DE3520855C1 - Galvanic cell with press contact - Google Patents

Description

in the area of the contact hole (13) is compressed to 10 to 40% of the original thickness that

e) in the area of the through hole (12) between the electrode of opposite polarity and the one on the Edges of the pipe section (6; 7) (contact sleeve) pressing the contact holes a layer of insulating material (10) (insulating sleeve) is arranged, the

el) the free space between the pipe section and the electrode of opposite polarity essentially fills in and

e 2) whose axial length is shorter than the axial length of the pipe section and that

f) springs (125; 225) are provided at the ends of the current-carrying elements, which compress the electrode stack independently of the pressure on the pipe sections.

Chen correspond to the through hole (12) of the electrodes (1; 2).

4. Galvanic cell according to one or more of claims 1 to 3, characterized in that the pole anchor bolt (104; 105; 204) in the region of the end plate (122; 222) has a collar (123; 223) .

5. Galvanic cell according to one or more of claims 1 to 4, characterized in that the condensed zone of the electrode in the area of the contact hole (13) concentric to the center point of the contact hole and is larger in diameter than the diameter of the insulating sleeve (10).

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35 A major problem in the manufacture of galvanic cells, in particular accumulators with alkaline electrolytes, is the electrical connection between the electrode plates, the current lugs and the pole bolts protruding from the cell or the accumulator.

These connections must, on the one hand, have the lowest possible electrical resistance, on the other hand, a have high mechanical strength. In addition, the pole bolt must be electrically isolated from the housing and be sealed.

In the usual construction, sheet metal flags are attached to the electrode plates by means of spot welding, which in turn either by screwing or by welding on pole bridges and / or pole studs be attached. Difficulties exist because of both the electrode frameworks and current lugs have unequal cross-sections and material properties, as well as the cross-sections of the current lugs and the pole bridges or the pole bolts are very different. The making of these connections requires a high level of device and control technology, the electrodes are made of fiber material, which is niche effort and is therefore very expensive.

There are particular difficulties when instead of sintered electrodes those made of fiber structures are used especially those where the plastic core of the fibers has not been removed.

From the German patent application ρ 39 477 IVa / 2IbD (class 21b, group 7/01) a galvanic cell with sintered electrodes for the extraction of small currents is known, in which contact pins are driven perpendicular to the electrode surface into a hole in the electrode. The hole diameter is smaller than the diameter of the contact pin and provided with radial slots, so that when the pin is driven in, a radial tension and thus contact is created, which is caused by tubes pushed onto the contact pin, the end faces of which have inwardly directed conical surfaces on the edges of the contact surface press, is supported. In order to achieve insulation between the alternately stacked positive and negative electrodes, the electrode is provided with a larger hole around the opposite pole, which is arranged parallel to the described pole, so that no contact can be made at this point. The electrode pushed above or below is arranged rotated by 180 ° in the plane, so that the positive electrodes are assigned to one pole and the negative electrodes are assigned to the other pole and are insulated from one another.
When assembling such cells, however, arise

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2. Galvanic cell according to claim 1, characterized in that in addition to the springs (125; 225) which compress the electrode stack, further springs (235) stronger than these springs are provided which exert pressure on the pipe sections (6; 7; 107; 207) , which press on the edges of the contact holes.

3. Galvanic cell according to claims 1 or 2, characterized in that the separators have holes (14), the diameter of which is essentially

Difficulties, ζ. Β. in that an electrode is rotated about the bolt contacting it can. Then the edge of the larger hole also touches the opposite pole, thereby forming the cell destructive short-circuit occurs. To prevent this, the housing must be very tight around the cells and in order to Avoid short circuits by touching the cell wall, as shown in the cited application Be plastic. In cell systems that are under higher gas pressure (e.g. nickel-hydrogen cells) but this is not possible for reasons of strength. Such systems require a metallic housing.

The invention is based on the problem of perfect contacting in a compact cell stack To obtain electrodes of the same polarity made of fiber material, which even with fluctuations in thickness of the electrode plates between the charged and discharged state What is certain is perfect insulation between the differently polarized electrodes and good internal insulation Centering of the cell parts to each other ensures that they are metallic even with the best possible use of space Cell housing can be used. In addition, in the production of cell stacks a the smallest possible expenditure on equipment may be required.

This object is achieved in a galvanic cell with press contact according to the preamble of the patent claim 1 solved by its characteristic features.

The essence of the invention is thus that electrode frames made of fiber material are used, where the fiber material is filled or impregnated with active material in the area of the contact hole is compressed to 10 to 40% of the original thickness. It is also in the area of the through hole between the electrode of opposite polarity and the pipe section pressing on the edges of the contact holes Layer of insulating material arranged, which the free space between the pipe section and the opposite polarity Electrode essentially fills and the axial length of which is shorter than the axial length of the pipe section. In addition, springs are provided at the ends of the current-carrying organs, which the electrode stack compress regardless of the pressure on the pipe sections.

The electrodes have two holes through which the positive and negative pole bolts are passed, namely a large hole (through hole) compared to the pole bolt and a smaller hole, which is in the essentially corresponds to the diameter of the pole bolt. From this smaller hole takes place over the on The pipe pieces pushed onto the pole bolts make contact while the wide hole is used for insulation serves against the corresponding pole bolt and the piece of pipe pushed onto it. In the field of small holes used for contacting (contact holes), the fiber material of the electrode is approx. 10 to 40% of the original thickness compressed. A small compression of the electrode framework of z. B. 40% has the advantage of better adaptability due to better natural springiness, which is an advantage if, for example, many electrodes are used, but it also has the disadvantage of inferior Making contact. A very high compression on z. B. only 10% of the original thickness results in excellent Contacts, but requires high accuracy of the components of the stack and high pressing forces, the must be applied by the pole anchor bolts.

Particularly good results, both in terms of contact and resilience, are achieved when compaction to 30 to 20% of the original framework thickness is carried out.
In the battery, the individual positive and negative electrodes are alternately arranged in a stack with separators interposed. Between each pair of electrodes of the same polarity, which are connected to the pole bolt via the tube piece pushed onto the corresponding contact bolt and pressing on the edges of the contact holes, there is an electrode of opposite polarity, which is located at the point where the contact bolt and the tube of the two other electrodes is provided with the aforementioned large hole. In order to prevent the electrodes of opposite polarity from accidentally shifting during assembly and thus causing a short circuit, a layer of insulating material is arranged in the area of the large through hole between the opposite polarity electrode and the piece of pipe pressing on the edges of the contact holes, which creates the free space between the pipe section and the electrode of opposite polarity is essentially filled. This layer of insulating material can consist of a sleeve made of insulating material pushed over the pipe section, but can also be a layer of paint or plastic applied directly to the pipe section. Because the free space is filled by the layer of insulating material, not only is the possibility of a short circuit effectively prevented, but the scope for possible displacements is also reduced, so that the individual electrodes are also precisely fixed in position. This fixation is particularly valuable since the outer dimensions of the electrode block can be kept within particularly narrow limits in this way, which makes it possible to use particularly good space even with metallic housings. In this context, it is very advantageous to provide the separators with holes whose diameter corresponds approximately to the through hole of the electrodes, so that the separators are also very well centered or fixed in their position in relation to the electrodes.

To be sure that after assembling a cell stack when tightening mainly the pipe pieces (Contact sleeves) penetrate the compacted area of the electrode, the should over the contact sleeves inserted insulating sleeves must be slightly shorter in axial length than the contact sleeves. You shouldn't, however be too short so that the disc-shaped thin components (e.g. the separators) are laterally removed during assembly cannot slip. It is particularly advantageous to reduce the length of the insulating sleeves the length of the contact sleeves to be maintained by about 5 to 10%, and instead of the insulating sleeves a suitable insulating layer can be applied to the contact sleeves. For this reason, the Above-described compression of the fiber material in the area of the contact hole in its areal expansion be so large that it corresponds at least to the outer diameter of the insulating sleeve, but better is a little bigger. In addition, there is due to the difference between the contact sleeve diameter and the diameter of the compression zone a kind of resilient membrane that allows a certain mobility in the direction of the bolt axis, which is advantageous during operation of the battery with respect to the Stretching and shrinking of the electrodes is. A white

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Another advantage of the compression of the fiber material on the bolt in the area of the end plate with a collar and contact point results from the fact that the other is provided with a thread on the following one. the penetration of the active mass less active mass Advantageously, the pole anchor bolts se occur at this point, which on the one hand results in a material saving at the same time for holding the stack on the cell housing of active mass, but on the other hand also uses 5 se. In this case it is beneficial for the Polana to also prevent any deterioration in contact. to extend bolt after the federal government and this part It is known that also to be provided with a thread when operating galvanic. The two cells with electrolytes bound in the separator and a pole anchor bolt arranged in parallel can then have a specific contact pressure applied to the surface of the electrode through appropriately designed openings on the stack of buildings. This is carried out in particular and, by means of suitable means, both in the case of hybrid cell systems, such as e.g. B. Nickel-Was- electrically insulated as well as sealed with the housing hydrogenation cells, the case. This contact pressure will be relaxed. It is easily possible to apply the electrode stack by means of tie rods via the end plates to one of the pole anchor bolts at one end of the cell housing. In the present galvanic cell with press contact, the end of the cell housing, what is the timing, this tie rod function through the pole, as is well known, results in good current conduction in a cell, bolts are also perceived. A special advantage arises when, for example, a component is required to connect the stack pressing pressure, the two cell stacks one behind the other in a housing, contacting pressure and the current transport (bi-cell). In this case, a work-place, quite apart from the already mentioned 20 pole anchor bolts, can penetrate both stacks and provide centering of the electrodes and separators. Corresponding contacting within the stacks In order to ensure good contacting of the electrodes through pole connectors between the stacks. To achieve the two contact sleeves, the bracing of their parallel pole anchor screws should be as tight as possible at the contact point. Contact pressures at the contact point 25 and are the two poles of the Bi-cell are particularly suitable for being separated and oppositely from the stacks. of at least 50 N / mm ² . This is achieved using the illustration, as an example, the structure is shown in that a corresponding details and stacking arrangements are shown on the last contact sleeve by means of a cell stack with axial press contact and on the pole bolt screwed nut. It shows when pressure is being applied. individual

Since, as already mentioned, an electrode during the 30 F i g. 1 shows a longitudinal section of an electrode stack

Cycling (loading, unloading) a change in thickness with press contacting,

learns, it can be too rigid a construction that this F i g. 2 the top view of an electrode framework,

Change in thickness suppressed by displacing the F i g. 3 the top view of a separator,

Electrolytes in unfavorable zones for deterioration F i g. 4 the view with partial longitudinal section of a complete

come to the cell. To enable the 35 th cell to move with spring elements for the stack,

Ensuring electrodes in the direction of thickness are therefore to be F i g. 5 shows an electrode stack with spring elements

half, regardless of the one on the pipe pieces (contact for the stack and those for the press contact,

sleeves) acting pressure springs provided that a F i g. 6 the structure of a gas-tight bi-cell,

Breathing the electrode stack with a certain degree of efficiency. 7 the structure of a cell with parallel-connected

enable tension. These springs can stack flat electrodes.

if supported on the nut. The one of these feathers on F i g. 1 shows an enlarged section of a cell-the electrode stack, the contact pressure exerted is lenstapels with continuous pole armature bolts. As is about 0.05 to 0.4 N / mm ² , so is significantly below the position, the positive electrodes (positives) are 1 contact pressure at the contact point. The thickness and the negative electrodes (negatives) 2 alternation of the electrode stack moves in the size-wise stacked. Between the electrodes there is an order of about 1 to 3%. Separators 3 introduced. The positives 1 are associated with the When building stacks of cells with a large number of electrical right pole anchor bolts 4 and the negatives 2 with the linden, there is a risk that the ken pole anchor bolts 5 will be assigned over time. Contact points on the electrode frameworks slightly creep. The tubular small pieces placed over the left-hand bolt and thus a higher contact resistance to 50 contact sleeves 6 are between the negatives and the contact sleeves. This disadvantage can be successfully counteracted by the contact sleeves 7 fitted over the right-hand bolt, even if arranged between the positives. The contact sleeves, the contact sleeves and the pole pin ends (nut) penetrate slightly into the disc springs due to the axial compression. These disc springs must have contact zones 8 and 9, respectively. About the contact sleeves are sen parallel to the springs for the stack 55 insulating sleeves 10 slipped.

and according to the different force relationships- They are slightly shorter in length than the contacts be designed. Taking into account two sleeves. Instead of the insulating sleeve, a suitable pole anchor bolt can also be used and the above specified coating is applied to the contact sleeves Pressing as well as the surfaces for stacks and cones.

contact zones results in a ratio of the contact press 60 The pre-pressed, compacted zone 11 at the electrical

force to half the stack pressing force of approx. 1: 1 to 5: 1. that in the area of the contact hole 13 is in diameter

With such an arrangement it is then possible that something larger than the outer diameter of the insulating sleeve

the two directions of movement between the stack and sen.

Contact zone can even be opposite without In F i g. 2 is a plan view of an electrode shown

that the prerequisites for a flawless job. The larger, left hole (12) (through hole)

a cell stack can be injured. For an optimal corresponds to the diameter of the insulating sleeve and that

Setting of the contact pressure and the contact is smaller, right hole (13) (contact hole) that of the

it is favorable if, for example, one end of the pole anchor pole anchor bolt. Zone 11 around the smaller hole is

Pressed symmetrically into the electrode on both sides.

F i g. 3 shows a separator 3 in plan view. The two holes 14 have the same center distance as that Electrode holes and their diameters both correspond to the outer diameter of the insulating sleeves 10 or the through holes 12.

In Fig. 4 shows a view with a partial longitudinal section of a complete gas-tight cell (e.g. Ni / H2). In The cell stack 121 is concentric to the metallic vessel 120 by means of the pole anchor bolts 104 and 105 built-in. The cell stack is covered at the top and bottom with an end plate 122 made of insulating material and braced between the collar 123 and the nut 124. To ensure a defined stacking movement, A plate spring 125 is inserted between the lower end plate and the nut. This is based on the side the nut on a washer 126 and on the end plate side on another washer 127. The end contact sleeves 107, which make contact from the pole anchor bolt 104 to the last positives 101, are through the insulating end plates 122 are passed through and are supported on the collar 123 at the top and on the disk 127 at the bottom. The pole anchor bolt has a thread 128 at its lower end. By means of the nut 124 and the plate spring 125, a targeted contact pressure on the stack 121 can thus be set.

Over the upper part of the pole anchor bolt 104 is a Spacer 129 made of plastic material. It serves to support the cell stack on the vessel lid 130. Since the interior of the cell is under high pressure (e.g. 40 ... 50 bar) and the pole anchor bolt 104 is opposite the cell cover 130 must be electrically isolated, the cell cover is at the point of passage of the Pole anchor bolt is provided with an inwardly directed passage 131. Between the passage 131 and an O-ring 132 is pressed into the pole anchor bolt 104. It provides both insulation and sealing. So that the O-ring through the gas pressure cannot be pushed outwards, the top of the lid is covered with an insulating plastic washer 133 covered. It extends a little into the area of the radius at the passage. The spacer 129 is in The upper part is sunk in such a way that the passage 131 just fits into it. Thus, the O-ring is, so to speak, in one Annular chamber included. The upper part of the pole anchor bolt is also threaded for bracing purposes 134 provided. However, this must stop above the O-ring, otherwise the tightness is endangered. By means of a further nut 124, between which a washer 126 is placed and the plastic washer, can then the tension between the inner parts of the cells and the cell vessel can be made.

This design allows and ensures precise centering of the cell stack to the housing, a solid mount, a simple but perfect seal, good current dissipation and a very easy cell assembly.

The in Fig. The example shown in Figure 4 deals with a cell with a relatively short cell stack. However, it is over If a very long stack of cells is required for higher capacity, there may be difficulties between the coordination of the contact pressure of the cell stack and that for the contact sleeves come. To counter this, FIG. 5 shows a cell stack 221 in which the end contact sleeves 207 and the end plates 222 are each supported by separate resilient means. The disc springs 225 for the stack are softer than the disc springs 235 for the contact sleeves and are connected in parallel to one another. For support the disc springs 225 and 235 on the collar 223 or on the nut 224 of the pole anchor bolt 204 and the spring 225 on the plastic end plate 222, metal disks 226 and 227 are interposed.

These spring assemblies are attached to the two ends of the stack and the pole anchor bolts, see above that overall a greater elasticity and a uniform stack compression and movement ensured is.

In Fig. 6 a Bi cell is shown. It is about around a cell in which the electrode stack, connected electrically in series, is housed in a vessel 320 are. This doubles the cell voltage and, like a single cell, there are still only two Pole bushings necessary. Here, the upper left pole anchor bolt 305 is only connected to the upper cell stack 321 connected, while the right pole anchor bolt 304 extends through both stacks. The lower left pole anchor bolt 350 is in turn only contacted with the lower cell stack 421. The positive electrodes of the The upper stack 321 is in contact with the left upper pole anchor bolt 305 and the negative electrodes with the upper part of the continuous pole anchor bolt 304. In the case of the lower stack, it is exactly the opposite. Thus, the continuous pole anchor bolt is the cell connector of the two cell stacks. The one from the top Pole anchor bolt 305 passed through part of cell 320 serves as a positive connection pole and the one passed through at the bottom Pole anchor bolt 350 as a negative connection pole.

The sleeve 336 is made of plastic and also serves as a centering and spacer piece, while the metallic Intermediate contact sleeve 337 to support the pressing of the not shown in the stack Contact sleeves and the power line is used. In the course of manufacturing simplification, it is also possible to use the intermediate contact sleeve to be composed of several contact sleeves, provided the dimensions of the contact sleeves allow this. The caps 351 at the ends of the pole anchor bolt 304 are made of an elastomer and support the stacks opposite the cell vessel tips.

In Figure 7 is an example of a gas-tight hybrid cell shown, in which two electrode stacks are electrically connected in parallel and in a common Housing are housed. The two pole anchor bolts each extend through both stacks and are isolated from one another and diametrically to one another passed through the cell vessel on one side. All electrodes both stacks, which are assigned to a pole anchor bolt, have the same electrical polarity. Such Cell arrangement is advantageous in terms of heat dissipation from the stacks and the welding of the Cell vessel parts.

With the help of the press contact construction described, it has been possible to meet several requirements such as contacting, Centering, holding and good chamber filling to meet in a simple manner and at the same time an inexpensive one Enable manufacture.

It is easy to see how complicated and time-consuming a construction would be if instead of press contacting each individual electrode would be provided with a current plume and these then to each other and with them of a second stack and the cell poles would have to be connected, not to mention that additional Brackets for the stacks would be necessary.

For this purpose 4 sheets of drawings

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Claims (1)

Patent claims: 1. Galvanic cell with press contact, consisting of a) alternately arranged electrode plates with the interposition of a separator, the a 1) with an opening of approximately the same cross-section as the current-carrying element (Contact hole) and a 2) an opening of larger cross-section (through hole) is provided, and at them a 3) the perforations are provided with a hole border made of more densely pressed material,
the electrode plates b) by means of second bolt-shaped current-carrying organs penetrating as contact and insulating holes are held together or pressed together to form an electrode stack that each of the electrodes of one polarity with the Current-carrying element conductively connected in the contact holes and against the polarity opposite Electrodes and against the other current-carrying member penetrating the through-holes are isolated by an insulating distance and where c) on the current-carrying element between the fastening holes of two homopolar electrodes in the through hole of the opposing polarity electrodes in between, on the edges the contact holes pressing pipe section (contact sleeve) made of corrosion-resistant metal is, characterized in that