BATTERY PACK SET CONTAINING AT LEAST TWO BATTERY PACKS CONNECTED IN SERIES

Abstract

One aspect of the invention relates to a set 2 of battery packs 2a, 2b for a vehicle 1 comprising at least two battery packs 2a, 2b arranged to supply a power electrical network of a vehicle 1, each battery pack 2a, 2b comprising modules 4 as well as a first power contactor 7 and a second power contactor 8 arranged to electrically isolate the battery pack 2a, 2b, each module 4 comprising electrochemical cells 5, said set 1 of battery packs 2a, 2b being notable in that the at least two battery packs 2a, 2b are electrically connected in series. Figure 1

Description

Title of the invention: BATTERY PACK ASSEMBLY COMPRISING AT LEAST TWO BATTERY PACKS CONNECTED IN SERIES

[0001] The present invention relates to a battery pack assembly for an electric or hybrid motor vehicle comprising at least two battery packs arranged to power an electrical power network for said vehicle. The invention thus relates to the technical field of battery packs. This aspect of the invention finds particularly interesting, but not exclusive, applications in the field of electric or hybrid vehicles with a power electrical network, for example, of the 48V or 400V type.

[0002] As described in document EP-B13926785, a battery pack usually comprises a plurality of modules, each module comprising individual electrochemical cells connected to each other via respective terminals to allow the storage and release of electrical energy.

[0003] Depending on the available space constraints in the vehicle, the battery pack can be divided into a first battery pack and a second battery pack of the same voltage, said first and second battery packs being connected in parallel. Thus, for example, instead of using a single 400V battery pack with eight modules, a first 400V battery pack with eight modules and a second 400V battery pack with eight additional modules are used.

[0004] When the vehicle is started, if the first and second battery packs have a voltage difference, it is known to implement voltage balancing between the first and second battery packs. This balancing can be achieved by activating one or more direct current-direct current converters (also referred to as DC / DC converters) arranged to transfer energy from one battery pack to the other. This balancing ensures optimal performance of the battery packs.

[0005] When a misjudgment of the voltage differences between the two battery packs occurs, an overcurrent generated by one of the battery packs is likely to damage power contactors included in said battery pack, the power contactors being arranged to electrically isolate the battery pack from the electrical power network.

[0006] The invention offers a solution to the problem mentioned above, by proposing a set of battery packs for an electric or hybrid motor vehicle arranged so as not to damage the power contacts contained in said battery packs.

[0007] In this context, the invention relates, in its broadest sense, to a set of battery packs for an electric or hybrid motor vehicle comprising a cell balancing system, at least two battery packs arranged to supply an electrical power network of the vehicle, each battery pack comprising modules as well as a first power contactor and a second power contactor arranged to electrically isolate said battery pack, each module comprising electrochemical cells, said set of battery packs being remarkable in that the at least two battery packs are electrically connected in series.

[0008] Thus, according to the invention, since the battery packs are no longer connected in parallel but in series, the voltage of each battery pack is halved. Their voltages may differ, which will not prevent the vehicle from starting because there will be no high power to switch. Therefore, there is no longer a risk of damaging the power contactors due to a significant voltage difference between the two battery packs.

[0009] The most charged battery pack will nevertheless be progressively discharged using the cell balancing system, for example, a cell balancing circuit included in a battery management system (BMS), in order to ultimately provide the customer with the full charge and discharge capacity of all the battery packs. The power of these packs is managed as if they were a single battery pack.

[0010] In addition to the characteristics mentioned in the preceding paragraph, the battery pack assembly according to this aspect of the invention may have one or more additional characteristics from among the following, considered individually or according to all technically possible combinations.

[0011] According to a non-limiting aspect of the invention, within each battery pack, the modules are electrically connected in series.

[0012] According to a non-limiting aspect of the invention, each module comprises n groups of cells connected in series, each group comprising m pair(s) of cells connected in parallel. Thus, according to this embodiment, within the same group, 2, 4, 6, 8, 10,... cells can be connected in parallel.

[0013] According to a non-limiting aspect of the invention, each battery pack includes a pre-charge circuit connected in parallel with one of the first or second power contactors, said pre-charge circuit including a pre-charge contactor.

[0014] According to a non-limiting aspect of the invention, the first or second power contactor connected in parallel with the pre-charge circuit is a power contactor connected to a positive terminal of the battery pack.

[0015] According to a non-limiting aspect of the invention, the battery pack assembly comprises a first battery pack having a voltage of the order of 200V and a second battery pack having a voltage of the order of 200V.

[0016] Another aspect of the invention relates to an electric or hybrid motor vehicle comprising a set of battery packs according to any one of the aforementioned aspects of the invention.

[0017] According to a non-limiting aspect of the invention, the assembly comprises two battery packs arranged under a floor of the vehicle, a first battery pack being arranged at the front of a wheel assembly of the vehicle and a second battery pack being arranged at the rear of said wheel assembly.

[0018] According to a non-limiting aspect of the invention, the wheel assembly is a rear wheel assembly and the vehicle also includes a hydrogen tank disposed under the floor, said hydrogen tank being further disposed between a front wheel assembly of the vehicle and said first battery pack disposed in front of the rear wheel assembly.

[0019] A different aspect of the invention relates to a method for controlling a set of battery packs according to any one of the aforementioned aspects of the invention of a vehicle according to any one of the aforementioned aspects of the invention, when a request is made to power up the vehicle's electrical network, the method executes, via vehicle control means, the steps of: • Control the closing of the first and second power contactors of n-1 battery pack(s); • Control the closing of the first power contactor of battery pack n; • Control the closing of the pre-charge contactor of the pre-charge circuit of said battery pack n, said pre-charge circuit being connected in parallel with a second power contactor of said battery pack n; • When the output voltage of the battery pack assembly reaches an operating voltage, control the closing of said second power contactor of said battery pack n; • Control the opening of the pre-charge contactor of the pre-charge circuit.

[0020] The invention also relates to a computer program product downloadable from a communication network and / or recorded on a computer-readable medium and / or executable by a processor, the computer program product comprising program code instructions for the implementation of the aforementioned method, when the program is executed on a computer.

[0021] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures.

[0022] [Fig-1] illustrates, schematically, a top view of a vehicle according to a non-limiting example of the invention, said vehicle being equipped with two battery packs electrically connected in series.

[0023] [Fig.2] illustrates, schematically, four power contactors and two pre-charge circuits included in the two battery packs illustrated in [Fig.1].

[0024] [Fig.3] illustrates, schematically, a hydrogen hybrid vehicle according to the invention.

[0025] [Fig.4] illustrates, schematically, a method of controlling a set of two battery packs such as that illustrated in [Fig.2].

[0026] The figures are presented for illustrative purposes only and are in no way limiting of the invention.

[0027] Unless otherwise specified, the same element appearing on different figures presents a unique reference.

[0028] Fig. 1 illustrates a motor vehicle according to a non-limiting example of the invention.

[0029] This vehicle 1 includes a set 2 of two battery packs 2a, 2b arranged to supply an electrical power network (not shown) of the vehicle 1. The electrical power network supplies, for example, an electric traction machine of the vehicle 1. Without limitation, this power network may be of type 48V, 400V or 800V.

[0030] This set 2 of two battery packs 2a, 2b also includes a cell balancing system 3. According to this non-limiting embodiment, each battery pack 2a, 2b comprises two modules 4, each of the modules 4 comprising electrochemical cells 5 arranged to store and supply electrical energy.

[0031] It should be noted that the two battery packs 2a, 2b are electrically connected in series. Furthermore, within each battery pack 2a, 2b, the modules 4 are electrically connected in series.

[0032] According to this non-limiting embodiment, each module 4 comprises three groups 6 of cells 5. These three groups 6 are connected in series. In addition, each group 6 comprises four cells 5 connected in parallel, i.e., two pairs of cells connected in parallel.

[0033] Fig. 2 illustrates schematically four power contactors and two pre-charge circuits included in the two battery packs 2a, 2b of assembly 2.

[0034] According to this non-limiting embodiment, each battery pack 2a, 2b comprises a first power contactor 7 and a second power contactor 8. These first and second power contactors 7, 8 are arranged to isolate electrically the battery pack 2a, 2b, for example when there is a short circuit in the vehicle's power electrical network 1.

[0035] According to this non-limiting embodiment, each battery pack 2a, 2b further comprises a pre-charge circuit 9 connected in parallel with the second power contactor 8, which in this example is a power contactor connected to the positive terminal of the battery pack. In a different embodiment, the pre-charge circuit 9 may be connected in parallel with the first power contactor 7, which in this example is a power contactor connected to the negative terminal of the battery pack. In addition, each pre-charge circuit 9 includes, in particular, a pre-charge contactor 10 arranged to activate or deactivate the operation of the pre-charge circuit 9.

[0036] These first power contactor 7, second power contactor 8, and pre-charge circuit 9 can be controlled via control means 11, for example, a battery management system (BMS). The cell balancing system 3 can be part of these control means 11.

[0037] Thanks to this particular arrangement, for a 400V application, two 200V battery packs 2a, 2b connected in series are used instead of a single 400V battery pack. The voltage of each of the battery packs 2a, 2b is lower, and there is no longer a risk of damaging the electromechanical power contactors 7, 8 due to a significant voltage difference between the two battery packs 2a, 2b.

[0038] Fig. 3 illustrates a hydrogen hybrid vehicle 1 equipped with a set of two battery packs 2a, 2b according to the invention.

[0039] According to this non-limiting embodiment, the vehicle 1 comprises two battery packs 2a, 2b arranged under a floor 12 of the vehicle 1. More particularly, a first battery pack 2a is arranged at the front of a rear wheel assembly 13 of the vehicle 1 and a second battery pack 2b is arranged at the rear of the rear wheel assembly 13.

[0040] The vehicle 1 further comprises a hydrogen tank 14 arranged under the floor 12. According to this non-limiting embodiment, the hydrogen tank 14 is arranged between a front wheel assembly 15 of the vehicle 1 and the first battery pack 2a arranged in front of the rear wheel assembly 13.

[0041] The use of two battery packs 2a, 2b instead of one is advantageous in that the storage space under the floor 12 is limited by the placement of the hydrogen tank 14.

[0042] Fig. 4 illustrates schematically a method 100 for controlling an assembly 2 consisting of two battery packs 2a, 2b such as those illustrated in Fig. 2.

[0043] When a request is made to power up the electrical network of vehicle 1, the method 100 executes, via the control means 11 of vehicle 1, a step 101 piloting the closing of the first and second power contactors 7, 8 of a first 2a battery pack.

[0044] The method 100 then includes a step, executed via the control means 11, of controlling 102 the closing of the first power contactor 7 of the second battery pack 2b, connected in the illustrated example to the negative terminal of the second battery pack 2b.

[0045] The method 100 executes, via the control means 11, a step of controlling 103 the closing of the pre-charge contactor 10 of the pre-charge circuit 9 of the second battery pack 2b. In this non-limiting embodiment, the pre-charge circuit 9 is connected in parallel with the second power contactor 8 of the second battery pack 2b. This second power contactor 8 is connected in the illustrated example to the positive terminal of the second battery pack 2b.

[0046] Then, when the output voltage of the set 2 of the two battery packs 2a, 2b in series reaches an operating voltage, the process 100 executes, via the control means 11, a step of driving 104 the closing of the second power contactor 8 of the second battery pack 2b.

[0047] As soon as the second power contactor 8 of the second battery pack 2b is closed, the process 100 executes, via the control means 11, a step of controlling 105 the opening of the pre-charge contactor 10 of the pre-charge circuit 9.

[0048] In other words, when the vehicle's electrical power system is switched on, the power contactors of one of the battery packs are closed to allow current to flow. The power contactors of the second battery pack are then sequentially closed so that it pre-charges the electrical power system, as if it were the only battery in the vehicle.

[0049] The various aspects of the invention mentioned above offer numerous advantages. Among these are: • Maintain the proper functioning of the power contactors; • Adapt to the available space for installing the battery packs; • Facilitate voltage balancing between two battery packs. • This allows for a reduction in the number of components used in battery packs; the same number of modules are used to create a 200V or 400V battery pack, only the module arrangement changes. For example: • For a 200V battery pack, eight 2P6S modules are used, each module 4 has six groups 6 of cells 5 connected in series, each group 6 having two pairs of cells 5 connected in parallel; • For a 400V battery pack, eight 1P12S modules are used; each module contains twelve groups of connected cells. in series, each group 6 comprising a pair of cells 5 connected in parallel.

Claims

Demands

1. Assembly (2) of battery packs (2a, 2b) for an electric or hybrid motor vehicle (1) comprising a cell balancing system (3), at least two battery packs (2a, 2b) arranged to supply an electrical power network of a vehicle (1), each battery pack (2a, 2b) comprising modules (4) as well as a first power contactor (7) and a second power contactor (8) arranged to electrically isolate said battery pack (2a, 2b), each module (4) comprising electrochemical cells (5), said assembly (1) of battery packs (2a, 2b) being characterized in that the at least two battery packs (2a, 2b) are electrically connected in series.

2. Set (2) of battery packs (2a, 2b) according to the preceding claim, characterized in that within each battery pack (2a, 2b), the modules (4) are electrically connected in series.

3. Assembly (2) of battery packs (2a, 2b) according to any one of the preceding claims, characterized in that each module (4) comprises n groups (6) of cells (5) connected in series, each group (6) comprising m pair(s) of cells (5) connected in parallel.

4. Set (2) of battery packs (2a, 2b) according to any one of the preceding claims, characterized in that each battery pack (2a, 2b) comprises a pre-charge circuit (9) connected in parallel with one of said first or second power contactor (7, 8), said pre-charge circuit (9) comprising a pre-charge contactor (10).

5. Set (2) of battery packs (2a, 2b) according to the preceding claim, characterized in that the first or second power contactor connected in parallel with the pre-charge circuit (9) is a power contactor (8) connected to a positive terminal of the battery pack (2a, 2b).

6. Electric or hybrid motor vehicle (1) characterized in that it comprises a set (2) of battery packs (2a, 2b) according to any one of the preceding claims.

7. Vehicle (1) according to the preceding claim, characterized in that the assembly (2) comprises two battery packs (2a, 2b) arranged under a floor (12) of said vehicle (1), a first battery pack (2a) being disposed at the front of a wheel assembly (13) of said vehicle (1) and a second battery pack (2b) being disposed at the rear of said wheel assembly (13).

8. Vehicle (1) according to the preceding claim, characterized in that the wheel assembly (13) is a rear wheel assembly and in that it comprises a hydrogen tank (14) disposed under the floor (12), said hydrogen tank (14) being further disposed between a front wheel assembly (15) of said vehicle (1) and said first battery pack (2a) disposed in front of said rear wheel assembly (13).

9. Method (100) for controlling a set (2) of battery packs (2a, 2b) according to any one of claims 4 or 5 of a vehicle (1) according to any one of claims 6 to 8, when a request is made to energize an electrical power network of said vehicle (1), the method (100) executes, via control means (11) of said vehicle (1), the steps of: - Controlling (101) the closing of the first and second power contactors (7, 8) of n-1 battery pack(s) (2a); - Controlling (102) the closing of a first power contactor (7) of a battery pack n (2b); - To control (103) the closing of a pre-charge contactor (10) of a pre-charge circuit (9) of said battery pack n (2b), said pre-charge circuit (9) being connected in parallel with a second power contactor (8) of said battery pack n (2b);- When the output voltage of the set (2) of battery packs (2a, 2b) reaches an operating voltage, control (104) the closing of said second power contactor (8) of said battery pack n (2b); - Control (105) the opening of said pre-charge contactor (10) of said pre-charge circuit (9).

10. Product computer program downloadable from a communication network and / or recorded on a computer-readable medium and / or executable by a processor, characterized in that it includes program code instructions for implementing the method (100) according to the preceding claim, when the program is executed on a computer.

Images