JPS6110452Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a battery charging device.

In rapid charging of batteries, it is necessary to detect a predetermined state of charge of the battery to be charged in order to prevent overcharging, and conventionally there are methods for detecting the voltage of the battery, methods for detecting increased temperature, etc.

The voltage detection method is a method for detecting battery voltage, but it is difficult to set a detection voltage close to full charge due to variations in battery manufacturing, and it generally has the disadvantage that the battery cannot be sufficiently charged. On the other hand, the battery temperature detection method is able to ensure the amount of charge of the battery because the battery temperature starts to rise near full charge, and in conventional devices, a thermostat or heat-sensitive resistance element is thermally coupled to the battery to be charged. .

However, the conventional device simply detects the battery temperature, and since the battery temperature is affected by the ambient temperature, the range of ambient temperatures in which the charging device can be used is narrow. It is also possible to correct the battery temperature detection based on the ambient temperature, but in conventional devices, both the battery temperature detection element and the ambient temperature detection element for correction are housed in the power supply box together with the battery to be charged. However, there are disadvantages in that the battery to be charged cannot be removed and used, and it is difficult to thermally separate the two detection elements.

The present invention has been devised in view of these points, and one embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a battery charging circuit diagram, where A is a charger and B is a battery body. Charger A is configured as follows. That is, the secondary coil N _{2 of the drop-down transformer T whose primary coil N 1 is} connected to the commercial power supply terminal has an intermediate tap P ₀ , which is connected to the negative line.
L ₁ and both ends of the secondary coil N ₂ are connected to a diode D ₁ ,
are respectively connected to the positive line _L2 via _D2 . A diode forming a trickle charging path is connected to the positive line.
A first transistor Q ₁ is inserted in which a series circuit of D ₃ and a resistor R ₁ are connected in parallel, and the emitter and collector of a second transistor Q ₂ are inserted between the base and collector of the first transistor Q _{1 .} The base is connected to the positive line L ₂ through a resistor R ₂ as well as a diode D ₄ and a silicon-controlled rectifier (hereinafter
Negative line L ₁ through a series circuit of S (referred to as SCR)
connected to. A start switch SW and a charging display element _D2 are connected between both ends of SCR (S),
Further, a capacitor _C1 for maintaining continuity of the SCR is connected in parallel via a resistor _R3 , and the capacitor is charged via a diode _D6 . Between the gate and cathode of the SCR (S) is a correction heat-sensitive element that corrects the detected temperature of heat-sensitive element Th ₁ , which will be described later, according to the ambient temperature.
A negative characteristic resistance element as Th ₂ and a malfunction prevention capacitor C ₂ are connected in parallel. Charger A has the first terminal P ₁ connected to the positive line L ₂ and the negative line
It has a second terminal P ₂ connected to L ₁ and a third terminal P ₃ connected to the gate of SCR(S).

On the other hand, the battery body B has a detection heat-sensitive element that detects the temperature rise of the charged battery Ba and the outer can of the battery.
Th ₁ and has fourth to sixth terminals P 4 to _{P 6} connected to first to third terminals P ₁ to P ₃ , _respectively . The detection thermosensitive element Th ₁ is connected between the sixth terminal P ₆ and the positive electrode of the battery Ba, and is composed of a negative characteristic low pore element.

In the above charging circuit, the start switch SW
By temporarily closing the SCR (S), the SCR (S) enters the cut-off state, lights up the charging display element _D5 , and conducts the first and second transistors _Q1 and _Q2 , so that the battery Ba receives a charging current of, for example, 1c. will be charged quickly. When battery Ba reaches a fully charged state, the battery
As the temperature of the exterior can of Ba rises, the resistance value of the negative characteristic low pore element as the detection thermosensitive element Th ₁ decreases, and the gate potential of SCR (S) decreases in relation to the resistance value of the correction thermosensitive element Th ₂ . It rises and conducts ignition of SCR (S). Therefore, the first and second transistors Q ₁ and Q ₂ are cut off, the large charging current to the battery Ba is cut off, and a trickle charging current flows thereafter. The SCR (S) is maintained in a conductive state by the charge of the capacitor _C1 , and the completion of charging is indicated by turning off the charging display element _D2 .

Next, Fig. 2 is a perspective view of the battery body B. The battery to be charged Ba is composed of NiCd batteries, and consists of two rows of unit cells (X) and (Y), with a total of eight cells, four in each row. Unit cells are connected in series, and the exterior case 1 of one unit cell is exposed. The outer can 1 is normally covered with a paper tube 2 for insulation, but a part of the outer can 1 is exposed so that the detection heat-sensitive element Th ₁ is closely attached. The detection heat-sensitive element Th ₁ is wound and fixed with an aluminum tape 3 and positioned in the valley 4 formed between the cell rows (X) and (Y), and the heat-sensitive element Th ₁ does not protrude from the valley 4. It is installed as follows. In this state, it is housed in a battery case 5 shown by two-dot chain lines, and the three lead wires 6 to 8 are connected to a socket (not shown).

The NiCd battery serving as the battery to be charged Ba is constructed so that the temperature of the outer can rapidly rises due to the charging chemical reaction. Generally, when charging a NiCd battery, before it is fully charged, a chemical reaction occurs at the anode: Ni(OH) ₂ +OH ^- →NiOOH+H ₂ O+ ^e -cathode: Cd(OH) ₂ +2e ^- →Cd+20H ^- . is an endothermic reaction, and the temperature of the battery case 1 hardly rises.

On the other hand, near full charge, anode: 40H ^- → C ₂ + 2H ₂ O + 4e ^- cathode: A chemical reaction occurs. The above equation on the cathode side of this reaction corresponds to the combustion reaction of Cd, which generates heat and increases the battery temperature.

However, in the conventional battery structure, the heat generation is generated substantially uniformly within the battery, so it takes time for the temperature of the battery case to rise. As a result, the amount of gas generated within the battery increases and the pressure becomes abnormally high, causing the safety valve to operate, but the gas escapes through the safety valve, causing deterioration of the battery.

Therefore, as the battery to be charged in the present invention, a battery is used in which the temperature of the outer can increases rapidly due to a charging chemical reaction. An example of a specific structure of such a battery will be explained based on FIG. 3. This figure is a cross-sectional view of a spiral electrode body as the internal structure of a battery. In this figure, 11 is a main separator, and an auxiliary separator 12 is attached to the central part of the separator, an anode plate 13 is a sintered nickel substrate filled with nickel hydroxide, and a sintered nickel substrate is filled with cadmium hydroxide. A separator 1 is placed between the cathode plate 14
1 or 11 and 12 are wound to form a spiral electrode body. In this case, since the separator is doubled at the center, the gas permeability of the separator is worse than that at the outer periphery, and the above-mentioned charging chemical reaction becomes active at the outer periphery, causing a rapid temperature rise in the outer can. become. In Fig. 3, the separator has a double structure in order to reduce the gas permeability in the center of the separator. It may be crushed.

As described above, according to the present invention, since the battery body having the detection heat-sensitive element for detecting the temperature rise of the battery to be charged and the outer case of the battery is provided separately from the charger connected to the battery body, The battery body can be used separately from the charger, and the detection heat-sensitive element is always in close contact with the battery to be charged, so when connecting the battery body to the charger, the detection heat-sensitive element and the battery to be charged are The relationship can be kept constant and variations in detection can be eliminated. In addition, since the charger is equipped with a correction heat-sensitive element that corrects the detected temperature of the detection heat-sensitive element according to the ambient temperature, it is possible to expand the operating temperature range of the detection heat-sensitive element and thermally separate the two heat-sensitive elements. Therefore, it is possible to accurately detect the temperature rise of the exterior can of the battery to be charged in accordance with the ambient temperature. In addition, since the battery to be charged is a battery whose temperature in the outer can increases rapidly due to a charging chemical reaction, the temperature of the outer can can be easily detected and there is no delay in detection, which prevents deterioration of the battery to be charged. .

[Brief explanation of the drawing]

The drawings show an embodiment of the charging device according to the present invention, in which FIG. 1 is a charging circuit diagram, FIG. 2 is a perspective view of a battery body, and FIG. 3 is a cross-sectional view of a spiral electrode body of a battery to be charged. Ba...Battery to be charged, 1...Exterior can, Th ₁ ...Thermosensitive element for detection, B...Battery body, A...Charger, 1
4... Cathode plate, 13... Anode plate, 12... Separator, Th ₂ ... Heat-sensitive element for correction.

Claims (1)

[Scope of utility model registration request] It consists of a battery body having a detection heat-sensitive element for detecting the temperature increase of the battery to be charged and the outer case of the battery, and a charger for charging the battery body, and the battery to be charged has a spiral cathode plate and a spiral cathode plate. , a separator located between the two electrode plates and having gas permeability at the center side worse than that at the outer periphery, and the charger includes a correction device for correcting the temperature detected by the heat-sensitive element according to the ambient temperature. A battery charging device comprising a heat-sensitive element for controlling charging of the battery by detecting a relative temperature rise value of the exterior can.