WO2014023544A1

WO2014023544A1 - Replacement cell for a battery system

Info

Publication number: WO2014023544A1
Application number: PCT/EP2013/065084
Authority: WO
Inventors: Karsten Haug
Original assignee: Robert Bosch Gmbh; Samsung Sdi Co., Ltd.
Priority date: 2012-08-08
Filing date: 2013-07-17
Publication date: 2014-02-13
Also published as: CN104521058A; CN104521058B; DE102012214092A1

Abstract

The invention relates to a replacement cell (20) for a battery system, said battery system comprising a housing (15) with two battery terminals (2) which are attached to the housing and are electrically connected to the replacement cell (20). Furthermore, the replacement cell (20) has a circuit (12) which is designed to identify the balancing parameters of the balancing method of a battery system, said balancing method being used to equalize the charge between the battery cells of the battery system, and to carry out an autonomous balancing procedure of the charge state of the replacement cell (20) using said balancing parameters.

Description

description

title

The present invention relates to a spare battery system battery having a circuit configured to identify the balancing parameters of the balancing method of a battery system for charge balance between the battery cells thereof and autonomously balancing the state of charge of the replacement cell using these balancing parameters.

State of the art

Battery packs or battery systems for electrical and / or

Hybrid vehicles consist of a larger number of battery cells. Over the life of the battery pack, these battery cells age differently, so that eventually the fastest aged battery cell

End of life of the battery pack determined. Also, the case may occur that one or more of its battery cells become defective. A

15 year follow-up commitment for battery cells represents for today's

Battery cell manufacturers pose a problem because the battery cells can not be stored for very long periods due to the calendar aging they are subject to. A re-production of battery cells is difficult, because after 15 years due to technical progress neither the

Original starting materials for the production of these battery cells, nor the corresponding manufacturing equipment itself are available.

If, for example, ten years after initial startup of a battery pack a failure of one of the battery cells installed in it, it can be assumed that no original battery cells for this

Battery pack are more available: It would then have battery cells much younger generations are installed with other properties, which, however, brings problems. For example, it can be expected that the battery cells of younger generations have higher performance data in terms of their energy and power density compared to the battery cells to be replaced. Because of this higher energy or

Power density, these younger battery cells usually have a smaller design. If an attempt is now made to incorporate such battery cells of a younger generation in an older battery pack, typically the following differences arise, among others, compared to the older battery cells:

The newer and smaller battery cells will no longer fit into the battery pack from their terminals (ie, their battery terminals). They also have a higher capacity even with the same nominal capacity, since they are at the beginning of their life and the capacity has not yet fallen compared to the nominal capacity due to aging. Furthermore, they have a lower internal resistance and less self-discharge.

Among other things, these differences result in an electrical behavior of the novel battery cells, which leads to problems in trying to use the same in battery packs of older generations. For example, younger battery cells are discharged weaker due to their lower self-discharge and higher capacity during operation. When charging, they then reach as the first of the battery cells of the battery pack, the maximum voltage, thus ending the charging process, so that the older, weaker

Battery cells are no longer fully charged. To prevent this, the battery management system or the balancing unit of the battery system in which the novel battery cell is installed, the same deliberately discharged with its balancing strategy. However, due to the higher capacity, the younger battery cells will then take up a high proportion of the available balancing time. This in turn means that less balancing time is available for the older battery cells of the battery pack and the balancing performance of the battery pack

Battery management system or the balancing unit of the battery system is no longer sufficient, so that the

Total capacity of the battery pack has dropped so far in a short time, Despite the replacement cell (s), the battery pack no longer meets the 15-year life limit.

Disclosure of the invention

According to the invention, a replacement cell for a battery system is provided which comprises a housing with two battery terminals mounted on the housing and electrically connected to the replacement cell. Furthermore, the spare cell has a circuit which is adapted to the

Balancing parameters of the balancing method of a battery system, which serves the charge balance between the battery cells of the battery system, to identify and autonomous balancing the state of charge of

Replacement cell to perform using these balancing parameters.

The advantage of a replacement cell designed in this way is that it can be installed and used within a battery system or battery pack that was originally designed for battery cells of an older generation, without compromising the functionality or the efficiency of the battery

Balancing process of the respective battery system or battery pack to affect or reduce the life of the battery pack. In this case, a replacement cell according to the invention, for example, realized in comparison to the already installed battery cells of smaller design, in a housing whose dimensions, mechanical interfaces and battery terminals allow the shoring and electrical connection of the spare cell in the battery system of an older battery cell generation. Furthermore, the replacement cell according to the invention is able to adapt the balancing parameters of the balancing method of the battery system of the older battery cell generation and to carry out an autonomous balancing of itself using the characteristic balancing parameters of the aforementioned balancing method. This makes it possible to provide a spare cell which can be installed in a battery system or battery pack, without requiring less balancing time for the older battery cells of the battery pack

Is available and the balancing performance of

Overall battery management system or the battery system is sufficient for efficient battery cell balancing. When installing a The replacement cell according to the invention therefore likewise does not occur

Reduction of the total capacity of the battery pack, causing the

Lifespan limit of 15 years for the entire battery pack can be achieved.

Preferably, the balancing parameters include the balancing current and / or the balancing duration and / or the balancing distance. These parameters are the most important balancing parameters with which a detailed description of the balancing procedure is possible. In the context of most battery system passive balancing, charging is done at a constant current, over a fixed time, at intervals, from a more heavily charged battery cell of the battery system

Load resistance converted into heat. For example, the average amount of current flowing during a balancing process can be used as a balancing current and the average amount of time over which the

Balancing current flows during a balancing process, known as balancing duration. The Balancing Distance describes the average time interval between two balancing operations. All three parameters are characteristic of the respective balancing method of a battery system.

In a preferred embodiment, the circuit has a control unit and / or a local balancing circuit for the autonomous balancing of the state of charge of the replacement cell. Preferably, the control unit is adapted to control the local balancing circuit. By such a local balancing circuit within the spare cell is in addition to the possibility of balancing by the battery management system or the balancing unit of the battery system in which the replacement cell according to the invention is installed, the further possibility of the battery cell regardless of the battery system or the battery management system thereof balances, respectively, to discharge.

Preferably, the local balancing circuit has at least one switching means and a load resistor connected in series therewith, wherein the two battery terminals on the housing of the replacement cell have at least one

Switching means of the local balancing circuit electrically with each other are connectable. It is particularly preferable to design the switching means as a transistor or as another semiconductor switch. As a result, the spare cell, for example, in the case of the presence of excess charge, be discharged directly.

In a preferred embodiment, the control unit comprises a

Microcontroller, which is adapted to the balancing parameters of the balancing method of a battery system, which serves for the charge balance between the battery cells of the battery system over

To identify histogram functions. Furthermore, the

Microcontroller particularly preferably a real time clock. Since the balancing of the state of charge of the battery cells within a battery system usually with a constant balancing current over a fixed, predetermined

Balancing duration, and a statistically recorded balancing distance, the balancing parameters are particularly well over

Determine histogram functions. In contrast to the load current flowing in normal operation of the battery system, which occurs stochastically distributed in the histogram, the balancing current in the histogram represents a narrow peak. If a microcontroller is realized with a real-time clock, the same can be used as

Time counters can be used to capture balancing duration and balancing distance. Microcontrollers are very well adaptable in performance and equipment to the respective application. Furthermore, they are very inexpensive compared to other computing systems. The circuit preferably also has a local voltage detection element and / or a local current detection element. With such a configuration of the replacement cell, it is easily possible to flow through the replacement cell

Balancing current or the voltage of the spare cell, for example, their open circuit voltage to measure.

In a preferred further development of this embodiment, the local voltage detection element and / or the local current detection element are connected to the analog ports of the microcontroller. The microcontroller can thus detect the electrical behavior, that is, the voltage and the current of the replacement cell over time and possibly evaluate. As a result, the electrical behavior of the replacement cell can be influenced or optimized take place, since it can be done depending on the historical or the currently measured current and / or voltage values.

In a preferred embodiment, the microcontroller is designed to perform an autonomous balancing of the state of charge of the replacement cell using the identified balancing parameters.

Particularly preferred is the microcontroller with the at least one

Switching means connected to the local balancing circuit, wherein the

Balancing on the opening or closing of the switching means takes place. In this way, the balancing of the replacement cell can be done reliably and optimized, since the microcontroller selbiges on the one hand depending on the already flowed current or the historical development of the cell voltage and the other using the identified

Balancing parameter is able to perform.

In a preferred embodiment, the microcontroller is configured to use the integral of the balancing current over the duration of the balancing

Balancing charge to determine. The balancing charge can be another

Parameters are used to optimize the autonomous balancing of the replacement cell.

Preferably, the microcontroller is configured to perform the autonomous balancing of the spare cell using the identified balancing parameters such that the actual balancing charge is a factor of X% below or above the balancing charge determined by the microcontroller.

Particularly preferably, X corresponds to a value of 10%. The balancing charge thus results arithmetically, as described above, from the integral of the balancing current over the balancing period during balancing

Operation within the battery system. The actual balancing charge is the charge that actually drains from the spare cell during a balancing process. In other words, the three

Balancing parameter chosen so that the actual balancing charge that flows from the spare cell or is absorbed by the same, by X% below the determined balancing charge of the battery cells of the

Battery system is located. In this way it can be ensured that the replacement cell is still partly balanced by the battery system, or the battery management system or the balancing unit thereof, but the charge to be balanced is of a similar order of magnitude as in an older battery cell.

Furthermore, it can be checked in this way whether the identified by the circuit or the microcontroller detected

Balancing parameters of the battery system with the actual

Balancing parameters for the autonomous balancing of the replacement cell

to match. Captures the microcontroller during the autonomous

Balancing, for example via histogram functions, the balancing duration and the balancing current and uses this for an autonomous balancing of the replacement cell, so in the embodiment described above to the reduction of the actual balancing distance, proportional to that reduced by X% Value of the balancing charge to be recognized that the microcontroller or the autonomous balancing of the spare cell works properly.

Further, a battery is provided with a spare cell according to the invention, wherein the battery is particularly preferably designed as a lithium-ion battery. An advantage of lithium-ion batteries is their comparatively high energy density.

Furthermore, a motor vehicle with a battery with a

According to the invention spare cell provided, wherein the battery is connected to a drive system of the motor vehicle.

In a preferred development of the above-described

According to an embodiment, the microcontroller is designed to execute a parameter recognition function for identifying the balancing parameters even after the identification of the balancing parameters until the determined values have been determined

Balancing parameters of the battery system safely within that of the

Microcontroller of the spare cell performed actual

Balancing parameters for the autonomous balancing of the spare cell and the balancing of the spare cell can thus be carried out autonomously. Advantageous developments of the invention are specified in the subclaims and described in the description.

drawings

An embodiment of the invention will be explained in more detail with reference to a drawing and the description below. It shows:

1 shows an embodiment of a spare cell according to the invention for a battery system.

Embodiments of the invention

FIG. 1 shows an exemplary embodiment of a replacement cell 20 according to the invention for a battery system. The replacement cell 20 is installed in a housing 15 whose dimensions correspond to those of the battery cells of a battery system, not shown in Figure 1. Furthermore, the housing 15 has two battery terminals 2 connected electrically to the replacement cell 20, which are arranged on the housing 15 in such a way that the housing 15, together with the replacement cell 20 installed in it, is inside the not shown

Install and connect the battery system, so that the spare cell 20 is operatively connected to the battery system.

The replacement cell 20 also has a circuit 12, which is designed to identify the balancing parameters of a balancing method of a battery system and to perform an autonomous balancing of the state of charge of the replacement cell 20 using these balancing parameters. In this embodiment, the circuit 12 includes for this purpose

Control unit 4, which is connected to a local balancing circuit 1 1 and has a microcontroller, which comprises a real-time clock. The type of execution of the control unit 4 with microcontroller with real-time clock is chosen in this embodiment of Figure 1 purely by way of example. It is also possible to use other components or computer systems or logical components within a control unit 4 for identifying the Balancing parameters or implementation of the autonomous balancing of the replacement cell 20 may be installed.

In this embodiment, the balancing parameters include the average balancing current, that is, the average during one

Balancing operation of the battery system in which the spare cell 20 is installed, for discharging current flowing, the averaged balancing duration, that is, the average duration of a balancing process and the

Balancing distance, that is the average between two

Balancing operations lying time. However, the balancing parameters may also have others and, alternatively or in addition, others

Include balancing parameters. Furthermore, it is in others

Embodiments of a spare cell 20 according to the invention also preferred, instead of the averaged balancing time or the averaged

Balancing streams, for example, to select the maximum measured balancing current or the maximum measured balancing time from a variety of recorded during several balancing operations balancing currents and times and to use for the autonomous balancing of the spare cell 20.

In the exemplary embodiment of FIG. 1, the local balancing circuit 1 1 comprises a switching means 6 and a load resistor 8 connected in series therewith and is arranged between the two battery terminals 2 such that they can be connected directly to one another by closing the switching means 6 via the load resistor 8 are. The switching means 6 is in this

Embodiment purely by way of example as a power transistor (not shown) executed and controlled by the microcontroller of the control unit 4. But the switching means 6 may also be different, for example, designed as an electromechanical switching means.

Furthermore, the circuit in this exemplary embodiment comprises a local voltage detection element 3 and a local current detection element 5. The local voltage detection element 3 is connected between the two battery terminals of the replacement cell 1 and is designed to operate between the two

Battery terminals of the spare cell 1 to measure falling voltage. The local

Current detection element 5 is located within the electrical connection between a battery terminal of the replacement cell 1 with a battery terminal 2 on the housing 15 of the spare cell 20. Thus, the current flow in or out of the replacement cell 20 can be measured via the local current detection element 5. However, only one or even none of the two local detection elements can be realized or the detection of current and voltage of the replacement cell 20 can be done elsewhere in a different manner. In this embodiment, the local power and

Voltage detecting members 3, 5 connected to the analog ports of the microcontroller.

In this embodiment, the microcontroller of the control unit 4 is adapted to a parameter detection function for identifying the

Performing balancing parameters using histogram functions and a function for the autonomous balancing of the spare cell 20 using the identified balancing parameters. For this he identifies

Microcontroller first the balancing parameters of the battery system, with which the spare cell 20 is electrically connected or in which the spare cell 20 is installed. The balancing parameters of the battery system are usually from the battery management system, the

Battery controller (BCU) or the balancing unit of the

Battery system specified. In this embodiment, the microcontroller first determines the balancing current and the balancing duration via histogram functions. The determination of the balancing parameters via histogram functions is selected purely by way of example in this exemplary embodiment. The balancing parameters can also be determined in other ways. While the balancing stream over the local

Current detection unit 5 measured and the measured value of the

Balancing current is transmitted to the microcontroller, the

Balancing duration determined in this embodiment via the real-time clock of the microcontroller. This is done by starting a balancing process

Time counter started as soon as the measured current has been determined

Balancing current corresponds. As soon as the current flow has changed significantly again, the time counter is stopped and the balancing duration of this balancing process is recorded and evaluated by the microcontroller. Over the course of time with multiple balancing operations, the average of all balancing durations recorded during the balancing operations is Histogram represents the averaged balancing duration, with which the charge states of the battery cells of the battery system are typically each balanced. The choice of the mean value from the balancing durations is chosen purely by way of example in this exemplary embodiment; for example, the maximum balancing duration in the histogram for an autonomous balancing of the

Spare cell 20 can be used. Also, the balancing distance is determined by the real-time clock, stored for each balancing process and of the

Microcontroller evaluated. The function described above is carried out by the microcontroller until the identified, that is, determined by the microcontroller balancing parameters safely with the actual

Balancing parameters for the autonomous balancing of the replacement cell 20

correspond. The identified, determined balancing parameters are in this case those balancing parameters with which the balancing of the battery cells takes place within the battery system in which the replacement cell 20 is installed. The actual balancing parameters are those balancing parameters with which the autonomous balancing of the replacement cell 20 takes place. However, the microcontroller calculates before running the autonomous

Balancings the replacement cell 20 in this embodiment previously still the balancing charge from the integral of the balancing current over the

Balancing duration to use as a benchmark for the function for the autonomous balancing of the spare cell 20.

After the balancing parameters have been determined, the microcontroller autonomously executes the function for the autonomous balancing of the replacement cell 20 with the actual balancing parameters in the exemplary embodiment of FIG. 1 via the activation of the MOSFET of the local balancing circuit 11. In this case, the actual balancing parameters for autonomous balancing are selected so that the actually occurring, ie the actual balancing charge during an autonomous balancing process by approximately 10% in this exemplary embodiment is 10% below the determined balancing charge ,

Claims

claims

Replacement cell (20) for a battery system, comprising

a housing (15) having two battery terminals (2) mounted on the housing (15) and electrically connected to the replacement cell (20), characterized in that

the spare cell (20) has a circuit (12) which is adapted to the balancing parameters of the balancing method

Battery system, which is the charge balance between the

Battery cells of the battery system serves to identify and perform an autonomous balancing of the state of charge of the replacement cell (20) using these balancing parameters.

A spare cell (20) according to claim 1, wherein the balancing parameters include the balancing current and / or the balancing duration and / or the

Include balancing distance.

Spare cell (20) according to one of the preceding claims, wherein the circuit (12) comprises a control unit (4) and / or a local

Balancing circuit (1 1) for autonomous balancing the state of charge of the replacement cell (20).

A spare cell (20) according to claim 3, wherein the local balancing circuit (11) comprises at least one switching means (6) and a load resistor (8) connected in series with the two battery terminals (2) on the housing (15). the spare cell (20) via the at least one switching means (6) of the local balancing circuit (1 1) are electrically connected to each other. The replacement cell (20) according to claim 3 or 4, wherein the control unit (4) comprises a microcontroller which is adapted to the Balancing parameters of the balancing method of a battery system, which the charge balance between the battery cells of the

Battery system serves to identify via histogram functions.

6. spare cell (20) according to any one of the preceding claims, wherein the

Circuit (12) further comprises a local voltage detection member (3) and / or a local current detection member (5).

7. spare cell (20) according to claim 5 and 6, wherein the local

Voltage sensing element (3) and / or the local current sensing element (5) are connected to the analog ports of the microcontroller.

8. A spare cell (20) according to claim 5 or 7, wherein the microcontroller is adapted to autonomously balancing the state of charge of the replacement cell (20) using the identified balancing parameters

perform.

9. spare cell (20) according to claim 2 and 8, wherein the microcontroller is adapted to the integral of the balancing current over the

Balancing duration to determine the balancing charge.

The equivalent cell (20) of claim 9, wherein the microcontroller is configured to perform the autonomous balancing of the spare cell (20) using the identified balancing parameters such that the actual balancing charge is under or over by a factor of X% the determined by the microcontroller balancing charge is located.

1 1. Battery with a replacement cell (20) according to one of claims 1 to 10.

12. Motor vehicle with a battery according to claim 1 1, wherein the battery is connected to a drive system of the motor vehicle.