DE10112162B4 - Rechargeable battery - Google Patents

Abstract

rechargeable Battery consisting of several the anode and cathode of the battery forming, one above the other stacked electrically conductive layers (27, 43, 45, 47), wherein between each two adjacent conductive layers (27, 43, 45, 47) an electrolyte layer (55, 57, 59) is inserted, the edges each conductive layer (27, 43, 45, 47) with a frame (35, 37, 39, 41, 49, 51, 53) are surrounded by an insulating material, the Frame (35, 37, 39, 41, 49, 51, 53) of the conductive layers (27, 43, 45, 47) are fixed together and one of these layers (27, 43, 45, 47) formed stack is S-shaped folded.

Description

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

For example, for power tools, there are nickel-cadmium or nickel-metal hydride batteries with different voltages and capacities. Like from the DE 35 02 449 C2 As can be seen, these accumulators - in short batteries - consist of several interconnected single cells, each of which has a voltage of z. B. 1.2V supplies. Usually, several such single cells are connected in series in the batteries for power tools, so that the battery has a total voltage of z. B. 9.6V, 14.4V, 18V or 24V provides. Each single cell of the battery has, as well as from the EP 06 03 397 A1 discloses an electrically conductive layer forming the anode, an electrically conductive layer forming the cathode and an electrolyte layer interposed therebetween. The stack formed from these three layers is rolled up and housed in a metal tube. The number of interconnected individual cells depends on how large the capacity and the voltage of the battery should be. The individual cells are electrically contacted via current-conducting webs. The contact points, which are soldering or welding points, form an internal resistance of the battery, which represents a heat source in the event of an electrical load on the battery. In a battery housing, in which several individual cells are packed together, there is a very different heat distributions. Because for those cells which are arranged in the vicinity of the housing wall of the battery, there is a better heat dissipation than for the cells further inside the battery housing. This differential heat distribution in the cells leads to an imbalance in the charge level of the individual cells. It can lead to a reversal of the cells with the lowest charge levels, which these cells can be destroyed. At high electrical load of the battery can also cause a thermal overuse of some cells, which causes the electrolyte is blown out of the cells, resulting in failure of the cells and eventually the entire battery. A built-up battery also does not use the volume optimally, since there are relatively large cavities between the constructed in the form of metal tubes single cells.

In the Japanese application JP 10208773 There is described a rechargeable battery which, as set forth above, consists of a plurality of the anode and cathode of the battery forming, stacked electrically conductive layers and disposed therebetween electrolyte layers. By folding the stack, a low-volume battery can be produced, which has a high capacity due to a very large surface of the folded layers. The number of layers stacked depends on the voltage the battery should deliver.

From the DE 44 19 418 A1 and the DE 828 730 B Flat plate batteries are known in which the plates have at the edges insulating frames, which serve either to support the plates between pole plates (see. DE 44 19 418 A1 ) or several layers (cf. DE 828 730 B ).

Of the Invention is based on the object, a rechargeable battery specify the type mentioned, the compact design has and with the easy to produce means a great security against short circuits between the individual layers can be achieved.

Advantages of invention

The said object is characterized by the features of claim 1 solved, that the edges of all the anode and cathode of the battery forming stacked conductive Layers surrounded by a frame of insulating material are that the frames of the conductive layers fixed together and that a stack formed from these layers is folded in an S-shape is. The insulating frames at the edges of the conductive layers on the one hand avoid unintentional electrical contact between adjacent conductive layers and on the other hand offer the possibility, mechanically fix the conductive layers to each other. The insulating frame also avoid that electrolyte-liquid from the space between the electrically conductive layers flows and thus a short circuit between electrically conductive layers could cause. A very space-saving rechargeable battery is created by the S-shaped Folding of the stack formed from the conductive layers.

Advantageous developments of the invention will become apparent from the dependent claims. It is expedient that the frames have a greater thickness than the conductive layers surrounded by them. Thus, the conductive layers, when their frames are placed one on top of the other, are kept at a distance from each other so that there is room between them for receiving electrons trolyt layers. The frames may be provided at one or more locations with apertures pointing out of the stack formed by the layers. The advantage of these openings is that they provide pressure equalization between the environment and the electrolyte-filled space between the conductive layers. It is advantageous that are formed on the frame in the region of their openings sockets extending out of the stack. These nozzles form pressure equalization channels and prevent electrolyte from entering the adjacent layers through the openings causing a short circuit.

Becomes the stack formed by the multiple layers by one or more insulating bodies folded over, so receives the stack thereby a good stability and is when folding against Break protected. To the layers of the folded pile and the individual layers within the stack against slippage or mutual displacement To secure, it is advantageous that through all the layers of the folded Stack one or more insulating bolts are plugged.

In the insulating bodies can one or more temperature sensors are integrated with which the heat generated in the rechargeable battery is measurable.

It is advantageous if one or more of the outer electrically conductive Layers of the stack of greater thickness are called inner conductive layers, around the entire stack one good mechanical stability to give.

in the Inside the stack can preferably one or more layers are arranged in the Compared to the other layers have a higher thermal conductivity. This higher thermal conductivity can z. B. be achieved by integrating in the layers of conduits for a cooling medium or that they have a greater thickness than have the other layers and / or of a better thermally conductive material consist. Thus, a more balanced heat distribution within the Stack can be achieved.

drawing

Based an embodiment shown in the drawing will be below the invention closer explained. Show it:

1 a cross-section through a rechargeable battery with an S-shaped stack of conductive layers and electrolyte layers,

2 a single conductive layer, which is edged with a frame and

3 a side view of a plurality of framed electrically conductive layers with inserted therebetween electrolyte layers in an exploded view.

description an embodiment

In the 1 is a cross section through a rechargeable battery (hereinafter referred to as battery) shown, wherein in the battery case 1 an S-shaped folded stack 3 composed of a plurality of conductive layers forming the anode and cathode of the battery and housed in a plurality of electrolyte layers interposed between the conductive layers. As below with reference to 3 explained in more detail, take turns in the pile 3 electrically conductive layers, which form the anode, with electrically conductive layers, which form the cathode of the battery from. Between each anode layer and cathode layer is an electrolyte layer consisting, for example, of an electrolyte-filled nonwoven material. All the conductive layers belonging to the anode and, separately therefrom, all the conductive layers belonging to the cathode are electrically connected to one another. This is in the 1 , because not subject of the invention, not shown. The belonging to the stack electrically conductive layers are preferably thin sheets, on one side z. B. coated with cadmium and on the other side with nickel. Instead of cadmium and nickel but other materials commonly used for rechargeable batteries in question.

The Number of superimposed stacked layers depends of which voltage the battery should ultimately deliver. The loading capacity the battery hangs of the area size of the layers from.

By, as in 1 shown, S-shaped folding of the stack 3 can very large layers in a relatively small volume housing 1 be housed.

It is convenient to the stack 3 around one or more insulating bodies 5 and 7 fold around, which are preferably thickened in the region of the strongest curvature of the stack, thereby preventing the stack is bent too much and thereby breaks. This insulating body 5 and 7 fill the remaining space in the battery case around the stack 3 which gives the stack a very high overall stability. The insulating body 5 and 7 are preferably composed of material so that they are temperature-dependent expansions of the stack 3 compensate.

In the or the insulating bodies 5 and 7 can have one or more temperature sensors 9 to get integrated. Thus, the temperature of the battery can be measured under load and make depending on a load-dependent control, for example, a power tool.

The entire package from the folded stack 3 and the insulating bodies 5 and 7 is by means of insulating bolts 11 and 13 held together, which across all layers of the stack 13 and the intervening insulating bodies 5 and 7 are inserted through it. These insulating bolts 11 and 13 prevent mutual shifting of the individual layers of the stack 3 ,

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

The S-shape of the pile 3 causes each conductive layer of the stack 3 partly on the outer walls of the housing 1 runs along and partly inside the housing 1 to be led. Thus, all layers run equally through both cooler areas (on the outer walls) of the housing 1 as well as warmer areas (in the center) of the housing 1 , This provides some balance of heat distribution in the layers of the stack 3 instead of. So there are no layers that are exposed to a significantly higher heat load than other layers. Of course, they are inside the pile 3 lying layers a slightly higher heat load than the located at the outer edges of the stack layers. Again, a balance can be created by having one or more inner conductive layers 23 are of greater thickness than the other conductive layers and thus have a higher thermal conductivity. Better thermal conductivity of this inner layer (s) 23 can also be achieved by selecting the material (eg copper). A particularly good heat dissipation is achieved in that in the inner layer (s) 23 Conduits are integrated (not shown in the drawing), through which a cooling medium, for. As air, refrigerant gas, coolant, flows. On the outside of the battery case 1 can be cooling fins 25 be arranged.

In the 2 is the top view of a single conductive layer 27 shown. In the conductive layer 27 are some holes 29 . 31 and 33 embedded, which as through holes for the or, the insulating bolts 11 . 13 serve. The outer edge of the conductive layer 27 is with a frame 35 surround. Likewise, the edges of the holes 29 . 31 and 33 inside the conductive layer 27 with frame 37 . 39 and 41 Mistake. The frames 35 . 37 . 39 . 41 consist of an insulating material. They serve to give each individual conductive layer a better mechanical stability. Furthermore, the frames have 35 . 37 . 39 . 41 the function of electrically insulating adjacent conductive layers against each other or excluding short circuits between electrically conductive layers.

The the 3 to be taken exploded view of z. B. three conductive layers 43 . 45 and 47 illustrates how through insulating frames 49 . 51 . 53 at the edges of the conductive layers 43 . 45 . 47 Short circuits between the conductive layers 43 . 45 . 47 be avoided. The frames 49 . 51 . 53 have a slightly larger thickness than the conductive layers you surround 43 . 45 . 47 , Now become the conductive layers 43 . 45 . 47 Stacked on top of each other, the frames touch each other 49 . 51 and 53 each other. Because of the larger thickness of the frame 49 . 51 . 53 remains between the conductive layers 43 . 45 . 47 Space for electrolyte layers 55 . 57 , which consist for example of a nonwoven impregnated with an electrolyte. When the conductive layers 43 . 45 . 47 with the frame 49 . 51 . 53 and the intermediate electrolyte layers 55 . 57 Stacked on top of each other, they can spread over the electrolyte layers 55 . 57 protruding edges of the electrically conductive layers 43 . 45 . 47 no longer touching each other and thus causing no short circuit. In addition, prevent the closely superimposed frame 49 . 51 . 53 in that conductive electrolyte fluid overflows the edges of electrically conductive layers from one gap to the other, resulting in a short circuit.

The insulating frame 35 . 37 . 39 . 41 . 49 . 51 . 53 can z. B. made of a thermoplastic, which is injected around the edges of the conductive layers. After all layers are stacked on each other, the frames are z. B. by gluing, embossing, ultrasonic welding, melting, encapsulation or similar methods. For better connection of the insulating frames with the respective conductive layer, the edges can be stamped or punched 59 (see. 2 ).

Again 2 it can be seen, the frame 35 around the outer edge of the conductive layer 27 an opening 61 on. About this opening 61 as part of 35 can be a pressure balance between the space filled with the electrolyte between two electrically conductive layers and the environment of the layer stack done. An overpressure inside the stack can occur in particular when the battery is heavily loaded. The one over the opening 61 Pressure equalization prevents overpressure inside the layer stack from destroying the battery. There may also be more than one opening in the frame of the individual electrically conductive layers 61 be provided. Decisive for the arrangement of the openings is that for each filled with electrolyte space between two electrically conductive layers, a pressure compensation channel is present. Preferably, in the region of the opening 61 to the frame 35 a spigot extending out of the layer stack 63 formed. Due to overpressure in the interior of the layer stack, electrolyte can penetrate into the openings and possibly cause a short circuit between adjacent layers. This can be prevented by means of the openings surrounding the openings; because the nozzles form an expansion space for the electrolyte.

Claims (11)

Rechargeable battery consisting of a plurality of the anode and cathode of the battery forming, stacked electrically conductive layers ( 27 . 43 . 45 . 47 ), wherein between each two adjacent conductive layers ( 27 . 43 . 45 . 47 ) an electrolyte layer ( 55 . 57 . 59 ), the edges of each conductive layer ( 27 . 43 . 45 . 47 ) with a frame ( 35 . 37 . 39 . 41 . 49 . 51 . 53 ) are surrounded by an insulating material, the frames ( 35 . 37 . 39 . 41 . 49 . 51 . 53 ) of the conductive layers ( 27 . 43 . 45 . 47 ) are fixed together and one of these layers ( 27 . 43 . 45 . 47 ) formed stack is folded S-shaped. Rechargeable battery according to claim 1, characterized in that the frames ( 35 . 37 . 39 . 41 . 49 . 51 . 53 ) have a greater thickness than the conductive layers surrounding them ( 27 . 43 . 45 . 47 ). Rechargeable battery according to one of claims 1 or 2, characterized in that the frames ( 35 ) at one or more locations openings ( 61 ) consisting of the stack formed by the layers ( 3 ) point out. Rechargeable battery according to claim 3, characterized in that the frame ( 35 ) in the area of the openings ( 61 ) Support ( 63 ) formed from the stack ( 3 ). Rechargeable battery according to claim 1, characterized in that the stack ( 3 ) around one or more insulating bodies ( 5 . 7 ) is folded over. Rechargeable battery according to one of the preceding claims, characterized in that through all the layers of the folded stack ( 3 ) one or more insulating bolts ( 11 . 13 ) are plugged. Rechargeable battery according to Claim 5, characterized in that in the insulating body (s) (s) ( 5 . 7 ) one or more temperature sensors ( 9 ) are integrated. Rechargeable battery according to claim 1, characterized in that one or more of the outer electrically conductive layers ( 15 . 17 ) of the stack ( 3 ) of greater thickness than inner conductive layers. Rechargeable battery according to claim 1, characterized in that inside the stack ( 3 ) one or more layers ( 23 ) are arranged, which have a higher thermal conductivity compared to the other layers. Rechargeable battery according to claim 9, characterized characterized in that in the layer with high thermal conductivity of conduit tubes for a cooling medium are integrated. Rechargeable battery according to claim 9, characterized in that the layer ( 23 ) having a high thermal conductivity of greater thickness than the other layers and / or consists of a better thermally conductive material.