Battery pack

1. A battery pack comprising:

a battery block including a plurality of battery cells arranged in a plurality of rows, each of the plurality of battery cells including a discharge valve provided at an end of the each of the plurality of battery cells, the discharge valve being configured to open when an internal pressure of the each of the plurality of battery cells exceeds a predetermined pressure;

a heat-resistant cap coupled to an end of the battery block; and

a battery case accommodating the battery block therein, the battery case having an exhaust opening configured to discharge exhaust gas from the discharge valve to an outside of the case, wherein

a valve-side end surface of the each of the plurality of battery cells at which the discharge valve of the each of the plurality of battery cells is disposed at a first end of the battery block to which the heat-resistant cap is coupled,

the heat-resistant cap includes:

a closing plate providing a first discharge gap between the closing plate and the battery block end surface;

a peripheral wall coupled to a periphery of the closing plate, the peripheral wall providing a second discharge gap between the peripheral wall and an outer circumference of the battery block; and

a partition wall provided on a surface of the closing plate facing an end of the battery block and between respective end surfaces of adjacent battery cells out of the plurality of battery cells, the partition wall partitioning the first discharge gap into portions on the respective end surfaces of adjacent battery cells, and

the first discharge gap and the second discharge gap constitutes a discharge gap configured to allow the exhaust gas discharged to the valve-side end surface of the each of the battery cells to pass through the discharge gap and be discharged from the exhaust opening to an outside of the battery pack.

2. The battery pack according to claim 1 , wherein

the battery block further includes a battery holder positioning the plurality of battery cells at predetermined positions, and

the second discharge gap is provided between the peripheral wall and the battery holder.

3. The battery pack according to claim 2 , wherein

the battery holder and the battery case are made of plastic, and

the heat-resistant cap is made of plastic having a higher heat resistance temperature than the battery holder and the battery case, and

the closing plate, the peripheral wall, and the partition wall are unitarily molded with plastic.

4. The battery pack according to claim 3 , wherein the heat-resistant cap is made of fiber-reinforced plastic reinforced with heat-resistant fibers.

5. The battery pack according to claim 4 , wherein the heat-resistant fibers are inorganic fibers.

6. The battery pack according to claim 1 , wherein

the battery block further includes a lead plate provided at an end surface of the first end of the battery block, the lead plate connecting the adjacent battery cells to each other, and

a leading edge of the partition wall contacts a surface of the lead plate.

7. The battery pack according to claim 1 , wherein the plurality of battery cells are a plurality of cylindrical batteries.

8. The battery pack according to claim 7 , wherein the partition wall is arranged in a valley formed on outer peripheries of adjacent cylindrical batteries out of the plurality of cylindrical batteries.

9. The battery pack according to claim 1 , wherein the plurality of battery cells are non-aqueous electrolyte secondary batteries.

10. The battery pack according to claim 9 , wherein the plurality of battery cells are lithium ion batteries.