Battery management system

Abstract

A first life module battery management system (10) including connections (6) for connection to a battery module (2) to provide first life battery management of the battery module (2) and one or more connections (8) for connecting to a 5 power module battery management system (20) to provide an augmented life battery management system.

Description

Battery Management SystemTECHNICAL FIELDThis disclosure relates to a battery management system (BMS) for electrical energy storage devices that may comprise multiple cells.BACKGROUND

[0001] The following paragraphs are not an admission that anything discussed in them is prior art or part of the knowledge of persons skilled in the art.

[0002] Electrical energy storage devices may comprise one or more of secondary or rechargeable cells, capacitors, supercapacitors, or hybrid supercapacitors. An individual electrical energy storage device will be referred to as a cell. Cells within a large energy storage device may be of varying types and varying energy storage capacity. Cells connected in parallel are called a supercell. Supercells connected in series are called a module. Modules connected in series are called a battery pack. Battery packs can also be formed of series connected supercells, however, it is common to break down a large string of supercells into modules.

[0003] Examples of secondary batteries are lithium ion (Li-ion) batteries, sodium ion batteries and lead-acid batteries.

[0004] Lithium ion (abbreviated Li-ion) technology is currently amongst the highest performing and is currently the most prevalent in commercial rechargeable batteries. However, even within this sub-category there are still multiple chemistries such as lithium cobalt oxide (LiCoO2), lithium iron phosphate (LFP), lithium manganese oxide (LMO), lithium nickel manganese cobalt oxide (NMC), lithium nickel cobalt aluminum oxide (NCA) and lithium titanate (LTO). Other popular rechargeable cell chemistries include lead acid, Nickel-Cadmium (Ni-Cad) and Nickel metal hydride (NiMH).

[0005] Sodium ion batteries are an example of a newer electrochemical storage technology capable of discharging down to 0 Volts.

[0006] Large electrochemical energy storage systems or batteries are becoming increasingly ubiquitous throughout the world. No longer are electrochemical cells confined to low power consumer electronic applications. They are being used to power vehicles at the tens of Kilowatt Hour scale and to provide support for the electricity grid at the multiple Megawatt Hour scale. These large applications are all built around connecting individual electrochemical cells (cells) in parallel to increase the amount of electrical current that can be drawn, and connecting those parallel groups in series to increase the overall voltage of the battery pack. The challenge with the topology is that the individual cells within a large pack will all degrade in a unique fashion. Practically, this means that each cell’s capacity and power capability will uniquely change over the life of the pack. In the worst case, a large pack will be limited in power and / or capacity by the weakest parallel group contained within it. In high voltage battery packs, there are hundreds of parallel groups in series. Therefore, the effects of the limitations of one parallel group are multiplied hundreds of times.

[0007] In addition to the weakest parallel group problem, a large amount of energy and many resources are required to make a single electrochemical energy storage cell. Therefore, these cells should be used until they are all completely exhausted and should not be prematurely retired due to the failure of one small part in a large battery pack. In addressing this problem, many original equipment manufacturers in the automotive industry are looking to use the battery packs from decommissioned vehicles in second life applications such as stationary storage. To date, there has not been an effective method, process, or device to recommission a battery pack from its first life application to a second life application. Second life applications can also be called augmented life applications.INTRODUCTION

[0008] The following introduction is intended to introduce the reader to this specification but not to define any invention. One or more inventions may reside in a combination or sub-combination of the apparatus elements or method steps described below or in other parts of this document. The inventor does not waive or disclaim his rights to any invention or inventions disclosed in this specification merely by not describing such other invention or inventions in the claims.

[0009] A first aspect of this disclosure provides a first life module battery management system comprising connections for connection to a battery module to provide first life battery management of the battery module and one or more connections for connecting to a power module battery management system to provide an augmented life battery management system.

[0010] In some examples, the first life module battery management system provides for a first type of balancing for the battery module and wherein the first life module battery management system is configured to control a power module battery management system in order to provide a second type of balancing for the battery module.

[0011] In some examples, the first and second types of balancing are different.

[0012] In some examples, the first and second types of balancing are the same.

[0013] In some examples, the second type of balancing provides for a greater degree of balancing than the first type of balancing.

[0014] In some examples, the first life module battery management system comprises terminals for providing at least a connection through the first life module battery management system for a main current path for current drawn from and supplied to the battery module.

[0015] In some examples, the first life module battery management system comprises at least one port for connection to at least one complementary port of a power module battery management system.

[0016] In some examples, the first life module battery management system may be provided in combination with a power module battery management system and a battery module, and may include a current sensor for sensing the current in a main current path through the battery module.

[0017] In some examples, the main current path passes at least once through one of the first life module and the power module battery management systems.

[0018] In some examples, the first life module battery management system provides for a first type of balancing for the battery module and the power module battery management system provides for a second type of balancing for the battery module.

[0019] In some examples, the first and second types of balancing are different.

[0020] In some examples, the first and second types of balancing are the same.

[0021] In some examples, the second type of balancing provides for a greater degree of balancing than the first type of balancing.

[0022] In some examples, the first type of balancing of the power module battery management system provides for at least one of active balancing and active loading of the battery module.

[0023] In some examples, the main current path passes at least once through the power module battery management system.

[0024] In some examples, the first life module battery management system comprises at least one port complementary to at least one port of the power module battery management system.

[0025] In some examples, the first life module battery management system comprises a logic controller for control thereof, and a connection is provided between the first life module and the power module batterymanagement system for the logic controller to control the power module battery management system.

[0026] In some examples, the first life module battery management system comprises a first life balancing network comprising a plurality of first balancing elements, and the power module battery management system comprises an augmented life balancing network comprising a plurality of second balancing elements.

[0027] In some examples, the power module battery management system comprises an augmented life active loader.

[0028] A second aspect of the present disclosure provides a battery pack comprising: a plurality of battery modules; a plurality of first life module battery management systems, with a first life module battery management system for each battery module; a main current path connecting the battery modules in series; and one or more connections for providing connections between the first life module battery management systems and a plurality of power module battery management systems for providing augmented life battery management systems.

[0029] In some examples, the battery pack may be provided in combination with a plurality of power module battery management systems, each power module battery management system corresponding to and being connected to a first life module battery management system.

[0030] In some examples, each first life module battery management system provides for a first type of balancing for the corresponding battery module and each corresponding power module battery management system provides for a second type of balancing for that battery module.

[0031] In some examples, the first and second types of balancing are different.

[0032] In some examples, the first and second types of balancing are the same.

[0033] In some examples, the second type of balancing provides for a greater degree of balancing than the first type of balancing.

[0034] In some examples, for each battery module, at least one current sensor for sensing the current in a main current path through that battery module, is connected to at least one of the respective first life module battery management system and the corresponding power module battery management system.

[0035] In some examples, each current sensor is provided within one of the corresponding first life module battery management system and the power module battery management systems.

[0036] In some examples, each first life module battery management system comprises at least one port for connection to at least one complementary port of the corresponding power module battery management system.

[0037] In some examples, each first life module battery management system comprises a logic controller for control thereof, and a connection is provided between the first life module battery management system and the power module battery management system for the logic controller to control the power module battery management system.

[0038] In some examples, each first life module battery management system comprises a first life balancing network comprising a plurality of first balancing elements, and each power module battery management system comprises an augmented life balancing network comprising a plurality of second balancing elements.

[0039] In some examples, each power module battery management system comprises an augmented life active loader.

[0040] A third aspect of the present disclosure provides a method of operating a battery pack comprising a plurality of battery modules and a plurality of first life module battery management systems, with a first life module battery management system for each battery module, the method comprising:connecting the plurality of battery modules in series; providing a main current path connecting the battery modules; operating the battery modules in a first life mode, wherein charging and discharging currents in the main current path are controlled by the first life module battery managements systems; at the end of the first life mode, providing a plurality of power module battery management systems, with a power module battery management system for each battery module and corresponding first life module battery management system, and connecting each power module battery management system to the corresponding first life module battery management system; and operating the battery modules in an augmented life mode.

[0041] In some examples, in the augmented life mode, the charging and discharging currents are limited to a second level lower than the first level.

[0042] In some examples, the first level is at least five times the second level.

[0043] In some examples, the first level is at least fifteen times the second level.

[0044] In some examples, the main current path passes at least once through each of the first life battery management systems and at least once through each of the power module battery management systems.

[0045] In some examples, the first life module battery management system provides for a first type of balancing for the battery module and the power module battery management system provides for a second type of balancing for the battery module.

[0046] In some examples, the first and second types of balancing are different.

[0047] In some examples, the first and second types of balancing are the same.

[0048] In some examples, the second type of balancing provides for a greater degree of balancing than the first type of balancing.

[0049] In some examples, the method further comprises the steps of: providing each first life module management system with a logic controller and a first balancing network comprising first balancing elements controlled by the logic controller; providing each power module battery management system with an augmented life balancing network comprising second balancing elements and controlling the second balancing elements with the logic controller of the corresponding first life module battery management system.

[0050] In some examples, each power module battery management system comprises an augmented life active loader.

[0051] Although a complete replacement of the BMS is possible, the present disclosure provides for keeping the same logic module(s) throughout the life of the battery pack, which is advantageous to ensure the complete history of the cells is not lost.

[0052] In the augmented life, the current demands and limits may be much lower than in the first life mode, but, due to degradation of the battery cells, it may be necessary to provide for a greater degree of cell balancing, which may be different from or in addition to balancing provided in the first life mode. By providing a separate power module BMS, this need only be designed to meet the lower current demand while simultaneously providing the greater degree of balancing required. Additionally, by only providing the power module BMS at the end of the first life when repositioning as a power module is required, the cost of the power module BMS is only incurred at that time.

[0053] Introducing a power module BMS later in the degradation lifecycle may provide a number of advantages, namely:• reducing the capital cost of the first life battery pack and reducing the cost of converting a degraded pack into an augmented life pack.• optimising lifetime design of the overall battery management system electronics• enabling the Power Module BMS to be appropriately sized for the augmented life application, e.g., providing for lower current levels. When cells degrade, they can no longer support large currents.BRIEF DESCRIPTION OF THE DRAWINGS

[0054] For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings which show, by way of example, the present invention and in which:

[0055] Figure 1 is a schematic of a battery connections in a battery module, with a First Life Module BMS, and how the battery module is represented in other figures;

[0056] Figure 2 is a schematic of a first embodiment of a battery pack comprising a plurality of battery modules, showing power connections through the battery pack, and a first embodiment of a First Life Module BMS;

[0057] Figure 3 shows a schematic of the battery pack of Figure 2, with a first embodiment of a Power Module BMS for each battery module;

[0058] Figure 4 is a schematic of a second embodiment of the battery pack comprising a plurality of battery modules, showing power connections through the battery pack, and a second embodiment of the First Life Module BMS;

[0059] Figure 5 shows a schematic of the battery pack of Figure 4, with a second embodiment of a Power Module BMS for each battery module;

[0060] Figure 6 is a schematic of a third embodiment of the battery pack comprising a plurality of battery modules, showing power connections through the battery pack, and a third embodiment of a First Life Module BMS;

[0061] Figure 7 shows a schematic of the battery pack of Figure 6, with a third embodiment of a Power Module BMS for each battery module; and

[0062] Figure 8 shows a schematic of the battery pack of Figure 2, with a fourth embodiment of a Power Module BMS for each battery module;

[0063] Figure 9 shows a battery pack First Life Module BMS, a Power Module BMS and other elements of the First Life Module and Power Module BMSs;

[0064] Figure 10 shows a further schematic of the first embodiment of the battery pack as shown in Figure 2 and the first embodiment of the Power Module BMS, similar to Figure 3, with different connections to the Power Module BMS; and

[0065] Figure 11 shows a schematic of an augmented battery pack using a subset of battery Modules indicating how the Power Module BMS could augment a First Life Module BMS to enable a single, or subset of Battery Modules, to operate in an augmented life application.DETAILED DESCRIPTION

[0066] Various apparatuses or methods will be described below to provide an example of an embodiment of each claimed invention. No embodiment described below limits any claimed invention and any claimed invention may cover apparatuses or methods that are not described below. The claimed inventions are not limited to apparatuses or methods having all of the features of any one apparatus or method described below or to features common to multiple or all of the apparatuses described below. It is possible that an apparatus or method described below is not an embodiment of any claimed invention. The applicants, inventors and owners reserve all rights in anyinvention disclosed in an apparatus or method described below that is not claimed in this document and do not abandon, disclaim or dedicate to the public any such invention by its disclosure in this document.

[0067] Figure 1 shows the detailed connections of a battery module 2 and a First Life Module BMS 10, and on the right-hand side of the figure how the battery module 2 and BMS 10 are represented in Figures 2 through 7, with some different reference numerals being assigned in other figures. Where applicable, the same reference numerals are used in multiple figures to denote the same component. Further, each of Figures 3, 5 and 7 show the battery packs of Figures 2, 4 and 6 modified to include Power Module BMSs, and Figure 8 shows a further alternative for inclusion of a Power Module BMS to the battery pack of Figure 2. Figure 9 shows some individual elements of a First Life Module BMS and a Power Module BMS, configured as in Figure 8, but generally applicable to those shown in other Figures. Figure 10 shows the First Life Module BMS and a Power Module BMS, configured as in Figure 3, but with different connections., In general and where applicable, the Power Module BMSs of the different figures can be applied to any one of the disclosed First Life Module BMS and associated battery pack configurations.

[0068] Figure 1 shows a detailed view of a Battery Module and how it is represented in further figures. Each Battery Module has several Parallel Signals that are monitored by the First Life Module BMS.

[0069] In Figure 1 , a set of sensor signal lines 6 designated as ‘Parallel Signals’ are connected to the Battery Module 2 measuring voltages (Vi, V2, V3, ...VN, VO) and temperatures (T1 , T2, T3, ... TN) of individual cells or supercells of the battery module 2. Other parallel signals are possible and this list is not exhaustive. They are called parallel signals in this context because the main current path of the battery system does not need to be broken, in order for these signals to be collected (unlike a current sensor in the main current path, for example). In a battery pack’s first life, The First Life Module BMS uses the parallel signals and connections to balance the cells or supercells 4 (Ci , C2, C3, ... CN) during operation. The First Life Module BMS can use one or more ofmany options of balancing typically found in large battery systems: passive balancing, active balancing, cell to module active balancing, cell to cell active balancing, cell to pack active balancing, etc. The battery module 2 has positive and negative connections 8 for the main current path. As shown on the righthand side of Figure 1 , for simplicity, the sensor signal lines 6 collectively are indicated by a chevron 9.

[0070] Figure 2 shows the power connections throughout a battery pack with a first life Module BMS that does not manage the current path.

[0071] Figure 2 shows one configuration for the power connections in a First Life Battery Pack using First Life Module BMSs 10. As shown a plurality of battery modules 2 are connected in series and each is provided with its own First Life Module BMS 10. As indicated in this and other figures, while three battery modules 2 are shown, the battery pack could have any number of battery modules depending upon the application. Together the modules 2 and BMSs 10 form a battery pack, indicated at 12, having negative and positive power connections 14, 16 connected directly to the battery modules 2 at either end of the series of battery modules. The main current or power path connecting the battery modules 2 is indicated at 18.

[0072] Figure 3 shows the battery pack 12 of Figure 2 provided with Power Module BMSs 20 connected to the First Life Module BMSs 10, to form an augmented BMS for each of the battery modules 2. A Power Module BMS 20 consists of electronics that augments the capability of a First Life Module BMS 10. The Power Module BMS 20 could include one or more of, or a combination of: a dc / dc converter, an active balancer, passive balancer, etc. As shown, from the positive power connection 16, the main current path 18 passes through one Power Module BMS 20, through terminals 22, to the positive connection 8 of one battery module 2, and then from the other negative connection 8 through the Power Module BMS 20, through terminals 24, to the main current path 18. This configuration is repeated for the other battery modules 2.

[0073] Figure 4 shows power connections in a Battery Pack 30 where First Life Module BMSs 32, for the battery modules 2, manage half of the current path. This may be desired so that each First Life Module BMS is able to sense the current flowing through it for state estimation purposes. Furthermore, it may make augmenting the pack simpler than the pack of Figure 2. The First Life Module BMSs 32 have terminals 34 for connection to the main current path. As shown, from the positive terminal 16, the main current path then passes through the First Life Module BMS 32, through the terminals 34, to the positive connection 8 of one battery module 2, and then the other negative connection 8 of the battery module 2 is connected to the main current path 8, again repeated for the other battery modules 2.

[0074] Figure 5 shows the modification of the battery pack 30 of Figure 4, to form an augmented life battery pack where the First Life Module BMS manages half of the current path and the Battery Pack is augmented with Power Module BMSs 40. The Power Module BMSs 40 have terminals 42, 44. As shown, from the positive power connection 16 the main current path 18 is connected through terminals 42 of one Power Module BMS 40, and then through the terminals 34 of the associated First Life Module BMS 32, to the battery module 2. The battery module 2, from its negative connection 8 is connected through terminals 44 of the Power Module BMS 40 to the main current path 18 and the next Power Module 40. The configuration is again repeated for each battery module 2.

[0075] In the configuration of Figure 5, augmenting the battery pack 30 may require some reconfiguration of the main current path connected to the negative terminal connection 8 of the Battery Module. However, the main current path 18 from the positive terminal of the Battery Module will require only minor reconfiguration. Furthermore, if the First Life Module BMS 32 has a current sensor, this sensor will not need to be duplicated in the Power Module BMS, but a connection may be provided for the sensed current signal to be received by the Power Module BMS 40 from the First Life Module BMS 32.

[0076] Figure 6 shows power connections in a Battery Pack 50 where First Life Module BMSs 52 manage the complete current path. This may be done for the same reasons as Figure 4, the half-managed current path, as well as to simplify the process of augmenting the battery pack later in its life.

[0077] The First Life Module BMSs 52 have terminals 54, 56 for connection to the main current path 18. As shown, from the positive terminal 16, the main current path then passes through the First Life Module BMS 52, through the terminals 54, to the positive connection 8 of one battery module 2, and then the other negative connection 8 of the battery module 2, through terminals 56 of the First Life Module BMS 52, to the next First Life Module BMS 52.

[0078] Figure 7 shows the modification of the battery pack 50 of Figure 6, to form an augmented life battery pack where the battery pack 50 is augmented with Power Module BMSs 60. The Power Module BMSs 60 having terminals 62, 64. As shown, from the positive power connection 16, the main current path 18 is connected through terminals 62 of one Power Module BMS 60, and then through the terminals 54 of the associated First Life Module BMS 52, to the battery module 2. The battery module 2, from its negative connection 8 is connected through terminals 56 of the First Life Module BMS 52. From the First Life Module BMS 52, the main current path is then connected through the terminals 64, and then to the next Power Module BMS 60. The configuration is again repeated for each battery module 2.

[0079] While each of Figures 3, 5 and 7 show respectively Power Module BMSs 20, 40 and 60 with the main current paths 18 passing through twice through each of the respectively Power Module BMSs 20, 40 and 60, this may not be necessary for all applications, and may depend on the type of balancing provided within each Power Module BMS. For some applications, it may be sufficient for the main current path to pass only once through the respective Power Module BMS as shown in Figure 10 For example, in the configuration of Figure 3 or 5, where main current path does not pass or only passes once through the First Life Module BMS, then it may simplify the addition of thePower Module BMS to provide for the main current path to pass only once through each Power Module BMS.

[0080] Figure 8 shows the modification of the battery pack 12 of Figure 2, to form an augmented life battery pack where the battery pack 12 is augmented with Power Module BMSs 70. The Power Module BMSs 70 do not manage the current through the main current path 18 but can only augment the balancing capability of the First Life BMSs 10. The Power Module BMSs 70 can augment the balancing capability of the First Life BMS by passive balancing and / or any type of active balancing, and may provide for balancing techniques not provided by the original First Life BMSs 10.

[0081] Although the battery packs have been described as pairs with the battery packs of Figures 3, 5 and 7 showing augmented or modified battery packs as shown in Figures 2, 4 and 6, other configurations are possible. Generally, the connections of the main current path 18 through the First Life Module BMS need not be retained for the augmented battery pack; alternatively, one or more connections for the main current path, not present originally in the first life BMS, may be included for the augmented battery pack.

[0082] Figure 9 shows a First Life Module BMS 80, connected as in other embodiments by the sensor signals 6 to the battery module 2. The First Life Module BMS 80 has connections 82 and 84 for the main current path 18. A Power Module BMS 90 is connected to the First Life Module BMS 80, and includes connections 92 and 94 for the main current path 18 as shown. The right hand side of Figure 9 shows the basic current connections between the battery module 2, the First Life Module BMS 90 and the Power Module BMS 90. Figure 9 shows all of the possible interconnections between the Battery Module, First Life Module BMS and the Power Module BMS. Not all features are present in all implementations.

[0083] The First Life Module BMS 80 has a main logic controller 86 connected to and controlling a balancing network 88. The balancing network 88 is shown connected through the sensor signal lines 6 to the battery module 2, and may have individual balancing elements. The balancing network 88 andtheir connections are shown schematically, and the balancing network 88 can be any combination of passive and active balancing elements, as required, with appropriate connections.

[0084] The Power Module BMS 90 is connected to the First Life Module BMS 80. As in earlier embodiments, it may be possible for the current path 18 to pass only once through each of the First Life and Power Modules 80, 90.

[0085] The Power Module BMS 90 includes an augmented life balancing network 96, which may use passive or active balancing elements. As shown, these can be connected through the First Life Module BMS 80 to the battery module 2. A logic controller 86 is connected to and controls the balancing elements of the augmented life balancing network 96. In some embodiments these balancing elements can be of the same type as the balancing elements of balancing network 88, but provide a larger amount of balancing, recognizing that when applied to older battery modules there may be larger variances in cell characteristics requiring a greater amount of balancing. The balancing elements of the augmented life balancing network 96 may be connected to and cooperate with the balancing elements 88, or they may be connected directly to the battery module 2. The Power Module BMS 90 may also have an augmented life active loader circuit 104 which is capable of managing the current and or voltage through the main current path, 18.

[0086] The First Life Module BMS 80 and the Power Module BMS 90 have a port 100 and port 102, respectively, which are used to facilitate a connection between the two. The main current path may or may not make a connection through port 100 and port 102.

[0087] The First Life Module BMS and the Power Module BMS may have one or more current sensors, 106. Four are indicated in Figure 9, as their possible locations along the main current path 18.

[0088] A communications bus and / or signals 108 are used to logically connect the logic controller 86 to each current sensor 106, the balancingnetwork 88, the augmented life balancing network 96, the augmented life active loader circuit 104.

[0089] Figure 10 shows the power connections through a battery pack that has a First Life Module BMS that does not manage the main current path, and a Power Module BMS which manages half of the current path.

[0090] While various embodiments describe a main current path 18 that passes at least once through at least one of the First Life Module BMS and the Power Module BMS, the main function of this configuration is to provide for a current sensor to sense and measure the current being drawn from or supplied to the battery module. In other configurations, one or more current sensors can be provided in the main current path and a signal for the current thus sensed can be supplied to one of both of the First Life Module BMS and the Power Module BMS.

[0091] The Power Module BMSs can be appropriately sized for the augmented life application. When cells degrade, they often can no longer support large currents. For example, the battery pack of the 2023 Tesla Model S Plaid supports currents of 1900 A, which corresponds to a C-rate of 7.6 C. In a stationary application with a C-rate demand of 0.5 C, the peak current of the pack will only be 125 A. C-rate is defined as Current (A)ZCapacity (Ah).

[0092] The augmented performance of a degraded battery pack should be superior with the addition of the Power Module BMSs, increasing the value of the augmented life battery pack.

[0093] At the time of augmentation with a Power Module BMS, such a module can be chosen to meet the augmented life application demands. Table 1 lists the peak C-rates of a small sample of electric vehicles currently on the market.

[0094] In a typical stationary storage application, the peak C-rate required is 0.5 C. Therefore, the Power Module BMS can be optimised for this much lower C-rate and corresponding maximum current, to be suitable for this augmented life application.

[0095] For some applications it may be desirable or necessary to only use a subset of the First Life Module BMS and their Battery Modules. Figure 11 shows an example of an augmented life battery pack consisting of a single First Life Module BMS and its associated Power Module BMS. A first life battery pack could be broken down in several augmented life battery packs. The Power Module BMS could include additional features such as contactor control, which may be handled by another components in the system in its first life.

[0096] For example, if the first life battery pack consists of 8 Battery Modules, this could be broken down into two battery packs of 4 Battery Modules each in its augmented life, or 8 battery packs of 1 Battery Module each in its augmented life. This may be necessary to remove failed or unwanted Battery Modules, or for a system requirement.

[0097] While the examples disclosed, all show battery modules connected in series, other configurations are possible. For example, there could be separate strings of two or more battery modules connected in series, and the strings of battery modules can then be connected in parallel, in the first life mode. In the augmented life mode, this configuration can be maintained, or the battery modules can be separated, as above, to effect isolation of defective modules and / or to provide one or more augmented life modules with desired voltage and current characteristics.

[0098] In some applications, the battery modules may be connected in parallel in the first life mode. Then, for the augmented life mode, this configuration may be maintained. Alternatively, again to effect isolation of defective modules and / or to provide one or more augmented life modules withdesired voltage and current characteristics, the battery modules can be divided into separate groups of modules, each provided with its respective Power Module BMS(s).

[0099] Further it may be possible, in the augmented life mode, to reconfigure the connections between the various battery modules, e.g. series connections in the first life mode may be replaced with parallel connections and parallel connections in the first life mode may be replaced with series connections.

Claims

CLAIMS:

1. A first life module battery management system comprising connections for connection to a battery module to provide first life battery management of the battery module and one or more connections for connecting to a power module battery management system to provide an augmented life battery management system.

2. A first life battery management system as claimed in claim 1 , wherein the first life module battery management system provides for a first type of balancing for the battery module and wherein the first life module battery management system is configured to control a power module battery management system in order to provide a second type of balancing for the battery module.

3. A first life battery management system as claimed in claim 2, wherein the first and second types of balancing are different.

4. A first life battery management system as claimed in claim 2, wherein the first and second types of balancing are the same.

5. A first life battery management system as claimed in claim 2, 3 or 4, wherein the second type of balancing provides for a greater degree of balancing than the first type of balancing.

6. A first life module battery management system as claimed in any preceding claim, wherein the first life module battery management system comprises terminals for providing at least a connection through the first life module battery management system for a main current path for current drawn from and supplied to the battery module.

7. A first life module battery management system as claimed in any preceding claim, comprising at least one port for connection to at least one complementary port of a power module battery management system.

8. A first life module battery management system as claimed in any preceding claim, in combination with a power module battery management system and a battery module, and comprising a current sensor for sensing the current in a main current path through the battery module.

9. A first life module battery management system as claimed in claim 8, wherein the main current path passes at least once through one of the first life module and the power module battery management systems.

10. A first life module battery management system as claimed in claim 8 or 9, wherein the first life module battery management system provides for a first type of balancing for the battery module and the power module battery management system provides for a second type of balancing for the battery module.

11. A first life module battery management system as claimed in claim 10, wherein the first and second types of balancing are different.

12. A first life module battery management system as claimed in claim 10, wherein the first and second types of balancing are the same.

13. A first life module battery management system as claimed in claim 10, 11 or 12, wherein the second type of balancing provides for a greater degree of balancing than the first type of balancing.

14. A first life module battery management system as claimed in any of claims 10 to 13, wherein the first type of balancing of the power modulebattery management system provides for at least one of active balancing and active loading of the battery module.

15. A first life module battery management system as claimed in any one of claims 8 to 14, wherein the main current path passes at least once through the power module battery management system.

16. A first life module battery management system as claimed in any one of claims 8 to 15, wherein the first life module battery management system comprises at least one port complementary to at least one port of the power module battery management system.

17. A first life module battery management system as claimed in any one of claims 8 to 16, wherein the first life module battery management system comprises a logic controller for control thereof, and a connection is provided between the first life module and the power module battery management system for the logic controller to control the power module battery management system.

18. A first life module management system as claimed in any of claims 8 to 17, wherein the first life module battery management system comprises a first life balancing network comprising a plurality of first balancing elements, and the power module battery management system comprises an augmented life balancing network comprising a plurality of second balancing elements.

19. A first life module battery management system as claimed in any of claims 8 to 18, wherein the power module battery management system comprises an augmented life active loader.

20. A battery pack comprising: a plurality of battery modules; a plurality of first life module battery management systems, with a first life modulebattery management system for each battery module; a main current path connecting the battery modules in series; and one or more connections for providing connections between the first life module battery management systems and a plurality of power module battery management systems for providing augmented life battery management systems.

21. A battery pack as claimed in claim 20, in combination with a plurality of power module battery management systems, each power module battery management system corresponding to and being connected to a first life module battery management system.

22. A battery pack as claimed in claim 20 or 21 , wherein, for each battery module, at least one current sensor for sensing the current in a main current path through that battery module, is connected to at least one of the respective first life module battery management system and the corresponding power module battery management system.

23. A battery pack as claimed in claim 22, wherein each current sensor is provided within one of the corresponding first life module battery management system and the power module battery management systems.

24. A method of operating a battery pack comprising a plurality of battery modules and a plurality of first life module battery management systems, with a first life module battery management system for each battery module, the method comprising: connecting the plurality of battery modules in series; providing a main current path connecting the battery modules; operating the battery modules in a first life mode, wherein charging and discharging currents in the main current path are controlled by the first life module battery managements systems; at the end of the first life mode, providing a plurality of power module battery management systems, with a power module battery managementsystem for each battery module and corresponding first life module battery management system, and connecting each power module battery management system to the corresponding first life module battery management system; and operating the battery modules in an augmented life mode.

25. A method as claimed in claim 24, wherein, in the augmented life mode, the charging and discharging currents are limited to a second level lower than the first level.

26. A method as claimed in claim 25, wherein the first level is at least five times the second level.

27. A method as claimed in claim 25, wherein the first level is at least fifteen times the second level.

28. A method as claimed in any one of claims 24 to 27, wherein the main current path passes at least once through each of the first life battery management systems and at least once through each of the power module battery management systems.

Images