EP0648381A1

EP0648381A1 - Method and device for sorting scrap batteries and accumulators

Info

Publication number: EP0648381A1
Application number: EP94912665A
Authority: EP
Inventors: Christian Calame-Rosset
Original assignee: FIRSTEC SA
Current assignee: FIRSTEC SA
Priority date: 1993-05-03
Filing date: 1994-05-03
Publication date: 1995-04-19
Also published as: WO1994025992A1

Abstract

A simplified method of sorting scrap batteries and accumulators of different shapes, sizes and chemical compositions consists in measuring several physical parameters during shifting of the batteries or accumulators through a measuring device: at least one dimension, the metallic mass and/or the mass (total weight), the ferromagnetic mass and preferably a derivative of the ferromagnetic mass by filtering of harmonics, or measurement of a colour or distinctive sign. For each type of battery or accumulator, an identification signal or signature consisting of a characteristic combination of the digital values of the measured parameters is established and, based on the identification signal, a sorting signal is determined according to battery or accumulator chemical composition.

Description

METHOD AND DISPOSTTTF OF TRT OF USED BATTERIES AND ACCUMULATORS

Technical area

The present invention relates to a method and a device for sorting used batteries and accumulators.

State of the art

About 200 to 250 types of batteries or accumulators of different size, shape and chemical nature are listed on the market, which poses problems when sorting from mixtures collected from the general public. In general, the sorting of used batteries or accumulators comprises a first preliminary mechanical sorting step in order to separate the batteries or accumulators according to their shape and / or their dimensions, followed by a second step, for a given shape and / or dimensions. , depending on the chemical nature of the batteries or accumulators, by measuring one or more parameters characteristic of the part concerned.

The chemical nature of a battery or accumulator can be determined by measuring its specific mass or by measuring thermal, acoustic or electrical properties. For example, the analysis of the speed of propagation of ultrasound through the body of the part to be analyzed, or the measurement of the heat dissipation power of the part after a short heating period, or the measurement of the residual electrical resistance , are indications directly linked to the composition and / or the internal structure of the used battery or accumulator. However, after use or during storage, these methods are not sufficiently reliable. The analysis of the internal composition of the battery or accumulator is necessary for the determination of their chemical nature, but this analysis must be carried out with unopened batteries or accumulators, by a method making it possible to remove the influence of the outer layers of the cell or accumulator shell.

The identification of a battery or accumulator by measuring several parameters has been envisaged, using several measurement and sorting stations in order to achieve a grouping of batteries and accumulators of the same type after several measurements and sorting in cascade.

Publication WO91 / 15036 describes a device and a method for sorting used batteries or accumulators according to their chemical nature, based on the analysis of the inductive effect produced by the materials contained in the battery or accumulator, including the ferromagnetic properties are different according to their chemical nature, this by the consecutive application to an excitation circuit of at least two different voltage amplitudes at the same frequency, or two different frequencies for the same voltage amplitude.

An improved method of sorting used batteries and accumulators of different shapes and sizes and of different chemical compositions, which comprises mechanical sorting according to shapes and dimensions, followed by sorting according to chemical composition, is described in publication W092 / 17791. Sorting according to the chemical composition involves the elaboration, by the passage at constant speed of a cell or an accumulator through a coil, of an inductive response with two components, representative of the ferromagnetic mass of the cell or the accumulator, and the distribution of the ferromagnetic mass. However, these sorting methods have certain shortcomings, linked in particular to the sorting head. Despite great efforts to increase the capacity, it has not been possible to develop heads allowing both efficient sorting at high throughput and a small percentage of sorting errors or rejects. Therefore, the treatment of high flow rates requires the use of several measuring heads for sorting according to the chemical composition, with several control computers, therefore a high cost.

Also, the determination of the ferromagnetic mass requires a very thorough preliminary mechanical sorting to separate the used batteries and accumulators according to their exact dimensions.

In addition to the need for a thorough preliminary dimensional sorting, the orientation of the batteries and accumulators, as well as their speed of movement through the head must be controlled, usually by means of a conveyor belt.

Certain spent batteries and accumulators present in the mixture have external contact parts, etc., which can distort the measurements.

As new kinds of batteries and accumulators are appearing on the market in different countries, it is necessary to adapt the sorting facilities to local conditions. It would therefore be desirable to have a head capable of sorting a flow of batteries or accumulators of different shapes and dimensions according to their chemical composition, and which could easily adapt on the spot to all kinds of batteries and accumulators encountered in the mixture to be sorted.

Description of the Invention

The subject of the invention is a simplified method and device for sorting and separating automatically used batteries or accumulators of different shapes and sizes depending on their chemical nature, and which in particular allow large flows to be processed. The method and the device specific to this invention obviate the drawbacks of known methods and devices and allow sorting and separation of used batteries or accumulators of different shapes and dimensions in a quick, reliable and economical manner according to their chemical nature.

The present invention therefore provides a simplified method for sorting used batteries and accumulators, as well as a sorting installation, according to the statement of claims. According to the invention, for each used battery or accumulator, an identification signal or "signature" is established consisting of a characteristic combination based on the measurement of several parameters, in particular a dimension (for example the length), the metallic mass , the ferromagnetic mass and, advantageously, a derivative of the ferromagnetic mass composed of filtered harmonics.

It is also possible to use another derivative of the ferromagnetic mass, for example the distribution thereof, or to carry out several measurements of the ferromagnetic mass at different frequencies or excitation voltages. However, the use of filtered harmonics is advantageous because the excitation circuit needs only one excitation coil, and because of the speed of the response.

It is also possible to measure other parameters, for example the mass (total weight), this by measuring the kinetic energy of the battery or accumulator in motion through the measuring device, for example by impact against a sensor or by slowing down. caused by the battery or accumulator. Or an optical measurement of the color or another distinctive sign, for example a barcode or the like. A another possibility is a measurement for detecting a coating of special composition, or of an added element such as a magnetic strip or wire or the like.

With this method and device, it is possible to reliably sort batteries and accumulators of different shapes and sizes, according to their composition, and this without a preliminary dimensional sorting being necessary or else with a rough preliminary sorting for n ' dispose of only very large or very small batteries or accumulators.

Sorting can be done by simply dropping the batteries and accumulators through the measuring device, for example in an inclined tube whose internal diameter is sufficient to allow the largest batteries and accumulators to be sorted to pass.

The method also allows a "learning" of the characteristics of all kinds of batteries and accumulators, allowing its rapid and simple adaptation to any new kind of battery or accumulator.

Description of Drawing

In the attached drawing:

- Figure 1 is a diagram of a sorting device according to the invention.

Detailed description

The device illustrated in Figure 1 by way of example consists of a tube 1 into which the battery 2 to be tested slides. The tube 1, preferably made of transparent material, for example acrylic, has an internal diameter capable of receiving the range of cells and accumulators to be sorted, for example of the order of 40-60 mm. This tube 1 is inclined at 45 ° or any other suitable angle for the fall of the batteries and accumulators. Along this tube 1 are arranged various detectors, the responses of which are transmitted to a microprocessor 3. The data received is processed by the microprocessor 3, allowing it to identify the type of battery and to direct it towards the place desired, by means of a sorting signal S.

The detectors arranged along the tube 1 are: an optical unit 4, a tuned coil 5, an excitation coil 6, and two receiving coils 7 and 8.

The optical unit 4 comprises several optical detectors arranged along the tube 1, for example four infrared cells 4a arranged two by two on the opposite edges of the lower part of the tube 1, and spaced along the tube, for example about 10 cm.

This judicious distribution of infrared cells 4a on the passage of the stack 2 allows the microprocessor 3 to calculate the length and the average speed of the stack in the tube 1. Other arrangements allow, if desired, the calculation of the diameter or the width of batteries and accumulators.

The tuned coil 5 is energized and tuned on a high frequency, about 50 to 200 kHz, and operates on the principle of a metal detector. During the passage of a battery 1, the circuit is detuned by modification of the self-induction and of the selectivity. After analog / digital conversion of this detuning, by the oscillator / converter 10, the microprocessor 3 supplies a digital signal which represents the metallic mass of the battery 2.

The excitation coil 6 is supplied from an amplifier 11 by a low frequency current, for example around 300 Hz, and thus creates a magnetic field in the tube 1. The receiver coils 7 and 8 are mounted in opposition, so that at rest, their magnetic fields cancel each other out.

During the passage of a battery 2 in front of the receiving coils 7 and 8, a current proportional to the magnetic mass of the battery 2 is induced in these coils 7 and 8.

It can be seen that the shape of the signal collected by the coils 7, 8 depends on the magnetic quality of the battery 2. The magnetic mass of a Ni-Cd accumulator is mainly defined by the presence of nickel in the accumulator, while the magnetic mass of other batteries is only defined by the mantle. By the saturation of the flux induced in this mantle, the signal collected by the coils 7, 8 for these other batteries has a higher harmonic rate than for Ni-Cd accumulators (mainly harmonic 3). In general, we can say that a good ferromagnetic quality causes few harmonics, while an average ferromagnetic quality causes more harmonics.

The first coil 7 collects the absolute magnetic signal, and it is the amplitude of this absolute signal, representative of the ferromagnetic mass of the battery 2, which is processed by the filter / converter 12. The signal from the second coil 8, after filtering, contains only the harmonics of the signal. After analog / digital conversion of these signals by the filters / converter 12, the microprocessor 9 can easily identify the Ni-Cd accumulators, which have a low harmonic rate.

The device described provides, for each battery 2, a "signature" composed of four values which make it possible to identify it, in this example: the length (optical unit 4), the metal mass (coil 5), the ferromagnetic mass (coil 7), and the ferromagnetic quality or harmonic rate (coil 8). These four values digitized by the microprocessor 3 are compared with reference values or signatures so as to produce the sorting signal S as a function of the chemical composition of the batteries and accumulators.

At the start, these four characteristic values are established by successive passages of a reference battery or accumulator in order to constitute these reference values or signatures. Each battery or accumulator is therefore identified by these four values which constitute an identification signal or signature. However, it is possible that certain stacks can be identified by several sets of four values, for example the rectangular stacks capable of crossing the tube 1 under different orientations. Knowing the composition of these reference batteries and accumulators, the reference values of each identification signal can be associated with a sorting signal chosen according to the chemical composition.

When sorting a mixture, the four values obtained for each cell or accumulator correspond either to the reference values, which causes the corresponding sorting signal, or are unknown and the cell or the accumulator is discarded. In this case, an examination of the battery or accumulator allows it to be assigned a sorting signal according to its composition.

The device described can be supplemented by other detectors, for example X-ray, optical

(color and / or distinctive signs detectors), impact / inertia (weight measurement), etc., in order to measure any other parameter allowing the identification of the battery or accumulator.

In a variant of the invention, in particular when it is a question of separating Ni-Cd batteries from the others, in particular where a dimensional sorting has already taken place, it is can be satisfied with inductively measuring the ferromagnetic mass as well as a filtered harmonic component representing the quality of the ferromagnetic mass as described above, and providing a sorting signal thereof in order to separate in particular the Ni-Cd batteries from other. It is also possible to include the measurement of other parameters such as those mentioned above.

Claims

Re end cations

1. A method of sorting used batteries and accumulators of different shapes and sizes and of different chemical compositions, by measuring at least one physical parameter when moving the batteries or accumulators through a measuring device, characterized in what:

for at least one battery or accumulator of each type of battery or accumulator to be sorted, several parameters are measured, including:

(a) the ferromagnetic mass, and

(b) at least two other parameters, preferably among: a derivative of the ferromagnetic mass, at least one dimension, the metallic mass, the mass (total weight) and the measurement of a color and / or an optical sign visible on the battery or the accumulator,

an identification signal is established for each type of cell or accumulator consisting of a characteristic combination of these parameters, and

in that, for a flow of batteries and accumulators of different shapes and different dimensions introduced individually through the measuring device, a sorting signal is provided for each cell or accumulator according to the chemical composition of the cell or of the accumulator, based on said identification signal.

2. Method according to claim 1, characterized in that the identification signal is a signal comprising four digital values which represent: a dimension, at least one of the metallic mass and mass (total weight), ferromagnetic mass and a derivative of ferromagnetic mass.

3. Method according to claim 1 or 2, characterized by measuring a value derived from the ferromagnetic mass which is a filtered harmonic component representing the quality of the ferromagnetic mass.

4. Method according to claim 1, 2 or 3, characterized in that the batteries or accumulators pass through the measuring device by the effect of gravity.

5. Method according to claim 4, characterized in that the batteries or accumulators pass through the measuring device in an inclined tube.

6. Method according to any one of the preceding claims, characterized in that the size of the batteries or accumulators is measured by means of an optical detector which, preferably, also measures their speed.

7. Method according to any one of the preceding claims, characterized in that the identification signal of each cell or accumulator is compared with the reference values established by the passage through the device for measuring cells or accumulators of compositions known.

8. Method according to any one of the preceding claims, characterized in that a sorting signal according to the composition is provided for the batteries or accumulators whose identification signals correspond to the reference values, and which is discarded unrecognized batteries or accumulators.

9. Sorting device for used batteries and accumulators of different shapes and sizes and of different chemical compositions, intended for producing a signal sorting (S) by measuring at least one physical parameter by moving the batteries or accumulators (2) through a measuring device, characterized in that:

the measuring device comprises means for measuring several parameters of each cell or accumulator (2), namely:

(a) means (6/7) for measuring the ferromagnetic mass;

(b) means (4; 5; 6/8) for measuring at least two other parameters, preferably among: a derivative of the ferromagnetic mass, at least one dimension, the metallic mass, the mass (total weight), and measuring a color and / or an optical sign visible on the battery or accumulator,

and that the device also comprises:

means (3, 10, 11, 12) for establishing an identification signal for each type of cell or accumulator consisting of a characteristic combination of these parameters measured by the measuring means, and

means (3) for supplying a sorting signal (S) according to the chemical composition of the cell or accumulator, based on said identification signal.

10. Device according to claim 9, characterized in that the means (3, 10, 11, 12) for establishing the identification signal comprise at least one analog-digital converter providing an identification signal comprising four digital values which represent : one dimension, at least one of the metallic mass and the mass (total weight), the mass ferromagnetic and a derivative of the ferromagnetic mass.

11. Device according to claim 10, characterized in that it comprises at least one excitation coil (6) and at least one receiving coil (7, 8) producing an inductive response representative of the ferromagnetic mass of the batteries or accumulators ( 2) when these pass through the magnetic field produced by the excitation coil (s) (6).

12. Device according to any one of claims 9 to 11, characterized in that the batteries or accumulators (2) pass through the measuring device by the effect of gravity, in an inclined tube (1).

13. Device according to any one of claims 9 to 12, characterized in that the measuring device comprises an optical detector.

14. Device according to any one of claims 9 to 13, characterized in that the device comprises a tuned coil (5) at high frequency which measures the metal mass of the batteries or accumulators (2) by modification of the self induction and selectivity when passing a battery or accumulator.

15. Installation for sorting used batteries and accumulators, comprising a sorting device according to any one of claims 9 to 14, and a device for switching sorted batteries and accumulators.

16. A method of sorting used batteries and accumulators of different shapes and sizes and of different chemical compositions, by measuring at least one physical parameter when moving the batteries or accumulators through a measuring device, characterized in what: _ -

- for at least one battery or accumulator of each type of battery or accumulator to be sorted, several parameters are measured, including:

(a) the ferromagnetic mass, and either

(b) a derivative of the ferromagnetic mass which is a filtered harmonic component representing the quality of the ferromagnetic mass, namely

(c) at least two other parameters, preferably among: a derivative of the ferromagnetic mass, at least one dimension, the metallic mass, the mass (total weight) and the measurement of a color and / or an optical sign visible on the battery or the accumulator,

- in that there is provided, for each cell or accumulator, a sorting signal according to the chemical composition of the cell or accumulator, based on said identification signal.