KR20090029704A - Liquid electrolyte battery heating device comprising a mixing device - Google Patents

Abstract

The invention relates to a liquid electrolyte battery heating device comprising a mixing device. A heating element (4) is arranged on the end on the base of the battery housing (1d) and extends in such a manner that the heatable area of the housing base (1d) runs over all of the electrode plates (2). A heat protection plate (5) is arranged above the heating element between the housing base (1d) and the lower edge (2a) of the electrodes (2). Between the perpendicular housing wall below which the heating element is arranged, and the lateral edge of the electrodes (2), a first flow channel plate (6) is arranged, the upper edge thereof (8) being arranged an outlet plate (8). The invention also relates to a dynamic mixing device having the following characteristics; a second flow channel plate (9), whose upper area is embodied as a funnel (11), is arranged on the housing wall below which the heating element is not arranged and the vertical electrode edges. A conductive plate (12) which extends between the housing base (1d) and the lower edges of the electrode (2a) is arranged on the lower edge of the second flow channel plate (9).

Description

LIQUID ELECTROLYTE BATTERY HEATING DEVICE COMPRISING A MIXING DEVICE}

The present invention relates to a liquid electrolyte battery heating device comprising a liquid electrolyte battery and a heating means such as a lead-acid battery, for example, used in motor vehicles as starter batteries. In the liquid electrolyte battery, a mixing device adapted to the heating means is arranged.

In the automotive industry, efforts to lighten the vehicle also include reducing the weight of the battery. At the same time, however, the demand for greater battery capacity also increases, for example, with conventional energy for starting a passenger car, such as a power window lifter, a servo motor for regulating the seat or for heating the seat electrically. Additional energy is also needed. In addition, it is desirable that the battery capacity be kept as high as possible over the life of the battery, since safety-related functional units such as steering and braking are increasingly controlled and operated electrically. Battery capacity refers to the capacity of the battery and the current supply or current consumption of the battery in the following. Battery capacity is affected by several factors known to those skilled in the art.

Various measures are known in the prior art to increase the capacity of liquid electrolyte batteries, such as lead-acid batteries. A particular problem with such batteries is that battery capacity depends heavily on battery temperature. In the acceptable operating range, a capacity reduction of at least about 0.6-0.8% per ° C is expected. For example, to operate the starter of an automobile, assuming that the optimum operating temperature is about 30 ° C. and the battery is operated at minus 20 ° C., the battery has only about 60% of its capacity. Of course, it is known to those skilled in the art that other factors also reduce the capacity of the battery. An important factor is the so-called stratification of the acid. That is, the acid concentration is not uniform with respect to the electrode face. This causes the electrode to corrode at a portion where the acid concentration is too high, thereby shortening the life of the battery, and at the electrode portion where the acid concentration is too low, the total capacity of the battery is not obtained.

It is generally known that an automobile with an internal combustion engine, which has stood for a long time, for example at least 8 hours at a temperature below 0 ° C., can be started well if the cooled battery is heated before starting.

Thus, a number of battery heating devices have been developed, which have different advantages and disadvantages and are described for example in DE 28 12 876, US 2,440,369, DE 1 496 134, DE 40 27 149 A1 or DE 100 14 848.

Battery heating devices can be classified according to different aspects.

One group relates to the heating of batteries by heat exchange. For example, a heat exchanger tube is provided on the outer wall of the battery and the warm engine coolant is guided through the heat exchanger tube.

Electrical heating is also shown, which can be divided into two subgroups.

There are several ways of placing a heating film or similar heating element on the outer wall or on the battery itself and supplying electrical energy from the 220 V main connection in the case of an automobile parked outside, for example in a garage. In this case, sufficient energy is always provided so that the battery can be kept at a predetermined temperature regardless of the external temperature. Likewise, when the car is running, energy can be extracted from the generator.

In the case of the second subgroup, the energy for heating the battery is drawn from this battery itself. This is necessary if the car is stationary on the road and there is no possibility of supplying electrical energy from the outside. It has already been suggested that the battery be thermally well insulated and maintained at the optimum temperature level possible by self heating. This method is preferred only if the car is to be reused after the car has cooled down standing only about 8 to 15 hours. That is, the thermal insulation of the battery must be good enough that the battery can be maintained at a predetermined temperature level by self heating within about 8 to 15 hours.

However, if the car is standing for several days, the energy content of the battery is not sufficient to keep the well insulated battery at the desired temperature. In this case, the battery only needs to be heated until the vehicle is started.

Therefore, it has been much proposed to heat cold batteries just before starting the car. One of the many possibilities for heating the battery quickly is to introduce heat into the battery base.

Therefore, in DE 100 14 848 C2 it is proposed to arrange the battery in a hot plate. In this regard, it does not matter whether the hot plate is a conventional electrically heatable hot plate or whether it is actually an electronic component used for other purposes, such as in DE 100 14 848 C2, which generates waste heat.

The starter battery, like the body of all materials, has a predetermined heat capacity. In order to raise the cold battery to a predetermined temperature level, predetermined thermal energy must be introduced. It is desirable that the battery can be heated in the shortest possible time. This is only possible if the hotplate is heated correspondingly.

However, because heat is distributed only relatively slowly due to the low thermal conduction of the acid, ie only temperature compensation is made slowly, electrode damage can occur at the place where thermal energy is introduced. It is known to those skilled in the art that lead-acid-batteries may be irreversibly damaged even with a short overheat, for example higher than 50 ° C.

Thus, the requirement to heat the battery quickly contradicts the demand that the battery be protected in such a way as to be as safe as possible, i.e. slowly heated. Solving such technical contradictions is a problem of the present invention.

The problem is solved by the liquid electrolyte battery heating apparatus according to claim 1.

In the battery housing the electrodes are arranged vertically. The housing is filled with liquid electrolyte. In the housing base an electric heating rail is arranged on one side according to the invention. The heating rails are arranged to extend at right angles to the electrode plate, which is described in detail with reference to the drawings in the embodiment.

The thermal and dynamic mixing device includes a horizontal heating plate, which is arranged along the heating rail between the housing base and the lower edge of the electrode. The face of the heat protection plate is at least 20% larger than the face of the heating rail in contact with the housing base.

A flow channel plate is disposed between the vertical right housing wall and the right side edge of the electrode so that a right flow channel is formed between the flow channel plate and the right housing wall, and the outer edge of the heat protection plate connects with the lower edge of the flow channel plate. do. The upper edge of the flow channel plate lies within the range of the electrolyte level and connects with the discharge plate extending horizontally with respect to the center of the housing.

A flow channel plate is likewise arranged between the vertical left housing wall and the left side edge of the electrode, thereby forming a left flow channel between the flow channel plate and the left housing wall. The upper region of the flow channel is formed as an overflow funnel. The overflow funnel means an enlargement of the volume of the upper end portion of the flow channel. The upper edge of the overflow funnel protrudes a few millimeters above the electrolyte level, so that the electrolyte spills into the overflow funnel upon movement of the battery in the vehicle, ie during acceleration or braking. Since the level in the flow channel is higher than the level of the electrolyte outside the flow channel, the difference volume flows out from the flow channel downwards, so that the two levels are readjusted according to the principle of the combined vessel. In order to mix the effluent electrolyte with the total electrolyte volume as well as possible, a guide plate is provided for the predetermined guidance of the discharged electrolyte. The guide plate is disposed at the lower edge of the left flow channel plate and extends between the housing base and the lower edge of the electrode plate.

Between the right side of the guide plate, that is, between the inner edge and the left edge of the heat-preventing plate, there remains a flow opening disposed almost in the center of the housing.

The function of the mixing device is described below:

When the heating rail heats the housing base of the battery on the right side, the electrolyte placed thereon is heated by thermal conduction. The electrolyte flows from the right flow channel upwards to the upper edge of the flow channel plate and flows back through the discharge plate back into the electrolyte volume. This results in an electrolyte circulation which leads to good mixing of the electrolyte, thus heating. By this thermal mixing of the electrolyte, no acid stratification occurs. The heat protection plate prevents the hot electrolyte from damaging it by contacting the lower edge of the electrode. If the battery does not move, for example if the car is not running, dynamic electrolyte mixing is not activated. That is, the electrolyte does not spill into the overflow funnel.

However, when the vehicle travels and braking and acceleration movements occur in the vehicle, the dynamic mixing of the electrolyte is achieved. This second mixing function is desirable when the battery temperature is high enough that further heating may be undesirable or even cause damage. Similarly, electrolyte stratification does not occur due to the dynamic mixing of the electrolyte.

It is clear to those skilled in the art that the two mixing functions may appear simultaneously without disturbing each other in flow technology.

According to claims 2 and 3 the discharge plate and the guide plate have holes. This ensures that the electrolyte flowing out of the discharge plate or out of the guide plate is evenly distributed over the electrolyte volume, so that unmixed volume parts are not produced. One skilled in the art can obtain optimum mixing by the selection of geometric parameters of the holes, such as hole size and their placement.

The present invention can be applied to all kinds of liquid electrolyte batteries where good mixing of the electrolytes in summer and winter and rapid heating of the electrolytes should be made in order to improve the capacity of the battery.

Other embodiments and advantages of the invention are set forth in the following description of the embodiments in conjunction with the accompanying drawings.

1 is a side cross-sectional view of a first embodiment of the present invention.

2 is a side sectional view of a second embodiment of the present invention;

3 is a perspective view of an empty battery box according to the prior art;

In the following, for the better understanding of the present invention, prior to the description of the present invention, the prior art of FIG. 3 will be described.

3 shows a battery box with six cells. When the battery box is placed on a heating rail at the edge, each cell is heated at the base on the edge side. All descriptions below relate to only one cell. The cells of FIGS. 1 and 2 are shown from the direction indicated by reference numeral 1c in FIG. 3. Since the individual cells are also independent batteries, only one battery is described below. Of course, the invention can be applied to a combination of individual cells and multiple cells.

1 shows a battery with a housing 1. In the housing 1 a vertical electrode 2 is arranged. The housing is filled with a liquid electrolyte 3, for example an acid.

An electrically heated heating rail 4 is disposed on the right edge of the housing base 1d. This means that the heating rail 4 can be fixed to the battery housing 1 or the heating rail is fixed in the motor vehicle and the battery is placed on the heating rail 4.

The heat preventing plate 5 is disposed in the region of the heating rail 4 under the lower electrode edge 2a. The face of the heat protection plate 5 is in this case 50% larger than the contact face of the housing base of the battery and the heating rail 4. Thus, the hot electrolyte 3 is prevented from contacting the electrode 2 and damaging the electrode. The right flow channel plate 6 is arranged at the outer edge of the heat protection plate 5. The right flow channel plate 6 extends between the vertical right housing wall 1b and the side edges of the electrode 2, thereby forming a right flow channel 7 between the flow channel plate 6 and the housing wall 1b. do. At the upper edge of the flow channel plate 6, a discharge plate 8 is arranged on top of the electrolyte level 3a.

 A dynamic mixing device is provided on the left housing side of the battery, which is described below:

The left flow channel plate 9 is arranged between the vertical housing wall 1 a and the side edges of the electrodes 2, thereby forming the left flow channel 10. An overflow funnel 11 is formed at the upper end portion of the flow channel plate 9. The upper edge of the overflow funnel 11 protrudes a few millimeters above the electrolyte level 3a so that when the battery in the vehicle moves, the electrolyte 3 is spilled into the overflow funnel 11 and spilled upwards of the same size. The electrolyte volume is discharged again at the bottom of the flow channel 10.

In order for the outflow of the electrolyte 3 to take place in the sense of optimum electrolyte mixing, a guide plate 12 is provided. The guide plate 12 is disposed at the lower edge of the flow channel plate 9 and extends between the housing base 1d and the lower edge 2a of the electrode plate 2. A flow opening 13 remains between the right edge of the guide plate 12 and the left edge of the heat protection plate 5.

The function of the mixing device is described below:

When the battery is heated and the electrolyte 3 must be mixed, the heating rail 4 is heated. The energy for the heating rail 4 can be extracted from the battery itself or from an external energy source. The electrolyte volume 3b between the heat preventing plate 5 and the portion 1dt of the housing base 1d heated by the heating rail 4 is first heated by heat conduction. In this embodiment the heating rail 4 is temperature controlled so that the predetermined maximum temperature is not exceeded.

The heated electrolyte 3b flows upwards in the flow channel 7 and flows back through the discharge plate 8 to the center of the electrolyte volume, as indicated by the arrow. This electrolyte circulation allows rapid heat distribution, ie rapid heating of all volume parts of the battery, while at the same time a certain mixing of the electrolyte 3 is achieved to avoid stratification known to those skilled in the art.

If the battery does not need to be heated because the battery is warmed by, for example, a high vapor phase external temperature, the heat mixing device is not switched on. In this case, only dynamic mixing appears, and when the vehicle runs, i.e., during acceleration, a small amount of electrolyte continues to spill into the overflow funnel 1, flows downward and is guided towards the battery center by the guide plate 12. The flow arrows shown indicate the flow direction of the electrolyte.

A particular advantage of the present invention is that both mixing effects can be used simultaneously at low external temperatures, resulting in particularly effective mixing and rapid heating of the electrolyte.

2 shows a variant embodiment of the invention. Holes 14, 15 are provided in the discharge plate 8 and the guide plate 12. The small hole has a hole size of 1 mm and the maximum hole has a hole size of 3 mm. Since the size and distribution of the holes is determined by some experiments, complete and rapid mixing of the electrolyte is achieved. The experiment can be carried out, for example, by a transparent battery box model, where the dye is dissolved in the liquid and it is observed how the dye is distributed after heating of the heating rail and / or upon movement of the battery box. These measures are well known to those skilled in fluid mechanics and will not be described in detail. This embodiment is the most preferred embodiment of the present invention. With reference to the described embodiments, those skilled in the art can fully understand the technical spirit of the present invention. It is clear that the above embodiments can be further developed, modified or combined by those skilled in the art using the idea according to the present invention. Accordingly, other embodiments, not specified or shown, are also included within the scope of protection of the claims.

Claims (3)

A liquid electrolyte battery heating device having a mixing device, wherein the mixing device a. Heating means 4 and b. A liquid electrolyte battery, wherein the liquid electrolyte battery A housing 1 with a housing base 1d, An electrode 2 arranged vertically in the housing 1, A liquid electrolyte 3, and A heating means 4 arranged on the housing base 1d. A liquid electrolyte battery heating device having a mixing device, The heating means 4 are arranged on one side and extend so that the heatable region of the housing base 1d extends at right angles over all the electrode plates 2, A heat mixing device is arranged in the battery housing 1 as follows: A heat prevention plate 5 is arranged on the heating rail 4 between the housing base 1d and the lower edge 2a of the electrode 2, the face of the heat prevention plate 5 being the housing 20% larger than the surface of the heatable area of the base 1d, A first flow channel plate 6 is arranged between the vertical housing wall 1b disposed above the heating means 4 and the side edge of the electrode 2, At the upper edge of the flow channel plate 6 a horizontal discharge plate 8 is arranged above the electrolyte level, the length of the discharge plate being between 25% and 70% of the length of the upper edge of the electrode plate 2; ego, Also A dynamic mixing device is arranged in the battery housing 1 as follows: A second flow channel plate 9 is arranged between the vertical wall edge and the housing wall 1a not arranged above the heating means, the upper region of which is formed as an overflow funnel 10 and the overflow funnel The upper edge of 10 protrudes several millimeters above the electrolyte level 3a so that when the battery in the vehicle moves, the electrolyte 3 spills into the overflow funnel 10, A guide plate 2 is arranged at the lower edge of the second flow channel plate 9, the guide plate 12 extending between the housing base 1d and the electrode lower edge, the right side of the guide plate Liquid electrolyte battery heating device with a mixing device, characterized in that a flow opening (13) remains between the edge and the left edge of the heating plate. A liquid electrolyte battery heating apparatus according to claim 1, wherein said discharge plate has holes (14). The liquid electrolyte battery heating apparatus according to claim 1 or 2, wherein the guide plate has holes (15).

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