ITTO20110614A1 - BATTERY PACKAGE SAFETY SYSTEM. - Google Patents

Description

TITLE: SYSTEM FOR SECURING BATTERY PACKS

The present invention relates to a system for securing one or more battery packs, which comprise a plurality of cells. Said system electrically dissects portions of said battery pack, in order to obtain at the ends of said reduced cell sets a safety low voltage perfectly compatible with the electrical safety standards.

In the field of electrical energy storage, battery packs are known which comprise a plurality of cells suitably connected to each other, so that at the ends of said battery pack there is a predetermined voltage, and the same battery pack is able to supply a current suitable for powering electronic devices, for example motor vehicles with even electric traction. The battery packs suitable for powering said vehicles are large in size and comprise a large number of electrically interconnected cells.

Typically, the voltage of a single cell is low enough to be considered safe; in fact, normally each cell does not exceed 4Vdc.

Typically, the battery pack in its entirety comprises control devices capable of securing the battery pack in the event of short circuits or other electrical problems of the electronic device to which it is connected.

Furthermore, the contact by an operator, for example a maintenance person, with the casing of the battery pack itself is completely safe.

In the event of an accident, in which the integrity of the battery pack is compromised, it is possible that part of the casing of the battery pack, or of the casing of the electronic device, is subjected to a voltage equal to a fraction of the voltage of the battery pack itself. .

In fact, it is possible that, due to the compromise of the integrity of a battery pack, a portion of the cells of which it is made up, energize a portion of the casing where the battery pack is located.

The construction of battery packs does not include safety devices, adapted to section the battery pack itself into a plurality of sections at the ends of which there is a low safety voltage, and that the current that can be supplied by said portion is lower than a predetermined threshold of safety.

At present, there are no safety systems capable of securing the battery pack, cutting it into electrically safe portions, in the event that the integrity of the battery pack itself is compromised.

Also known are switch systems suitable for sectioning a circuit. These systems comprise switches of the semiconductor type which interrupt or at least reduce the flow of a current inside said circuit, without however guaranteeing galvanic isolation of the contacts; therefore, said type of switches cannot be applied to safety systems.

The use of relays in safety systems is also known as they guarantee galvanic isolation between the contacts. Said relays, to ensure the opening of an electric load in "DC", are made with oversized contacts, therefore expensive, and with excitation coils with high consumption.

The present invention aims to solve the aforementioned problems by realizing a system for securing battery packs, which comprises at least one central unit and at least one peripheral unit, in such a way as to allow the securing of battery packs, also of large dimensions, by sectioning said battery pack at the level of modules comprising one or more cells.

An aspect of the present invention relates to a system for securing battery packs with the characteristics of the attached independent claim 1.

The accessory characteristics are reported in the attached dependent claims.

The characteristics and advantages of the system, according to the present invention, will be better clear and evident from the description of different embodiments of the system, and from the attached figures which respectively illustrate:

Figure 1 shows a block diagram of the system according to the present invention;

Figure 2 shows an embodiment of the electrical diagram of the system of figure 1;

Figure 3 shows a further embodiment of the general electrical diagram of the system of figure 1;

• figure 4 shows, in detail, the wiring diagram of figure 3.

With reference to the aforementioned figures, the safety system, according to the present invention, applicable to one or more battery packs "B" for the accumulation of electrical energy, each comprising a plurality of cells "C", in use, electrically connected in a plurality of "M" modules.

Said system comprises at least one central unit 3 and at least one peripheral unit 4.

Said at least one central unit 3 comprises at least one control unit 32, and is electrically connected to one or more modules "M" of cells "C".

Said at least one peripheral unit 4 is electrically connected to at least one module "M" and with said central unit 3 and comprises a plurality of switches (43, 33), electrically controlled and suitably connected to one or more cells "C" included in said module "M".

Said at least one central unit 3, following the pressure of at least one emergency button 1, suitable for signaling damage to the battery pack "B", is able, through said control unit 32, to isolate at least one module "M" , interrupting the current in said module "M", and disconnecting said module "M", opening said plurality of switches (43 33), in such a way that said module "M" is galvanically isolated and that at its ends there is at most a pre-established safety low voltage.

For the purposes of the present invention, the term at the ends there is at most a predetermined safety voltage means that at the ends of the module "M" there is a voltage between OVdc and a predetermined safety voltage as defined by Safety Extra Low Voltage.

As illustrated in Figure 1, the central unit 3 is connected to the battery pack "B", from which it also draws energy for powering the electronic devices included in the system according to the present invention, through one or more cells "C".

One or more peripheral units 4 are connected to said central unit 3, suitably connected to each other, for example connected in parallel or in series, depending on the characteristics of the battery pack "B".

To each peripheral unit 4 is connected one or more modules "M" of cells "C", in which said modules "M" each comprise at least one cell "C".

During normal use of the battery pack "B", each peripheral unit 4 connects in series and / or in parallel the various cells "C" included in each module "M" connected to it.

The ends of one or more modules "M" connected to the respective peripheral units 4 reach said central unit 3.

Each peripheral unit 4 is connected to the central unit 3 via at least one data line 5, preferably a serial line, for example implementing the RS-485 standard.

Through said data line 5, the central unit 3 and in particular the control unit 32, can communicate with the individual peripheral units 4, in order to disconnect one or more portions of the battery pack "B", in case of danger or during the maintenance phases of the battery pack "B", for example in the event of a fault.

In the embodiment illustrated in Figure 2, the control unit 32 is able to manage a plurality of switches 33, in use closed, included in the peripheral unit 4, able to open, so that at least one module "M" , or a section of it "Μ '", is galvanically isolated and that at its ends there is at most a predetermined low safety voltage.

For the purposes of the present invention, the term switch means an electromechanical device adapted to interrupt the current in at least one portion of the electrical circuit by providing galvanic isolation between the contacts.

In the embodiment of Figure 2 said switches 33 are normally open electromechanical relays. Said relays comprise a coil which must be traversed by current, in order to be able to cause said switch 33 to close the contact in order to form the module "M". The use of relays allows to have a galvanic isolation between the contacts through an air gap, therefore fully applicable in safety systems.

Removing the power supply voltage of the relays causes them to open, opening the electrical contact.

The opening of the switches 33, in a substantially simultaneous manner, causes the interruption and sectioning capacity required of each individual switch 33 to be reduced. This solution makes it possible to use relays with reduced contact dimensions, which can therefore be easily integrated into an electronic system, and with low-consumption excitation coils.

The opening of the switches 33, included in a module "M", allows the sectioning of the module "M" itself, for example at the level of each single cell "C", intrinsically placing at least said portion of the battery pack "B" sectioned, in safety, since this portion is damaged for example due to an impact or an accident.

Preferably, two switches 33 are connected to each cell "C" included in the module "M", respectively a first switch connected to the cathode terminal and a second switch connected to the anode terminal of each cell "C".

As mentioned above, the activation of the system according to the present invention occurs following the pressure of at least one emergency button 1 connected to the system according to the present invention. Preferably, said at least one pushbutton 1 is connected to the central unit 3 and is placed in series with an emergency line. Said at least one emergency button 1, according to the electrical safety standards, is a continuous switch, preferably a pressure switch, so that in the event of danger, for example damage to said battery pack "B", it is possible to put safely at least a portion of the battery pack "B", for example the damaged portion of the battery pack itself.

This at least one emergency button 1, in addition to being pressed in case of danger, can be pressed by an operator assigned to maintain the battery pack before starting maintenance.

In the alternative embodiment, illustrated in Figure 3, the peripheral unit 4 comprises a plurality of switches (43, 33), and in particular at least one switch 33 adapted to interrupt a direct current in at least one module "M", and one or more disconnectors 43, suitable for sectioning said module "M" into a plurality of sections "M '" galvanically insulated from the rest of the battery pack "B".

Said switch 33 is a relay adapted to open a direct electric contact, interrupting the flow of current in the module "M", extinguishing the electric arc generated during the opening of the contacts, ensuring electrical insulation.

Preferably, each switch 33 is placed in series with a module "M", and has structural characteristics suitable for interrupting the current flowing inside the module "M" itself. In particular, said switch 33 is a relay, which comprises an electromechanical switch and a solid state switch, placed in parallel, so as to increase the performance of the switch 33.

A method of reducing the breaking capacity required of the switch 33, for opening the contacts, and the consequent interruption of the current in the module "M", it is possible to place more than one switch 33 in series, for example two.

On the other hand, said one or more disconnectors 43 are adapted to section said module "M" into a plurality of sections of module "Μ '".

For the purposes of the present invention, the term disconnector refers to a switch capable of opening a line, ensuring galvanic isolation between the contacts when current flow is substantially absent on said line.

For the purposes of the present invention, the term substantially zero current means a current lower than 1/10 of the rated current flowing, in use, in the module "M".

In particular, said disconnectors 43 have technical and functional characteristics such as to ensure isolation with an air gap, but without the current breaking capacity being required.

If at least one emergency button 1 is pressed, the switch 33 is opened, blocking the flow of current in at least one module "M", for example damaged due to an accident. Following the interruption of the current in the module "M", the plurality of disconnectors 43 is able to disconnect said module "M", guaranteeing galvanic isolation between the contacts.

Said disconnectors 43 are preferably adapted to section the module "M" at the level of each single cell "C" included in the module itself. In particular, said disconnectors 43 can be, for example, two-exchange relays.

Preferably, two disconnectors 43 are connected to each cell "C" included in the module "M", respectively a first disconnector connected to the cathode terminal and a second disconnector connected to the anode terminal of each cell "C".

In the embodiment illustrated in detail in Figure 4, said central unit 30 comprises at least one energy storage device 34, capable of temporarily supplying said safety system in the event of a power failure by the battery pack "B" itself, a due to damage to the battery pack.

Said energy storage device 34, in a preferred embodiment, comprises a capacitor suitable for guaranteeing a predetermined voltage value, a capacitor charging device, suitable for stabilizing the energy coming from the battery pack "B", in order to to charge said capacitor, and at least one control device adapted to manage the charge of the capacitor itself in order to preserve its performance.

Said control unit 32 comprises a data processor 322, able to detect the pressure of at least one emergency button 1 and transmit the appropriate signals to the peripheral units 4.

In particular, said data processor 322 is able to detect a change of state on the lines on which such at least one button 1 is positioned. If it detects a change of state caused by the pressure of at least one button 1, the data processor 322 causes the system, according to the present invention, secures the battery pack "B", or at least a portion of it.

Said control unit 32 is also suitable for executing a computer program, suitably stored on a non-volatile memory support, suitable for carrying out a series of operating steps, preferably consecutive, suitable for securing a battery pack "B" for 1 accumulation of electricity.

Said program carries out the following operating phases: • monitoring of emergency buttons 1;

• pressure detection of at least one button 1; • opening of the electric circuit of one or more "M" modules;

• sectioning of module "M", in module sections «jy [r n.

• galvanic isolation of the module section "Μ '" with a maximum of a predetermined safety low voltage at its ends.

The emergency pushbutton monitoring step 1 provides that the data processor 322 monitors the lines on which the emergency pushbuttons 1 are connected in order to detect a change of logic state on at least one line where said at least one pushbutton 1 is present.

Said data processor 322 continues to monitor the line, for example at regular intervals. In case of detection of a change of logic state on a line due to the pressure of an emergency button, at least one button 1 is pressed. electric circuit opening phase of one or more "M" modules. In said phase, the control unit 32, preferably the data processor 322, sends the opening command to the switches 33, to which, in the preferred embodiment, the coil is de-energized by opening the relay contacts.

The sectioning step of module "M", in sections of module "Μ '", in the embodiment, illustrated in Figure 2, takes place simultaneously with the step of opening the electric circuit mentioned above. The control unit 32, preferably the data processor 322, simultaneously sends the opening signal to all the switches 33.

In the embodiment illustrated in figures 3 and 4, the sectioning takes place after the electric circuit opening step after a predetermined period of time. In fact, the control unit 32, preferably the data processor 322, initially sends the opening signal to the circuit breaker 33 and subsequently, after a predetermined period of time, the opening signal to the disconnectors 43. This predetermined period of time is substantially the average time necessary for the circuit breaker 33 to reduce the current circulating inside the module "M" below a predetermined threshold close to zero. This period therefore corresponds on average to the reaction time of the circuit-breaker 33. It is therefore possible to set the time between the opening signal of the circuit-breaker 33 and the disconnectors 43, according to the technical characteristics of both the circuit-breaker 33, and in particular the switching time, and of the disconnectors 43, for example contact size.

Preferably, said sectioning step of module "M" is carried out after the complete cancellation of the current in module "M" following the step of opening the electric circuit.

Subsequently, the phase of galvanic isolation of the module section "M '" is passed with at its ends a predetermined low safety voltage at its ends. In said phase, following the sectioning phase, the galvanic isolation at the ends of said portions of the module "Μ '" is guaranteed. At the ends of these portions of the module "Μ '" there is a low voltage in compliance with the electrical safety regulations. Preferably, said portions of module "Μ '" comprises a single cell "C" since the sectioning of module "M" occurs at the level of each single cell "C" which at its ends, in use, has a voltage fully compliant with the standards in electrical safety scope.

Both the central unit 3 and each peripheral unit 4 are fully compliant with the regulations in the field of electromagnetic compatibility, for example in the automotive field.

In the embodiment, illustrated in Figures 3 and 4, each peripheral unit 4 is connected to a single module "M", which is composed of a plurality of cells "C", and comprises a switch 33 a plurality of disconnectors 43 , preferably two disconnectors 43 for each cell "C" included in the module "M".

The system according to the present invention can be connected to a computer or personal computer for remote monitoring of the system through a connection implementing, for example, the Ethernet protocol. In particular, the central unit 3 can be connected to a computer network and the system, according to the present invention, can be activated remotely.

In an alternative embodiment not shown, there are a plurality of equally distributed sensors on the external surface of the battery pack "B" suitable for signaling the sophistication of the battery pack "B", for example due to an accident such as a strong impact. Said sensors are connected to the central unit 3 and placed in parallel to the lines where said at least one emergency button 1 is connected, in order to activate the system according to the present invention in the event of an accident even if said button 1 is not held down.

Claims (6)

CLAIMS: 1. System for securing one or more battery packs (B) for the accumulation of electrical energy, each battery pack (B) comprising a plurality of cells (C), in use, electrically connected to each other in a plurality of modules (M); characterized by the fact of understanding: • at least one central unit (3), electrically connected to one or more modules (M) of cells (C), comprising at least one control unit (32); • at least one peripheral unit (4), electrically connected to at least one module (M), and with said central unit (3) comprising a plurality of switches (43, 33), electrically controlled and suitably connected to one or more cells (C ) included in said module (M); said at least one central unit (3), following the pressure of at least one emergency button (1), suitable for signaling damage to the battery pack (B), is able, through said control unit (32), to isolate at least one of the modules (M) connected to it, interrupting the current in said module (M), and disconnecting said module (M), opening said plurality of switches (43), so that said module (M) is galvanically isolated and that at its ends there is at most a pre-established low safety voltage. System according to claim 1, wherein said plurality of switches (43, 33) comprises: <■> at least one switch (33) adapted to interrupt a direct current, One or more disconnectors (43), suitable for sectioning said module (M) into a plurality of galvanically insulated sections (Μ ') thereof. System according to claim 1, wherein said central unit (30) comprises an energy storage device (34), powered by one or more cells (C), included in the battery pack (B), adapted to temporarily power said system safety in the event of power failure by the battery pack (B) itself due to damage to the battery pack itself. System according to claim 1, wherein said control unit (32) comprises a data processor (322), able to detect the pressure of at least one emergency button (1) and transmit the appropriate signals to the peripheral units (4) . System according to claim 1, wherein the system comprises a plurality of switches (33), each one adapted to isolate a single module (M). 6. System according to claim 1 or 5, in which each peripheral unit (4) is connected to a single module (M) and comprises a plurality of disconnectors (43) suitable for sectioning the module (M) by isolating each single cell (C ) included in form (M).