DE19545833B4 - Battery with several single cells connected in series - Google Patents

Abstract

battery with several single cells connected in series common power line for charging the cells are connected to each other, with single-cell modules, each monitoring the state of the individual cells and suitable for receiving and implementing an individual charging signal are, characterized in that the power line for transmission from status logs of the individual cells to the central unit and the individual charging signals from the central unit to the individual cells can be used and the single-cell modules from the respective single cell are supplied with electrical energy.

Description

The The invention relates to a battery having the features of the preamble of claim 1.

Such a battery is out of the FR 2 589 008 B1 known. The charging process takes place for all individual cells simultaneously and depending on the individual state of charge. There is also no way to individually control the charging process.

Such a possibility exists in a microcontroller-controlled means for analyzing the state of charge and for charging a multi-cell battery, as known from the DE 42 31 732 C2 is known. In this case, the battery is provided with a plurality of double lines, each leading to one or more individual cells and over which the differential charge of the connected individual cells is performed. Due to the large number of double lines, such a battery is extremely susceptible to interference and less suitable for use under high mechanical load, such as in a vehicle.

In this context, it is from the DE 42 25 746 A1 it is known to charge the individual cells individually by direct connection to a charger in a battery with several individual cells. The information about the state of charge is also obtained directly by means of the parallel-connected and supplied with electrical energy single-cell module.

Furthermore, from the DE 33 12 600 A1 a single-cell battery is known in which a recharge can be made according to the withdrawn capacity. An excitation, with a battery of several series-connected single cells without additional external wiring to provide the possibility of an individual charge and verification of each individual cell, does not arise from this.

Of the Invention is based on the object, a battery of the above to create the type mentioned, in which the possibility of an individual Single-cell charge with low circuit and wiring costs is realized.

The Invention solves This object is achieved by the features of patent claim 1.

The Single-cell modules now also have the option of to receive and implement individual charging signals. The levy the individual charging signals is done by the central unit via the Power line that can be configured as a modulated fieldbus. Thereby can complex and fault-prone wiring connections (Double lines) from the central unit to the single-cell modules omitted. Additional line connections are saved, that the single cell modules supplied with electrical energy from the individual cell are.

advantageous Embodiments of the invention are the subject of claims 2 to 11 and will be explained with reference to the drawing.

1 the basic structure of a battery according to the invention,

2 the electrical construction of single-cell modules used therein,

3 a constructive version of the module of 2 .

4 to 6 Details of the module of 3 .

7 Single cells with modules on a cell connector,

8th a functional representation of the current distribution,

9 the embodiment of the module as a cell cap and

10 Embodiments of a circuit breaker used in the modules of 2 to 9 Application finds.

In the 1 Battery shown consists of several single cells E, which are connected via a power line 1 connected to each other and each of which a single cell module 2 assigned. The modules 2 are over the power line 1 with a central unit 3 connected and exchange with this data on the state of each individual cell E. Furthermore, you will receive individual charging signals from the central unit on the basis of which they control the charging process of the respective single cell. This will be explained in detail below.

The modules 2 are arranged in the immediate vicinity of the individual cells, for example on the housing, on the cell connector or on the cell cap (explained) and supplied with electrical energy from the respective individual cell.

The of the modules 2 supplied data be through the central unit 3 interrogated cyclically, which can be accommodated at any point, for example in an on-board battery charger. The central unit 3 collects the data of all single cells and can control the charging current of each single cell within certain limits by means of the modules 2 influence. The central unit 3 in turn, may be off-line (eg for diagnostic purposes) and / or on-line with other on-board systems in the data exchange (not shown).

• • Datenaustausch zur Zentraleinheit
• • Messung der Einzelzellenparameter (Zelltemperatur, Zellspannung, ...)
• • Steuerung des Leistungsteils

The single-cell module ( 2 ) consists of a logical unit ( 4 ), which performs the following tasks:

• • Data exchange to the central unit
• • Measurement of single cell parameters (cell temperature, cell voltage, ...)
• • Control of the power unit

• • Einzelzellenspannung
• • Temperatur (eine oder mehrere), (5 bezeichnet einen Temperatursensor).

For measuring the physical quantities known sensors are used. In the basic version the following parameters are planned:

• • single-cell voltage
• Temperature (one or more), 5 denotes a temperature sensor).

• • Einzelzellendruck
• • Elektrolytpegel
• • Elektrolytdichte
• • Elektrolytdurchfluß
• • Isolationsfehler
• • Zellstrom
• • pH-Wert
• • Sauerstoff-/Wasserstoffkonzentration

Further, it may be advantageous to measure other parameters depending on the type of battery, for example

• • single cell pressure
• • electrolyte level
• • electrolyte density
• • electrolyte flow
• • Insulation error
• • cell current
• • PH value
• • oxygen / hydrogen concentration

It is used for signal separation of the power line, ie for coupling and decoupling the signals between the central unit and modules. It consists in the simplest case of a capacitor 6 ,

The power unit 7 serves to divert a portion of the total charging current around the individual cell concerned, the bypass current thus does not contribute to the charge. The overall efficiency of the battery charge does not deteriorate. With conventional charging, the first full cell must deliver this energy by gassing heat. The cell is heavily overloaded and damaged. The result is a disproportionate capacity change during operation.

The Power unit is preferably as possible from the other components decoupled. This ensures that a thermal influence is minimized. Next, it can be avoided that in the case a total failure of the performing parts the other system components damaged become. The logic unit reports the failure of the central unit Power element (semiconductor switch, relay, ...).

Around in the event of damage, the impact is optional Fuse in the performer Provide line. In the simplest case, the lead-out pole is so measured that this in case of short circuit sure burns fast.

The easiest way to realize this by using printed conductors on printed circuits, which have a correspondingly dimensioned bottleneck as a security element 13 . 3 ,

The power supply 8th . 2 , The single cell module takes place from the single cell.

The task of this system part is to raise and stabilize the tension to the required level. Next is a certain amount of energy 9 be stored to ensure the operation of the module in case of failure of a single cell, ie in case of failure of the power supply of the module so long that a corresponding message can be delivered to the central unit.

embodiments

The structural design depends in particular on the execution of the battery individual cells.

• • eigenständige Funktionseinheit (3)
• • als Teil der Polverbinder (6)
• • als Teil des Einzelzellengehäuses (9)
• • als Batteriekappe (9)

Basically, 4 versions are shown, which are identical in their operation, but their performance varies slightly. Described are the versions as

• • independent functional unit ( 3 )
• As part of the pole connector ( 6 )
• As part of the single cell housing ( 9 )
• • as a battery cap ( 9 )

1. single cell module as independent functional unit

All components are on a printed circuit board ( 3 ), the circuit board has two holes 10 that have the spacing and diameter of the single cell terminals.

The Circuit boards are on the connectors each individual cell is mounted, i. there are no other attachment points necessary.

execution

connections

In the area of mounting holes 10 are the boards by metal inserts such as blind rivets 11 strengthened. The surfaces serve as a contact and to measure the screw forces. Under this Anschraubfläche, which has a close thermal coupling to the battery terminals and thus to the cell interior, preferably the temperature sensors are arranged 5 ,

arrangement of the components

control parts 4 and power section 7 are preferably spatially decoupled. This ensures that in case of thermal failure of the power amplifier, the control part is not damaged. The decoupling can be improved, in which the circuit board between the control and power part is partially excluded 12 ,

fuse

In order to exclude damage to the single cell even in the event of failure of the switching element, a fuse must be provided. This is preferably accomplished by providing a trace portion 13 is dimensioned so that it burns off when the maximum current density is exceeded.

2. single cell module as part of the pole connector

The structure is preferably carried out as a highly integrated module 17 , The connection to the ground terminal is preferably carried out as a large-area connection, 14 which in turn is applied over a large area of the substrate (pole connector). This ensures a good thermal coupling to the ground. Attaching the single cell unit at a location of the single cell that is thermally representative, the temperature sensor can 5 be arranged on this contact surface.

The ground plane 14 can also serve at the same time to dissipate the resulting heat loss of the power section. The temperature increase has been determined and stored by the module during idle operation of the battery by switching on the power transistor with early temperature measurement.

characteristic Temperatures prevail on many battery systems at the connection poles, since these have a functionally good connection to the electrodes.

For this reason, it is proposed the modules 17 preferably on the connecting straps 22 to arrange the individual single cells ( 6 ).

Of the Cultivation is preferably at the opposite of the adjacent single cell Page. This is a far-reaching thermal decoupling to the neighboring cell ensured.

The connection to the positive pole is made by a short line 15 represented, at the end of a suitable cable lug 16 is provided in order to clamp the positive terminal with below the corresponding single cell terminal can.

In order to results in a compact unit consisting of connecting strap, Single cell module and connection cable with cable lug.

These Elements can preferably symmetrical so that pro Single cell type only one version is necessary of elements that are only in the logical Distinguish address.

These Arrangement can be not only inexpensive but also minimizes the storage and allows a very easy replacement in case of damage.

3. single cell module as part of the single cell housing

versions as described, can also be directly on the outside of the single cell housing Fasten.

Preferably a module is used. The module can be directly in the single cell housing to get integrated.

4. single cell module as part of a single cell cap

To protect against contact of the battery / single cell poles are preferably cell caps 26 intended ( 9 ).

Of the Replacement of individual cell modules is achieved through integration the cell modules in the plugged cell cap easy. The electric and thermal contacting of the single cell module and attachment the isolated cell cap is preferably across the poles.

The following structure is provided:
The connection line 15 is executed as a spring. This spring is in the cell cap 26 attached.

The spring presses over a pressure disc movably mounted in the cell cap 27 on the terminal poles of the battery and thus establishes an electrically conductive connection.

On one side is between the resilient connecting line 15 and the pressure piece 27 a single cell module 1 inserted.

In order to The cell module is easily interchangeable and without further connecting lines safe and protected housed in the cell cap.

Of the Central unit is the measuring and control center of the battery monitoring system.

The Cell modules are preferably addressed in a fixed time grid and return the cell data.

The central unit 3 compresses the data and applies single cell statistics over battery life.

These values, compared with a likewise stored cell map (F _{T, Q, I, V,...} ), Derive the control signals which are transmitted to the respective single-cell module. The circuit breaker of the module is activated, allowing individual charging of the single cell.

The early Detection of strongly scattering cell parameters using the battery statistics allows a timely message via the diagnostic interface at the service. The maintenance and a possibly necessary cell replacement will be Detected in time without battery failure in the vehicle. The Central unit indicates the cell number of the defective single cell at the diagnosis out.

Of the Central unit monitored the charge and the discharge of the battery. The charge and discharge becomes the weakest Individual cell adapted, So that the natural Tolerance of the cells over the Life is preserved. When discharging depends on State of charge and the temperature of the single cell, when undershooting or exceeding a predetermined maximum size in the maps a signal for power reduction given to the consumer. The bypass power on, by the Central unit is controlled, preferably before in time constants blocks per cell. The balance of the net invited to the cells Ah will be without big analytical effort precise. The battery charge indicator, the smallest in terms of charge Derive cell is thereby gaining accuracy ("fuel gauge").

The Single cell unit contains preferably a non-volatile Memory (EEPROM), which in the battery configuration the cell address is programmed. The address preferably corresponds to the single cell number. It can If required, but also other data such as manufacturing data or the like be filed. Inside a battery must be the addressing of the single cell unit to be clearly.

In the data traffic has the central unit 3 , ( 1 ) the master function, the modules 1 have slave function.

The Central unit responds cyclically to one slave each, takes the Communication on and receives the current measured values or fault messages the modules and sends control commands to the respective modules.

The data transmission takes place by means of a high-frequency modulated signal, which is on the power line 2 is transmitted.

central processing unit and modules couple the high-frequency information to common ones Fashion e.g. Capacitive or inductive to the DC rail one. Conceivable, and above all, more cost-effective, can be used for transmission the signals from the individual modules to the central unit also one single connection acting as bus line to the central unit used on the battery connector via an additional Auxiliary pin is guided.

The central unit 3 collects all data from the individual modules 1 , stores them and further processes the data such as averaging or linking data to the diagnosis. In the central unit, all physical measured variables are statistically evaluated and stored.

The Central unit knows thereby the cell parameters and loads the single cells as required and individually different.

All processed data can be made available online or offline to other systems, eg consumers, energy management systems or battery chargers (external / internal). The data transmission can be both via a serial 17 as well as via a parallel interface 18 any configuration or modulated over the power lines done.

Offline can e.g. Transfer diagnostic data to a stationary diagnostic device become.

loaded the battery is powered by a charger. Normally, through the series circuit requires, each single cell of a strand with the same amount of charge applied. Parallel connection of strands or due to tolerances of different cell sizes, different results Power Levels of the single cells. Known systems can each by means of an additional Recharge a single cell or a cell block.

In order to minimize the effort, a solution by means of a bypass current is proposed ( 8th ).

The total current 19 , which is fed into the battery and flows through all the single cells of a strand, can be divided over each individual cell. This is done by a bypass element 7 which is part of the single cell module.

This allows a certain part of the charge 20 be guided past each individual cell. This causes single cells with less charge need less charge 21 single cells with high demand but the full charge.

ever according to requirement and battery type can be two different Systems are used whose function is the same however, differ in the structure and operation of the power unit.

In the bypass path are a switch 23 , ( 10 ) eg a transistor and a resistor 24 disposed 9a , The switch is either open or closed. When closed, the current is limited by the resistor. A power control is possible by means of clocking the switch.

is a single cell largely fully charged, may be part of the charge passed the single cell are, i. a single cell is compared with other single cells less charged, i. the single cells reach at the same time the wished State of charge. Alternative: Single cells with lower capacity will also a part of the charging current over bypassed the bypass. As a result, they reach the end of loading not before but also ideally simultaneously with the weaker single cells. Since detecting the current state of charge is sometimes difficult, Advantageously, a self-learning system can be used.

At the The first charging process is determined by the system, which single cells need more or less charge. This information is saved. During the subsequent charging process The single cells, which can store less charge, already early with less power, i. the bypass line opens earlier.

This "learning process" is repeated with each load and updated, after a few passes can with good accuracy a uniform loading end all individual cells can be achieved.

At the Discharge the battery the modules only the detection of the measured variables in the central unit control unit for education the Abbuchkriterien be required with discharged battery.

Bypass element with active current control

In this embodiment, only one active component is in the bypass branch 25 provided (resistor is omitted), with which the current can be regulated.

The advantage of this solution is a cost-effective design of the numerous modules. In case of failure, this component may represent a short circuit of the cell, which brings a fuse in the lead to this component to respond. This can ensure that the single cell can not discharge itself after failure of the switch. The release of the cell in case of failure of the power element 25 By "burning free" happens during charging or discharging, the current pulse is taken from one of the traction cells.

Claims (11)

Battery having a plurality of individual cells connected in series, which are connected to one another via a common power line for charging the cells, with single-cell modules, each of which monitor the state of the individual cells and are suitable for receiving and implementing an individual charging signal, characterized in that the power line to Transmission of status logs of the individual cells to the central unit and the individual charging signals from the central unit to the individual cells can be used and the individual cell modules are supplied from the respective single cell out with electrical energy. Battery according to claim 1, characterized that the modules have a bypass line through a control unit the module is controllable and the individual charge by partial flow diversion controls. Battery according to Claim 2, characterized in that a securing element is arranged in the bypass line. Battery according to Claim 3, characterized that the fuse element is a fuse. Battery according to one of Claims 2 to 4, characterized that the modules have a power unit, which by the respective Control unit is controlled. Battery according to one of claims 2 to 5, characterized in that the control unit, the Power unit, the bypass line and possibly the fuse element form a structural unit. Battery according to Claim 6, characterized that the assembly sits on a common board. Battery according to Claim 7, characterized that the board is placed between the poles of the single cells is. Battery according to Claim 6, characterized that the unit is housed in the Zellenpolkappe. Battery according to Claim 6, characterized that the unit in the cell housing, preferably in a chamber hermetically sealed above the electrolyte between the cell poles is arranged. Battery according to Claim 6, characterized that the unit is screwed onto the cell connectors and the bypass line attached to the other cell pole.