Composite battery pack and heterogeneous battery mixing type composite battery pack

Abstract

Provided is a long-life composite battery pack in which a spark countermeasure at the time of opening a switch is taken into consideration. A composite battery pack 10 comprises a plurality of battery packs 12, an integrated battery management system 14, and a lead storage battery pack 16. Each of the plurality of battery packs 12 incorporates a plurality of lithium-ion batteries 12a and further includes a contactor switch 12c. The lead storage battery pack 16 is connected in parallel with the plurality of battery packs 12. The integrated battery management system 14 performs control so as to open the contactor switch 12c of a specific battery pack 12 when the voltage of the specific battery pack 12 deviates from a predetermined operation voltage range, and performs control so as to close the contactor switch 12c when the voltage difference ΔV between the plurality of battery packs 12 and the lead storage battery pack 16 is a voltage difference less than the product value of the maximum current I which can be made to flow by each battery pack 12 and the internal resistance R of each battery pack 12.

Description

Combined battery pack and heterogeneous battery mixed combined battery pack

[0001] The present invention relates to a combined battery pack and a heterogeneous battery mixed type combined battery pack configured with a plurality of lead acid batteries and a plurality of lithium ion batteries connected in series with each other.

[0002] It has been known that a combined battery in which a lead-acid battery and a lithium-ion battery are connected in parallel can increase the stored energy per unit weight and improve the low-temperature power performance in particular. Various techniques have been disclosed to improve the safety of combined batteries.

[0003] On the other hand, with regard to safety when the secondary batteries that make up the energy storage device deteriorate, Patent Document 1 discloses a charge / discharge control device that measures the current value of each cell during charging, and controls a switching element to disconnect any abnormal cells detected based on these measured values ​​from the parallel connection.

[0004] Patent Publication No. 2013-038884

[0005] However, Patent Document 1 has a problem in that it does not take into consideration measures against sparks when the switch is opened.

[0006] The present invention has been made in consideration of the above-mentioned problems in the prior art, and an object of the present invention is to provide a long-life combined battery pack that takes into consideration measures against sparks when the switch is opened.

[0007] That is, a first embodiment of the present invention provides a combined battery pack including a plurality of battery packs each incorporating a plurality of lithium-ion batteries and each equipped with a battery management system and a contactor switch, the combined battery pack including an integrated battery management system that collects battery information such as voltage, current, and temperature from the battery management system of each battery pack and controls the contactor switch based on the results of the collection of battery information, and when the combined battery pack is charged or discharged, if a specific battery pack deviates from a predetermined operating voltage range, the contactor switch of the specific battery pack is opened, and in order to avoid sparks from being generated when the contactor switch is opened, a lead-acid battery pack is connected in parallel to the battery pack to minimize the voltage difference across the contactor switch after the contactor switch is opened, and in order to reduce inrush current when the contactor switch is closed, the voltage difference between the battery pack and the lead-acid battery pack is ΔV<I*R, where I is the maximum current that the battery pack can pass and R is the internal resistance of the battery pack, and the contactor switch is closed when the voltage difference is such that ΔV<I*R.

[0008] Furthermore, a second embodiment of the present invention provides a heterogeneous battery mixed combined battery pack formed by connecting in parallel a plurality of battery packs having different operating voltage ranges, each of the plurality of battery packs being formed by connecting a plurality of lithium ion batteries in series and parallel, and each of the plurality of battery packs being provided with an on-off switch that is controlled to be closed when the voltage of the heterogeneous battery mixed combined battery pack is within the operating voltage range of each battery pack and to be open at voltages outside the operating voltage range, the heterogeneous battery mixed combined battery pack being provided with lead acid battery packs formed by connecting lead acid batteries in series and parallel, and the lead acid battery packs being lead acid battery packs that operate in a voltage range from the maximum operating voltage to the minimum operating voltage of the heterogeneous battery mixed combined battery pack.

[0009] According to the combined battery pack of the present invention, measures against sparks when the switch is opened are taken into consideration, so that the battery pack can have a long life.

[0010] 1 is a block diagram showing a combined battery pack according to a first embodiment of the present invention; FIG. 2 is a block diagram showing a combined battery pack of a mixed type with different batteries according to a second embodiment of the present invention;

[0011] The combined battery pack and the heterogeneous battery mixed type combined battery pack of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings. First, the combined battery pack of the first embodiment of the present invention will be described in detail. Figure 1 is a block diagram showing the combined battery pack of the first embodiment of the present invention.

[0012] A combined battery pack 10 according to a first embodiment of the present invention includes a plurality of battery packs 12, an integrated battery management system 14, and a lead-acid battery pack 16. Each of the plurality of battery packs 12 contains a plurality of lithium-ion batteries 12a and further includes a battery management system 12b and a contactor switch 12c. The lead-acid battery pack 16 is connected in parallel with the plurality of battery packs 12 to prevent sparks from occurring when the integrated battery management system 14 opens the contactor switch 12c.

[0013] The integrated battery management system 14 controls the contactor switch 12c based on battery information including voltage, current, and temperature collected from the battery management system 12b of each battery pack 12. When the voltage of a specific battery pack 12 deviates from a predetermined operating voltage range during charging / discharging of the combined battery pack 10, the integrated battery management system 14 controls the contactor switch 12c of the specific battery pack 12 to open. In order to reduce inrush current when the contactor switch 12c is closed, the integrated battery management system 14 controls the contactor switch 12c to close when the voltage difference ΔV between the multiple battery packs 12 and the lead-acid battery pack 16 is less than the product of the maximum current I that each battery pack 12 can pass and the internal resistance R of each battery pack 12.

[0014] The multiple battery packs 12 constituting the combined battery pack 10 are connected in parallel. The multiple lithium-ion batteries 12a constituting the battery pack 12 are connected in series, in parallel, or in both series and parallel. The multiple lead-acid batteries constituting the lead-acid battery pack 16 are connected in series, in parallel, or in both series and parallel. Here, the lithium-ion battery refers not only to lithium-ion battery cells but also to lithium-ion battery modules in which multiple lithium-ion battery cells are connected in series, in parallel, or in both series and parallel as components of each battery pack. A spark is a spark phenomenon that occurs between the positive and negative contacts of the contactor switch 12c due to discharge. Sparks can deteriorate or damage the contacts and the surrounding plastic materials. The operating voltage range refers to the voltage range in which the battery pack 12 or the lead-acid battery pack 16 can be charged and discharged.

[0015] With this configuration, the combined battery pack of the first embodiment of the present invention has a lead-acid battery pack connected in parallel to the battery pack, and by reducing the magnitude of the voltage difference across the contactor switch after the contactor switch is opened, measures to prevent sparks when the switch is opened are taken into consideration, resulting in a long life. Furthermore, the combined battery pack of the first embodiment of the present invention has measures to prevent inrush current when the switch is closed, so sparks and voltage fluctuations can be significantly reduced. The combined battery pack of the first embodiment of the present invention is basically configured as described above.

[0016] Next, a second embodiment of the heterogeneous battery mixed combined battery pack of the present invention will be described in detail below. Fig. 2 is a block diagram showing the heterogeneous battery mixed combined battery pack of the second embodiment of the present invention.

[0017] A heterogeneous battery mixed combination battery pack 20 according to a second embodiment of the present invention includes a first battery pack 22, a second battery pack 24, and a lead-acid battery pack 26. The first battery pack 22, the second battery pack 24, and the lead-acid battery pack 26 have different operating voltage ranges and are connected in parallel to one another.

[0018] The first battery pack 22 includes a plurality of first lithium-ion batteries 22a (e.g., NMC) and a first on-off switch 22b. The plurality of first lithium-ion batteries 22a are connected in series and parallel to one another. The second battery pack 24 includes a plurality of second lithium-ion batteries 24a (e.g., LFP) and a second on-off switch 24b. The plurality of second lithium-ion batteries 24a are connected in series and parallel to one another. The lead-acid battery pack 26 includes a plurality of lead-acid batteries 26a connected in series and parallel to one another. A series-parallel connection means connecting the batteries in series, in parallel, or in series and parallel.

[0019] The first on / off switch 22b is controlled to close when the voltage of the heterogeneous battery mixed combined battery pack 20 is within the operating voltage range of the first battery pack 22, and is controlled to open when it is outside the operating voltage range. The second on / off switch 24b is controlled to close when the voltage of the heterogeneous battery mixed combined battery pack 20 is within the operating voltage range of the second battery pack 24, and is controlled to open when it is outside the operating voltage range. The lead-acid battery pack 26 has an operating voltage range that covers the range from the highest operating voltage to the lowest operating voltage of the heterogeneous battery mixed combined battery pack 20.

[0020] The first battery pack 22 preferably further includes a first battery management system 22c, an integrated battery management system 22d, and a first container 22e. In this case, the first battery management system 22c collects battery information, including the voltage, current, and temperature, of the first lithium-ion battery 22a. The integrated battery management system 22d controls the opening and closing of the first intermittent switch 22b. The first container 22e houses the first lithium-ion battery 22a, the first intermittent switch 22b, the first battery management system 22c, and the integrated battery management system 22d.

[0021] The second battery pack 24 preferably further includes an energy management system 24c, a power control system 24d, and a second container 24e. In this case, the energy management system 24c collects battery information, including the voltage, current, and temperature, of the second lithium-ion battery 24a and controls the opening and closing of the second on-off switch 24b. The power control system 24d converts the DC output of the heterogeneous battery mixed combined battery pack 20 into AC output. The second container 24e houses the second lithium-ion battery 24a, the second on-off switch 24b, the energy management system 24c, and the power control system 24d.

[0022] The lead-acid battery pack 26 preferably further includes a third battery management system 26b and a third container 26c. In this case, the third battery management system 26b collects battery information including the voltage, current, and temperature of the lead-acid battery 26a. The third container 26c houses the lead-acid battery 26a and the third battery management system 26b therein. The heterogeneous battery mixed combined battery pack 20 preferably further includes an integrated energy management system 28. In this case, the integrated energy management system 28 may transmit battery information of each lithium-ion battery and each lead-acid battery to an external device, and may also transmit the open / close status of each on-off switch to an external device.

[0023] Next, the relationship between the operating voltage and the on-off switch will be described. For example, assume that the operating voltage of the first battery pack 22 is in the range of 525 to 648 V and the operating voltage of the second battery pack 24 is in the range of 635 to 731 V. In this case, when the voltage of the heterogeneous battery mixed combined battery pack 20 is less than 525 V, both the first on-off switch 22b and the second on-off switch 24b are open. When the voltage is 525 to 635 V, the first on-off switch 22b is closed and the second on-off switch 24b is open. When the voltage is 635 to 648 V, both the first on-off switch 22b and the second on-off switch 24b are closed. When the voltage is 648 to 731 V, the first on-off switch 22b is open and the second on-off switch 24b is closed. When the voltage is 731 V or higher, both the first on-off switch 22b and the second on-off switch 24b are open. The number of series connections is set so that the operating voltage of the lead-acid battery pack 26 falls within a range including 525 to 731 V. In the above description, A to BV means a voltage range equal to or greater than A volts and less than B volts.

[0024] With this configuration, the heterogeneous battery mixed combined battery pack of the second embodiment of the present invention has a lead-acid battery pack connected in parallel to the first battery pack and the second battery pack, and by reducing the magnitude of the voltage difference across at least one of the first and second intermittent switches after opening the switch, measures against sparks when the switches are opened are taken into consideration, thereby achieving a long life. Furthermore, since the heterogeneous battery mixed combined battery pack of the second embodiment of the present invention is configured by connecting multiple battery packs with different operating voltage ranges in parallel, it can operate over an extremely wide voltage range. The heterogeneous battery mixed combined battery pack of the second embodiment of the present invention is basically configured as described above.

[0025] The combined battery pack and the heterogeneous battery mixed type combined battery pack of the present invention have been described in detail above, but the present invention is not limited to the above description, and various improvements and modifications may be made without departing from the spirit and scope of the present invention.

[0026] The combined battery pack and the heterogeneous battery mixed combined battery pack of the present invention are industrially useful because they take into consideration measures against sparks when the switch is opened, and therefore have the effect of being able to have a long life.

[0027] REFERENCE SIGNS LIST 10 Combined battery pack 12 Battery pack 12a Lithium ion battery 12b Battery management system 12c Contactor switch 14 Integrated battery management system 16 Lead acid battery pack 20 Heterogeneous battery mixed combined battery pack 22 First battery pack 22a First lithium ion battery 22b First interrupter switch 22c First battery management system 22d Integrated battery management system 22e First container 24 Second battery pack 24a Second lithium ion battery 24b Second interrupter switch 24c Energy management system 24d Power control system 24e Second container 26 Lead acid battery pack 26a Lead acid battery 26b Third battery management system 26c Third container 28 Integrated energy management system

Claims

1. A combined battery pack comprising multiple battery packs each containing multiple lithium-ion batteries and each equipped with a battery management system and a contactor switch, wherein the combined battery pack comprises an integrated battery management system that collects battery information such as voltage, current, and temperature from the battery management system of each battery pack and controls the contactor switch based on the results of the collection of battery information; when the combined battery pack is charged or discharged, if a specific battery pack deviates from a predetermined operating voltage range, the contactor switch of that specific battery pack opens; and to avoid sparks from opening the contactor switch, a lead-acid battery pack is connected in parallel to the battery pack, minimizing the voltage difference across the contactor switch after opening the contactor switch; and to reduce inrush current when the contactor switch closes, the voltage difference between the battery pack and the lead-acid battery pack is ΔV<I*R, where I is the maximum current that the battery pack can pass and R is the internal resistance of the battery pack, and the contactor switch closes when the voltage difference between the battery pack and the lead-acid battery pack is such that ΔV<I*R, where I is the maximum current that the battery pack can pass and R is the internal resistance of the battery pack.

2. A heterogeneous battery mixed combined battery pack formed by connecting in parallel a plurality of battery packs having different operating voltage ranges, each of the plurality of battery packs being a battery pack formed by connecting a plurality of lithium ion batteries in series and parallel, each of the plurality of battery packs being provided with an on-off switch, the on-off switch being an on-off switch controlled to be closed when the voltage of the heterogeneous battery mixed combined battery pack is within the operating voltage range of each battery pack and to be open at voltages outside the operating voltage range, the heterogeneous battery mixed combined battery pack being provided with a lead-acid battery pack formed by connecting lead-acid batteries in series and parallel, the lead-acid battery pack being a lead-acid battery pack that operates in a voltage range from the maximum operating voltage to the minimum operating voltage of the heterogeneous battery mixed combined battery pack.

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