WO2014122904A1

WO2014122904A1 - Cell system

Info

Publication number: WO2014122904A1
Application number: PCT/JP2014/000509
Authority: WO
Inventors: 誠人西川; 公彦古川; 省吾平原; 横谷　和展
Original assignee: 三洋電機株式会社
Priority date: 2013-02-08
Filing date: 2014-01-31
Publication date: 2014-08-14
Also published as: JPWO2014122904A1; JP6279493B2

Abstract

Through the present invention, the safety of a cell system is improved, while mitigating increase in cost. In a secondary cell, a positive contact (RYp) and a negative contact (RYm) are housed in the same battery case. According to a prescribed arrangement of the cell system (100), the positive contact (RYp) and/or the negative contact (RYm) is arranged at a higher position than the secondary cell.

Description

Battery system

The present invention relates to a battery system.

In recent years, hybrid vehicles (HV), plug-in hybrid vehicles (PHV), and electric vehicles (EV) have become widespread. These cars are equipped with secondary batteries as key devices. Nickel metal hydride batteries and lithium ion batteries are mainly used as in-vehicle secondary batteries. In the future, the spread of lithium ion batteries with high energy density is expected to accelerate.

The in-vehicle secondary battery has a high output and requires input / output of a large current exceeding 100 A. Therefore, the secondary battery needs to be cooled. In particular, a vehicle having an EV mode is equipped with a high-capacity secondary battery, so that heat generated by the secondary battery is likely to accumulate, and an excellent cooling capacity is required. The cooling of the secondary battery is roughly classified into an air cooling type and a liquid cooling type (for example, refer to Patent Documents 1 and 2).

JP 2011-1000061 A JP 2009-134936 A

In a typical power supply device adopting a liquid cooling system, a flow path such as a coolant pipe is arranged in a battery case in which a secondary battery is accommodated, and a cooling liquid such as a coolant liquid circulates in the flow path. Configured. As a cooling structure for cooling the cooling liquid, a configuration using various cooling devices such as a heat radiating fin and a compressor can be employed. The battery is cooled by transferring the heat of the secondary battery to the cooling liquid flowing in the flow path. In such a configuration, the cooling efficiency of the secondary battery can be improved as the number of members interposed between the secondary battery and the flow path is smaller. Therefore, it is necessary to arrange the flow path close to the secondary battery, and the flow path and the secondary battery are often arranged in the battery case.

However, when liquid as a cooling medium leaks from this flow path, there is a possibility that the secondary battery or junction box in the battery case may be immersed. There is a possibility that the power supply line of the secondary battery may be in liquid junction due to the immersed liquid. In addition, a battery case that houses a vehicle-mounted secondary battery may be a waterproof case or a sealed case to prevent water from entering or dust from entering from the outside. In particular, in such a structure, since the liquid leaking into the battery case cannot be easily discharged from the battery case, the possibility that the secondary battery or the junction box in the battery case is immersed further increases.

On the other hand, a typical power supply device adopting an air cooling type arranges the secondary battery in the battery case in a state where a gap is formed so that the cooling air flows along the surface of the secondary battery. In the battery case, a duct is formed that communicates with a gap formed along the surface of the secondary battery, and the cooling air is forced along the surface of the secondary battery by forcibly blowing air using a cooling fan. Configured to flow. The air-cooled power supply device has an advantage that it can be manufactured at low cost, and the configuration of the battery case is often simplified. For this reason, it may not be possible to completely prevent water from entering or dust from entering from the outside, and the secondary battery or junction box in the battery case may be immersed.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for ensuring safety against liquid intrusion into a battery case.

In order to solve the above problems, a battery system according to an aspect of the present invention is a battery system including an external positive electrode terminal and an external negative electrode terminal, the secondary battery having a positive electrode terminal and a negative electrode terminal, and the positive electrode of the secondary battery. A positive contactor inserted in a current path connecting the terminal and the external positive terminal, a negative contactor inserted in a current path connecting the negative electrode terminal of the secondary battery and the external negative terminal, a secondary battery, and a positive contactor A negative electrode side contactor and a case in which the flow path is accommodated. The secondary battery, the positive electrode side contactor, and the negative electrode side contactor are installed such that at least one of the positive electrode side contactor and the negative electrode side contactor is disposed at a higher position than the secondary battery in a predetermined installation state of the battery system.

According to the present invention, the object of the present invention is to improve safety while suppressing a decrease in cooling efficiency of the liquid-cooled battery system.

It is a schematic diagram for demonstrating the structure of the battery system which concerns on embodiment of this invention. It is a figure for demonstrating the circuit structure of the battery system which concerns on embodiment of this invention. It is a flowchart for demonstrating control of the contactor in the battery system which concerns on embodiment of this invention. It is a schematic diagram for demonstrating the arrangement example 1 of a contactor in the battery system which concerns on embodiment of this invention. It is a schematic diagram which shows the state which the battery system of FIG.1 (b) rolled over. It is a schematic diagram for demonstrating the arrangement example 2 of a contactor in the battery system which concerns on embodiment of this invention. It is a schematic diagram for demonstrating the arrangement example 3 of a contactor in the battery system which concerns on embodiment of this invention. It is a schematic diagram for demonstrating the contactor arrangement example 4 in the battery system according to the embodiment of the present invention. It is a flowchart for demonstrating control of the contactor in the battery system which concerns on embodiment of this invention in consideration of rollover of a vehicle.

FIG. 1 is a schematic diagram for explaining the structure of a battery system 100 according to an embodiment of the present invention. FIG. 1A shows a diagram viewed from above in a prescribed installation state, and FIG. 1B shows a diagram seen from the side in a prescribed installation state. Specifically, the figure seen from the A direction of Fig.1 (a) is shown.

The battery system 100 is mounted on HV, PHV, and EV, and is used as a power supply device for supplying power to the traveling motor. The battery system 100 includes a secondary battery 10, a cooling mechanism, and a junction box 50, which are housed in one battery case. The battery case may be a waterproof case or a sealed case in order to prevent water from entering and dust from entering. Further, the battery case may be constituted by a case different from the vehicle-side frame, or the battery case may be constituted by the vehicle-side frame. In other words, the battery system 100 can be configured such that the battery case containing the secondary battery 10, the cooling mechanism, and the junction box 50 is fixed to the vehicle-side frame, or the battery case is configured by the vehicle-side frame. By arranging a secondary battery or the like in the vehicle-side frame, the secondary battery 10, the cooling mechanism, and the junction box 50 can be accommodated in the battery case.

The secondary battery 10 is constituted by a series connection or a series-parallel connection of a plurality of battery cells. For example, a nickel hydride battery, a lithium ion battery, or the like can be used for the battery cell. In the present embodiment, the secondary battery 10 is formed by serial connection of eight cell stacks 10a to 10h, and outputs a high voltage of 300V or more. Each cell stack is formed by serial connection of a plurality of battery cells. The cell stack 10a and the cell stack 10b are disposed with the cooling plate 20a interposed therebetween. Similarly, the cell stack 10c and the cell stack 10d are disposed with the cooling plate 20b interposed therebetween, and the cell stack 10e and the cell stack 10f have the cooling plate 20c interposed therebetween. The cell stack 10g and the cell stack 10h are arranged with the cooling plate 20d interposed therebetween.

The cooling plates 20a to 20d are configured to be in thermal contact with the cell stacks 10a to 10h through an insulating heat conductive sheet (not shown). Since the outer can of the battery cell constituting the cell stack is made of aluminum or an aluminum alloy, and the cooling plate is also made of metal in order to increase thermal conductivity, the cooling plates 20a to 20d and the cell stacks 10a to 10h are It is necessary to insulate via an insulating heat conductive sheet or the like. Moreover, the heat conductive sheet has the objective of improving the contact property of a cell stack and a cooling plate. Note that when the outer can of the battery cell is formed of an insulating material, the heat conductive sheet is not necessarily used. As the number of members interposed between the cooling plate and the cell stack decreases, the cooling efficiency of the secondary battery can be improved.

In this embodiment, a liquid cooling method is used as a cooling method. In the battery case, a coolant pipe 30 is disposed as a flow path for flowing a cooling liquid (hereinafter referred to as a coolant liquid) for cooling the secondary battery 10. The coolant pipe 30 for injection connected to the coolant inlet 30i and the coolant pipe 30 for discharge connected to the coolant outlet 30o are connected to the respective cooling plates 20a to 20d. The coolant liquid is injected from the coolant inlet 30i, and the injected coolant liquid circulates in the coolant pipe 30 and the cooling plates 20a to 20d, and is discharged from the coolant outlet 30o.

The junction box 50 includes a positive contactor RYp and a negative contactor RYm. The junction box 50 is covered with a resin case, for example. The plus side contactor RYp and the minus side contactor RYm are constituted by large relays. The plus side contactor RYp and the minus side contactor RYm are provided in a current path between the secondary battery 10 and a vehicle side load (specifically, a driving motor, an inverter, a precharge capacitor) (not shown). Used to electrically shut off. Specifically, the positive contactor RYp is inserted on the positive wiring 40p that connects the positive terminal of the secondary battery 10 and the external positive terminal in the high voltage (HV) interface T1. The negative contactor RYm is inserted on a negative wiring 40m that connects the negative terminal of the secondary battery 10 and the external negative terminal in the high voltage interface T1. The high voltage interface T1 is an interface for energizing the battery system 100 with the vehicle side.

FIG. 2 is a diagram for explaining a circuit configuration of the battery system 100 according to the embodiment of the present invention. Battery system 100 according to the embodiment is controlled by controller 200. FIG. 2 shows the circuit elements in the junction box 50 in more detail. A current sensor CT, a positive contactor RYp, and a fuse F1 are inserted between the positive terminal of the secondary battery 10 and the external positive terminal in the high voltage interface T1. A negative contactor RYm is inserted between the negative terminal of the secondary battery 10 and the external negative terminal in the high voltage interface T1.

The current sensor CT detects the value of the current flowing through the plus wiring and outputs it to the controller 200. As the current sensor CT, a shunt resistor or a Hall element can be used. The fuse F1 is blown when a large current of a specified value or more flows to disconnect the secondary battery 10 and the vehicle-side load.

Furthermore, a series circuit of a current limiting resistor R1 and a precharge contactor is connected in parallel with the plus side contactor RYp. When starting energization from the secondary battery 10 to the vehicle-side load, the controller 200 first closes the precharge contactor RYc before closing the plus side contactor RYp and the minus side contactor RYm. As a result, charges are stored in a precharge capacitor (not shown) on the vehicle side. Thereafter, the controller 200 closes the positive contactor RYp and the negative contactor RYm. By this control procedure, the inrush current to the traveling motor can be suppressed.

When an event that should stop power supply from the secondary battery 10 to the vehicle-side load occurs, the controller 200 opens the plus-side contactor RYp and the minus-side contactor RYm so that the secondary battery 10 and the vehicle-side load Disconnect. For example, when an abnormal current is detected by the current sensor CT, an abnormal voltage is detected by a voltage detection sensor (not shown), or an abnormal temperature is detected by a temperature sensor (not shown) When a leakage is detected by the leakage sensor that does not, or when a power supply stop instruction is received from the ECU on the vehicle side.

Return to Figure 1. The battery case that houses the secondary battery 10 is generated in a waterproof specification. Thereby, it is possible to prevent water from entering from the outside. However, there is a possibility that the battery case may be submerged from the inside due to cracks in the coolant pipe 30, liquid leakage from a gap in the connection portion of the coolant pipe 30, and the like. As a result, the junction box 50 is immersed, and the plus-side contactor RYp and the minus-side contactor RYm enter an unintended passage state, and the high-voltage power supply line may be in liquid junction. Specifically, when the contactor is in a conductive state, a voltage is applied to the high voltage power supply line in the junction box, so that the high voltage power supply line is liquidated via the liquid that has entered the junction box. There is a risk of entanglement.

Therefore, as shown in FIGS. 1A and 1B, the plus-side contactor RYp and the minus-side contactor RYm are arranged at a higher position than the secondary battery 10 in the prescribed installation state of the battery system 100. More specifically, the junction box itself does not necessarily need to be arranged at a position higher than the secondary battery 10, and it is important that the plus side contactor RYp and the minus side contactor RYm be arranged at a position higher than the secondary battery 10. It is. According to this configuration, even if the junction box is immersed, if both the plus side contactor RYp and the minus side contactor RYm are not immersed, the liquid junction of the high voltage power supply line in the junction box can be prevented. Strictly speaking, when the junction box is immersed, a liquid junction of the high-voltage power supply line is generated, but by immediately opening the positive-side contactor RYp or the negative-side contactor RYm, the high-voltage power supply line has a high voltage. Is not applied, and the liquid junction state of the high-voltage power supply line can be stopped. The short circuit of the circuit due to the liquid junction suppresses the temperature rise to some extent until the liquid causing the liquid junction evaporates. Therefore, even if a liquid junction occurs, the positive contactor RYp or the negative contactor RYm is immediately opened. By doing so, the current path between the secondary battery and the high-voltage power supply line can be electrically cut off, and the power supply device can be safely stopped.

FIG. 3 is a flowchart for explaining control of the contactor in battery system 100 according to the embodiment of the present invention. When the battery system 100 is powered on (Y in S10), the controller 200 first closes the precharge contactor RYc, and then closes the positive contactor RYp and the negative contactor RYm (S11). When leakage of coolant occurs and leakage is detected by a leakage sensor (not shown) (Y in S12), the controller 200 opens the positive contactor RYp, the negative contactor RYm, and the precharge contactor RYc (S14). When they are opened, the controller 200 transmits an alert signal indicating power-off to the ECU (S15). When the leakage is not detected (N in S12), step S14 and step S15 are skipped. When the power supply of the battery system 100 is turned off (Y in S16), the controller 200 opens the plus-side contactor RYp, the minus-side contactor RYm, and the precharge contactor RYc (S17).

FIG. 4 is a schematic diagram for explaining a contactor arrangement example 1 in the battery system 100 according to the embodiment of the present invention. FIG. 4A shows a diagram viewed from above in a prescribed installation state, and FIG. 4B shows a diagram seen from the side in a prescribed installation state. Specifically, the figure seen from the A direction of Fig.4 (a) is shown. In the arrangement example 1, the plus-side contactor RYp and the minus-side contactor RYm are arranged at a higher position than the secondary battery 10 in the prescribed installation state of the battery system 100 as shown in FIGS. 1 (a) and 1 (b). To do. In order to simplify the drawing, the precharge contactor RYc is omitted, but the precharge contactor RYc is disposed at a position adjacent to the plus-side contactor RYp.

FIG. 5 is a schematic diagram showing a state in which the battery system 100 of FIG. As shown in FIG. 5, when the battery system 100 rolls over and leaks from the coolant pipe 30, the junction box 50 is immersed first. In the configuration of the battery system 100 according to the embodiment shown in FIG. 1 and FIG. 4, as illustrated in FIG. 5, the liquid junction of the high-voltage power supply line located in the junction box is prevented when the vehicle rolls over. Is difficult. When the vehicle rolls over due to an accident or a driving mistake, the rollover state may continue for a long time, and the junction box 50 may be immersed even with a small amount of liquid leakage. The battery system according to the embodiment of the present invention shown in FIG. 6 to FIG. 8 is an embodiment suitable particularly when the rollover of the vehicle is taken into consideration.

FIG. 6 is a schematic diagram for explaining a contactor arrangement example 2 in the battery system 100 according to the embodiment of the present invention. FIG. 6A shows a diagram viewed from above in a prescribed installation state, and FIG. 6B shows a diagram seen from the side in a prescribed installation state. In the arrangement example 2, one of the positive side contactor RYp and the negative side contactor RYm is arranged at a position higher than the secondary battery 10 in the prescribed installation state of the battery system 100, and the other is set to be approximately the same height as the secondary battery 10. Place it at the position. Of the plus side contactor RYp and the minus side contactor RYm, the contactor to which the precharge contactor RYc is connected in parallel is arranged at a position higher than the secondary battery 10. In the present embodiment, the precharge contactor RYc is connected in parallel, and the positive contactor RYp is arranged at a higher position than the secondary battery 10.

As described above, according to the arrangement example 2, by arranging the plus-side contactor RYp and the minus-side contactor RYm so as to be shifted up and down, the power supply line can be in liquid junction when the battery system 100 as shown in FIG. 5 rolls over. Can be lowered. If either the plus-side contactor RYp or the minus-side contactor RYm is not immersed, the state where a high voltage is applied to the high-voltage power supply line in the junction box is stopped by opening the non-immersed contactor. It is possible to prevent liquid junction even if the power supply line is immersed.

It is possible to make the junction box 50 or the contactor all waterproof, but this increases the cost. According to the arrangement example 2, while suppressing an increase in cost, the possibility of liquid junction due to internal water immersion can be reduced, and safety can be improved. Compared with the arrangement example 1 of FIG. 4, the design change is made when the arrangement example 1 is changed to the arrangement example 2 by moving the contactor to which the precharge contactor RYc is not connected in parallel downward. It can be kept light.

In the above description, the configuration in which the plus-side contactor RYp is disposed at a position higher than the secondary battery 10 has been described. However, the minus-side contactor RYm may be disposed at a position higher than the secondary battery 10. Specifically, the minus-side contactor RYm is arranged at a position higher than the secondary battery 10, and the plus-side contactor RYp is arranged at a position lower than the minus-side contactor RYm.

FIG. 7 is a schematic diagram for explaining a contactor arrangement example 3 in the battery system 100 according to the embodiment of the present invention. Fig.7 (a) shows the figure seen from the top in a regular installation state, and FIG.7 (b) shows the figure seen from the side in a regular installation state. In FIG. 7, in order to simplify the drawing, a part of the plus wiring 40p and the minus wiring 40m is omitted. The same applies to FIG. 8 described later.

In the third arrangement example, as in the first arrangement example, the positive contactor RYp and the negative contactor RYm are arranged at a higher position than the secondary battery 10 in the prescribed installation state of the battery system 100. In the arrangement example 3, one of the plus side contactor RYp and the minus side contactor RYm is waterproof.

7 (a) and 7 (b), a concave waterproof wall 55 is placed over the minus-side contactor RYm to which the precharge contactor RYc is not connected in parallel. When the battery system 100 rolls over, the waterproof wall 55 covers the bottom and side surfaces of the negative contactor RYm, and exhibits a waterproof effect. In the specified installation state, the lower surface of the negative contactor RYm is opened, but the lower surface serves as a wiring port. When the lower surface is closed and the negative contactor RYm is sealed, it is necessary to separately open a wiring port on either surface, which increases costs.

As described above, according to the arrangement example 3, by making one of the plus side contactor RYp and the minus side contactor RYm waterproof, it is possible to reduce the liquid junction due to internal flooding at a lower cost than when both are made waterproof. realizable. Further, by waterproofing the contactor having a smaller circuit scale, to which the precharge contactor RYc is not connected in parallel, the size and installation cost of the waterproof wall 55 can be suppressed.

FIG. 8 is a schematic diagram for explaining a contactor arrangement example 4 in the battery system 100 according to the embodiment of the present invention. FIG. 8A shows a view seen from above in a prescribed installation state, and FIG. 8B shows a view seen from the side in a prescribed installation state. In the arrangement example 4, at least one of the plus side contactor RYp and the minus side contactor RYm is arranged at a higher position than the secondary battery 10 in the prescribed installation state of the battery system 100. Both of them may be arranged at a high position as in arrangement examples 1 and 3, or only one of them may be arranged at a high position as in arrangement example 2. 8A and 8B illustrate an example in which both are arranged at a high position. In Arrangement Example 4, at least one of the plus-side contactor RYp and the minus-side contactor RYm arranged at a position higher than the secondary battery 10 is arranged at the central portion in the battery case.

As described above, according to the arrangement example 4, not the complete rollover as shown in FIG. 5 but the internal state that may occur when the vehicle and the battery system 100 are stationary for a long time in a state biased in any direction. It is possible to realize liquid junction countermeasures by flooding. For example, it may occur that the right side wall or the left side surface of the vehicle becomes a bottom surface due to an accident or a driving mistake. In some cases, the vehicle may ride on obstacles with the front wheels floating. In addition, a part of the vehicle body may be fitted in a groove or the like with the front facing. According to the arrangement example 4, even if the battery system 100 is biased in any direction, in the battery case, the installation positions of the plus side contactor RYp and the minus side contactor RYm are avoided from being easily accumulated in the coolant liquid. it can. Further, by using in combination with the arrangement example 2 or the arrangement example 3, it is possible to realize a liquid junction countermeasure against a complete rollover state.

FIG. 9 is a flowchart for explaining contactor control in the battery system 100 according to the embodiment of the present invention in consideration of vehicle rollover. The flow of detection of leakage by the leakage sensor is the same as that in FIG.

When the vehicle rolls over, the ECU detects the vehicle rollover from the output value of a gyro sensor (not shown). When detecting the rollover of the vehicle, the ECU notifies the controller 200 of a power-off instruction. When the controller 200 receives a power-off instruction based on vehicle rollover from the ECU (Y in S13), the controller 200 opens the plus-side contactor RYp, the minus-side contactor RYm, and the precharge contactor RYc (S14). When they are opened, the controller 200 transmits an alert signal indicating power-off to the ECU (S15).

If no electric leakage or vehicle rollover is detected (N in S12, N in S13), Steps S14 and S15 are skipped. When the power supply of the battery system 100 is turned off (Y in S16), the controller 200 opens the plus-side contactor RYp, the minus-side contactor RYm, and the precharge contactor RYc (S17).

The present invention has been described based on the embodiments. Those skilled in the art will understand that these embodiments are exemplifications, and that various modifications can be made to the combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. By the way.

In the embodiment of the present invention, the case where the liquid cooling method is used as the cooling method has been described. However, an air cooling method can also be used. As described above, the air-cooled power supply device has an advantage that it can be manufactured at low cost, and the configuration of the battery case is often simplified. For this reason, it may not be possible to completely prevent water from entering or dust from entering from outside. Even when the coolant pipe is not disposed in the battery case, there is a possibility that the secondary battery or the junction box in the battery case may be immersed in the case where water is generated in the battery case.

Accordingly, it is understood by those skilled in the art that the present invention functions effectively even in a power supply apparatus that uses an air cooling system as a cooling system, and that such modifications are within the scope of the present invention.

100 battery system, 10 secondary battery, 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h cell stack, 20a, 20b, 20c, 20d cold plate, 30 coolant pipe, 30i coolant inlet, 30o coolant outlet, 40p Positive wiring, 40m negative wiring, 50 junction box, CT current sensor, R1 current limiting resistor, RYp positive side contactor, RYm negative side contactor, RYc precharge contactor, F1 fuse, T1 high voltage interface, 200 controller.

Claims

A battery system comprising an external positive terminal and an external negative terminal,
A secondary battery having a positive terminal and a negative terminal;
A positive electrode side contactor inserted in a current path connecting the positive electrode terminal of the secondary battery and the external positive electrode terminal;
A negative contactor inserted in a current path connecting the negative electrode terminal of the secondary battery and the external negative electrode terminal;
A case in which the secondary battery, the positive electrode side contactor and the negative electrode side contactor are accommodated, and
The secondary battery, the positive electrode side contactor and the negative electrode side contactor so that at least one of the positive electrode side contactor and the negative electrode side contactor is disposed at a higher position than the secondary battery in a prescribed installation state of the battery system. A battery system characterized in that is installed.
2. The battery system according to claim 1, wherein one of the positive electrode side contactor and the negative electrode side contactor is disposed at substantially the same height as the secondary battery in a predetermined installation state of the battery system. .
In the specified installation state of the battery system, the negative electrode side contactor is disposed at a position higher than the secondary battery, and the positive electrode side contactor is disposed at substantially the same height as the secondary battery. The battery system according to claim 2.
A precharge contactor is connected in parallel to one of the positive electrode side contactor and the negative electrode side contactor,
The contactor of the positive electrode side contactor and the negative electrode side contactor to which the precharge contactor is connected in parallel is disposed at a position higher than the secondary battery. Battery system.
In the specified installation state of the battery system, both the positive electrode side contactor and the negative electrode side contactor are arranged at a position higher than the secondary battery,
The battery system according to claim 1, wherein one of the positive electrode side contactor and the negative electrode side contactor is designed to be waterproof.
In the specified installation state of the battery system, both the positive electrode side contactor and the negative electrode side contactor are arranged at a position higher than the secondary battery,
2. The battery system according to claim 1, wherein one of the positive electrode side contactor and the negative electrode side contactor is covered with a recessed waterproof wall from above in a prescribed installation state of the power supply device.
A precharge contactor is connected in parallel to one of the positive electrode side contactor and the negative electrode side contactor,
6. The battery according to claim 5, wherein the recessed waterproof wall is covered from the top of the contactor to which the precharge contactor is not connected among the positive electrode side contactor and the negative electrode side contactor. system.
In the specified installation state of the battery system, at least one of the positive electrode side contactor and the negative electrode side contactor arranged at a position higher than the secondary battery is arranged at a central portion in the case. The battery system according to claim 1.
The battery system according to any one of claims 1 to 8, wherein the battery system is mounted on a vehicle.