures 2 and 3.

[0014] [Internal pressure calculation process] 2 is a flowchart showing the flow of the internal pressure calculation process according to one embodiment of the present invention. The flowchart shown in FIG. 2 starts when the ignition power is turned off, and the internal pressure calculation process proceeds to step S1.

[0015] In the process of step S1, the ECU 10 uses the battery temperature sensor 11 and the ambient temperature sensor 12 to measure the temperature of the battery 2 and the ambient temperature immediately before the ignition power is turned off, and records the measured data of the temperature of the battery 2 and the ambient temperature in a non-volatile storage device such as a ROM. The ECU 10 also turns on the timer 10a to measure the duration of the ignition power off state. This completes the process of step S1, and the internal pressure calculation process proceeds to the process of step S2.

[0016] In the process of step S2, the ECU 10 selects a battery temperature transition map corresponding to the temperature of the battery 2 and the ambient temperature measured in the process of step S1 from among a plurality of pre-stored battery temperature transition maps 10b that show the time changes in the temperature of the battery 2 for each combination of the temperature of the battery 2 and the ambient temperature. This completes the process of step S2, and the internal pressure calculation process proceeds to the processes of steps S3 and S4.

[0017] In the process of step S3, the ECU 10 measures the temperature of the battery 2 (actual battery temperature) when the ignition power is turned on using the battery temperature sensor 11. This completes the process of step S3, and the internal pressure calculation process proceeds to the process of step S5.

[0018] In the process of step S4, the ECU 10 turns off the timer 10a in response to the ignition power being turned on. Then, the ECU 10 reads information on the temperature of the battery 2 (estimated battery temperature) measured by the timer 10a after the ignition power has been off for a certain period of time from the battery temperature transition map selected in the process of step S2. This completes the process of step S4, and the internal pressure calculation process proceeds to the process of step S5.

[0019] In the process of step S5, ECU 10 determines whether the actual battery temperature measured in the process of step S3 is lower than the estimated battery temperature obtained in the process of step S4. If the result of the determination is that the actual battery temperature is lower than the estimated battery temperature (step S5: Yes), ECU 10 proceeds to the process of step S6 in the internal pressure determination process. On the other hand, if the actual battery temperature is equal to or higher than the estimated battery temperature (step S5: No), ECU 10 proceeds to the process of step S7 in the internal pressure determination process.

[0020] In the process of step S6, the ECU 10 sets the battery temperature transition map selected in the process of step S2 as shown in Fig. 3(a) as the temperature history data of the battery 2. This completes the process of step S6, and the internal pressure calculation process proceeds to the process of step S8.

[0021] In the process of step S7, as shown in Figure 3(b), the ECU 10 generates a time transition map of the temperature of the battery 2 by linearly interpolating the temperature of the battery 2 when the ignition power is off and the temperature of the battery 2 when the ignition power is on, and uses the generated time transition map as data on the temperature history of the battery 2. This completes the process of step S7, and the internal pressure calculation process proceeds to the process of step S8.

[0022] In the process of step S8, the ECU 10 calculates the internal pressure of the battery 2 using the temperature history data of the battery 2 determined in the process of step S6 or step S7. This completes the process of step S8, and the series of internal pressure calculation processes ends.

[0023] As is clear from the above description, in the internal pressure calculation process according to one embodiment of the present invention, ECU 10 first selects a time-varying map to be used in subsequent processes from among multiple pre-stored battery temperature time-varying maps based on the battery temperature and ambient temperature immediately before the ignition power is turned off. Next, ECU 10 acquires the battery temperature when the ignition power is on and estimates the battery temperature based on the selected time-varying map and the duration of the ignition power being off. If the acquired battery temperature is lower than the estimated battery temperature, ECU 10 calculates the battery internal pressure using the estimated battery temperature. If the acquired battery temperature is equal to or higher than the estimated battery temperature, ECU 10 calculates the battery internal pressure using the acquired battery temperature. This allows the internal battery pressure to be calculated accurately, thereby enabling accurate assessment of battery deterioration over time.

[0024] Although the present invention has been described above as an embodiment, the present invention is not limited to the description and drawings that form part of the disclosure of the present invention. In other words, other embodiments, examples, and operational techniques that can be made by those skilled in the art based on the present invention are all included in the scope of the present invention. [Explanation of symbols]

[0025] 1 vehicle 2 batteries 10 ECU 10a Timer 10b Battery temperature transition map 11 Battery temperature sensor 12 Ambient temperature sensor

Claims

[Claim 1] a means for selecting a time transition map to be used in subsequent processing from among a plurality of pre-stored time transition maps of battery temperature based on the battery temperature and ambient temperature immediately before the ignition power is turned off, obtaining the battery temperature when the ignition power is on, estimating the battery temperature based on the selected time transition map and the duration of time the ignition power is off, calculating an internal battery pressure using the estimated battery temperature if the obtained battery temperature is lower than the estimated battery temperature, and calculating an internal battery pressure using the obtained battery temperature if the obtained battery temperature is equal to or higher than the estimated battery temperature.

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