DE10112162A1 - Rechargeable battery has stacked electrically conducting layers with edges enclosed by insulating frames, intermediate electrolyte layers; conducting layer frames are fixed to each other - Google Patents

Abstract

The rechargeable battery consists of several conducting layers (43,45,47) forming the anodes and cathodes of the battery with an electrolyte layer (55,57) inserted between each two adjacent conducting layers. The edges of each conducting layer are enclosed by a frame (49,51,53) of isolating material and the frames of the conducting layers are fixed to each other.

Description

State of the art

The present application relates to a rechargeable Battery consisting of several the anode and the cathode the battery forming, stacked electrically conductive layers, each between two adjacent conductive layers an electrolyte layer is inserted.

For example, there are nickel-cadmium or nickel-metal hydride batteries with different Tensions and capacities. As from DE 35 02 449 C2 emerges, these accumulators exist - in short Batteries - from several interconnected single cells, each of which has a voltage of e.g. B. 1.2 V. There are usually several in the batteries for power tools such single cells connected in series so that the battery overall a voltage of z. B. 9.6 V, 14.4 V, 18 V or 24 V. provides. Every single cell of the battery has, as well EP 06 03 397 A1 shows one that forms the anode electrically conductive layer, a cathode forming electrically conductive layer and an interposed Electrolyte layer. The one formed from these three layers Stack is rolled up and in a metal tube accommodated. The number of such interconnected  Single cells depends on how large the capacity and the voltage of the battery should be. The individual cells are electrically contacted with each other via current-conducting webs. The contact points, which are soldering or welding points, form an internal resistance of the battery, which is a heat source represents an electrical load on the battery. In one Battery case in which several individual cells are packed together are very different Heat distribution. Because for those cells in the Are arranged near the housing wall of the battery better heat dissipation than for those further inside the Battery cells located. This different Heat distribution in the cells leads to one Imbalance in the charge level of individual cells. It can lead to a polarity reversal of the cells with the least Loading levels come in, which destroys these cells can. If the battery is under high electrical load, it can thermal overload of some cells come, which leads to electrolyte from the cells is blown out, causing cell failure and finally leads the entire battery. A so constructed Battery also does not make optimal use of the volume because it between those built in the form of metal tubes Single cells have relatively large cavities.

In Japanese application JP 10208773 there is one Rechargeable battery described as introductory set out from several the anode and cathode of the battery forming, stacked one above the other electrically conductive Layers and electrolyte Layers. By folding the stack one can low-volume battery can be manufactured due to a very large surface area of the folded layers a high Has capacity. The number of stacked Layers depend on the voltage of the battery should deliver.

The invention is based on the object rechargeable battery of the type mentioned to specify, in which a simple to manufacture means great security against short circuits between the individual Layers can be achieved.

Advantages of the invention

This object is achieved with the features of claim 1 solved that the edges of all the anode and cathode of the battery forming conductive stacked one above the other Layers with a frame made of an insulating material are surrounded and that the frame of the conductive layers are fixed together. The insulating frame on the Edges of the conductive layers on the one hand avoid one unintended electrical contact between neighboring conductive layers and on the other hand offer the possibility to fix the conductive layers mechanically to each other. The insulating frames also avoid that Electrolyte liquid from the space between the flows out electrically conductive layers and thus one Short circuit between electrically conductive layers could cause.

Advantageous developments of the invention can be seen in the Sub-claims emerge. It is appropriate that the framework have a greater thickness than those surrounded by them conductive layers. So the conductive layers, if their frames are placed on top of each other at a distance kept apart from each other so that space remains between them for the absorption of electrolyte layers. The frames can be openings are provided in one or more points which point out from the stack formed by the layers. The advantage of these openings is that they are for one Pressure equalization between the environment and the one Electrolyte-filled space between the conductive layers  to care. It is advantageous to attach the frame to the area their openings are integrally formed from the Extend the stack. Form these sockets Pressure equalization channels and prevent electrolyte over the openings penetrate into adjacent layers and caused a short circuit there.

A very space-saving rechargeable battery is created through an S-shaped fold of the stack. If the from stacks formed in several layers around one or more insulating body folded around, so the stack gets this provides good stability and is used when folding Break protected. To the layers of the folded stack and against the individual layers within the stack Slipping or securing a mutual displacement, it is advantageous that through all layers of the folded Stack one or more insulating bolts can be inserted.

One or more can be in the insulating bodies Temperature sensors are integrated with which the in the Rechargeable battery generated heat is measurable.

It is advantageous if one or more of the outer electrically conductive layers of the stack of larger Thicknesses are called inner conductive layers to the whole To give stacks good mechanical stability.

One or more can preferably be inside the stack Layers arranged in comparison to the others Layers have a higher thermal conductivity. This higher thermal conductivity z. B. can be achieved that in the layers conduit pipes for a cooling medium be integrated or that they have a greater thickness than that have other layers and / or from a better one consist of thermally conductive material. Thus a more even heat distribution within the stack can be achieved.  

drawing

Using one shown in the drawing The invention is described in more detail below explained. Show it:

Fig. 1 is a cross-sectional view of a rechargeable battery with an S-folded stack of conductive layers and electrolyte layers,

Fig. 2 shows a single conductive layer which is bordered with a frame and

Fig. 3 is a side view of several framed electrically conductive layers with electrolyte layers inserted between them in an exploded view.

Description of an embodiment

In Fig. 1 is a cross-sectional view of a rechargeable battery (hereinafter referred to as a battery designated), wherein an S-shaped folded in the battery casing 1 stack 3 of a plurality of conductive layers which form the anode and cathode of the battery, and from several electrolyte layers inserted between the conductive layers is accommodated. As explained in more detail below with reference to FIG. 3, in the stack 3 electrically conductive layers, which form the anode, alternate with electrically conductive layers, which form the cathode of the battery. There is an electrolyte layer between each anode layer and cathode layer, which consists, for example, of a fleece material filled with electrolyte. All conductive layers belonging to the anode and separately all conductive layers belonging to the cathode are electrically contacted with one another. This is not shown in FIG. 1 because it is not the subject of the invention. The electrically conductive layers belonging to the stack are preferably thin sheets which, on one side, e.g. B. are coated with cadmium and on the other side with nickel. Instead of cadmium and nickel, other materials commonly used for rechargeable batteries can also be used.

The number of layers stacked on top of each other depends depending on what voltage the battery will ultimately deliver should. The charging capacity of the battery depends on the area size of layers.

Due to the S-shaped folding of the stack 3 , as shown in FIG. 1, very large-area layers can be accommodated in a relatively small-volume housing 1 .

It is expedient to fold the stack 3 around one or more insulating bodies 5 and 7 , which are preferably thickened in the region of the greatest curvature of the stack, thereby preventing the stack from being bent too much and thereby breaking. These insulating bodies 5 and 7 fill the remaining space in the battery housing around the stack 3 , as a result of which the stack is given a very high overall stability. The insulating bodies 5 and 7 are preferably composed of the material in such a way that they compensate for temperature-dependent expansions of the stack 3 .

One or more temperature sensors 9 can be integrated in the insulating body 5 and 7 . This allows the temperature of the battery to be measured under load and, depending on this, to carry out a load-dependent control of, for example, a power tool.

The entire package of the folded stack 3 and the insulating bodies 5 and 7 is held together by means of insulating bolts 11 and 13 which are inserted across all layers of the stack 13 and the insulating bodies 5 and 7 lying between them. These insulating bolts 11 and 13 prevent mutual displacement of the individual layers of the stack 3 .

It is expedient to provide one or more of the outer conductive layers 15 and 17 of the stack 3 with a greater thickness than the other layers. This increases the mechanical stability of the stack 3 . Contact surfaces 19 and 21 can also be provided on the outer conductive layers 15 and 17 , to which an anode and a cathode connecting line can be soldered or welded.

The S-shape of the stack 3 has the effect that each conductive layer of the stack 3 runs partly along the outer walls of the housing 1 and is partly guided inside the housing 1 . All layers thus run equally through both cooler areas (on the outer walls) of the housing 1 and through warmer areas (in the center) of the housing 1 . This results in a certain compensation of the heat distribution in the layers of the stack 3 . So there are no layers that are exposed to a significantly greater thermal load than other layers. Of course, the layers lying inside the stack 3 experience a somewhat higher thermal load than the layers located on the outer edges of the stack. Here, too, a compensation can be created in that one or more inner conductive layers 23 are thicker than the other conductive layers and thus have a higher thermal conductivity. A better thermal conductivity of this inner layer (s) 23 can also be achieved through the selection of the material (e.g. copper). A particularly good heat dissipation is achieved by integrating 23 conduit tubes (not shown in the drawing) into the inner layer (s), through which a cooling medium, e.g. B. air, cooling gas, cooling liquid flows. Cooling fins 25 can be arranged on the outside of the battery housing 1 .

In FIG. 2 is a plan view of a single conductive layer 27 is shown. A number of holes 29 , 31 and 33 are embedded in the conductive layer 27 and serve as through-holes for the insulating bolt (s) 11 , 13 . The outer edge of the conductive layer 27 is surrounded by a frame 35 . Likewise, the edges of the holes 29 , 31 and 33 in the interior of the conductive layer 27 are provided with frames 37 , 39 and 41 . The frames 35 , 37 , 39 , 41 consist of an insulating material. They serve to give each individual conductive layer better mechanical stability. Furthermore, the frames 35 , 37 , 39 , 41 have the function of electrically isolating adjacent conductive layers from one another or of eliminating short circuits between electrically conductive layers.

The FIG. 3 to be removed exploded view of z. B. three conductive layers 43 , 45 and 47 illustrates how short circuits between the conductive layers 43 , 45 , 47 can be avoided by insulating frames 49 , 51 , 53 at the edges of the conductive layers 43 , 45 , 47 . The frames 49 , 51 , 53 have a somewhat greater thickness than the conductive layers 43 , 45 , 47 surrounded by them. If the conductive layers 43 , 45 , 47 are now stacked on top of one another, the frames 49 , 51 and 53 touch one another. Because of the greater thickness of the frames 49 , 51 , 53 , there is space between the conductive layers 43 , 45 , 47 for electrolyte layers 55 , 57 , which consist, for example, of a fleece impregnated with an electrolyte. If the conductive layers 43 , 45 , 47 with the frames 49 , 51 , 53 and the intermediate electrolyte layers 55 , 57 are stacked on top of one another, the edges of the electrically conductive layers 43 , 45 projecting beyond the electrolyte layers 55 , 57 can be , 47 no longer touch each other and thus do not cause a short circuit. In addition, the closely spaced frames 49 , 51 , 53 prevent conductive electrolyte liquid from passing from one space into the other via the edges of electrically conductive layers, which would result in a short circuit.

The insulating frame 35 , 37 , 39 , 41 , 49 , 51 , 53 can e.g. B. consist of a thermoplastic which is injection molded around the edges of the conductive layers. After all layers are stacked on top of each other, the frames are z. B. connected by gluing, embossing, ultrasonic welding, melting, extrusion coating or similar methods. To improve the connection of the insulating frame with the respective conductive layer, the edges can be provided with embossments or punchings 59 (see FIG. 2).

As can be seen from FIG. 2, the frame 35 has an opening 61 around the outer edge of the conductive layer 27 . Via this opening 61 in the frame 35 , a pressure equalization between the space filled with the electrolyte between two electrically conductive layers and the surroundings of the layer stack can take place. Overpressure inside the stack can occur especially when the battery is heavily loaded. The pressure equalization via the opening 61 prevents overpressure in the interior of the layer stack from destroying the battery. More than just one opening 61 can also be provided in the frame of the individual electrically conductive layers. It is crucial for the arrangement of the openings that there is a pressure equalization channel for each space filled with electrolyte between two electrically conductive layers. In the region of the opening 61 , a connection piece 63 , which extends out of the stack of layers, is preferably formed on the frame 35 . Overpressure inside the layer stack can cause electrolyte to penetrate the openings and possibly cause a short circuit between adjacent layers. This can be prevented by means of the connecting pieces surrounding the openings; because the nozzle form an expansion space for the electrolyte.

Claims (12)

1. Rechargeable battery, comprising a plurality of stacked electrically conductive layers ( 27 , 43 , 45 , 47 ) forming the anode and cathode of the battery, with an electrolyte between each two adjacent conductive layers ( 27 , 43 , 45 , 47 ). Layer ( 55 , 57 , 59 ) is inserted, characterized in that the edges of each conductive layer ( 27 , 43 , 45 , 47 ) with a frame ( 35 , 37 , 39 , 41 , 49 , 51 , 53 ) made of an insulating Material are surrounded and that the frames ( 35 , 37 , 39 , 41 , 49 , 51 , 53 ) of the conductive layers ( 27 , 43 , 45 , 47 ) are fixed together. 2. Rechargeable battery according to claim 1, characterized in that the frames ( 35 , 37 , 39 , 41 , 49 , 51 , 53 ) have a greater thickness than the surrounding conductive layers ( 27 , 43 , 45 , 47 ). 3. Rechargeable battery according to one of claims 1 or 2, characterized in that the frames ( 35 ) have openings ( 61 ) at one or more locations which point out of the stack ( 3 ) formed by the layers. 4. Rechargeable battery according to claim 3, characterized in that on the frame ( 35 ) in the region of the openings ( 61 ) connecting pieces ( 63 ) are formed, which extend out of the stack ( 3 ). 5. Rechargeable battery according to one of the preceding claims, characterized in that the stack ( 3 ) formed from the layers is folded in an S shape. 6. Rechargeable battery according to claim 5, characterized in that the stack ( 3 ) is folded around one or more insulating bodies ( 5 , 7 ). 7. Rechargeable battery according to one of the preceding claims, characterized in that one or more insulating bolts ( 11 , 13 ) are inserted through all layers of the folded stack ( 3 ). 8. Rechargeable battery according to claim 6, characterized in that in the (the) insulating body (s) ( 5 , 7 ) one or more temperature sensors ( 9 ) are integrated. 9. Rechargeable battery according to one of claims 1 or 5, characterized in that one or more of the outer electrically conductive layers ( 15 , 17 ) of the stack ( 3 ) are of greater thickness than inner conductive layers. 10. Rechargeable battery according to one of claims 1 or 5, characterized in that one or more layers ( 23 ) are arranged in the interior of the stack ( 3 ), which have a higher thermal conductivity compared to the other layers. 11. Rechargeable battery according to claim 10, characterized characterized that in the layer with high Thermal conductivity pipes for a cooling medium are integrated.   12. Rechargeable battery according to claim 10, characterized in that the layer ( 23 ) with high thermal conductivity is of greater thickness than the other layers and / or consists of a more thermally conductive material.