JPH0347249Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a secondary battery for a vehicle, and particularly to an improved secondary battery for a vehicle that is installed in an electric vehicle or the like that is charged while the vehicle is stopped.

[Prior Art] Conventionally, lead batteries have been mainly used as secondary batteries for vehicles, and iron-nickel batteries, zinc-nickel batteries, etc. are also expected to be used as secondary batteries for electric vehicles.

This type of battery generates electricity due to the potential difference between negative and positive electrode plates. For example, in a lead battery, the following electrochemical changes occur within the battery during charging and discharging.

Cathode Pb + Electrolyte 2H ₂ SO ₄ + Anode PbO ₂ Discharge --→ ← -- Charging Cathode PbSO ₄ + Electrolyte 2H ₂ O + Anode PbSO ₄ Here, sulfuric acid (H ₂ SO ₄ ) generated during charging
has a high specific gravity and settles at the bottom of the battery container, resulting in an extremely large difference in the concentration of sulfuric acid between the electrolyte at the top and bottom of the battery container, resulting in a decrease in the electrical capacity of the secondary battery, a shortened lifespan, and a deterioration in charging/discharging efficiency. This causes various problems that reduce the performance of secondary batteries.

Since such non-uniformity of electrolyte concentration within the battery container cannot be resolved by vibrations alone during vehicle operation, a method has been devised in which the electrolyte is forcibly circulated using a pump, etc.; The disadvantage is that the device is complicated and expensive, and energy is consumed to drive the pump.

Therefore, the inventor of the present invention devised a storage battery in which an auxiliary chamber is provided in the battery container, and the electrolyte inside the bean tank is circulated through this auxiliary chamber during vehicle operation (Utility Application 188325-1985), which is cost effective. It has been shown to be effective in improving the performance of secondary batteries without increasing the

However, even in such an improved secondary battery, there is a drawback that the charging efficiency is not very good when charging is performed during a vehicle power outage, such as when used as a battery for an electric vehicle.
This is because when charging while the vehicle is stopped, the electrolyte in the subchamber is not used effectively, and as the sulfuric acid concentration increases, the electromotive force of the battery increases, so the charging speed is lower than that of the electrode plate. is inversely proportional to the sulfuric acid concentration. Conventional secondary batteries have had a problem in that sulfuric acid generated during charging stays around the lower part of the electrode plate, increasing the sulfuric acid concentration and reducing the charging efficiency at the lower part of the electrode plate.

[Purpose of the invention] The present invention was devised in view of the above-mentioned conventional problems, and its purpose is to solve the problem without increasing the cost.
The objective is to improve the performance of secondary batteries, especially the charging efficiency when the vehicle is stopped.

[Structure of the invention] In order to achieve the above object, the present invention provides a secondary battery for a vehicle that includes an electrolyte in a battery case and an electrode plate immersed in the electrolyte. A frame is provided between the bottom of the tank and the space formed by the electrode plate and the bottom and sides of the tank, and the frame is provided with a through hole, into which the electrolyte can be poured either. A feature is that a check valve that allows passage in only one direction is provided, and the electrolytic solution at the bottom of the battery container can be moved only in one direction determined by the check valve.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 is a longitudinal sectional view of a secondary battery for a vehicle according to an embodiment of the present invention, and FIG. 2 is a side sectional view thereof.

In the figure, an electrode plate 14 is installed inside a battery case 12 of a secondary battery 10, and as shown in FIG.
It is constructed by alternately disposing positive electrode plates and negative electrode plates on both sides of the electrode.

A feature of the present invention is that an electrolyte reservoir is provided at the bottom of the battery case to temporarily store the electrolyte with high electrolyte concentration generated during charging. is electrode plate 1
5 between the bottom of the battery case 12 and the bottom of the battery case 12 relative to the vertical side of the electrode plate.
By installing a frame 22 with a height of about 30%, a gap is provided between the bottom of the electrode plate 14 and the bottom of the battery case 12, thereby forming an electrolyte reservoir 20.

Furthermore, the present invention is characterized in that the electrolyte with high electrolyte concentration stored in the electrolyte storage section 20 during charging is circulated by vibrations during vehicle operation, thereby making the electrolyte concentration uniform. For this purpose, the electrolytic solution reservoir 20 is provided with a check valve that allows the electrolytic solution to move in only one direction, but in this embodiment, the electrode plate 14
And the frame 22 is closely held between the battery case 12, and the frame 2 is
2 is provided with a check valve 24 consisting of a reed valve, and the electrolytic solution is moved in only one direction as indicated by arrow A in FIG. Note that in this embodiment, the frame 22 can also serve as a support for the electrode plate 14.

In addition, in this embodiment, in order to restrict the movement of the electrolyte in the upper part of the battery case 12 and increase the effect of electrolyte circulation, electrodes are provided at both ends of the upper part of the electrode plate 14, which are approximately equal in width to the inner wall of the battery case 12. A partition plate 26 is provided with a height that slightly projects from the top of the plate 14 to the surface of the electrolyte.

The secondary battery according to this embodiment is constructed as described above, and its operation will be explained below.

In the figure, when the secondary battery 10 is charged, the active material constituting each electrode plate is deposited on the cathode and anode of the electrode plate 14, and an electrolyte (sulfuric acid in the case of a lead battery) is generated and released into the electrolytic solution. Therefore, the electrolyte concentration of the electrolyte around the electrode plate becomes high, but the specific gravity of the electrolyte with a high electrolyte concentration is higher than that of an electrolyte with a low electrolyte concentration.
4 and the battery container 12 and settle to the bottom. In the present invention, since the electrolyte reservoir 20 is provided at the bottom of the container, the electrolyte with high electrolyte concentration is stored in the electrode plate 14.
As the high electrolyte concentration electrolyte settles, it is stored in the electrolyte reservoir 20 without stagnation in the surroundings, and the electrode plate 14
During charging, an electrolytic solution with a relatively high electrolyte concentration always faces the battery. Therefore, as shown in Fig. 3, the charging voltage of the conventional battery increases significantly in about 3.5 hours as shown in the charging curve a, and the charging efficiency decreases, whereas the secondary battery according to this embodiment As shown in curve b, it takes about 4.5 hours for the charging voltage to increase significantly, indicating that charging efficiency has been improved.

The secondary battery 10 charged as described above is in a discharged state to drive the vehicle drive motor and the like when the vehicle is operated. Here, when driving a vehicle, the secondary battery 1
0 vibrates or is given acceleration, so the electrolyte circulation effect described above is performed. That is, when the secondary battery 10 moves in the B direction, the electrolytic solution tends to move in the A direction with respect to the battery case 12 due to its inertia, so the electrolytic solution in the electrolytic solution reservoir 20 passes through the check valve. 24 is pushed open and the water flows out to the right side of the lower part of the battery case 12. The outflowing electrolyte is gradually pushed upwards by the subsequent electrolyte. At this time,
Since the partition plate 26 is provided above the electrode 14, the movement of the electrolytic solution above the electrode plate 14 is restricted by the partition plate 26, so that movement of the electrolytic solution above the battery container 12 is small. The electrolytic solution with a high electrolyte concentration that has flowed out to the right side of the battery case flows over the partition plate 26 to the upper part of the electrode plate 14 due to vibrations of the vehicle, or leaks between the electrode plates and circulates within the battery case. becomes.

Next, when the secondary battery 10 moves in the direction of arrow A, the electrolyte tends to move relatively in the direction of arrow B, so the check valve 24 is closed and the electrolyte concentration in the electrolyte reservoir 20 is high. Electrolyte does not move.

At this time, the movement of the electrolytic solution is restricted by the partition plate 26 in the upper part of the battery case 12, but the electrolytic solution moves beyond the partition plate 26 in response to movement with a large acceleration.

Therefore, when the vehicle is operated, the vibration or acceleration causes the electrolyte to circulate in the direction of arrow C, and the electrolyte concentration of the electrolyte in the battery container 12 becomes uniform, as shown in FIG. As can be seen, the voltage drop in the discharge curve b' of the secondary battery according to this example is smaller than the discharge curve a' of the conventional secondary battery, and it is understood that the capacity is increased and the discharge efficiency is also increased. be done.

As described above, charging efficiency is increased by always facing the electrolyte with a low electrolyte concentration to the electrode plate during charging, and discharging efficiency is improved by equalizing the electrolyte concentration of the electrolyte during vehicle operation. can.

In this embodiment, the check valve is provided at only one location within the electrolyte reservoir, but it may be provided at two or more locations as shown in FIG. 4 without causing any inconvenience.

Furthermore, the partition plate 26 is not an essential requirement for obtaining the effects of the present invention, and even if the partition plate is not provided as shown in FIG.
Due to the action of the check valve 24 provided in the battery case 12
The electrolytic solution in the lower electrolytic solution reservoir 20 moves to the right in FIG. 4 due to vibrations, etc., and further moves upward along the inner wall of the battery case 12, so that circulation of the electrolytic solution can be achieved.

[Effects of the invention] As explained above, the present invention improves charging efficiency even when charging while the vehicle is stopped by providing an electrolyte reservoir at the bottom of the battery container and providing a check valve in the electrolyte reservoir. This has the effect of being able to improve discharge efficiency during vehicle operation.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a secondary battery for a vehicle according to an embodiment of the present invention, FIG. 2 is a side sectional view of the secondary battery for a vehicle shown in FIG. 1, and FIG. FIG. 4 is a comparative diagram of the charging and discharging efficiency of a secondary battery and a normal secondary battery, and is an explanatory diagram showing another example. 10... Secondary battery, 12... Battery container, 14... Electrode plate, 16... Separation plate, 20... Electrolyte reservoir,
22... Frame, 24... Check valve, 26... Partition plate.

Claims (1)

[Claims for Utility Model Registration] In a secondary battery for a vehicle comprising an electrolytic solution and an electrode plate immersed in the battery case, the above-mentioned A frame is provided to divide the space formed by the electrode plate and the bottom and side parts of the battery case, and the frame is provided with a through hole,
The through hole is provided with a check valve that allows the electrolyte to pass in only one direction, and the electrolyte at the bottom of the battery container can be moved only in one direction determined by the check valve. Secondary batteries for vehicles.