NL1018691C2 - Battery has closed housing in which are one or more cells which have spaced, opposing metal plates between which is electrolyte solution - Google Patents

Abstract

The battery (10) has a closed housing (2) in which are >=1 cells, which have spaced, opposing metal plates (3-9), between which is an electrolyte solution. The battery is provided with ventilation devices for feeding in and out gases. The ventilation devices comprise tubular membrane (11,12) running inside housing. The membrane is permeable to battery gases from outside of housing to inside. Similarly, the membrane is impermeable from the outside to the inside of the housing to electrolyte solution. The membrane is inert in relation to the electrolyte solution but chemically resistant to it. It is located preferably above the electrolyte solution.

Description

Battery vent

The present invention relates to a battery, comprising a substantially closed housing with one or more battery cells therein, wherein the battery cells are of the type comprising two metal plates spaced opposite to each other with an electrolyte solution between the metal plates, the battery is provided with ventilation means for discharging battery gases and / or admitting gases from the house to the environment outside the house, for example in the event of a temperature drop.

Such batteries are generally known and are for instance used on a large scale in cars. Usually, lead plates are used which are contained in a hydrochloric acid solution. At the top of the battery, a cap is usually provided per cell in which one or more passages are formed for venting or aeration. As is known, the chemical processes occurring during the charging or discharging of the battery release gases, so-called battery gases. With many batteries it is desirable to remove these gases from the battery housing in order to prevent overpressure in the battery housing and sometimes also accumulation of explosive gases and / or gas mixtures. As further known, variants of such batteries are also known in which metal plates of a metal other than lead and / or of a specific metal alloy are used, as well as in which other electrolyte solutions than sulfuric acid solutions are used. When a battery of the type described above with a vent, which will generally be provided at the top, lies at the top or bottom, the battery will leak through the vent holes. This is undesirable in view of the highly aggressive electrolyte solution contained in the battery. This not only results in environmental problems, but also in dangerous situations. In the case of a car that has been knocked over, it is conceivable, for example, that leaking electrolyte solution comes into contact with, for example, parts of the car's wiring, eats up this wiring and subsequently causes a fire due to a short circuit. In the case of an electric wheelchair, there is a risk that the patient will come into contact with corrosive acid when the battery is leaking. Another important disadvantage is that with a battery standing on the head or side it is no longer possible to discharge gases. This results in pressure build-up, with all the associated dangers. The leakage through vent holes in usually the individual caps or central drain of a battery can be prevented by providing a membrane in 1018691 '' * 2 that is permeable to so-called battery gases and impermeable to the electrolyte solution. However, an important disadvantage of such a solution is that the venting capacity leaves much to be desired.

The present invention has for its object to provide an improved battery of the type indicated at the outset, which battery can be used for cars and other vehicles, for example, and which battery is in particular provided with ventilation means that leak the battery through the prevent ventilation means, preferably completely or at least for a certain period of time.

According to the invention, the aforementioned object can be achieved in that the ventilation means comprise a tubular membrane extending into the interior of the housing, in particular a hollow fiber membrane, which tubular membrane has an exterior facing the interior of the housing and one of the interior of the housing. the inside of the housing is remote, connected to the environment outside the housing, the tubular membrane being permeable from the outside to the inside thereof for the battery gases. With such a tubular membrane, the membrane surface through which the battery gases can be passed through is considerably increased. Thus, the venting capacity increases considerably. Moreover, the tubular membrane can be guided through the interior of the battery in such a way that at any position of the battery at least a part of the membrane comes into contact with the gas phase. This guarantees a free gas outflow.

If the tube-like membrane is placed in the housing of the battery in such a way that under normal circumstances it does not come into contact with the electrolyte solution and, moreover, the inner diameter of the tube-like membrane is sufficiently small, then it is possibly conceivable that this tube-like membrane of the is that for the electrolyte solution it is still permeable. Namely, when the electrolyte solution has penetrated through the membrane wall and is in the interior of the tubular membrane, this will still be prevented from flowing freely and quickly outside the battery housing due to the resistance experienced by the small internal diameter. It will be clear, however, that according to the invention it is preferable if the tubular membrane is impermeable, at least substantially impermeable, from the outside to the inside for the electrolyte solution. A possible leakage via the tubular membrane is thus limited to a minimum, if not completely excluded.

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In order to ensure a long service life of the tubular membrane, it is preferred according to the invention if the tubular membrane is inert with respect to battery gas, or is at least chemically resistant to battery gas.

Since the electrolyte solution used in batteries of the type to which the present invention relates is generally a solution of a strong acid, it is of great advantage in view of the required leakproofness if the tubular membrane is inert with respect to the electrolyte solution, at least chemically resistant to the electrolyte solution. It is thus ensured that the tubular membrane does not dissolve in the electrolyte solution or that the electrolyte solution accidentally passes through and can thus form a source of leakage. Chemically resistant to the electrolyte solution is herein understood to mean in particular that the tubular membrane can withstand the electrolyte solution for at least a few hours, such as for example one or two hours.

According to an advantageous embodiment of the invention, the tubular membrane extends at least partly through the electrolyte solution. This means in particular that the tubular membrane passes through the electrolyte solution under normal conditions of use or placement of the battery. The advantage of this is that the battery gases to be discharged from the battery then do not first have to separate from the electrolyte solution before it can be discharged. These battery gases can pass directly from the electrolyte solution through the tubular membrane to the interior of the tubular membrane and then be discharged from the battery housing via the interior of the tubular membrane. It thus becomes theoretically possible to completely fill the interior of the battery housing with electrolyte solution.

In order to increase the venting capacity of the tubular membrane, it is preferred according to the invention if the tubular membrane is at least partially, preferably entirely, above the electrolyte solution. It is thus achieved that the contact between the tubular membrane and the battery gases to be discharged via the tubular membrane is as intense as possible.

In order for the tubular membrane itself to remain in position in the interior of the housing, it is preferred according to the invention if the tubular membrane runs loop-like in the interior of the housing. Namely, the tubular membrane will be bent against a spring force for the purpose of lying in loop form, which spring force keeps the loop in shape and thus, of course, naturally holds the tubular membrane in place to a reasonable extent.

According to the invention, it is possible both for one of the ends of the tubular membrane to open on the outside of the housing and for both ends of the tubular membrane to open on the outside of the housing. The ends of the tubular membrane can hereby protrude through the wall of the housing. Thus, so-called battery caps, at least as regards venting, can be omitted altogether. A further advantage is that insofar as the battery caps are still desired, the tubular membrane can be kept away from the passages for the purpose of the battery caps and thus the tubular membrane is shielded against possible external influences that the tubular membrane could to damage. The insertion of a fiber end through the wall can also be realized by using a separate insert, so that the screw caps can be opened and closed without damaging the membrane.

However, the tubular membrane according to the invention can also protrude through one or both so-called battery caps with one or both ends.

The tubular membrane to be used with the battery according to the invention can be made of any suitable material. Those of ordinary skill in the field of tubular membranes will readily realize from which materials such tubular membranes can be made when they are to be used in the environment of a battery determined by the metal plates and the electrolyte solution. Such tubular membranes can be made from, inter alia, polypropylene (PP), polyethylene (PE), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and polysulfone (PSU). Tubular membranes made from such materials may optionally also be provided with a coating. With regard to the resistance to chemical action, PTFE is the preferred membrane material. Tubular membranes of PE and PP are preferred from a cost point of view. It will further be clear to a person skilled in the art that the tube-like membranes to be used with the battery according to the invention can have relatively different diameters. For example, the tubular membranes in an accumulator according to the invention may have an internal diameter of 0.05 to 1 mm (so-called hollow fiber membranes), but the inner diameter may also be greater than 1 mm, for example up to 2 to 4 mm (so-called 1 L ic.

5 capillary membranes) or possibly even larger (so-called tube membranes).

With regard to tubular membranes which can be used with the battery according to the invention, reference can be made in the foregoing connection to, for example, the applicant's PCT application WO 97/02883.

In addition to tubular membranes of a plastic material, it will be clear to a person skilled in the art that with a battery according to the invention tubular membranes of other materials, such as ceramic material (such as silica, alumina, titania, zeolite, or composites thereof) or carbon, can also be used. to be.

Among tubular membranes, the invention has in particular one or more of the following properties: the wall thickness is in the range of 0.01 to 1 mm, the porosity value is in the range of 10% to 90%, and the pore size is in the range of 0.1 to 5 µm.

The present invention will be explained in more detail below with reference to the exemplary embodiments shown in the drawing, the invention.

15 Herein shows:

FIG. 1 is a schematic, perspective, partly cut-away view of a battery according to a first embodiment of the invention;

FIG. 2 is a schematic, longitudinal sectional view of a battery according to a second embodiment of the invention; FIG. 3 is a schematic, longitudinal sectional view of a battery according to a third embodiment of the invention;

FIG. 4 is a schematic, perspective, partly cut-away view of a battery according to a fourth embodiment of the invention; and

FIG. 5 as a detail, a schematic cross-sectional view of a battery cap attachment 25 with puncture for a hollow fiber membrane.

In the FIG. 1, 2 and 3 the same reference numbers are used for identical parts.

FIG. 1 shows a battery 10 according to a first embodiment, FIG. 2 shows a battery 20 according to a second embodiment, FIG. 3 shows a battery 30 according to a third embodiment, and FIG. 4 shows a battery according to a fourth embodiment. In the FIG. 1,2 3 and 4 is indicated by 2 as a substantially closed housing, by 3,4,5,6,7, 8 and 9 are indicated the lead plates, by 1 is designated the so-called battery caps through which one accesses the interior of the housing 2, for example 1 for filling up so-called demineralized water, the liquid level of the electrolyte solution is indicated with 17 (only shown in Figs. 2 and 3) and is with 18 (only Figs. 2 and 3) indicate the electrolyte solution. With regard to FIG. 1 and 4 it should be noted that neither the liquid level of the electrolyte solution nor the electrolyte solution itself are indicated herein, mainly for the sake of clarity. The liquid level of the electrolyte solution in the battery 10 according to the invention will be above the upper edges 22 of the metal plates 3-9 and, in the shown position of embodiment according to Fig. 4, will preferably be just above the lead plate 9, as it is in Fig. 3. case.

In the following, successively, FIG. 1,2 3 and 4 are entered separately.

FIG. 1 shows a more or less conventional battery. Two tubular membranes, in particular hollow fiber membranes, 11 and 12 extend above the upper edges 22 of the metal plates 3-9. These tubular membranes 11 and 12 extend from the left-hand side wall to the opposite right-hand side wall. With their ends 13 and 14, the tubular membranes 11 and 12 protrude through both the right and the left side wall. The tubular membranes 11 and 12 preferably extend above the position shown in FIG. 1 fluid level of the electrolyte solution not indicated. However, it is also very conceivable that both tubular membranes 11 and 12 extend below the liquid level of the electrolyte solution through the electrolyte solution or that one tubular membrane 11 (or 12) extends below the liquid level of the electrolyte solution through the electrolyte solution and the other tubular membrane 12 (or 11) extends above the liquid level of the electrolyte solution. It will be clear that a battery 10 according to FIG. 1 may also contain more, for example a bundle fiber, or fewer tubular membranes than in FIG. 1 are shown. It is also possible that the tube-like membranes 11,12 only protrude through one side wall, in which case the tube-like membranes 11 and 12 at the opposite other side wall can be mutually connected via a bend into one tube-like membrane.

The battery 20 according to FIG. 2 differs mainly from the battery 10 according to FIG. 1 in that the tubular membranes 11 and 12 have been replaced by a tubular membrane 16 which lies as a loop above the liquid level 17 of the electrolyte solution 18 and whose ends protrude through bore-fitted 1, 1, 7 battery caps 15 for this purpose. For the rest, the battery caps 15 broadly correspond to the battery caps 1.

The battery 30 according to FIG. 3 differs from that according to FIG. 2 essentially on two points. The first point of distinction is the position of the battery 30. The second point of distinction is that the tubular membrane 19 with its two ends projects through one and the same battery cap 21. To this end, the battery cap 21 is provided with two bores and, for the rest, roughly the same as the battery caps 1. The battery cap 21 may, for example, be discussed in accordance with the further description. 5 have been carried out. As a result of the vertical position of the accumulator 30 versus the horizontal position of the accumulator 20, the tubular membrane 19, which otherwise runs in the same region of the accumulator as the tubular membrane 16, extends for the most part through the electrolyte solution and only with a small part, namely the bend part 23, through the battery gas-containing space 24. It will be clear that the battery 20 according to FIG. 2 can be placed in a vertical position without any modification to the battery 20, other than that the amount of electrolyte solution contained in the battery may have to be supplemented in order to prevent the upper battery plate 9 or 3 from becoming dry . The battery 10 according to FIG. 1 if desired, place itself in a vertical position instead of the horizontal position shown.

The battery 40 according to FIG. 4 differs from that according to FIG. 3 essentially at a point, namely the manner in which the tubular membrane 41 passes through the battery 40. This tubular membrane is arranged to run along the edges of two side faces of the battery in such a way that, both in the position shown and in a position on the rear face 43 remote from the open front face shown, a very large part, namely along the then upper face portion of the tubular membrane above the liquid level. It will be clear that the tubular membrane 41 can also be provided in such a way that it runs along the edges of the rear surface 43 and bottom surface 44 in a corresponding manner. In order to achieve the latter, a second tubular membrane with a course which is mirrored relative to membrane 41 can also be provided.

The batteries 10, 30 and 40 have in common that the tubular membrane 11, 12, 16 and 19 is permeable to the gases occurring in a battery. The tubular membrane 19 of the battery 30 must moreover be impermeable to the electrolyte solution used in the battery and also inert to that solution. If it is also desired to be able to use the batteries 10 and 20 in a vertical position of use (instead of the shown horizontal position of use), then the tubular membranes 11, 12 and 16 for the electrolyte solution will also have to be impermeable and with regard to the electrolyte solution should be inert.

The tubular membranes 11, 12, 16 and 19 will pass through the so-called battery gases, so that these so-called battery gases end up in the interior of the tubular membranes and can then be discharged outside the battery housing 2 via the interior of the tubular membranes. With the battery 10 this will be done via the opposite ends of the tubular membranes 11 and 12 projecting through the opposite side walls, and with the battery 20 this will be via the ends of the tubular membrane protruding through the battery caps 15 16 and at the battery 30 this will be via the ends of the tubular membrane 19 protruding through the battery cap 21, in particular the tubular membrane 19, but preferably also the tubular membranes 11, 12 and 16 are capable of also allowing the battery gases from the electrolyte solution through.

FIG. 5 shows a battery cap 21 as shown in FIG. 3 and 4 as well as FIG. 1 and 2 could be applied. The battery cap 21 is, as it were, composed of two concentric parts, namely 51 and 52 which seal onto each other by means of a sealing ring 52. The outer part 53 is fixedly and sealingly attached to the battery cap passage 54. The outer part 53 is provided with a peripheral groove 55 through which the fiber ends 56 protrude. The actual, optionally removable, cap part 51 is sealingly received in the outer part 53 by means of sealing ring 52. The cap part 51 can be fixed by clamping in the outer part 53, but it can also be screwed tightly here, fixed by a snap connection, fixed with a bayonet fastener or otherwise fixed or not detachably herein.

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Claims (13)

1. Battery comprising a substantially closed housing with one or more battery cells therein, wherein the battery cells are of the type comprising two metal plates lying at a distance from each other and having an electrolyte solution between the metal plates, the battery being provided with ventilation means for discharging battery gases or admitting gases from the housing to the environment outside the housing, characterized in that the ventilation means comprise a tubular membrane extending into the interior of the housing, which tubular membrane is facing the interior of the housing has an outer side and an inner side remote from the interior of the housing and connected to the environment outside the housing, the tubular membrane being permeable from the outside to the inside thereof for the battery gases. 2. Battery according to claim 2, characterized in that the tubular membrane is a hollow fiber membrane. 3. Battery as claimed in any of the foregoing claims, characterized in that the tube-like membrane is impermeable, at least substantially impermeable, from the outside to the inside, for the electrolyte solution. 4. Battery according to one of the preceding claims, characterized in that the tubular membrane is inert with respect to the battery gas, or is at least chemically resistant to battery gas. 25 5. Battery according to any one of the preceding claims, characterized in that the tubular membrane is inert with respect to the electrolyte solution, or is chemically resistant to the electrolyte solution. 6. Battery according to one of the preceding claims, characterized in that the tubular membrane passes at least partially through the electrolyte solution. 1018691 Battery according to one of the preceding claims, characterized in that the tubular membrane is at least partially, preferably completely, above the electrolyte solution. A battery according to any one of the preceding claims, characterized in that the tubular membrane runs loop-like in the interior of the housing. 9. Battery according to one of the preceding claims, characterized in that one or both ends of the hollow-fiber membrane open onto the outside of the housing. Battery according to claim 9, characterized in that the one or both ends of the tubular membrane protrude through the wall of the housing. 11. Battery as claimed in any of the foregoing claims, characterized in that the tube-like membrane runs in the interior of the battery in such a manner that at least the position of the battery comes into contact with at least part of the tube-like membrane with the gas phase in the battery. 12. Battery as claimed in any of the claims 8-10, characterized in that the housing is provided with one or more, preferably one per cell, caps, and in that one or both ends of the tubular membrane are passed through a respective insert one of those caps or insert each through a different cap. 1 Q1 c "