JP2008258089A - Liquid level detection device for battery, and battery provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid level detection device of a lead battery electrolyte which has a reduced cost and an excellent precision without changing an inner structure of the lead battery to a large extent. <P>SOLUTION: The liquid level detection device is provided with a temperature sensor arranged at a position close to a lower limit level of the electrolyte of a lead battery case outer surface and a means to memorize temperature information with the passage of time obtained by the temperature sensor. By utilizing a difference thermal capacities between the electrolyte and space and by a variation amount and variation speed of the battery temperature detected by the temperature sensor, a position of the liquid level, especially, whether or not the electrolyte liquid level is higher than the lower limit position, can be detected at a reduced cost and in a high precision without changing a battery inner structure to a large extent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrolyte liquid level detection device for a battery for starting an engine of a vehicle, and a battery equipped with the liquid level detection device.

  In recent years, with the progress of motorization, the proportion of starter battery failures has increased as a cause of vehicle failure that requires rescue from the outside, and has become one of the biggest factors. Currently, many vehicles traveling in the city have a configuration in which an engine is used as a power source and a starter motor is operated by receiving electric power from a battery when the engine is started. In such a configuration, the engine cannot be started if a battery malfunction occurs. In such a case, the battery is replaced or the battery of another vehicle is connected to the battery of the failed vehicle, and the engine is restarted urgently.

  In any case, recovery from battery failure takes time and money, so it is desirable to prevent battery failure in advance. One of the main causes of battery failure is lack of electrolyte. In a lead battery, the amount of the electrolyte decreases due to electrolysis or evaporation of moisture in the electrolyte during charging, and when the electrode group is exposed from the electrolyte surface, the deterioration of the lead battery proceeds rapidly.

  Therefore, it is necessary to manage the electrolyte level of the lead battery. In general, the lower limit position of the electrolyte surface is set at a position slightly higher than the strap for performing collective welding of the electrode plates of the lead battery, and the lead battery is appropriately adjusted so that the electrolyte surface does not fall below the lower limit position. It is necessary to replenish with distilled water.

  As a method for checking the electrolyte level, display the lower limit position of the electrolyte level on the battery case of the lead battery body, see through the electrolyte level from the outside of the battery case, and set the electrolyte level and lower limit position. What is compared is common.

  However, as a countermeasure against thermal deterioration of lead batteries, in many vehicles, the surface of the electrolyte such as black or blue is visually recognized due to the requirement for thermal insulation covers on lead batteries, reuse of recycled resin materials, or battery design. Due to the use of a battery case having a color tone that cannot be used, the electrolyte surface cannot be visually confirmed from the outside.

  Under such circumstances, in order to facilitate the inspection of the electrolyte surface, there has conventionally been a method of checking the amount of the electrolyte by confirming the state of the float provided inside from the upper surface of the lead battery. Further, in order to obtain even higher convenience, a method for detecting the electrolytic solution level using an electrical detection element has been proposed.

For example, Patent Document 1 discloses a method in which a pressure sensitive element is provided under a battery, a decrease in battery weight is detected by the pressure sensitive element, and a liquid level is detected. Patent Document 2 discloses a method for detecting the liquid level by optically detecting the position of the float floating in the electrolytic solution, and Patent Document 3 includes an electrode for detecting the liquid level in the battery. A method for detecting the contact / non-contact between the electrode and the electrolyte and detecting the electrolyte surface is shown.
JP-A-8-315868 JP-A-2-262280 JP-A-6-318468

  However, in the conventional configuration as described above, a significant change in the battery structure is required, such as providing an electrode inside the battery or providing a float, which has been a major obstacle to commercialization. In addition, the pressure-sensitive element for detecting a decrease in the weight of the battery and the amplifier thereof have a cost comparable to the price of the battery, which also hinders practical use. In the case of the float type, there is a problem that the size of the battery increases because the float itself takes a large space, and the cost of the optical sensor for detection accounts for 10% or more of the battery cost.

  The method of detecting the contact between the electrode and the electrolyte has few problems in terms of cost, but it is necessary to provide a new electrode inside the battery and lead the lead wire from the inside of the battery to the liquid level detection device. A structure was needed. In addition, since the electrolytic solution has high corrosiveness, there is a problem that it is difficult to obtain a suitable electrode material including the material cost.

  The present invention provides a low-cost and accurate liquid level detection device for an electrolyte solution of a lead battery and a lead battery including the liquid level detection device without significantly changing the internal structure of the battery. It is.

  In order to solve the above-described problem, the invention according to claim 1 of the present invention is an apparatus for detecting the liquid level of an electrolytic solution in a battery case for starting an engine of a vehicle, and the lower limit of the liquid level. 1 shows a liquid level detection device for a battery having a temperature sensor arranged in the vicinity of a position and means for storing temperature information obtained by the temperature sensor over time.

  In the present invention, a temperature sensor is provided in the vicinity of the lower limit of the liquid level of the battery case, and the electrolytic solution level is detected by detecting the temperature change rate. When the battery electrolyte is at a level above the lower limit, the temperature sensor measures a value close to the electrolyte temperature. Since the electrolytic solution is a sulfuric acid aqueous solution, it has a higher specific heat than other components and air. For this reason, a gradual rise in temperature is shown due to a sudden rise in ambient temperature after engine startup.

  Similarly, the engine dissipates heat after stopping and the ambient temperature decreases, but at that time, it gradually decreases. When the battery starts to be used, the amount of temperature rise is stored. Thereafter, the temperature rise of the battery is measured over time, and the increase in temperature is detected to detect a decrease in electrolyte. Similarly, a decrease in engine stop temperature may be detected.

  According to a second aspect of the present invention, in the battery liquid level detection device of the first aspect, a temperature change rate is included as the temperature information. In order to detect the liquid level position with higher accuracy, attention is paid not only to the temperature change amount but also to the temperature change speed. The amount of temperature change is affected by the operating time of the engine such as the operating time. On the other hand, it is possible to grasp the change rate of the battery temperature under a certain condition by obtaining the rate of increase of the battery temperature when a certain time has elapsed after starting the engine or when the temperature rises. The decrease in the electrolyte can be obtained with high accuracy.

  According to a third aspect of the present invention, in the battery liquid level detection device according to the first or second aspect, the temperature information obtained at the beginning of the battery use is stored as a reference value, and the temperature measured sequentially The change of the liquid level is detected by comparing the information with the reference value.

  In the state where the electrolyte surface level is at a sufficient level within the regulation at the beginning of use of the battery, for example, the average value of the temperature change width of the battery for one month after the start of use is stored as a reference value. When the temperature change width exceeds the above-described reference value every period of about 1 day to 1 week, it is detected as a decrease in the electrolyte. As a result, it is possible to further reduce the adverse effect on the liquid level detection accuracy due to the difference in temperature rise in the engine room and the difference in the type of battery for each vehicle.

  According to a fourth aspect of the present invention, in the battery liquid level detection device according to any one of the first to third aspects, in addition to the temperature sensor, a second liquid level detection device disposed at a portion above the upper limit position of the liquid level. A temperature sensor is provided.

  By using such a second temperature sensor, it is possible to detect a decrease in the electrolyte with higher accuracy. The temperature sensor provided near the lower limit of the liquid level becomes slow when the electrolyte level is high. In order to determine the level more clearly, the temperature of the portion where the electrolyte solution does not exist above the upper limit of the electrolyte solution of the battery case is measured by the second temperature sensor, and both are compared. More specifically, when the temperature difference between the two exceeds a certain threshold, it can be detected that the liquid level is below the lower limit.

  Furthermore, the liquid level at the position where each temperature sensor is arranged can be obtained by simultaneously calculating the temperature change rate and the thermal time constant obtained by the temperature sensor and the second temperature sensor and comparing them. The presence or absence of can be detected. Further, by comparing with a portion without the electrolyte solution, it is possible to correct influences such as changes in operating time and ambient temperature, and to improve the accuracy of determination.

  According to a fifth aspect of the present invention, in the battery level detection device according to the first to fourth aspects, a third temperature sensor for measuring the temperature in the vicinity of the battery is provided. This corrects the influence of the change in battery ambient temperature obtained by the third temperature sensor. For example, the liquid level is detected only when the amount of temperature change measured at one minute intervals is within a predetermined range. When the battery ambient temperature change is abrupt, the liquid level detection accuracy is lowered. Therefore, the liquid level is not detected under such a situation, so that erroneous determination can be prevented.

  The invention according to Claim 6 of the present invention is the battery liquid level detection device according to any one of Claims 1 to 6, wherein a heat insulating material is provided on a side surface of the temperature sensor and / or the second temperature sensor that does not contact the battery case. Is arranged. As a result, it is possible to measure the temperature closer to the electrolyte when there is enough electrolyte, and the temperature closer to the temperature of the air in the battery case when the electrolyte is insufficient. Since the difference in temperature rise can be detected as a larger value, the liquid level can be detected more stably and accurately.

  The invention according to claim 7 of the present invention is characterized in that, in the battery level detecting device according to claims 1 to 6, a thermal time constant is used as the temperature information. The temperature information from the temperature sensor and / or the second temperature sensor that changes over time is used to predict the ambient temperature from the absolute temperature and the temperature change rate, and the thermal time constant is calculated. When this value decreases, the decrease in the electrolyte is detected. If the outside air temperature is measured by the third temperature sensor as described in claim 5, the detection accuracy is further improved.

  The invention which concerns on Claim 8 of this invention shows the battery provided with the liquid level detection apparatus for batteries of Claims 1-7.

  According to a ninth aspect of the present invention, in the battery according to the eighth aspect, the thickness of the battery case is greater than that of the other portion in the portion where the temperature sensor and / or the second temperature sensor is disposed. A thinned thin part is formed. With such a configuration, the temperature close to the electrolyte can be measured when the electrolyte is sufficient, and the temperature close to the temperature of the air in the battery case can be measured when the electrolyte is insufficient. Therefore, the decrease in the electrolyte level can be detected with higher accuracy.

  According to a tenth aspect of the present invention, in the battery according to the eighth to ninth aspects, the thin wall portion of the battery case is easily broken by the press-fitting of the temperature sensor and / or the second temperature sensor. The sealing of the electrolytic solution is achieved by the pressure contact.

  For example, a temperature sensor and / or a second temperature sensor is inserted into an acid-resistant protective sleeve, and the sleeve is press-fitted so as to break a thin portion of the battery case. By covering the outside of the mounting part with a heat insulating material, the effect of outside air is reduced. When there is sufficient electrolyte, the temperature is closer to the electrolyte, and when the electrolyte is insufficient, the temperature is closer to the temperature of the air in the battery case. Can be measured. As a result, the temperature behavior change due to the liquid level drop can be detected with higher accuracy.

  According to the present invention, a general-purpose and inexpensive temperature sensor can be obtained without substantially changing the battery structure, without using an expensive pressure-sensitive sensor, optical detection type float, corrosion-resistant liquid level detection electrode, or the like. By arranging it on the outer wall surface of the battery case, there is a remarkable effect that the liquid level drop of the lead battery can be accurately determined.

(Embodiment 1 of the present invention)
FIG. 1 is a diagram showing a battery liquid level detection device 4 according to Embodiment 1 of the present invention. The battery liquid level detection device 4 has a positive electrode connection terminal 1 for connection to the battery positive electrode and a negative electrode connection terminal 2 for connection to the battery negative electrode. The power for operation of the battery level detecting device 4 is supplied from the battery through these terminals.

  The battery liquid level detection device 4 includes a temperature sensor 6 such as a thermistor or a thermocouple, and is connected to the temperature sensor 6 via a connection lead wire 3. The battery liquid level detection device 4 includes an LED display unit 5, and the LED display unit 5 notifies the user of the state of the electrolytic solution level. The notification means may not be an LED, but may be another display device such as an LCD panel, or an audio / acoustic device such as an electronic sound or an electronic buzzer.

  The battery liquid level detection device 4 includes a microcomputer (not shown), a memory storage device (not shown), and an A / D converter (not shown).

  FIG. 6 shows a state in which the battery liquid level detection device 4 is connected to the battery 10. The battery liquid level detection device 4 can be fixed to the battery 10 with double-sided tape or the like. In the present invention, the temperature sensitive portion of the temperature sensor 6 is fixed near the lower limit position 10b of the electrolyte surface on the outer wall of the battery case 10a of the battery 10. The temperature sensor 6 can be fixed using an adhesive tape or the like. FIG. 6 shows an example in which a liquid start lead battery is used as the battery 10.

  FIG. 9 shows the voltage V of the battery 10 when the battery 10 equipped with the battery level detection device 4 of the present invention is mounted on a general ordinary passenger car and the engine is started and the engine is continuously operated for 20 minutes. The time change of the battery temperature T1 measured in the lower limit position 10b vicinity of the electrolyte solution surface of the outer wall of the battery case 10a by the temperature sensor 6 is shown.

  The battery 10 has two states: a state in which the electrolyte surface has an electrolyte surface at an upper limit position 10c located 25 mm from the lower limit position 10b, and a state in which the electrolyte surface is 5 mm below the lower limit position 10b. Thus, the battery temperature T1 was measured.

  Although the battery voltage V decreases instantaneously as the engine starts, the battery voltage V increases because charging is started simultaneously with the engine start. The portion where the battery voltage V appearing thereafter decreases corresponds to a state where the engine is stopped.

  The battery temperature T1 rises as the engine starts due to heat generated from the engine. A difference in the behavior of the battery temperature T1 is caused by the difference in the liquid level position. The time change amount of the battery temperature T1 when the electrolytic solution level is at the lower limit position 10b is much higher than the temperature time change amount of the battery temperature T1 when the electrolyte solution level is set to the upper limit position 10c exceeding the lower limit position 10b. large. In the present invention, it is possible to accurately detect whether or not the electrolytic solution level is below the lower limit position 10b by detecting the temperature behavior due to such a liquid level difference.

  FIG. 12 shows a vehicle running test 2 in which the battery temperature T1 measurement by the temperature sensor 6 disposed in the vicinity of the lower limit position 10b of the electrolyte surface is mounted on a general ordinary passenger car with the battery 10 shown in FIG. It is a figure which shows the result implemented annually.

  The vertical axis of the graph of FIG. 12 indicates the temperature change (ΔT1) in units of 10 minutes of the battery temperature T1 in the vicinity of the lower limit position 10b of the liquid level measured by the temperature sensor 6, and the horizontal axis indicates the number of days of vehicle running test. The battery temperature T1 is measured once a minute by the temperature sensor 6, and the difference between the maximum value and the minimum value is obtained every 10 minutes to obtain a temperature change (ΔT1), and the result is recorded in a memory storage device (not shown). To do. At the same time, the battery liquid level was inspected, and the relationship between the behavior of the temperature change (ΔT1) and the electrolyte level was grasped.

  As a result, it can be seen that the temperature change (ΔT1) amount suddenly increases when the electrolyte solution level falls below the lower limit position 10b after 515 days after the start of the test. The present invention uses this phenomenon to detect the liquid level. For example, in the example shown in FIG. 12, for example, by setting the liquid level determination criterion by temperature change (ΔT1) to 10 ° C., When the temperature change (ΔT1) is 10 ° C. or more, it is determined that the liquid level has fallen below the lower limit position 10b, and this is displayed using display means such as the LED display unit 5 or the like.

  When the electrolyte is sufficiently above the lower limit position 10b of the electrolyte, the battery temperature T1 by the temperature sensor 6 provided in the vicinity of the lower limit position 10b is affected by the electrolyte temperature and the temperature change becomes slow. When the electrolyte level becomes lower than the lower limit position 10b, the temperature change becomes severe due to the influence of the air temperature in the battery case.

  In this example, the example is shown in which the determination is performed based on the temperature change (ΔT1) for 10 minutes, but other time intervals may be adopted. Note that since the engine is stopped and the battery temperature T1 does not change, the temperature change (ΔT1) takes a small value regardless of the electrolyte surface position, and it is erroneously determined that the electrolyte surface position is above the lower limit position 10b. There is a fear. Therefore, after detecting the decrease in the electrolyte level, it is necessary to store and display this detection history. In addition, when distilled water is replenished in the battery 10 and the liquid level is set to a position equal to or higher than the lower limit position 10b, it is necessary to reset the display. This reset operation is manually performed after checking the liquid level. Alternatively, if a decrease in the electrolyte level is not determined again after 1 to 2 days, the display of the decrease in the electrolyte level may be reset.

(Embodiment 2 of the present invention)
The second embodiment of the present invention is obtained by changing the data processing method of the temperature measured by the temperature sensor 6 in the first embodiment. Other than that, there is no difference from the first embodiment.

  In the first embodiment, the temperature change (ΔT1) within a predetermined time of the temperature T1 of the battery 10 measured by the temperature sensor 6 disposed at the lower limit position 10b of the electrolyte surface is adopted as a parameter for determining the liquid surface position. In the second embodiment, the change rate (ΔT1 / Δh, h is time) of the temperature T1 of the battery 10 measured by the temperature sensor 6 arranged at the lower limit position 10b of the liquid level is calculated by a microcomputer (not shown).

  FIG. 13 shows the result of measuring the change rate (ΔT1 / Δh) of the temperature T1 during the vehicle running test of the battery 10 as in the first embodiment. The vertical axis represents the rate of change of battery temperature T1 for 1 minute (ΔT1 / Δh, ° C./min). The horizontal axis shows the number of days of vehicle running test. As shown in FIG. 13, it can be seen that the absolute value of the change rate (ΔT1 / Δh) of the battery temperature T1 increases abruptly when the electrolyte level falls below the lower limit position 10b. Utilizing this phenomenon, the determination criterion is set to, for example, 0.1 ° C./minute, and when the change rate (ΔT1 / Δh) of the battery temperature T1 exceeding the determination criterion is detected, the LED display unit 5 may be used to display that the electrolyte level has fallen below the lower limit position 10b.

  Note that the change rate (ΔT1 / Δh) of the battery temperature T1 is a value less than the determination reference value, for example, less than 0.1 ° C./min, regardless of the amount of the electrolyte while the vehicle engine is stopped. Therefore, after detecting the decrease in the electrolyte level, it is necessary to store and display this detection history. In addition, when distilled water is replenished in the battery 10 and the liquid level is set to a position equal to or higher than the lower limit position 10b, it is necessary to reset the display. This reset operation is manually performed after checking the liquid level. Alternatively, if a decrease in the electrolyte level is not determined again after 1 to 2 days, the display of the decrease in the electrolyte level may be reset.

(Embodiment 3)
FIG. 2 is a diagram showing a battery liquid level detection device 4 ′ according to Embodiment 3 of the present invention. The battery liquid level detection device 4 'has a positive electrode connection terminal 1 for connection to the battery positive electrode and a negative electrode connection terminal 2 for connection to the battery negative electrode. The power for operation of the battery level detecting device 4 ′ is supplied from the battery by these terminals.

  The battery liquid level detection device 4 ′ includes a temperature sensor 6 as a temperature sensor, and is connected to the temperature sensor 6 via a connection lead wire 3. The battery liquid level detection device 4 ′ has an LED display unit 5, and the LED display unit 5 notifies the user of the state of the electrolytic solution level. Note that the notification means may not be an LED, but may be another display device such as an LCD panel, or an audio / acoustic device such as an electronic voice or an electronic buzzer.

  The battery liquid level detection device 4 'incorporates a microcomputer (not shown), a memory storage device (not shown), and an A / D converter (not shown).

  In the third embodiment, the battery liquid level detection device 4 ′ includes a second temperature sensor 6 ′ as a second temperature sensor. As shown in FIG. 7, the temperature sensor 6 is arranged on the outer wall surface of the battery case 10a in the vicinity of the lower limit position 10b of the electrolyte surface, and the second temperature sensor 6 ' It fixes to the outer wall surface of the battery case 10a above the upper limit position 10c of the liquid.

  FIG. 7 shows a state in which the liquid level detection device 4 ′ according to Embodiment 3 of the present invention is attached to the battery 10. The battery level detection device 4 ′ can be fixed to the battery 10 with double-sided tape or the like. The temperature sensor 6 and the second temperature sensor 6 ′ can be fixed to the surface of the battery case 10a using an adhesive tape or the like.

  The battery 10 equipped with the battery liquid level detection device 4 'is measured by a battery voltage V when mounted on a general ordinary passenger car and the engine is started, and a temperature sensor 6 attached to the lower limit position 10b of the liquid level. FIG. 10 shows changes with time of the battery temperature T1 and the battery temperature T2 measured by the second temperature sensor 6 ′ mounted above the upper limit position 10c of the liquid level. The battery temperatures T1 and T2 are determined when the electrolyte level in the battery 10 is 5 mm below the lower limit position 10b and the upper limit position 10c where the electrolyte level is 25 mm from the lower limit position 10b. Measurement was performed in two states.

  From the results shown in FIG. 10, the behavior of the battery temperature T2 by the second temperature sensor 6 ′ is almost constant without being influenced by the position of the electrolyte surface. On the other hand, the behavior of the battery T1 by the temperature sensor 6 varies greatly depending on the position of the electrolyte surface, and the temperature change of the battery temperature T1 measured when the electrolyte surface is less than the lower limit position 10b indicates that the electrolyte surface is at the upper limit position 10c. In this case, the battery temperature T1 is significantly larger than the measured temperature change. Accordingly, the battery temperature difference (T2−T1) between the temperature sensor 6 and the second temperature sensor 6 ′ is monitored, and when the temperature difference (T2−T1) approaches 0, a decrease in the electrolyte level can be detected. it can.

  The battery 10 equipped with the battery liquid level detection device 4 'of the present invention was mounted on a general ordinary passenger car, and a running test was conducted for two years. The result is shown in FIG. The temperature is measured at a frequency of once per minute, and the temperature difference (T2-T1) between the two battery temperatures obtained by the temperature sensor 6 and the second temperature sensor 6 'is obtained. In FIG. 14, the vertical axis represents the temperature difference (T2−T1) (° C.), and the horizontal axis represents the vehicle running test days. At the same time, when the liquid level position was confirmed, the electrolytic solution level was lower than the lower limit position 10b after 515 days from the start of the test.

  From FIG. 14, it can be seen that the temperature difference (T2-T1) is drastically reduced from the time when the electrolytic solution level falls below the lower limit position 10b. In the present embodiment, it is only necessary to detect a rapid decrease in this value and detect that the electrolyte surface level is below the lower limit position 10b.

  Actually, a determination reference value for the temperature difference (T2-T1) is set, and when the temperature difference falls below the reference value, the electrolyte level is set to the lower limit position 10b by the notification means such as the LED display unit 5. What is necessary is just to notify a user that it was less.

  In addition, since the value of the temperature difference (T2-T1) becomes small even when the engine is stopped, it may be erroneously determined that the electrolyte surface is in a normal position that is equal to or higher than the lower limit position. Therefore, it is necessary to continue to store and display this detection history when it is detected that the electrolytic solution surface has fallen below the lower limit position 10b. In addition, when distilled water is replenished in the battery 10 and the liquid level is set to a position equal to or higher than the lower limit position 10b, it is necessary to reset the display. This reset operation is manually performed after checking the liquid level. Alternatively, if a decrease in the electrolyte level is not determined again after 1 to 2 days, the display of the decrease in the electrolyte level may be reset. Alternatively, the electrolytic solution surface position may be determined only during engine start in which the temperature change speed of the two temperatures T1 and T2 by the temperature sensor 6 and the second temperature sensor 6 ′ is large.

(Embodiment 4)
FIG. 3 is a diagram illustrating a battery liquid level detection device 4 ″ according to Embodiment 4 of the present invention. The battery liquid level detection device 4 ″ includes a positive electrode connection terminal 1 for connection with a battery positive electrode, a battery negative electrode, It has a negative electrode connection terminal 2 for connection. The power for operation of the battery liquid level detection device 4 ″ is supplied from the battery through these terminals.

  The battery liquid level detection device 4 ″ includes a temperature sensor 6 as a temperature sensor, and is connected to the temperature sensor 6 via a connection lead 3. The battery liquid level detection device 4 ″ is connected to the LED display unit 5. The LED display unit 5 notifies the user of the state of the electrolyte surface. The notification means may not be an LED, but may be a display device such as an LCD panel or a voice / acoustic device such as an electronic voice.

  The battery liquid level detection device 4 ″ includes a microcomputer (not shown), a memory storage device (not shown), and an A / D converter (not shown).

  In the fourth embodiment, the battery liquid level detection device 4 ″ includes a third temperature sensor 6 ″ as a third temperature sensor. As shown in FIG. 8, the temperature sensor 6 is arranged on the surface of the battery case 10a near the lower limit position 10b of the electrolyte surface, and the third temperature sensor 6 ″ is placed around the battery 10 as in the first embodiment. By being arranged, the ambient temperature Ta of the battery 10 and the battery temperature T1 are measured.

  FIG. 11 shows a battery voltage V and a temperature sensor when the battery 10 equipped with the battery level detecting device 4 ″ according to the fourth embodiment of the present invention is mounted on a general ordinary passenger car and the engine is started. 6 shows the time change of the battery temperature T1 at the lower limit position 10b of the liquid level of the battery 10 detected by 6 and the ambient temperature Ta of the battery 10 obtained by the third temperature sensor 6 ″. The ambient temperature Ta and the battery temperature T1 are measured in a state where the electrolyte surface in the battery 10 has an electrolyte surface at the upper limit position 10c located 25 mm from the lower limit position 10b, and 5 mm from the lower limit position 10b. It was performed in two states, the state when set downward.

  As is clear from FIG. 11, there is almost no difference in the temporal change of the ambient temperature Ta regardless of the position of the electrolyte surface. On the other hand, the change in the battery temperature T1 measured at a position where the electrolyte level is lower than the lower limit position 10b is larger than the change in the battery temperature T1 measured in a state where the electrolyte level is at the upper limit position 10c. In the present invention, it is possible to detect the liquid level position of the battery 10 by detecting the variation of the temperature difference (Ta−T1) between the battery temperature T1 and the ambient temperature Ta due to the electrolyte level position.

  In the present embodiment, the position of the electrolyte surface of the battery 10 can be detected by the following method. In the present embodiment, by using the battery temperature T1 and the ambient temperature Ta of the battery 10, the liquid level position can be detected with high accuracy even when the ambient temperature Ta changes.

  As an example of this embodiment, the ambient temperature Ta is measured at predetermined time intervals, and when a temperature increase of a predetermined value or more, for example, a temperature increase of 0.5 ° C./min or more appears in the Ta value, the engine is started. judge. Thereafter, the temperature rise of the battery temperature T1 is calculated while the difference (Ta−T1) between the ambient temperature Ta and the battery temperature T1 at the lower limit position 10b of the electrolyte surface reaches a predetermined temperature difference, for example, a 10 ° C. difference. To do.

  As another example of the present embodiment, the ambient temperature Ta is measured at predetermined time intervals, and the engine is started when a temperature increase of a predetermined value or more, for example, a temperature increase of 0.5 ° C./min or more appears in the Ta value. It is determined that After it is determined that the engine is started, the change in the battery temperature T1 for a predetermined time, for example, 1 minute from the time when the temperature difference (Ta-T1) between the ambient temperature Ta and the battery temperature T1 reaches a predetermined temperature difference, for example, 10 ° C difference. From the speed (temperature T1 / min), the thermal time constant defined in Equation 1 is obtained, and the electrolyte surface position can be detected from this thermal time constant.

  The battery 10 equipped with the battery level detecting device 4 ″ according to the fourth embodiment of the present invention was mounted on a general ordinary passenger car, and a vehicle running test was conducted for two years. During this period, the battery temperature T1 increased. The thermal time constants were obtained in the same vehicle running test, and the electrolyte level dropped to the lower limit position 10b on the 515th day from the start of the test. Shown in

  In FIG. 15, the vertical axis represents the temperature rise (° C.), and the horizontal axis represents the number of days traveled by the vehicle. In FIG. 16, the vertical axis represents the thermal time constant (minutes) and the horizontal axis represents the number of days traveled by the vehicle. As the electrolyte level decreases from the lower limit position, the temperature rise increases rapidly, and the thermal time constant decreases rapidly, so each criterion value is set in advance and compared with this criterion value. Thus, the electrolyte surface position can be detected. Even in the present embodiment, since the electrolyte level is erroneously determined while the engine is stopped, the electrolyte level is determined only during engine operation, and the determination result is retained as a history while the engine is stopped. Needless to say.

  Note that the detection based on the temperature rise amount and the detection based on the thermal time constant may be performed independently or in combination.

  In the fourth embodiment, since the ambient temperature Ta is taken into account, the accuracy of the electrolyte surface position is not lowered even when the ambient temperature Ta changes due to seasonal variations in the outside air temperature, which is preferable.

  In each of the above embodiments, the temperature sensor 6, the second temperature sensor 6 ′, and the third temperature sensor 6 ″ may be any temperature detection element, and therefore, a temperature detection element such as a thermocouple other than the temperature sensor is used. May be.

  Moreover, although the temperature sensor 6 is arrange | positioned in the vicinity of the lower limit position 10b of the electrolyte solution on the outer wall surface of the battery case 10a, the temperature sensor 6 may be additionally arranged between the lower limit position 10b and the upper limit position 10c. In such a case, it is possible to detect which position between the upper limit position 10c and the lower limit position 10b the electrolyte surface is, which is preferable.

  Furthermore, in the lead storage battery for starting, a monoblock type battery in which a plurality of cells are integrated is used, and liquid level management is required for each cell. By providing the temperature sensor 6 'for each cell, it is possible to detect variations in electrolyte between cells, which is more preferable.

  Further, in each of the above-described embodiments, as shown in FIG. 4, when the temperature sensor 6 and / or the second temperature sensor 6 ′ are disposed in contact with the surface of the battery case 10a, the temperature sensor 6 and / or the second temperature sensor 6 ′ are arranged. The heat insulating material 7 is arrange | positioned on the side surface which does not contact the battery case 10a of temperature sensor 6 '.

  Since the heat insulating material 7 can measure the battery temperature T1 and / or the battery temperature T2 without being affected by the ambient temperature Ta of the battery 10, the liquid level detection accuracy can be further increased. Further, by disposing an adhesive on the surface of the heat insulating material 7 facing the battery case 10a, the heat insulating material 7 is also used as a member for fixing the temperature sensor 6 and / or the second temperature sensor 6 'to the battery. Can be convenient.

  Further, in each of the above-described embodiments, the thin portion 10d in which the wall thickness of the battery case 10a is thinner than other portions is formed in the temperature sensor 6 and / or the second temperature sensor 6 'of the battery case 10a. be able to. By disposing the temperature sensor 6 and / or the second temperature sensor 6 'in the thin wall portion 10d, the temperature of the electrolyte or the space inside the battery can be measured under conditions that are less susceptible to the influence of the ambient temperature Ta, which is preferable. . In each of the embodiments of the present invention described above, in order to detect the presence or absence of the electrolytic solution at that position based on the difference in heat capacity due to the presence or absence of the electrolytic solution, it is possible to measure the temperature as close to the electrolytic solution as possible. More preferable for accurately detecting the position.

  Furthermore, in the above embodiment, the temperature sensor 6 and / or the second temperature sensor 6 ′ is press-fitted through the sleeve 8 into the battery case 10 a.

  As shown in FIG. 5, after the temperature sensor 6 and / or the second temperature sensor 6 'are inserted into the sleeve 8, the sleeve 8, the temperature sensor 6 and / or the second temperature sensor 6' The space between is filled with resin 9 and sealed.

  The sleeve 8 is press-fitted into a predetermined position of the battery case 10a. According to such a structure, the temperature sensor 6 and / or the second temperature sensor 6 ′ can be fixed in the battery 10, so that the electrolyte in the battery and the temperature of the space are less affected by the ambient temperature. It can be measured under conditions, which is preferable for the purpose of increasing the liquid level detection accuracy.

  In each of the above-described embodiments, the description has been made by comparing the state where the electrolyte is sufficiently present and the state below the lower limit position 10b. However, the determination reference value in each embodiment varies depending on the shape of the battery and how it is mounted on the vehicle. . Therefore, at the beginning of use of the battery 10 (about 1 to 2 months from the start of use), each determination parameter (temperature change (ΔT1), change rate (Δ1T / Δh), temperature difference (ΔT2-T1), A determination reference value can be calculated by obtaining an initial value of the battery temperature T1 (temperature rise, thermal time constant) and multiplying this by a certain coefficient.

  In addition, although the example which mounted | wore the battery 10 with the battery liquid level detection apparatus 4,4 ', 4' 'was shown, of course, it is also possible to install in the position mutually separated.

  Although the temperature sensor 6 is set near the lower limit position of the electrolyte surface on the outer wall surface of the battery case 10a, it is caused by the difference in battery heat capacity between the state where the electrolyte surface is above the lower limit position and the state below the lower limit position. Set in the vicinity of the range where the temperature behavior difference can be detected. Actually, the temperature sensor 6 is arranged at various positions near the lower limit position 10b, and actual temperature measurement is performed, so that the determination reference value of each determination parameter is experimentally determined according to the distance between the temperature sensor 6 and the lower limit position 10b. What is necessary is just to set the position of the temperature sensor 6 in the vicinity of the lower limit position 10b within a range in which a decrease in the electrolyte surface position can be obtained with sufficient detection accuracy.

  In addition, although the example which provided the temperature sensor 6 and 2nd temperature sensor 6 'in the outer wall of the battery case 10a was shown, for example, as shown in FIG. 17, it is a hollow cylinder from the lid | cover 10e which covers the battery case 10a. The temperature sensor 6 may be disposed in the cylinder portion 10f after the portion 10f is provided in a hanging manner and the cylinder portion 10f is positioned in the vicinity of the lower limit position 10b of the electrolyte surface.

  Similarly, for the second temperature sensor 6 ', a hollow second cylindrical portion 10f' is suspended from the lid 10e, and the second temperature sensor 6 'is provided in the second cylindrical portion 10f'. May be arranged.

  As described above, according to the present invention, the present invention provides a low-cost and accurate liquid level detection device for an electrolyte solution of a lead battery, without significantly changing the internal structure of the lead battery, and the liquid level detection device. It is possible to provide a lead battery provided with a remarkable effect.

  The present invention can be applied to the liquid level detection of various lead batteries including a lead storage battery for starting.

The figure which shows the liquid level detection apparatus for batteries of this invention The figure which shows the liquid level detection apparatus of the other battery of this invention. The figure which shows the liquid level detection apparatus of the other battery of this invention. The figure which shows the arrangement state of the battery case and the temperature sensor The figure which shows the other arrangement state of a battery case and a temperature sensor The figure which shows the state which mounted | wore the battery with the liquid level detection apparatus for batteries of this invention. The figure which shows the state which mounted | wore the battery with the liquid level detection apparatus for other batteries of this invention. The figure which shows the state which mounted | wore the battery with the liquid level detection apparatus for other batteries of this invention. The figure which shows an example of the time-dependent change of the battery temperature at the time of engine starting The figure which shows another example of the time-dependent change of the battery temperature at the time of engine starting The figure which shows another example of the time-dependent change of the battery temperature at the time of engine starting The figure which shows the battery temperature change in the vehicle running test The figure which shows the battery temperature change speed in the vehicle running test The figure which shows the difference by the measurement part of the battery temperature in the vehicle running test The figure which shows the change of the temperature rise parameter of the battery in the vehicle running test Diagram showing change in thermal time constant in vehicle running test The figure which shows the state which has arrange | positioned the temperature sensor and the 2nd temperature sensor to the lid | cover.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positive connection terminal 2 Negative connection terminal 3 Connection lead wire 4,4 ', 4 "Battery level detection apparatus 5 LED display part 6 Temperature sensor 6' 2nd temperature sensor 6" 3rd temperature sensor 7 Thermal insulation 8 Sleeve 9 Resin 10 Battery 10a Battery case 10b Lower limit position 10c Upper limit position 10d Thin portion 10e Lid 10f Tube portion 10f ′ Second tube portion

Claims (10)

A device for detecting a liquid level of an electrolyte solution in a battery case for a battery for starting an engine of a vehicle, a temperature sensor disposed near a lower limit position of the liquid level, and temperature information obtained by the temperature sensor over time A battery level detecting device having means for storing in the battery. The liquid level detection device for a battery according to claim 1, wherein the temperature information includes a temperature change rate. The temperature information obtained at the beginning of battery use is stored as a reference value, and the change in the liquid level is detected by comparing the temperature information measured sequentially with the reference value. Battery level detector. The liquid level detection device for a battery according to claim 1, further comprising a second temperature sensor disposed in a portion above the upper limit position of the liquid level in addition to the temperature sensor. The liquid level detection device for a battery according to claim 1, further comprising a third temperature sensor that measures a temperature in the vicinity of the battery in addition to the temperature sensor. The liquid level detection device for a battery according to claim 1, wherein a heat insulating material is disposed on a side surface of the temperature sensor and / or the second temperature sensor that does not contact the battery case. The liquid level detection device for a battery according to claim 1, wherein a thermal time constant is used as the temperature information. A battery comprising the battery liquid level detection device according to claim 1. The battery according to claim 8, wherein a thin wall portion having a thinner wall thickness than other portions is formed in a portion of the battery case where the temperature sensor and / or the second temperature sensor is disposed. The thin-walled portion of the battery case is easily broken by press-fitting the temperature sensor and / or the second temperature sensor, and sealing of the electrolytic solution is achieved by press-contact with the temperature sensor. Battery.

Images