DE3106203A1 - MULTI-CELL ELECTRIC ACCUMULATOR AND METHOD FOR THE PRODUCTION THEREOF - Google Patents

Description

CHLORIDE GROUP LIMITED February 18, 1981

52 Grosvenor Gardens AL / II / ho

London SW1W OAU K 2011 England

description

Multi-cell electric accumulator and process for its manufacture

The invention relates to electrical storage batteries and particularly, but not exclusively, to lead storage batteries .

The invention relates to accumulators of the so-called "closed" type or with a "recombining means". Included are accumulators in which the amount of electrolyte present is so limited that none free unabsorbed electrolyte is present in the cells, and in which the during operation or the Charge's evolving gases "are allowed to recombine within the accumulator.

It has been shown that in contrast to the traditional Teaching recombination accumulators or batteries that have almost no free, unabsorbed electrolyte in the cells do not necessarily have to be sealed from one another in order to prevent premature accumulator failure due to an ionic intercell leakage "" avoid.

The invention is accordingly based on the object of creating an electrical accumulator that is simple and

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can be produced economically and built up from materials and has good discharge characteristics with strong discharge values.

** The problem outlined above is achieved by the Invention as set forth in the claims.

According to the invention, a multi-cell electrical accumulator comprises a compartmentalized container, the is covered by a lid or a cap and has two or more cells, each alternating contain positive and negative electrodes, which are made of a compressible fibrous separator material absorbent material and largely without free unabsorbed electrolyte consecutively are provided. The other electrode in the two end cells is a unipolar plate, and the the remaining electrodes form one half of a bipolar plate, the other half of which is in an adjacent

th cell is connected by means of a bridging part.

The bridging parts constitute intercell connectors which are arranged around at least one side of the intercell partition walls walking around.

The invention also includes a method of manufacture or assembling such a battery, comprising the provision of a battery container with one or more inter-cell partitions that divide the "- relevant container into compartments. In the relevant The container is a layer of electrodes and a compressible fibrous absorbent separator material used. One electrode is placed in each compartment. Then there are other such layers th used until the container is largely full. The other electrode is in the End fans a unipolar plate, while the remaining electrodes form one half of the bipolar plates,

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which are connected to the other half in an adjacent compartment by means of a bridging part, which extends around an edge of an intercell partition. The intercell connectors in the finished accumulator are formed by the bridging parts. Furthermore, a quantity of an electrolyte is poured into each compartment, in which the relevant amount of electrolyte is largely absorbed by the electrodes and the separator material will. The method preferably includes a subsequent insertion of the electrodes and separator material Process step according to which a cover plate with slots corresponding to the intercell partition walls is inserted will. The cover plate in question is moved into a position in which the electrodes and the separator material are under pressure. In this position the .Associated cover plate secured.

As noted above, the cells contain essentially no free unabsorbed electrolyte. In the mei-

Most preferred state of the cells, the amount of electrolyte is not sufficient to the pores in the electrodes and in to saturate the separators. The electrolyte absorption ratio of the separator material is preferably larger than one hundred percent.

The electrolyte absorption ratio is the ratio - like a percentage ratio - of the volume of the the wetted part of the separator material absorbed electrolyte to the dry volume of the wetted in question Part of the separator material in the event that a strip of the dry separator material is vertical above a mass of an aqueous sulfuric acid electrolyte having a density of 1.27, which is 0.01 percent by weight Containing sodium lauryl sulfanate, is suspended so that 1 cm of the lower end of the relevant Strip is immersed in the electrolyte after a steady state by wicking at 20 ° C and a relative humidity of less than 50 pro

cent is reached.

The thickness measurement, at least with regard to the measurement of the electrolyte absorption ratio, is carried out with the aid of a micrometer with a load of 10 kilopascals (1.45 psi) and an area of 200 mm ² (in accordance with the method according to British Standard No. 3983). The dry volume of the examination object is thus determined in that the width and the length of the relevant sample are multiplied by its thickness, which is determined in the manner described.

Preferably, the separator material should have a wick height of at least 5 cm above the sample, so that namely, the electrolyte has risen to a height of at least 5 cm above the surface of the electrolyte is into which the strip of separator material

is immersed when the steady state is reached. 20th

It has been found that these two requirements are met by fibrous blotting paper-like materials with fibers whose diameter is in the range from 0.01 micrometers or less to 10 micrometers. The mean value of the diameter of the fibers in question is less than 10 micrometers, and preferably it is less than 5 micrometers. The ratio of weight to fiber density, namely the ratio of the weight of ^ _n fibrous material in grams / square meter based on the density in grams / cubic centimeter of the material concerned from which the individual fibers, is at least to 20 and preferably 30 and especially at 50.

This combination of properties leads to a substance or material that has a strong resistance to it shows a "growing through", nine compared to the growing

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of lead dendrites from the positive electrode of the lead accumulator s to the negative electrode to produce short circuits, while at the same time even in the event that large Amounts of absorbent electrolyte are present, yet a significant amount of gas transfer capability is available.

Lead accumulators with a recombining agent can work under Uber atmospheric pressure when charging, for example at a pressure of 1.1 bar and above. Due to the limited amount of electrolyte, due to the high electrolyte absorption ratio of the separator, as well as due to the fact that the capacity of the negative active mass is generally at least as large as that of the positive active mass, as well as due to the higher electrochemical Efficiency of the negative electrode, the cell works under the so-called "oxygen cycle", in which oxygen during charging or overcharging at the positive electrode, presumably by the gas phase in the separator is transported to the surface of the negative electrode moistened with sulfuric acid. There takes place a recombination with the lead with the formation of lead oxide, which is converted into lead sulfate by the sulfuric acid will. A loss of water is therefore a result

excessive gas pressure within the cell is avoided. In the loading state when oxygen is generated at a speed higher than ^v EIT with the VELOCITY at which the oxygen to the negative electrode can be transported to and reacted there, then the excess

Oxygen is led out of the cell through venting.

The amount of electrolyte added is not much critical, since it has been observed that when a small excess of electrolyte is added, the

The electrolyte content exceeds that which is required to saturate the porosity of the cell components Recombination mechanism is prevented and the electrolyte is lost through electrolysis until the

Electrolyte volume has reached the correct value for the cell in question, i.e. until the cell porosity is correct Level of unsaturation has reached when the recombination mechanism gets going again and a Steady state recombination occurs.

The gas venting devices are preferably in shape a check valve is provided so that air does not have access to the interior of the accumulator or the battery can be obtained, although gas generated in the interior space concerned can escape to the atmosphere.

In the case of accumulators with one with regard to the means of recombination decreased electrolyte it is considered important that the plates and the separators are in intimate contact, so that the entire surface of the plates for their electrochemical needs has sufficient electrolyte available. Under manufacturing conditions, the thickness of the panels tends to increase however, to vary a little. If the plates were only inserted into one compartment, the intimate There is no contact or the panels concerned may be too close together due to the variations in the plate thickness. One way to overcome this problem is to find the elements of each Assemble the cell outside of the container and then close them with the help of plastic straps connect so that a certain compressive force is exerted. However, this is inconvenient in manufacture

^ Q and uneconomical in terms of the time required. However, the use of plates which can slide along the inner cell partition walls and the subsequent pressing together of these plates and holding in the relevant position by means of the cover plate overcomes

to a large extent these problems in an economical and simple manner.

3 (Ul (EiS 1 / D63A

The invention is explained below with reference to drawings explained in more detail using two special exemplary embodiments.

FIG. 1 shows a perspective view of an accumulator or battery container with an electrode layer.

Figure 2 shows a plan view of a closure plate on a reduced scale.

• Figures 3a and 3b show views of a unipolar electrode or a bipolar electrode.

Figure 3c shows how the separator material is arranged

to cover the two halves of a bipolar plate '^.

Figure 3d shows in a perspective view a modification in which one half of the bipolar plates with

is coated with a separator material. 20th

FIGS. 4, 5, 6a and 6b show a modified embodiment in views similar to FIGS. 1, 2, 3a and 3b.

Figure 7 shows an electron scanning photomicrograph of a preferred separator material in 10,000 times Enlargement.

FIG. 8 shows a view similar to FIG. 7 at 30

400X magnification.

Figure 1 shows an accumulator or battery container made of polypropylene with a bottom 2 _f two front or

End walls 4 and 6 and a side wall 8. The top wall 35

and the other side wall of the container are omitted. The container is divided into six equal-sized compartments by five Inter-cell partition walls 10, which are connected to the bottom 2 and the side wall 8, are divided. Forehead-

walls and the inter-cell dividing walls each run up to a point about 5 mm in front of the front the side wall 8 is located. To assemble the battery, the container is like this illustrated in Figure 1, placed so that its side wall faces downward. A unipolar plate 12, such as it is illustrated in Figure 3a is placed in each of the end compartments. Two bipolar plates 14, each consist of two halves which are connected at one end by means of a bridging part 16 and those as generally 'TT-shaped or as flattened upside down U can be understood, as illustrated in Figure 3b, are so in the other four subjects inserted that each of the four subjects concerned

¹ ^ contains one half of a plate. The bridging part 16 (at the upper end of the plate according to FIG. 3b) extends over the top of the intercell partition walls 10. The bridging parts have a width of approximately 3 mm; they are arranged so that they do not have the

* ^w top of the side wall 8 extend. A top strip and the bridging part of the respective plate are made of solid metal, which means that these parts are not expanded. A rectangular strip 17 made of a separator material on which below

will be discussed in more detail, is then inserted into the respective subject, so that it is the underlying Plate completely covered and over its edges in the upper area as well as in the lower area and on the sides survives (see Figure 3c). Then a white

tere plate layer inserted into the container, comprising three bipolar plates 14. It should be noted that the bridging parts 16 of these three bipolar plates may be offset from those of the plates below

will. Further strips of a separator material 35

are then inserted, followed by a third layer of plate similar to the first layer of plate. Of the The process is repeated until the container is full.

In the case of accumulators or batteries with an electrolyte that is reduced in terms of the recombination agent it is believed important that the plates and separators be kept in intimate contact with one another, so that the entire surface of the plates has sufficient electrolyte for their electrochemical needs has available. For this reason, a cover plate 20, as illustrated in FIG. 2, is then used and having slots 22 corresponding to the partitions 10, on the top of the stack of panels and Put separators on and then push down to put the plates and separators under pressure. The cover plate is then in the relevant position on the bottom wall, the side walls and the dividing walls of the container attached, by welding or gluing. Then a side wall with a size of the wall 8 the same size attached to the battery or accumulator, also by welding or gluing, to give the battery or accumulator in question a neat, finished look.

Each of the unipolar plates 12 in the two end compartments is provided with a laterally protruding connection attachment 24. The accumulator or the battery thus has a number of such approaches that are to the side of the respective The end of the battery or the accumulator run up to a plane which is slightly below the top of the side walls lies. Then a line of sealing material, such as an epoxy resin, is made of a ^ m by heat

fusible adhesive or the like along each of the Rows of lugs are applied up to the level of the side walls, and then the container is secured by means of a cover. kels sealed by welding or gluing. The approaches of the respective series are then connected, both

for example by soldering or potting molten lead in a mold around the lugs, around terminal connectors to build. The electrolyte can be added to the cells before the lid is placed on the container.

13QQ51 // Q634

is set or thereafter / for example by injection through holes contained in the cover in question. the The amount of electrolyte added is typically in the range of 7 to 12 ml of sulfuric acid with a Density of 1.27 per cell in the discharged cell state per ampere hour of cell capacity.

It will be appreciated that the bridging members 16 form the intercell connectors and therefore it it is not necessary to form intercell connectors in a separate step. This saves a big one Proportion of lead that is commonly used in the relatively massive plate tapes and intercell connectors. Moreover, the measure in question leads to a

Shortening of the current paths within the battery or the accumulator and thus a reduction in the internal resistance of the battery or accumulator concerned and an increase in the discharge characteristics for a discharge at high discharge rates. The bridging parts are opposite the intercell partition walls or the battery or the accumulator is not sealed. However, the accumulator or battery capacity is not significantly affected, since the intercell ion leakage is not a serious problem with accumulators or batteries. Represents batteries with a reduced electrolyte in terms of the means of recombination. However, it can be desirable be to provide means to prevent the occurrence of intercell ion leakage currents along the Prevent OQ bridging parts.

A modified embodiment is shown in FIGS. 4, 5, 6a and 6b, in which the same reference symbols are used are how they are used to designate the corresponding EIeoc ments have been used previously. In the present embodiment, the partition walls 10 hang with only one Wall of the container together, in this case with the side wall 8. The two halves of the respective bipolar Plates are connected by two bridging parts

connected to each other. These bridging parts are located at the ends of the relevant plate. The bipolar plates can thus generally be regarded as O-shaped with a central slot that goes through at the respective end ^ a bridging part 16 is closed. This bipolar Plates are therefore structurally more stable than the U-shaped plates. The provision of two bridging parts per bipolar plate increases the area of the conductive paths between neighboring cells and thus leads to one further reduction of the internal resistance of the battery or accumulator. The procedure of assembly is identical to the procedure described above.

The electrode carriers are cast or drawn from prismatic grids made of lead, 0.07 percent calcium, 0.7 percent tin alloy. The grids are 1.2 mm thick; they are stable, self-supporting and resist deformation even under load.

The separators are illustrated in FIGS. 7 and 8. It is a highly absorbent, blotting paper-like one short-stacked gas fiber mat with a thickness of about 1 mm, the fibers 61 having a diameter of

about 0.2 micrometers and the fibers 60 have a diameter of 25

of about 2 microns. The mean diameter of the fibers is about 0.5 micrometers.

It turns out that although the material has a strong absorbing effect, it still has a very large proportion of an open one Has intermediate space between the individual fibers. During the test, the electrolyte got through the material with 113 percent of its own dry volume is absorbed. This value represents the electrolyte absorption ratio of the material in question.

The separator material weighs 200 g / m ² ; it has a porosity of 90 to 95 percent as measured by

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i - 17 -

the mercury Exndringmeßverfahren. The density of the glass from which the fibers of the separator are made is 2.69 g / cm ² ; the ratio of weight to fiber density is thus 74.
5

In both embodiments, the two halves of the respective bipolar plate act as plates opposite one another Polarity. Although it would be possible to have the two halves with positively active ground and negatively active, respectively Coating bulk would complicate the assembly process, so it is preferred to use the bipolar To cover plates with a universally active electrode mass, i.e. with an electrode mass that is after electrolytic formation as either positively or negatively active mass, depending on the formation works. In a corresponding manner, the unipolar plates are expediently provided with a universal active material coated to avoid having two types of unipolar

Records are to be retained.
20th

According to a modification of the methods described above, the separator material 17 is used simultaneously with at least some of the plates. This can expediently take place in that one half of the respective bipolar plate is wrapped or wrapped (see FIG. 3d). This ensures that the separator material is present between each pair of adjacent plates and results in a considerable simplification of assembly. When the separator material is wrapped around the bipolar plates, the crease can appear at the bottom of a plate edge or along the bottom. If desired, the respective bipolar plate as a whole can also be wrapped around or enveloped qc in this way. In this case there will be two layers of the separator material between adjacent bipolar plates. The separator material typically has a weight of 100 g / m ² .

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- 18 -

According to a further modification, the bridging parts 16 are sealed on the partition walls and on the container, for example with an epoxy to eliminate the possibility of intercell ion leakage.

According to yet another modification, the connection lugs run 24 from the unipolar plates upwards and thus through the lid or cap of the finished Battery through. The connections in question can be soldered together in the conventional manner. It it should be seen that in this case the end walls 4 and 6 extend as far as the side wall

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Claims (18)

PATENT AND LAWYERS *,. * ~ Η> * ηαη ** o I Ub <c U ο LAWYER PATENTANWÄLTEJOCHEN PAGENBERG dh.jur..ll _m . harvard WOLFGANG A. DOST dr .. d.pi -c «.. ·· UDO W. ALTENBURG d, _pl -phys GALILEIPLATZ 1, 8000 MUNICH 80 TELEPHONE (0 89) 98 66 64 TELEX: (06) 22 791 pad d CABLE: PADBÜRO MUNICH date 1 9. February 1981 • K 2011 AL / II / ho Claims 1/. Multi-cell electric accumulator with a compartment which is divided into compartments and covered with a lid and which has two or more cells each having alternating positive and negative electrodes, which are nested with a separator material, characterized in that the Separator material a granular, fibrous absorbent Material (17) contains, which largely without is free, unabsorbed electrolyte, 10 that the other electrode is in the two end cells is a unipolar electrode (12), that the other electrodes are one half of a bipolar plate (14), which with its other half in one adjacent cell connected by a bridging part (16) is, and in that the bridging members (16) form intercell connectors extending around at least one side of the sides walk around the intercell partition walls (10). 130051/063 * 2. Accumulator according to claim 1, characterized in that the two halves of the respective bipolar plate (14) are connected by a single bridging part (16) which surrounds one edge of the associated intercell partition (10) walking around. 3. Accumulator according to claim 1, characterized in that the two halves of the respective bipolar plate (14) are connected by two bridging parts (16), which run around two opposite edges of the associated intercell partition (10). 4. Accumulator according to one of claims 1 to 3, characterized in that the respective bridging part (16) without sealing on the container (2, 4, 6, 8) or the intercell partition (10) is provided in such a way that that the cells concerned are in communication with one another. 5. Accumulator according to one of claims 1 to 4, characterized characterized in that the end walls (4, 6) run parallel to the intercell partition walls (10) and are shorter are than the side walls (2), that each unipolar plate (12) has a connection extension (24) which extends laterally over an end wall (4, 6) protrudes, and that the connection lugs with the respective end to form a connection connector with one another are connected. 6. Accumulator according to claim 5, characterized in that that the gap between the cover and the end walls (4, 6) through which the connection lugs (24) protrude, is filled with a sealing material and that the lid is sealed on the side walls (2) and on the sealing material. 130051/0634 7, accumulator according to one of claims 1 to 4, characterized in that the end walls (4, 6) parallel to the inter-cell partition walls (10) and have the same height as the side walls (2), that each unipolar plate (12) has a connection extension (24) which through the battery cover upwards runs, and that the connection lugs (24) at the respective end -in with one another to form a connection connector are connected" 8. Accumulator according to one of claims 1 to 7, characterized characterized in that a cover part (20) runs transversely to the intercell partition walls (10) and has slots (22) through which the intercell partition walls (10) run, and that the cover part (20) is secured in the relevant position such that the electrodes (12, 14) and ™ the separator material (17) are kept in intimate contact. 9. Accumulator according to one of claims 1 to 8, characterized in that one half of the respective bipolar ^ ⁵ ren plate (14) is covered with the separator material (17). 10. Accumulator according to one of claims 1 to 9, characterized characterized in that the separator material (17) is a Is fiberglass material with a microfine diameter. 11. Accumulator according to one of claims 1 to 10, characterized in that the amount of electrolyte present is insufficient to completely saturate the pores of the separator material (17) and the electrodes (12, 14). 12. Method of manufacturing or assembling a Multi-cell electrical accumulator according to one of Claims 1 to 11, using a storage battery container, which has one or more intercell partition walls that divide the container in question into compartments subdivide, characterized in that in the relevant container (2, 4, 6, 8) a layer of electrodes (12, 14) and a compressible fibrous absorbent separator material (17) introduced in this way that there is an electrode in each compartment, that further such layers are then introduced until the container (2, 4, 6, 8) is almost full, with every other electrode in the end compartments a unipolar electrode (12) and all other electrodes half of bipolar plates (14 ) form, which are bridged with the other half in an adjacent compartment through a Uberbrückungsteil (16) which extends around an edge of an intercell separating ₉ _ wall (10), wherein the intercell connectors in the finished battery through the bridging parts (16) are formed, and that such a quantity of an electryte is introduced into the respective compartment that the relevant Amount of electrolyte almost completely absorbed by the electrodes (12, 14) and the separator material (17) will. 13. The method according to claim 12, characterized in that that with the omission of two at right angles to the partition walls (10) extending adjacent container walls the layers of the electrodes (12, 14) and the separator material (17) in the container (2, 4, 6, 8) almost parallel to the intercell partition walls (10) are brought into position in such a way that the relevant Walls run at right angles to the partitions (10), and that the two walls in question then be connected to the container. 14. The method according to claim 12 or 13, characterized in that that each bipolar plate (14) has two halves, which are separated by a single bridging member (16) at or near one end. 15. The method according to claim 12 or 13, characterized in that that the inter-cell partition walls (10) are contiguous with only one wall (8) of the container formed or sealed on this and that the two halves of the respective bipolar plate (14) are connected to one another by two bridging parts (16) each of which is provided at one end of the plate. 16. The method according to any one of claims 12 to 15, characterized characterized in that the electrodes (12, 14) and the separator material (17) of the respective layer are sequential to be introduced. 17. The method according to any one of claims 12 to 15, characterized characterized in that one half of the respective bipolar plate (14) is surrounded by the separator material (17) or wrapped in such a way that the bipolar plates "_" (14) are simultaneously with their associated separator material (17) should be introduced. 18. The method according to any one of claims 12 to 17, characterized characterized in that following the introduction of the OQ electrodes (12, 14) and the separator material (17) a cover plate (20) with the intercell partition walls (10) corresponding slots (22) inserted or is used, that the cover plate (20) is moved into a position in which the electrodes (12, 14) and the separator material (17) are under pressure, and that the relevant cover plate (20) is secured in the relevant position. 13QÖ51 / Q634