JPS60189876A - Specific gravity sensor for lead-acid battery - Google Patents

Abstract

PURPOSE:To continuously and accurately detect specific gravity of electrolyte by forming a specific gravity sensor with two Pb-PbO2 electrode pairs and staggering charging periods so that periods indicating steady voltage of two electrode paris are duplicated. CONSTITUTION:Specific gravity sensors are formed with two lead-lead dioxide electrode pairs. One electrode pair is charged first, then other electrode pair is charged so that part of the final charging period during which polarization of charging of the former electrode pair reaches equilibrium voltage and this voltage is kept is duplicated to the period during which polarization of the latter electrode pair reaches equilibrium voltage. Two electrode pairs are alternately charged and voltage of a electrode pair which reaches equilibrium voltage in advance is measured to detect specific gravity. Therefore, the electrode pair is periodically charged and self-discharge deterioration caused by reaction with electrolyte is eliminated. Moreover, since either one of electrode pairs shows steady voltage, continuous, detection is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting the electrolyte specific gravity of a lead battery, particularly lead (lead)
(hereinafter referred to as Pb) and lead dioxide (hereinafter referred to as Pb).

The aim is to improve the C/C type using a pair of electrodes made of PbO2 (PbO2).

As is well known, the state of charge of a lead battery is expressed in the specific gravity of the electrolyte. Recently, lead-acid batteries have become smaller and have smaller capacities in comparison to the size of the load, but the output of chargers has increased, making it easier to quickly charge batteries when they are discharged. I was able to do it now. Therefore, there is a growing need for a power sensor 9- for detecting the state of charge of a battery and transmitting electricity back to the charger.

Various types of electrode-type sensors have been tried as the above-mentioned specific gravity sensors, which measure the voltage of a pair of electrodes: 1) b electrode and PI) 02 electrode. However, this specific gravity sensor consisting of a pair of electrodes had the following drawbacks.

(1) PbO2 electrode and Pb electrode are 181Ii! If it is left in an acid, it will self-discharge and turn into lead sulfate (Pb SO4) and will no longer show a normal potential after about 111 minutes.

<2) Pb 02 ffi? 4ii'Pb N-pole LiTi<m(D) On the other hand, there is a difference in overvoltage during charging, and even if the voltage of the electrode pair during charging is measured, the error is too large and difficult to use as a specific gravity sensor.

(3-)PbOz electrode or pb electrode, especially PI102
When the electrode is put into a circuit state after charging, it takes a little more than 20 hours for the potential to stabilize, depending on the magnitude of the charging current. Also, the error is large, and the viscosity of the sensor is low.

The present invention eliminates the above-mentioned drawbacks of the conventional pH02 electrode and provides a highly accurate specific gravity sensor capable of continuously detecting the state of charge over a long period of time.

That is, the present invention consists of two pairs of PI) PI) 02 electrodes, and the charging of the other electrode pair is stopped by the end of the period in which the voltage after charging of one electrode pair is stable and specific gravity can be detected. In order to stabilize the voltage after charging, the two electrode pairs are charged at intervals, and the specific gravity detection is alternated during the period when the voltage of each electrode pair is stable. By using a sensor that detects specific gravity alternately with a certain voltage,
This prevents functional deterioration due to self-discharge and enables long-term use.

Next, the principle of the present invention will be explained using figures.

FIG. 1 shows the change in polarization of a specific gravity sensor 115 made of a pb-PbOz electrode pair when it is left unused after being charged. This figure shows p
b and the polarization changes of the PbO2 electrode are also shown [1]. After charging is stopped, the sensor voltage is stable (1111
It can be seen that the reason why the polarization changes over a long period of time until it reaches the (equilibrium voltage value) is due to the slow decay rate of the polarization of the pH02 electrode. This is thought to be due to the microporous nature of the PbO2 electrode, which slows down the diffusion of sulfuric acid into the electrode, and causes the active material to have an unstable non-stoichiometric composition immediately after charging. Therefore, the unstable potential phenomenon of the pb 02 electrode is an essential phenomenon unique to the PI) 02 electrode, and no h method has been found so far that can eliminate this problem in a short time.

The present invention uses two pairs of Pb-PbO2 electrodes, and by staggering the charging periods so that the periods showing stable voltages of both pairs of electrodes overlap, the electrolyte is constantly and continuously charged to the electrolyte by one of the pairs of electrodes. This makes it possible to detect specific gravity. Based on the present invention, two sets of pb-Pb 02
FIG. 2 shows the change in the indicated value of the specific gravity of the electrolyte when the ratio m sensor equipped with the electrode pair was used while being alternately charged. 12
As is clear from the figure, according to the present invention, 311! Subsequently, we were able to accurately detect specific gravity.

Since the present invention is as described above, it has the following features.

(1) Since the ff2 pole pair is regularly charged, there is no self-discharge or deterioration caused by reaction with the LLI solution.

(2) Since either one of the electrode pairs always receives a stable voltage, specific gravity detection can be performed continuously for 3 hours, so there is no time period during which specific gravity cannot be detected.

(3) Since a stable voltage is always used, the state of charge of the battery can be monitored by highly accurate specific gravity detection.

As described above, the present invention provides a clear electrolyte specific gravity sensor for monitoring the state of charge of a lead-acid battery.
Its ISi value is great.

[Brief explanation of drawings]

Figure 1 is a characteristic diagram showing the change in polarization of the l゛)l+ -pl+ Q2 electrode pair while it is left after charging, and Figure 2 is a characteristic diagram of the two pairs of P
I) It is a diagram showing the 11 [transition] of the electrolyte specific gravity indicated value when a specific gravity sensor υ equipped with a pair of PbO2 electrodes is used while being alternately charged. (A mackerel) Spicy

Claims (1)

[Claims] In a specific gravity sensor equipped with two lead-lead dioxide electrode pairs, one electrode pair is charged first, and the polarization after charging reaches an equilibrium voltage value and at the end of the period during which this voltage is maintained; Next, while charging the two electrode pairs alternately, the equilibrium voltage value is first set so that the polarization of the other electrode pair to be charged after charging attenuates and reaches the equilibrium voltage value. Alternating the voltage of the electrode pair reaching 3! A phase ratio sensor for lead batteries that detects specific gravity by measuring the specific gravity.